Nov 17, 2006 - Penyelidikan, atau disertasi bagi pengajian secara kerja kursus dan penyelidikan, atau Laporan Projek Sarjana Muda (PSM).
PSZ 19:16 (Pind. 1/97)
BORANG PENGESAHAN STATUS TESIS♦ JUDUL: LANDFILL LEACHATE TREATMENT USING SUBSURFACE LANDFILL LEACHATE TREATMENT USING SUBSURFACE FLOW FLOW CONSTRUCTED WETLANDS ENHANCED WITH CONSTRUCTED WETLANDS ENHANCED WITH MAGNETIC MAGNETIC FIELD FIELD SESI PENGAJIAN: 2006/2007 Saya
NAZAITULSHILA BINTI RASIT______________________ (HURUF BESAR)
mengaku membenarkan tesis (PSM/Sarjana/Doktor Falsafah)* ini disimpan di Perpustakaan NAZAITULSHILA BINTI RASIT Universiti Teknologi Malaysia dengan syarat-syarat kegunaan seperti berikut: 1. Tesis adalah hakmilik Universiti Teknologi Malaysia. 2. Perpustakaan Universiti Teknologi Malaysia dibenarkan membuat salinan untuk tujuan pengajian sahaja. 3. Perpustakaan dibenarkan membuat salinan tesis ini sebagai bahan pertukaran antara institusi pengajian tinggi. 4. **Sila tandakan ( 9 )
submitted in partial fulfilment of the keselamatan atau maklumat yang berdarjah SULITA project report(Mengandungi requirements for the award of the degree of kepentingan Malaysia seperti yang termaktub di dalam Master of Engineering (Civil – Environmental Management) RAHSIA RASMI 1972) AKTA (Mengandungi maklumat TERHAD yang telah ditentukan oleh organisasi/badan di mana penyelidikan dijalankan)
TERHAD
9
TIDAK TERHAD
Faculty of Civil Engineering Universiti Teknologi Malaysia ____________________________________ (TANDATANGAN PENULIS)
__________________________________ (TANDATANGAN PENYELIA)
Alamat Tetap: 118 TAMAN PURNAMA, KUALA IBAI, 20400 KUALA TERENGGANU NOVEMBER 2006 TERENGGANU DARUL IMAN Tarikh:
17 NOVEMBER 2006
CATATAN * **
Disahkan oleh
DR JOHAN BIN SOHAILI Nama Penyelia
Tarikh: 17 NOVEMBER 2006
Potong yang tidak berkenaan Jika tesis ini SULIT atau TERHAD, sila lampirkan surat daripada pihak berkuasa/organisasi berkenaan dengan menyatakan sekali sebab dan tempoh tesis ini perlu dikelaskan sebagai SULIT atau TERHAD. Tesis dimaksudkan sebagai tesis bagi Ijazah Doktor Falsafah dan Sarjana secara Penyelidikan, atau disertasi bagi pengajian secara kerja kursus dan penyelidikan, atau Laporan Projek Sarjana Muda (PSM).
7
“I/We* hereby declare that I/we* have read this project report and in my/our* opinion this project report is sufficient in terms of scope and quality for the award of the degree of Master of Engineering (Civil - Environmental Management)”.
Signature
:
Name of Supervisor : Dr Johan Sohaili Date
: 17 November 2006
LANDFILL LEACHATE TREATMENT USING SUBSURFACE FLOW CONSTRUCTED WETLANDS ENHANCED WITH MAGNETIC FIELD
NAZAITULSHILA BT RASIT
A project report submitted in partial fulfilment of the requirements for the award of the degree of Master of Engineering (Civil – Environmental Management)
Faculty of Civil Engineering Universiti Teknologi Malaysia
NOVEMBER, 2006
ii
I declare that this project report entitled “Landfill Leachate Treatment Using Subsurface Flow Constructed Wetlands Enhanced with Magnetic Field” is the result of my own research except as cited in the references. The project report has not been accepted for any degree and is not concurrently submitted in candidature of any other degree.
Signature
:
Name
: Nazaitulshila Binti Rasit
Date
: 17 November 2006
iii
Dedicated to my loved most Engku Ahmad Rizani Engku Adam Engku Ahmad Rizani And My Family
iv
ACKNOWLEDGEMENT
“In the name of God, the most gracious, the most compassionate” Firstly, I devote this thesis to my husband and son, Engku Ahmad Rizani and Engku Adam. Without their love, support, patience and encouragement, my work would not have been possible. And also for all my family members, especially Mr. Hj. Rasit and Hjh Nik Kamariah, who are responsible for what I am today. I wish to extend my sincerest thanks to my Supervisor, Dr. Johan Sohaili for walking me through the wetland and magnet. Your encouragement for me to do my own thing, with support, advice and generosity, was forum for a great learning experience. I would like to recognize Proffesor Brian Shutes, professor of Ecotechnology from Middlesex University for providing very useful comments and suggestions. His vast knowledge in the field of constructed wetlands has assisted me throughout this thesis project. Finally, I wish to express my heartfelt thanks to all my colleagues and environmental laboratories technicians, especially to Pak Usop, En Ramlee Ismail, En Muzaffar and En Azlan for their timely support during my stay in the laboratories. “May Allah bless us with His Taufik and Hidayat. May we benefit from the knowledge He has given us. May we always be under His Protection and Guidance. May He forgive us for our sins, those we know and those we do not know. May He place us on the righteous path and steadfast our Imans. May He shower our one and true Prohphet Muhammad Alaihisalam and his family and followers, with eternal blessings. Amin amin, ya rabbal-alamin”
v
ABSTRACT
Leachate is a complex and highly polluted wastewater. Constructed wetlands are potentially good, low-cost and appropriate technological treatment systems for treating leachate. Thus, the purpose of this study was to assess the impact of magnetic field towards the performance of vertical and horizontal subsurface flow constructed wetland (SSF) vegetated with Limnocharis flava for leachate treatment. The metals uptake by plants also been investigated. The main parameters evaluation are total suspended solid (TSS), turbidity, ammoniacal nitrogen (NH4-N), nitrate (NO3-N), phosphorus and metals (ferum and manganese). Experiments were run in two systems, which were vertical SSF and horizontal SSF, conducted in duration of 18 days for each. Each of the system consists of control, vegetated and vegetated with magnet tanks. Results show that the capability of emergent plant in the removal of all parameters did show a performance compared to unplanted control. Presence of the vegetation did show there were a substantial removal shown for NH4-N>80%, NO3-N>70% and heavy metals (Fe>96 and Mn>83%). However, the capability of emergent plant has lower removal efficiency in TSS (86% for TSS, complete removal for Fe and for Mn, removal was >88%. The effect of different flow format used in this study had shown that vertical flow format do provide a good condition for nitrification but no denitrification. On the other hand, horizontal flow format cannot provide nitrification because of their limited oxygen transfer capacity. The treatability of vertical SSF had showed greater removal in NH4-N (>87%) and Mn (>78%) while horizontal flow had showed greater removal of NO3-N (>66%). Others parameters did not contribute to substantial differences between vertical and horizontal SSF constructed wetlands. The result for metals uptake by Limnocharis flava shows that the plants leaves and roots are capable to absorb Fe and Mn in leachate.
vi
ABSTRAK
Air larut resap adalah sesuatu yang rumit dan merupakan air sisa yang sangat tercemar. Tanah bencah buatan berpotensi bagus, berkos rendah dan merupakan sistem rawatan berteknologi yang sesuai untuk merawat air larut resap. Oleh itu, kajian ini bertujuan untuk menilai kesan medan magnet terhadap tanah bencah buatan jenis vertical dan horizontal aliran sub permukaan (SSF) yang ditanam dengan Limnhocharis flava untuk rawatan air larut resap. Keupayaan tumbuhan dalam menyerap logam juga dikaji. Parameter utama untuk dikaji adalah pepejal terampai (TSS), kekeruhan, ammonia nitrogen (NH4-N), nitrate (NO3-N), phosphorus (P) dan logam (ferum dan manganese). Dua sistem eksperimen telah dijalankan iaitu vertical SSF dan horizontal SSF yang berlangsung selama 18 hari bagi setiap sistem. Setiap sistem mengandungi tangki kawalan, tumbuhan dan tumbuhan dengan magnet. Keputusan menunjukkan keupayaan tumbuhan untuk menyingkirkan semua parameter berbanding kawalan. Kehadiran tumbuhan menunjukkan penyingkiran yang banyak bagi NH4-N>80%, NO3-N>70% dan logam (Fe>96 dan Mn>83%). Walaubagaimanapun, keupayaan tumbuhan untuk menyingkirkan TSS adalah rendah (86% untuk TSS, penyingkiran semua untuk Fe dan untuk Mn, penyingkiran adalah sebanyak >88%. Kesan terhadap perbezaan format aliran dalam kajian ini menunjukkan format aliran vertical menyediakan keadaan sesuai untuk nitrification dan bukan denitrification. Dengan kata lain, format aliran horizontal tidak boleh untuk nitrification kerana keupayaan pemindahan oksigen yang terhad. Rawatan bagi vertical SSF menunjukkan penyingkiran lebih bagus bagi NH4-N (>87%) dan Mn (>78%) manakala aliran horizontal menunjukkan penyingkiran lebih bagus bagi NO3-N (>66%). Parameter lain tidak menyumbang kepada perbezaan penyingkiran yang banyak di antara tanah bencah buatan jenis vertical dan horizontal. Keputusan keupayaan penyerapan logam oleh Limnocharis flava menunjukkan daun dan akar tumbuhan berkeupayaan untuk menyerap Fe dan Mn dalam air larut resap.
vii
TABLE OF CONTENT
CHAPTER
1
2
TITLE
PAGE
DECLARATION
ii
DEDICATION
iii
ACKNOWLEDGEMENT
iv
ABSTRACT
v
ABSTRAK
vi
TABLE OF CONTENTS
vii
LIST OF TABLES
x
LIST OF FIGURES
xii
LIST OF SYMBOLS
xv
LIST OF APPENDIXS
xvi
INTRODUCTION 1.1
Introduction
1
1.2
Problem Statement
2
1.3
Objectives of the Study
3
1.4
Scope of the Study
4
LITERATURE REVIEW 2.1
Introduction
6
2.2
Landfill Leachate
7
2.2.1 Leachate Quantity
8
2.2.2 Leachate Quality
11
2.2.3 Leachate Treatment
14
viii 2.3
2.4
2.5
3
4
Wetland
16
2.3.1 Constructed Wetland
17
2.3.2 Types of Constructed Wetland
18
2.3.3 Wetlands Vegetation
21
2.3.4 Wetlands Function and Values
23
2.3.5 Treatment Processes Mechanisms
24
2.3.6 Treatment Performance
28
Magnet and Magnetism
29
2.4.1 Effect of Magnetic Field to Molecules
33
2.4.2 Magnetic Mechanism
36
2.4.3 Magnetic Treatment
38
Conclusion
41
METHODOLOGY 3.1
Introduction
43
3.2
Leachate Collection
45
3.3
Experimental Set up
45
3.3.1 Magnetic Devices
48
3.3.2
49
Media
3.3.3 Plant
50
3.4
Analysis Procedure
51
3.5
Analysis of heavy metals in plant tissues
51
RESULTS AND DISCUSSION 4.1
Introduction
52
4.2
Treatment Process Mechanisms
53
4.3
Suspended Solid (TSS) Removal
53
4.4
Turbidity Removal
57
4.5
Nutrients Removal
59
4.5.1 Ammoniacal Nitrogen (NH4-N) Removal
59
4.5.2 Nitrate (NO3-N)
62
4.5.3 Phosphorus (P)
64
Metals Removal
68
4.6
ix
5
4.6.1 Ferum (Fe)
68
4.6.2 Manganese (Mn)
71
4.7
ANOVA Analysis
73
4.8
Uptake by Plant
75
4.9
Physical Appearance of Plants
77
4.10
Conclusion
81
CONCLUSIONS 5.1
Conclusions
82
5.2
Recommendations
83
REFERENCES
85
APPENDICES
99
x
LIST OF TABLES
TABLES
TITLE
2.1
Alternative method for management of leachate
2.2
Indications of typical leachate concentrations for various constituents
PAGE
7
in time
8
2.3
Data on the composition of leachate from landfills
9
2.4
Representative biological, chemical and physical processes and operations used for the treatment of leachate
14
2.5
Important functions and values of natural wetlands
24
2.6
Comparison of different performance constructed wetlands
30
2.7
Summary of magnetic treatment
39
3.1
Description of the plant
50
3.2
Method applied for parameter analysis
51
4.1
Comparison between initial and effluent quality of leachate
53
4.2
Summary of removal mechanisms in wetlands for the pollutants in wastewater
4.3
Significant differences between control, vegetated and vegetated with magnet treatment systems for vertical SSF
4.4
73
Significant differences between control, vegetated and vegetated with magnet treatment systems for horizontal SSF
4.5
54
73
ANOVA analysis comparing vertical and horizontal SSF for control, vegetated and vegetated with magnet treatment systems
74
4.6
Accumulation of Fe in leaves and roots
77
4.7
Accumulation of Mn in leaves and roots
77
xi 4.8
Amount or partial and complete wilting of plant’s leaves in vegetated and vegetated with magnet treatment in vertical SSF constructed wetlands
4.9
78
Amount or partial and complete wilting of plant’s leaves in vegetated and vegetated with magnet treatment in horizontal SSF constructed wetlands
78
xii
LIST OF FIGURES
FIGURE
TITLE
PAGE
2.1
Water balance components and direction of leachate to a wetland
10
2.2
COD and BOD5 versus time
12
2.3
Types of constructed wetlands
19
2.4
General arrangement for the constructed wetland with (a) a horizontal flow and; (b) a vertical flow
20
2.5
Submerged aquatic plants; (a) hydrilla; (b) coontail
22
2.6
Floating aquatic plants; (a) water hyacinth; (b) water lettuce
22
2.7
Emergent aquatic plants; (a) bulrush; (b) cattail; (c) reeds
23
2.8
Right-hand rule
33
2.9
Magnetic field directed out from north pole (N) to south pole (S)
34
2.10
Positioning of fields and force
34
2.11
Nonpolar displacement
35
2.12
Polar displacement
35
2.13
Reaction of charged ion in solution when exposed to magnetic field
36
2.14
Classification of permanent magnet type
37
2.15
Illustration of classes of magnetic devices by installation location
38
2.16
Illustration of classes of non-permanent magnet devices
38
3.1
Flow chart of the experiments
44
3.2
Schematic plan of the SFS system used in the experiments; (a) Control; (b) Vegetated and; (c) Vegetated with magnet treatment systems
46
3.3
Subsurface flow constructed wetlands for overall experiments
47
3.4
Tank (a) Control; (b) Vegetated; and (c) Vegetated with magnet
47
3.5
Magnetic devices used in the experiment
48
xiii 3.6
Schematic magnetic devices used in the experiments
49
3.7
Cross section of magnetic devices used in the experiments
49
3.8
Limnhocharis flava (yellow burhead)
50
4.1
Suspended solids removal for vertical and horizontal SSF system
55
4.2
Comparison of TSS concentration (C/Co) for; (a) Vertical and; (b) Horizontal SSF system
56
4.3
Turbidity removal for vertical and horizontal SSF system
57
4.4
Comparison of turbidity concentration (C/Co) for; (a) Vertical and; (b) Horizontal SSF system
58
4.5
Ammoniacal nitrogen removal for vertical and horizontal SSF system
60
4.6
Comparison of NH4-N concentration (C/Co) for; (a) Vertical and; (b) Horizontal SSF system
61
4.7
Nitrate removal for vertical and horizontal SSF system
63
4.8
Comparison of NO3-N concentration (C/Co) for; (a) vertical and; (b) horizontal SSF system
64
4.9
Phosphorus removal for vertical and horizontal SSF system
65
4.10
Comparison of P concentration (C/Co) for; (a) vertical and; (b) horizontal SSF system
67
4.11
Ferum removal for vertical and horizontal SSF system
69
4.12
Comparison of Fe concentration (C/Co) for; (a) vertical and; (b) horizontal SSF system
70
4.13
Manganese removal for vertical and horizontal SSF system
71
4.14
Comparison of Mn concentration (C/Co) for; (a) Vertical and; (b) Horizontal SSF system Fe uptake by root and leaves for (a) vertical and; (b) horizontal SSF
72
4.15
system
75
4.16
Mn uptake by root and leaves for (a) vertical and; (b) horizontal SSF system
4.17
Physical appearance of plants in (a) vegetated and; (b) vegetated with magnet after 6 days of treatment in vertical SSF
4.18
78
Physical appearance of plants in (a) vegetated and; (b) vegetated with magnet after 12 days of treatment in vertical SSF
4.19
76
79
Physical appearance of plants in (a) vegetated and; (b) vegetated with magnet after 18 days of treatment in vertical SSF
79
xiv 4.20
Physical appearance of plants in (a) vegetated and; (b) vegetated with magnet after 6 days of treatment in horizontal SSF
4.21
Physical appearance of plants in (a) vegetated and; (b) vegetated with magnet after 12 days of treatment in horizontal SSF
4.22
79
80
Physical appearance of plants in (a) vegetated and; (b) vegetated with magnet after 18 days of treatment in horizontal SSF
80
xv
LIST OF SYMBOLS
B
-
Magnetic field
BOD
-
Biochemical Oxygen Demand
CaCO3
-
Calcium carbonate
COD
-
Chemical Oxygen Demand
F
-
Magnetic field force
Fe
-
Ferum
FWS
-
Free Water Surface
HF
-
Horizontal flow
I
-
Current
mg/g
-
milligram per gram
mg/L
-
milligram per liter
mL/s
-
milliliter per second
Mn
-
Manganese
NH4-N
-
Ammoniacal Nitrogen
NO3-N
-
Nitrate
P
-
Phosphorus
SSF
-
Sub Surface Flow
TSS
-
Total Suspended Solid
TOC
-
Total Organic Carbon
TDS
-
Total Dissolved Solids
TKN
-
Total Kjeldahl-N
TN
-
Total Nitrogen
TP
-
Total Phosphorus
VF
-
Vertical Flow
VFA
-
Volatile Fatty Acids
VSB
-
Vegetated Submerged Bed
XOC
-
Xenobiotic Organic Compound
xvi
LIST OF APPENDICES
APPENDIX
TITLE
PAGE
A
Raw Data
99
B
Varian Analysis Calculation (ANOVA)
104
CHAPTER 1
INTRODUCTION
1.1
Introduction
The mass of solid waste produced globally is increasing at a rapid pace. Although improvements are being made in reducing, reusing and recycling of waste, protecting the environment and human health continues to be a challenge. One of the major consequences of rapid economic growth, urbanization, industrialization and population growth is the massive generation of solid wastes. As a country that moving forward to achieve the industrialized country status by the year 2020, Malaysia is grappling with solid waste management problems. The solid waste disposal method in Malaysia is solely landfill. Other methods such as incineration and composting are at an imperceptible scale. The municipal solid wastes in Malaysia that have gone for landfilling is approximately 95% and only 5% are recycled. Even though there is a huge amount of municipal solid waste that goes to landfill, the landfilling practice in Malaysia is far from environmentally sounded. According to Ministry of Housing and Local Government Malaysia (1999), out of 177 landfills in Peninsular Malaysia, estimated only 6% are sanitary landfills, 44% are control tipping landfill and 50% are crude dumping sites.
2 However, leachate production when water is allowed to come in contact with the waste and generation of gases from biodegradation of the waste at landfill sites may cause environmental pollution (Wilson, 1981). Leachate is a liquid consisting of moisture generated from landfill during the waste degradation process. When leachate is produced and moving inside the landfill, it picks up soluble, suspended or miscible materials removed from such waste (Corbitt, 1994). Leachate has high content of iron, chlorides, organic nitrogen, phosphate and sulphate (Preez and Pieterse, 1998). When this highly contaminated leachate leaves landfill and reaches water resources, over time, it will cause surface water and ground water pollution. The contamination of water is affecting with the human body and environment.
The high strength of wastewater characteristics in leachate makes it difficult to treat by itself thus biological wastewater treatment technologies can be adapted for treatment of leachate. The technology for treatment and pretreatment of leachate include wetlands treatment. These systems employ natural or man-made (constructed) wetlands systems that treat wastewater utilizing natural processes of sedimentation, adsorption and organic degradation (Corbitt, 1994).
Application of constructed wetlands is significant because the wetlands have often been assumed to possess a specific capacity to absorb and retain particulate matters, nutrients or other pollutants which enters water bodies through surface runoff, domestic wastewater, and industrial wastewater and also from plantations (Hughes et al, 1992). Besides constructed wetlands are used to treat wastewater (Brix, 1994) and leachate from landfills (Wittgren and Maehlum, 1997; Robinson, 1990; Staubitz et al., 1989; Surface et al., 1993), wetlands are also used in the treatment of industrial waste from textile industries and food processing industries.
1.2
Problem Statement
There is a lack of proper leachate collection and treatment in developing countries including Malaysia. The majority of the landfills in Malaysia are without leachate collection and treatment facilities. A regional survey on 30 local authorities,
3 only 4 out of 69 landfills being surveyed have leachate collection (Nasir et al, 1998). There is a lack of leachate and an impermeable liner system in most landfill , leachate will easily leach out and contaminate the nearby water. With respect to the environment, this situation should be changed. Due to the financial situation and to the more stringent standards, leachate treatments are much more developed in industrialized countries (Aslam et al., 2004). High technology leachate treatment systems are often avoided because of high cost of construction and operation. An alternative is cost efficient natural treatment systems such as constructed wetlands for secondary or tertiary treatment, due to their characteristic properties including simple construction, simple operation and maintenance, process stability and cost effectiveness (Surface et al., 1993; Lin et al., 2002). Hence, the potential to expand the use of constructed wetlands to the treatment of leachate is relevant in today’s context.
Constructed wetland technologies have already shown good results in treating wastewater. Wetland treatment of landfill leachates has been successfully tested at several locations. Reed beds are used to treat leachate in United Kingdom (Robinson, 1990) and a facility at Ithaca, New York has utilized SSF wetlands and has been operating since 1989 (Staubitz et al., 1989; Surface et al., 1993). Although, constructed wetland using magnetic technology is a relatively new idea in Malaysia and the potential of magnets has not yet been discovered. Increasing research and knowledge of wetland have led to the trend to construct wetlands enhanced with magnetic field that obviously duplicate the environmental friendly benefit to the ecosystem. Therefore, this study was carried out to study the effectiveness of a magnetic field to leachate treatment using subsurface flow constructed wetland (SSF) planted with Limnocharis flava.
1.3
Objectives of the Study
The aim of this study is to investigate the feasibility of applying subsurface flow constructed wetlands (SSF) treatment process enhanced with magnetic field. The objectives of the study are:
4
(i)
To investigate the capability of an emergent plant (Limnocharis flava) with and without magnetic field for the removal of ammonia nitrogen, nitrate nitrogen, phosphate, ferum, manganese, SS and turbidity in treating landfill leachate using constructed wetland;
(ii)
To evaluate the treatability of vertical subsurface flow (VF) and horizontal subsurface flow (HF) constructed wetland;
(iii)
To determine the heavy metal (Fe and Mn) uptake by Limnocharis flava in roots and leaves.
1.4
Scope of the Study
Increasing research and knowledge of the role of natural wetlands in controlling water pollution have led to the trend to construct wetlands that duplicate the environmental benefit to the ecosystem. Hence, the following criteria will form the principal for the scope of the study:
(i)
There were two systems performing subsurface flow constructed wetlands (SSF) and each system was operated for a period of 18 days. The first system was conducted as vertical flow (VF) while the second system was horizontal flow (HF) constructed wetlands;
(ii)
Each system contained 3 tanks. Tank A was not planted for control purposes whilst tanks B and C were planted with 8 clusters of Limnocharis flava. In addition, sample discharged from tank C was treated with magnetic field for 6 hours;
(iii)
The vegetation species that was used in this study is Limnocharis flava;
5 (iv)
Six sets of permanent magnet with 0.55 Tesla was used in the experiment;
(v)
The efficiency of leachate treatment for each system was evaluated for ammonia nitrogen, nitrate nitrogen, phosphate, ferum, manganese, SS and turbidity. HACH DR/4000 spectrophotometer equipment was used for analysis of each parameter;
(vi)
Heavy metal (Fe, Mn) by plant uptake are two components which were investigated by looking at the concentration in plant leaves and roots;
(vii)
All experiments were carried out in Environmental Engineering Laboratory, Faculty of Civil Engineering, Universiti Teknologi Malaysia.
CHAPTER 2
LITERATURE REVIEW
2.1
Introduction
Landfill is utilized as one of the significant methods to manage solid wastes among other disposal method. This scenario is widespread and will continue for the envisage future. In spite of the low capital cost and low expertise is needed when compared to other disposal or treatment methods, landfill can accept all sorts of waste (Ridhuan, 1995). Other treatment methods such as composting, incineration, pyrolysis and biogastification can significantly reduce the waste volume and can recover resources during the treatment process, but they will always have some residual left for final disposal at the landfill. In countries such as Japan and Switzerland where the incineration rate is high, 74% and 80% respectively (Agamuthu, 2001), landfill is still needed as the ultimate disposal method.
Hence, the matters of concern are the consequences of the past and ongoing use of landfills because of the potential for possess negative impacts to the environment. Landfill is a complex system. Hence, the incentive for comprehensive control strategies must be developed, which are now used in current landfill designs. These control strategies have included the implementation of leachate collection systems. If the landfilling could be carried out in a proper manner coupled with well-managed solid waste and leachate collection and transportation system, this
7 would form the very fundamental level for the solid waste management (Rylander, 1998). However, leachate collection must be dealt as part of the long-term commitment for solid waste management (McBean and Rovers, 1999). And once the collection of the leachate has become part of a solid waste management system, a series of leachate treatment options must be examined. The potential alternative methods for the management of landfill leachate are shown in Table 2.1. Wetlands provide a useful natural treatment system, either for from old wastes or for partial treatment of leachates from newer wastes.
Table 2.1: Alternative method for management of leachate (McBean and Rovers, 1999) Alternative Method
Spray irrigation on adjacent grassland Recirculation of leachate through the landfill Disposal off site to sewer for treatment as an admixture with domestic sewage Physical-chemical treatment Anaerobic biological treatment Aerobic biological treatment Wetlands
2.2
Landfill Leachate
Leachate is the liquid that has passed through or emerged from solid waste and contains dissolved, suspended, or immiscible materials removed from the solid waste (Tchobanoglous et al., 1993). The characteristics of leachate vary with the age of the landfill (Paredes, 2003; Baig et al., 1999) and the material placed in the landfill (Wilson, 1981). The composition of the leachate will depend on the heterogeneity and composition of the waste. For biodegradable wastes, the stage of biodegradation reached by the waste, the moisture content and the operational procedures will vary the composition of the waste (Kjeldsen et al, 2002). According to McBean and Rovers (1999), factors that influence leachate composition include waste type and composition, waste density, pretreatment, placement sequence and depth, moisture infiltration, ambient air temperature, landfill management practices and time. Typical leachate concentrations for an array of constituents are shown in
8 Table 2.2. Since all sanitary landfills generate leachate and since leachate may migrate from the waste and contaminate the surface water and groundwater (Paredes, 2003), collection and treatment of leachate is a necessary part of the overall facility (Wilson, 1981).
Table 2.2: Indications of typical leachate concentrations for various constituents in time (McBean and Rovers, 1999) Constituent
BOD TKN Ammonia-N TDS Chloride Sulfate Phosphate Calcium Sodium and Potassium Iron and Magnesium Aluminium and Zinc
2.2.1
1 Year 20,000 2,000 1,500 20,000 2,000 1,000 150 2,500 2,000 700 150
Concentration (mg/L) 5 Years 15 Years 2,000 50 400 70 350 60 5,000 2,000 1,500 500 400 50 50 900 300 700 100 600 100 50 -
Leachate Quantity
Rainwater falling directly on the landfill and off-site stormwater flowing across the site are the major source of water for leachate generation (Lu et al., 1980; Wang, 2004; Wilson, 1981). Chemical and biological reactions occur when infiltrating water percolates through wastes (Kouzeli-Katsiri et al., 1999; Wang, 2004). The ongoing reactions within the waste will produce complex combination and transport by the infiltrating water. Besides the chemical and biological reactions, physical processes such as sorption and dissolution also take place during the passage of water through the waste (McBean and Rovers, 1999). Leachate has high content of iron, chlorides, organic nitrogen, phosphate, sulphate (Preez and Pieterse, 1998) and high in organic matters and inorganic ion concentrations (Uygur, A. and Kargi, F., 2004). Typical data on leachate composition are illustrates in Table 2.3.
Leachate generation is induced by precipitation. It is also produced as a result of biochemical processes that convert solid materials to liquid form. The leachate
9 generated from the biochemical reactions is characterized by very high concentrations of organic and inorganic contaminants (McBean and Rovers, 1999). Bagchi (1990) states that water percolating through the landfill surface from infiltration will actually dilute contaminants in the leachate, as well as aid in the formation of new leachate.
Table 2.3: Data on the composition of leachate from landfills (Tchobanoglous et al, 1993) Constituent* BOD5 (5-day Biochemical Oxygen Demand) TOC (Total Organic Carbon) COD (Chemical Oxygen Demand) Total Suspended Solids Organic Nitrogen Ammonia Nitrogen Nitrate Total Phosphorus Ortho Phosphorus Alkalinity as CaCO3 pH Total hardness as CaCO3 Calcium Magnesium Potassium Sodium Chloride Sulfate Total Iron
Range 2000-30,000 1500-20,000 3000-45,000 200-1000 10-600 10-800 5-40 1-70 1-50 1000-10,000 5.3-805 300-10,000 200-3000 50-1500 200-2000 200-2000 100-3000 100-1500 50-600
Typical 10,000 6000 18,000 500 200 200 25 30 20 3000 6 3500 1000 250 300 500 500 300 60
*All units in milligrams per liter except pH.
The temporal variability of leachate quantities and qualities is influenced by features including the meteorology, the cover overlying the waste, the vicinity of the site, and numerous characteristics of the waste such as age, composition and degree of compaction (McBean and Rovers, 1999). The features of water balance, such as precipitation, interception and surface runoff, evapotranspiration by vegetation and infiltration at a landfill site, are schematically depicted in Figure 2.1.
In Malaysia, solid waste composition reported by Agamuthu (2001) is mainly organic in nature and has high moisture content at about 75%. These waste characteristics have caused more leachate being produced than inorganic waste with low moisture content. The annual precipitation in Malaysia ranges from 2000mm to
10 2500mm and the heavy rainfall precipitation have further increased leachate production.
Interception and Evapotranspiration by Vegetation
Precipitation Infiltration Surface Runoff
Moisture Content of waste at time of placement
Leachate Collection Tiles
Wetland
Figure 2.1: Water balance components and direction of leachate to a wetland (McBean and Rovers, 1999)
2.2.2
Leachate Quality
The characteristics of the leachate are influenced by the waste material deposited in the site. For example, inert wastes will produce a leachate with concentrations of components, whereas a hazardous waste leachate tends to have a wide range of components with highly variable concentrations. The decomposition rate of the waste also depends on aspects such as pH, temperature, aerobic or anaerobic conditions and the associated types of micro-organism. Associated with leachate is a malodorous smell, due mainly to the presence of organic acids (Williams, 2005).
The toxicity of leachate based on bioassay testing of leachate with various organisms has reported high toxicity levels in leachate, derived from municipal solid
11 waste landfills (Kjeldsen et al 2002). Several studies of leachate toxicity report that ammonia, chloride, acidity or alkalinity and heavy metal concentrations are the main toxic pollutant in landfill leachate. It has also been suggested that leachate from municipal solid waste landfill sites may be mutagenic and carcinogenic (Kjeldsen et al, 2002).
The pollutants found in leachate from municipal solid waste landfill sites can be broadly categorized into four main groups (Kjeldsen et al, 2002):
(i)
Dissolved organic material (COD and TOC), volatile fatty acids and fluvic and humic-like material;
(ii)
Inorganic macrocomponents including calcium, magnesium, sodium, potassium, ammonium, iron, manganese, chloride, sulphate and bicarbonate compounds;
(iii)
Heavy metals such as cadmium, chromium, copper, lead, nickel and zinc compounds;
(iv)
XOC which are compounds not degraded by organisms in the environment and include aromatic hydrocarbons, pesticides, plasticizers, chlorinated aliphatic compounds, etc. These compounds originate from household and industrial chemicals and are present in low concentrations.
A series of phases is detectable in the decomposition of solid waste (Figure 2.2). Phase I known as the hydrolysis and acidification phase, involving aerobic decomposition, is typically brief, and lasts for less than a month. Once the available oxygen within the waste is utilized, except in the vicinity of the landfill surface, aerobic decomposition terminates (McBean and Rovers, 1999).
12
Figure 2.2: COD and BOD5 versus time (McBean and Rovers, 1999) Phase II known as initial methane generation phase, begins with the initiation of activities of anaerobic and facultative organisms (involving acetogenic bacteria). They hydrolyze and ferment cellulose and other putrescible materials, producing simpler, soluble compounds such as VFAs (which produce a high BOD value) and ammonia. Phase II can last for years, or even decades. Leachates produced during this stage are characterized by high BOD values which commonly greater than 10,000 mg/L and high ratios of BOD to COD (commonly greater than 0.7), indicating that high proportions of soluble organic materials are readily biodegradable. Other typical characteristics of phase II leachates are acidic pH levels (typically, 5 to 6), strong, unpleasant odors, and high concentrations of ammonia, in the range of 500 to 1000 mg/L. The aggressive chemical nature of this leachate assists in dissolution of other components of the waste, and produces high levels of iron, manganese, zinc, calcium, and magnesium in the leachate (McBean and Rovers, 1999).
Phase II also involves slower-growing methanogenic bacteria gradually becoming established and consuming simple organic compounds, with the production of a mixture of carbon dioxide, methane, and other trace gaseous
13 constituents that constitute landfill gas. The transition from phase II to phase III decomposition can take many years, may not be completed for decades, and is sometimes never completed (McBean and Rovers, 1999).
In phase III, bacteria gradually become established that are able to remove the soluble organic compounds, mainly fatty acids, which are largely responsible for the characteristics of phase II leachates. There is a depletion of both COD and BOD over time in phase III (McBean and Rovers, 1999).
Leachates generated during phase III are often referred to as “stabilized,” but in the life cycle of a landfill at this stage the landfill is biologically at its most active level. A dynamic equilibrium is eventually established between acetogenic and methanogenic bacteria, and wastes continue to actively decompose. Leachates produced during phase III are characterized by relatively low BOD values and low ratios of BOD to COD. However, ammonia nitrogen continues to be released by the first-stage acetogenic process and will be present at high levels in the leachate. Inorganic substances such as iron, sodium, potassium, sulfate and chloride may continue to dissolve and leach from the landfill refuse for many years (McBean and Rovers, 1999).
The composition of phase III leachate is characterized by neutral pH levels, strongly reducing redox potential, low concentrations of VFAs and higher concentrations of refractory organic matter. The methanogenic phase is the longest and most important phase of waste stabilization, with phases 1V and V occurring as the refuse becomes depleted of degradable organics (McBean and Rovers, 1999).
2.2.3
Leachate Treatment
Leachate is often so polluted. Thus, available leachate treatment should be evaluated to be treated before it can be passed into a sewer or receiving water course. Table 2.4 indicates operations used for the treatment of leachate.
14 Table 2.4: Representative biological, chemical and physical processes and operations used for the treatment of leachate (Tchobanoglous et al., 1993) Treatment Process Biological processes
Application
Comments
Activated sludge
Removal of organics
Defoaming additives may be necessary; separate clarifier needed
Sequencing batch reactors
Removal of organics
Similar to activated sludge, but no separate clarifier needed; only applicable to relatively low flow rates
Aerated stabilization basins
Removal of organics
Requires large land area
Fixed film processes (trickling filters, rotating biological contactors)
Removal of organics
Commonly used on industrial effluents similar to leachates, but untested on actual landfill leachates
Anaerobic lagoons and contactors
Removal of organics
Lower power requirements and sludge production than aerobic systems; Requires heating; greater potential for process instability; Slower than aerobic systems
Nitrification/ denitrification
Removal of organics
Nitrification/denitrification can be accomplished simultaneously with the removal of organics
Neutralization
pH control
Of limit applicability to most leachates
Precipitation
Removal of metals and some anions
Produces sludge, possibly requiring disposal as a hazardous waste
Oxidation
Removal of organics; detoxification of some inorganic species
Works best on dilute waste streams; use of chlorine can result in formation of chlorinated hydrocarbons.
Wet air oxidation
Removal of organics
Costly; works well on refractory organics
Removal of suspended matter
Of limited applicability alone; may be used in conjunction with other treatment processes.
Chemical processes
Physical operations Sedimentation/ flotation
15 Treatment Process Filtration
Application Removal of suspended matter
Comments Useful only as a polishing step
Air stripping
Removal of suspended matter
May require air pollution control equipment
Steam stripping
Removal of volatile organics
High energy costs; condensate steam requires further treatment
Adsorption
Removal of organics
Proven technology; variable costs depending on leachate
Ion exchange
Removal of dissolved inorganic
Useful only as a polishing step
Ultrafiltration
Removal of bacteria and high molecular weight organics
Subject to fouling; Limited applicability to leachate
Reverse osmosis
Dilute solutions to inorganic
Costly; Extensive pretreatment necessary
Evaporation
Where leachate discharge is not permissible
Resulting sludge may be hazardous; Can be costly except in arid regions
Some forms of pretreatment or complete treatment as previously shown in Table 2.4 are required when leachate recycling and evaporation is not used and the direct disposal of leachate to a treatment facility is not possible. The problem with leachate treatment is that leachate changes in terms of strength, biodegradability, and toxicity as the wastes in the landfill age over time. The treatment process or processes selected will depend to a large extent on the contaminants to be removed.
2.3
Wetland
The word "wetland" by itself conveys mixed meanings. One of the earliest definitions of the term natural wetlands was presented by the U.S. Fish and Wildlife Service in 1956 (Shaw and Fredine, 1956):
“Wetlands” refers to lowlands covered with shallow and sometimes temporary or intermittent waters. They are referred to by such names as
16 marshes, swamps, bogs, wet meadows, potholes, sloughs, and riveroverflow lands. Shallow lakes and ponds, usually with emergent vegetation as a conspicuous feature, are included in the definition, but the permanent waters of streams, reservoirs, and deep lakes are not included.
Perhaps the most comprehensive definition of wetlands was adopted by wetland scientists in the U.S. Fish and Wildlife Service in 1979, after several years of review. The definition was presented in a report entitled Classification of Wetlands and Deepwater Habitats of the United States (Cowardin et al., 1979):
“Wetlands are lands transitional between terrestrial and an aquatic system where the water table is usually at or near the surface or the land is covered by shallow water. Wetlands must have one or more of the following three attributes: (1) at least periodically, the land supports predominantly hydrophytes, (2) the substrate is predominantly undrained hydric soil, and (3) the substrate is nonsoil and is saturated with water or covered by shallow water at some time during the growing season of each year”
Wetlands vary widely because of regional and local differences in soils, topography, climate, hydrology, water chemistry, vegetation, and other factors, including human disturbance (USEPA, 1983). Water saturation (hydrology) largely determines how the soil develops and the types of plant and animal communities living in and on the soil.
2.3.1 Constructed Wetland
Constructed wetland is a water treatment facility duplicating the processes occurring in natural wetlands. In natural system, the processes occur at “natural” rates however, constructed wetland introduced by USEPA (1993) is defined as a wetland specifically constructed for the purpose of pollution control and waste
17 management, at a location other than existing natural wetlands. Duplicating the processes occurring in natural wetlands, constructed wetlands are complex, integrated systems in which water, plants, animals, microorganisms and the environment; sun, soil and air interact to improve water quality. The systems are designed to maximize the physical, chemical and biological abilities of natural wetlands to reduce the BOD, TSS, TN, P and pathogens as wastewater flows slowly through the vegetated subsurface. Bioaccumulation, biotransformation and biodegradation of metals are also possible (Kadlec and Knight, 1996). The mechanisms of pollutant removal include both aerobic and anaerobic microbiological conversions, sorption, sedimentation, volatilization and chemical transformations (Aslam et al., 2004; Robert, 1999; Vymazal, 2005a).
In 1970s and 1980s, constructed wetlands were nearly exclusively built to treat domestic or municipal sewage. Since 1990s, the constructed wetlands have been used for all kinds of wastewater including landfill leachate, runoff (e.g. urban, highway, airport and agricultural) (Tanner et al, 1995a; Kern and Idler, 1999), food processing (e.g. winery, cheese and milk production), industrial (e.g. chemicals, paper mill and oil refineries) (Mays and Edward, 2001; Panswad and Chavalparit, 1997), agriculture farms, mine drainage or sludge dewatering (Bastian et al, 1989; Vymazal, 2005a) and stormwaters (Carleton et al, 2000; Wong et al, 1995). The use of constructed wetlands has several advantages over conventional wastewater treatment methods. The initial cost of constructed wetlands is considerably lower than conventional treatments (Aslam et al., 2004; Kadlec and Knight, 1996). While constructed wetlands efficiently remove many pollutants from wastewater streams, constructed wetlands also enhance the environment by providing a habitat for vegetation, fish, birds, and other wildlife (Aslam et al., 2004; Bays et al, 2002).
Both constructed and natural wetlands are being used at an increasing rate for treatment of wastewaters because of their consistent performance for pollutant removals. Knight (1997) reported that wetlands degrade most forms of organic matter to carbon dioxide and release trace elements in the process. Both particulate and soluble forms of BOD compounds are trapped and degraded in wetlands. Potentially toxic metals associated with particulate matter and soluble metals in ionic or complexed form are trapped and retained to varying degrees by the complex
18 biology and chemistry of treatment wetlands. Some organics are only slightly modified and may remain in a treatment wetland in a biologically toxic form for an indefinite time period.
2.3.2
Types of Constructed Wetlands
Constructed wetlands for wastewater treatment are classified by the flow path of the water in the system (Reed, 1988) as Figure 2.3, which is free water surface (FWS) and subsurface flow system (SSF) (Hammer, 1989; Kent, 1994). Both FWS and SSF systems are characterized by emergent vegetation. This study is concerned with the SSF wetland type.
FWS consist of basins or channels and barriers such as constructed clay layer or geotechnical material to prevent seepage (Lim et al., 1998), and have relatively shallow water depths and low flow velocities. The water surface is exposed to the atmosphere, and the intended flow path through the system is horizontal. In FWS, water flows over the soil surface from an inlet point to an outlet point or in a few cases is totally lost to evapotranspiration and infiltration within the wetlands. It is said to have properties in common with facultative lagoons and also to have some important structural and functional differences. In free water surface flow wetlands the surface layer is in aerobic condition whereas the deeper water and substrate are usually anaerobic. Some disadvantages of FWS system are larger land area is required and the water is easily exposed to human environments. Mosquito problems are also arising in the operation of FWS that breed easily in the water.
Subsurface flow systems (SSF), sometimes called vegetated submerged bed systems (VSB), consist entirely of subsurface flow conveyed to the system through a trench or bed underdrain network that contain suitable depth of porous media. As with FWS systems, they have barriers to prevent seepage and very low flow velocities. The wastewater will flow in a high level site of the wetland and then flow through the porous media of sand soil and plant rhizosphere. The wastewater is treated by the physical-chemical and biochemical complex processes of filtration, sorption and
19 precipitation processes in the soil and by microbiological degradation. Finally, the treated wastewater flows out in the bed that remains below the top of the porous media.
Types
Free Water Surface System
Subsurface Flow System
Diagram
Water Level Above ground surface
Below ground
Water Flow
Above ground
Through soil or gravel
Vegetation
Planted or colonized
Common reed, bulrush or cattail
Plants
Rooted and emergent
To bottom of bed
Figure 2.3: Types of constructed wetlands (Robert, 1999)
The SSF wetland types have several advantages if compared with the FWS wetland types. It is found that in the SSF system, the available through wastewater treatment is better than the constructed FWS one. Wastewater flowing subsurface media may also avoid of the little risk of heavy odors, dark-color exposure and insect vectors effects. The area application for SSF wetland can be smaller than a FWS system with the same wastewater withdraw conditions. Constructed soil-and gravel based in SSF wetlands are common used to treat mechanically pretreated municipal wastewaters in many places in the world.
SSF which by definition must be planted with emergent macrophytes can best be classified as horizontal flow or vertical flow (Figure 2.4). This classification is based on the flow direction to the soil-and gravel layers. This technology is generally limited to systems with low flow rates and can be used with less than secondary pretreatment (Kadlec et al, 1978).
20
(a) Horizontal flow
(b) Vertical flow
Figure 2.4: General arrangement for the constructed wetland with (a) a horizontal flow (Vymazal et al., 1998) and; (b) a vertical flow (Cooper et al., 1996)
The disadvantages of SSF wetlands are that they are more expensive to construct, on a unit basis than FWS wetlands. Because of the cost factor, SSF
21 wetlands are often used for small flows. SSF wetlands are maybe more difficult to regulate than FWS wetlands, and maintenance and repair costs are generally higher than for FWS wetlands. A number of systems have had problems with clogging and unintended surface flows.
2.3.3
Wetland Vegetation
In the wetland ecosystem, wetland plants play crucial ecological roles and predominantly contribute to water purifying property or water quality function. According to (Kadlec and Knight, 1996) constructed wetlands are designed to use water quality improvement processes occurring in natural wetlands, including high primary productivity, low flow conditions, and oxygen transfer to anaerobic sediments. Several of these processes are strongly linked to functional characteristics of macrophytes. There are many types of wetland plants; some of them are emergent, submerged and floating shown in Figure 2.5, 2.6 and 2.7, respectively.
As depicted in Figure 2.5, submerged plants are those that grow below the water surface. These species are not effective for wastewater treatment due to the requirement of light penetration into the water bodies. The second types of aquatic plant, namely the floating type as shown in Figure 2.6, have their root portions submerged but not attached to the soil. The submerged parts of the floating plant can serve as a good habitat for the bacteria responsible for waste stabilization. According to Polprasert (1989), many types of floating weeds are commonly used in polishing wastewater but there are also some drawbacks in the operation and maintenance of this kind of system because of the fast growth rate of floating plants and their mobility.
The emergent plants tower their shoots distinctly above the water surface and are attached to the soil by their roots such as cattail and bulrush as shown in Figure 2.7. These plants tend to have a higher potential in wastewater treatment, because can they serve as a microbial habitat and filtering medium. Reed et al., (1988) revealed the communities of the emergent plants have the capability of growing in a
22 wide range of substrates and variety of wastewaters. However, this research focused on the capability of emergent plant Limnocharis flava.
(a)
(b)
Figure 2.5: Submerged aquatic plants; (a) hydrilla (Hydrilla verticillata); (b) coontail (Ceratophyllum demursum) (Lim and Polprasert, 1998)
(a)
(b)
Figure 2.6: Floating aquatic plants; (a) water hyacinth (Eichhornia crassipes); (b) water lettuce (Pistia stratiotes) (Lim and Polprasert, 1998)
23
(a) (b) (c) Figure 2.7: Emergent aquatic plants; (a) bulrush (Scirpus longii); (b) cattail (Typha latifolia); (c) reeds (Pragmites communis) (Lim and Polprasert, 1998)
2.3.4
Wetlands Function and Values
Wetland functions are often referred to the physical, chemical and biological characteristics of wetlands. Similarly, the wetland values are referred to those characteristics of wetlands that are beneficial to society. Wetland functions involve the performance or execution of changes within the wetlands ecosystem. These functions include biological, chemical and physical transformations in the diversity forms and substances that exist within the wetland. Representative biological functions include providing habitat for reproduction, feeding, and resting. Representative physical functions include flood attenuation, groundwater recharge and sediment entrapment. Representative chemical functions include nutrient removal and toxics decontamination.
24
Wetland values on the other hand are sociological and subjective terms. Values of wetlands are based on anthropogenic properties by which the wetlands are determined to be useful, or impart beneficial to public. The value establishes a worth, excellence, utility or importance of a given wetland function.
The study of wetland functional and values is the essential step in understanding how wetlands perform as a wastewater treatment facility (USEPA 1983; Hammer 1989). Principal functions and values of wetlands are presented in Table 2.5.
Table 2.5: Important Functions and Values of Natural Wetlands (Kent, 1994) Functions Flood water storage Flooding reduction Erosion control Sediment stabilization Sediment/toxicant retention Groundwater recharge/discharge Natural water purification
2.3.5
Values Nutrient removal/retention Chemical and nutrient sorption Food chain support Fish and wildlife habitat Migratory waterfowl usage Recreation Uniqueness/Heritage values
Treatment Processes Mechanisms
Significantly, both natural and constructed wetland systems provide wastewater treatment by reducing oxygen-demanding substances such as BOD and ammonia, suspended solids, nutrients such as nitrogen and phosphorus, and other pollutants such as metals. Primary, secondary, and incremental removal mechanisms include physical, chemical and biological operations as well as plant uptake (Sherwood et al. 1979, Reed et al, 1988 and Hammer, 1989).
(a)
Biochemical Oxygen Demand
25 Biological metabolism is the primary process for removal of BOD in a wetland system. The diverse microbial populations in the water column consume the soluble organic waste products. In the soil and sediment layer, the organics are sorbed in the soil, and later, biologically oxidized into stable end products. Also, sedimentation in FWS systems, and filtration in SSF systems are processes that remove BOD associated with suspended organic materials. Typically, the wastewater will receive some level of pre-application treatment which would have removed essentially all BOD associated with suspended matter (Kent, 1994).
The principal biological activity in FWS wetlands is from algae and bacteria where microbial growths are attached to structures such as plant stems and litter, in the wetland. The phenomenon is akin to BOD removal in oxidation ponds and by attached growth (trickling filter) treatment facilities. Loading rates are lower on SSF wetland treatment systems due to the limited supply of oxygen which is characteristic of these systems. While plant root systems are the key to treatment performance, therefore making the selected plant species especially important.
(b)
Suspended Solids
Both FWS and SSF wetland systems effectively remove suspended solids (SS). Settleable suspended solids are readily removed in the early stages of a FWS by gravity settling in quiescent, shallow areas downstream of the system inlet. In the case of wastewaters receiving little pretreatment, the distributed inflow design will safeguard against development of adverse and detrimental conditions from sludge buildups. In the SSF wetland, settleable solids are removed by filtration as the wastewater moves through the underdrain system. For colloidal suspended solids, the primary removal mechanism is bacterial metabolism in both types of wetland treatment systems. Some filtering and sorption will occur in an SSF system (Kent, 1994).
In the FWS wetland suspended solids may be produced in the form of algae, which also will produce diurnal swings in dissolved oxygen concentrations. In the initial system cells, algae performs important treatment functions, as in an oxidation pond, but the system design should limit the algae population in the later stages of
26 the wetland system so as to avoid permit violations. Nutrient reductions through the system will help effect this requirement (Kent, 1994).
(c)
Nutrients
Constructed wetlands are an effective means to control the discharge of nutrients such as nitrogen and phosphorus. The mechanisms for nutrient removal in a wetland system are;
(i)
Direct plant uptake;
(ii)
Chemical precipitation;
(iii)
Uptake by algae and bacteria;
(iv)
Soil absorption;
(v)
Denitrification;
(vi)
Loss by insect and fish uptake.
The density and types of plants in the system will determine the direct and indirect performance rates of these mechanisms. Thus, it is extremely important to maintain a healthy plant community to ensure effective performance of the nutrient removal mechanisms. Plant selection should be based on the species ability to establish a stable community that will survive over the spectrum of the system’s hydroperiod and other environmental conditions (Kent, 1994).
Both nitrogen and phosphorus must be considered simultaneously. The wetlands community is composed of many different, interacting populations of organisms functioning in a way unique to the site’s environmental conditions. Often, either nitrogen or phosphorus is the limiting factor in an aquatic system, and the addition of excess nutrients causes eutrophication or other undesirable changes in the ecological community.
In a natural and constructed wetland system, the principal phosphorus removal mechanisms are precipitation of phosphates under elevated pH conditions, sorption within the bottom soils, uptake by the macrophytic plants and fixation by algae and bacteria. Unlike denitrification for nitrogen removal, there is no single
27 long-term sink for phosphorus removal or retention. This deficiency requires that all the phosphorus removal mechanisms be considered in the system design process.
In the wetland system, both organic and inorganic forms of phosphorus may occur in a dissolved or particulate state in the water column and soil. The interchange of phosphorus between the water and soil phases depends on several factors, such as concentration gradients, pH, dissolved oxygen, and system hydraulics. The latter includes velocity suspension of particulates and bottom scouring to re-suspend settled particulates.
Soil and bottom sediments can be a significant phosphorus sink in mineral soils. In this instance, dissolved inorganic phosphorus is removed through adsorption to clays and precipitation as insoluble complexes of aluminum, calcium, and iron. The aluminum and iron reactions prefer acid to neutral soils, whereas the calcium reactions require alkaline conditions. Plants may then uptake the phosphorus, especially which adsorbed to the soil.
To take advantage of mineral soils as a sink, the water in the system must be moving in the soil column to afford reaction opportunities. The SSF wetlands reduce the influence of water-soil interchanges of phosphorus and force movement through the soil column. However, this approach limits the system’s hydraulic capacity without a significant increase in wetland treatment area. If the area soils are mostly organic, special provisions would be required to seek deeper, more mineral soils in order to use the soil as a significant phosphorus removal mechanism (Kent, 1994).
Plant uptake influences the removal of nutrients and provides a significant short-term phosphorus sink during establishment of the wetland system, but it is not the principal phosphorus removal mechanism (Kent, 1994). Longer-term storage occurs when the plants die and form a litter zone which forms peat (organic soils). Likewise, fixation of phosphorus in algae and bacteria cells results in storage of phosphorus in the bottom sediments. The stability of these phosphorus sinks depends on several factors including the plant tissue decay rate, peat formation rate, and occurrence of scouring.
28 (d)
Metals
The processes that affect the fate of metals are considered to be (Lim and Polprasert, 1998): 1) adsorption or exchange of metals onto sediments in wetlands; 2) formation of insoluble sulfides in reducing zones catalyzed by bacteria metabolism; 3) ion co-precipitation of iron and manganese hydroxide; 4) formation of insoluble carbonates; 5) uptake by plants; and 6) physical filtration. The presence of clay soils in an SSF enhances the opportunities of removal by adsorption. Filtration also will remove suspended metals in an SSF wetland system. In a FWS system, sedimentation will occur, and the development of neutral to alkaline conditions will favor precipitation of metals. In both systems, metal uptake by plants may occur (Kent, 1994). However, the effectiveness of water treatment has proved highly variable at different sites (Fennesy, 1989). Although significant metals removals have been observed for most of the wetland studied, the removal mechanisms are poorly understood (Ying, 2003).
2.3.6
Treatment Performance
Although both SSF and FWS systems are known to be capable of effective removal of many contaminants, a review of the literature indicates more research efforts are being directed to SSF systems. The results of some studied of the performance constructed wetlands for various wastewaters from international and local researchers are summarized in Table 2.6. According to Lim and Polprasert (1998), this is due to the following perceived merits of SSF systems:
(i)
Mosquito and odor problems do not arise since the water remains subsurface; and
(ii)
Less surface area is required for SSF systems to achieve an equivalent performance to that of FWS systems.
2.4
Magnet and Magnetism
29 Many people find magnets to be strange and complete mysterious things. A magnet is an object that has a magnetic field. It can be in the form of a permanent magnet or an electromagnet. Since 1831, electromagnetic induction was discovered by Michael Faraday. He built two devices to produce what he called electromagnetic rotation that is a continuous circular motion from the circular magnetic force around a wire. His greatest discoveries were electromagnetic induction which means a generation of electricity in a wire by means of the electromagnetic effect of a current in another wire. The induction ring was the first electric transformer
The movement of a compass needle towards the North Pole and the attraction of a fridge magnet to the refrigerator are two examples of magnetism in our everyday lives. A magnet is an object that forms a magnetic field. As iron is a magnetic material, iron filings shaken around a magnet will form along the lines of force and produce the pattern of the magnetic field. Magnetic fields arise from charges, similarly to electric fields, but are different in that the charges must be moving. For example, electrons flowing in a wire will produce a magnetic field surrounding the wire as shown in Figure 2.8. The force of charge felt when moving through a magnetic field as depicted by the right-hand rule. The direction of the magnetic field due to moving charges will also depend on the right hand rule. For a current-carrying wire, the rule revealed that if the fingers of the right hand are placed around the wire so that the thumb points in the direction of current flow (I), the fingers will be pointing in the direction of the magnetic field produced by the wire.
Current, I Magnetic Field, B
Figure 2.8: Right-hand rule (Bruk et al, 1987)
30
Table 2.6: Comparison of different performance constructed wetlands. Reference
System type SSF cattail SSF reed SSF bulrush SSF gravel
Wastewater type Primary municipal wastewater
Roser et al. (1987)
SSF cattail SSF bulrush SSF gravel
Moore et al. (1994)
Wildeman and Laudon (1989)
Gersberg et al. (1986)
Removal efficiency (%) TP TN 28* 78* 94* 11*
BOD 74 81 96 69
COD -
SS 91 86 94 90
Fe -
Mn -
Secondary clarified sewage effluent
88 86 88
-
93 89 93
23 19 24
48 54 50
-
-
FWS cattail FWS bulrush FWS stones
Pulp mill waste
18 27 33
-
53 42 76
-
-
-
-
SSF mushroom compost SSF peat + aged manure + decomposed wood products SSF 10-15cm limestone rock and peat + aged manure + decomposed wood products
Acid mine drainage
-
-
-
-
-
38
10
-
-
-
-
-
35
2
-
-
-
-
-
30
0
Notes: BOD=Biochemical Oxygen Demand; COD=Chemical Oxygen Demand; SS=Suspended Solids; TP=Total phosphorus; TN=Total nitrogen; Fe=Ferum; Mn=Manganese * = ammoniacal-N
31
Table 2.6: Comparison of different performance constructed wetlands. (cont’) Reference
System type SSF bulrush SSF gravel HRT= 2 days
Wastewater type Dairy farm wastewater
BOD 76 60
COD -
SS 78 73
Crolla and Kensley (2002)
SSF cattail
Dairy milkhouse
-
-
-
58
Hammer et al. (1993)
SSF cattail SSF reed
Swine
-
-
-
Hunt and Poach (2000)
SSF bulrush SSF cattail
Swine
-
-
Kuusemets et al. (2002)
SSF bulrush
Domestic wastewater
Harish. (2001)
SSF cattail SSF mangrove fern SSF seaoxeye SSF sedge
Shrimp aquaculture wastewater
Tanner et al. (1995a)
-
-
Removal efficiency (%) TP TN -
Fe -
Mn -
72
-
-
75
90
-
-
-
35
81 to 94
-
-
59
5 (due to plant uptake) 48
8 (due to plant uptake) -
-
-
Notes: BOD=Biochemical Oxygen Demand; COD=Chemical Oxygen Demand; SS=Suspended Solids; TP=Total phosphorus; TN=Total nitrogen; Fe=Ferum; Mn=Manganese • = ammoniacal-N
32
Table 2.6: Comparison of different performance constructed wetlands. (cont’) Reference
System type SSF bulrush SSF cattail SSF reed
Wastewater type Cereal and dairy wastewater
Ydstebo et al. (2000)
SSF cattail
Greenway and Woolley (2000)
Removal efficiency (%) TP TN 20-44 -
BOD -
COD -
SS -
Agricultural runoff
-
-
-
70-85
SSF cattail
Municipal wastewater
-
-
-
Kim and Geary (2000)
SSF bulrush
Simulated high P loading
-
-
-
Navanitha (2005)
SSF cattail SSF gravel
Landfill leachate
66
56
Aeslina (2004)
SSF cattail with Safety Flow
Landfill leachate
70
Noor Ida Amalina (2005)
FWS water hyacinth enhanced with magnetic field
Landfill laechate
83
Braskerud (2000)
Fe -
Mn -
-
-
-
21 to 28
81 to 87
-
-
-
-
-
-
5 (due to plant uptake) 57
90*
-
-
80
-
80
90*
-
-
78
-
60
96*
69
60
Notes: BOD=Biochemical Oxygen Demand; COD=Chemical Oxygen Demand; SS=Suspended Solids; TP=Total phosphorus; TN=Total nitrogen; Fe=Ferum; Mn=Manganese • = ammoniacal-N
The strength of a magnet is given by its magnetic flux density, which is measured in units of gauss. The earth's magnetic field is on the order of 0.5 gauss (Marshall and Skitek, 1987). Typical household refrigerator magnets have field strengths of about 1,000 gauss. The SI unit of magnetic field strength is the tesla, and the SI unit of total magnetic flux is the weber. 1 weber = 1 tesla flowing through 1 square meter, and is a very large amount of magnetic flux. A smaller magnetic field unit is the Gauss (1 Tesla = 1,000 Gauss).
2.4.1
Effect of Magnetic Field to Molecules
Basically, magnets have locations on them, called poles. Pole comes in two types, which are called North poles and South poles. Opposite pole types attract as depicted in Figure 2.9, while poles of the same type repel each other. A magnetic field can be produced by aligning the positives and the negatives to opposite ends of any magnetic material. Poles of either type attract iron, steel, and a few other metals such as nickel.
Figure 2.9: Magnetic field directed out from north pole (N) to south pole (S) (Bruk et al., 1987)
34 A force on moving charges particle of magnetic field is called Lorentz force. As illustrated in Figure 2.10, the interaction between magnetic and electric fields will result a force generated in a direction perpendicular to the plane formed by the magnetic and electric field vectors. The moving charges or ions resulting weak electrical current giving additional force to the charged particle so called Lorentz force. The velocity of particle will increased as the changes of direction flow will occurred depending on strength of magnetic field and charge density (Spiegel, 1998). The molecules of a substance may be classified as either polar or nonpolar. A nonpolar molecule is one in which the center of gravity of the positive nuclei and the electrons coincide, while a polar molecule is one in which they do not. Symmetrical molecules like H2, N2, and O are nonpolar while molecules like H2O and N2O are polar.
Lorentz ForceForce in positive charge
90°
90°
90°
Electric
Magnetic Field (South Pole)
Figure 2.10: Positioning of fields and force (Bruk et al, 1987)
Under the influence of a magnetic field, the charges of a nonpolar molecule become displaced (Figure 2.11). These molecules are said to become polarized by the magnetic field and are called induce dipoles. The restoring force pulls the molecules together. The charges separate until the restoring force is equal and opposite to the force exerted on the charges by the field. Polar molecules are oriented
35 at random when no magnetic field is provided. When under the influence of a magnetic field the dipoles point toward the direction of the field (Figure 2.12).
Arrangement of nonpolar molecules in the absence of a magnetic field.
Arrangement of nonpolar molecules under the influence of a magnetic field.
Figure 2.11: Nonpolar displacement (Vickl, 1991)
Arrangement of polar molecules in the absence of a magnetic field.
Under the influence of a magnetic field
Figure 2.12: Polar displacement (Vickl, 1991)
2.4.2
Magnetic Mechanism
Colloidal particles dispersed in a solution are electrically charged due to their ionic characteristics and dipolar attributes. Negative charged ions in each particle
36 make them repel each other. Each particle dispersed in a solution is surrounded by oppositely charged ions. Collision with high velocity and reduction of repelling time will occur when the solution is applied to the magnetic field. Thus, the colloidal particles will form larger molecules to induce coagulation system. This reaction is shown by Figure 2.13.
Magnet
Magnetic Field
Flow
Magnet
Colloidal particle far each other
Magnetic Mechanism
Colloidal particle coagulate to form larger molecules
Figure 2.13: Reaction of charged ion in solution when exposed to magnetic field (Klassen, 1981)
Before the concept of colloidal system were revealed, the colloidal particle is hard to be eliminated because of same charged ions. To undergo this situation, the charges have to be neutralized through sedimentation and flocculation. Since findings from Vermeiran (1958); Klassen (1981) revealed the magnet potential, their proven are magnetic water treatment increased the efficiency of coagulation and flocculation total suspended solids in water. Others, magnetic treatment also increase coagulation processes in iron (Duffy, 1977; Tombaez et al, 1991).
Magnetic treatment devices are available in various configurations, which are electromagnets and single or arrays of permanent magnets with many different orientations of magnetic field. These devices can be placed in side or outside of the pipe. Gruber and Carda (1981) had proposed various orientation of permanent magnet as depicted in Figure 2.14, each employing different orientations of magnetic
37 field. Some units employ a field that is orientated approximately orthogonal to the direction of flow (class II and class III) whilst others employ a mostly parallel field (class I and IV). Where a study has used a particular device, this will be identified if possible to enable the reader to make comparisons about the effectiveness of each type.
Class I
Class II
Class III
Class IV
Figure 2.14: Classification of permanent magnet type (Baker and Judd, 1996)
Magnetic treatment devices can be arranged in two installation variations and three operational variations. First to be discussed are the two installation variations: invasive and noninvasive. Invasive devices are those which have part or all of the operating equipment within the flow field. Therefore, these devices require the removal of a section of the pipe for insertion of the device. This will necessitates an amount of time for the pipe to be out of service. Non-invasive devices are completely external to the pipe, and thus can be installed while the pipe is in operation. Figure 2.15 illustrates the two installation variations.
38
Magnet
Flow
Flow
Invasive Device
Non-Invasive Device
Figure 2.15: Illustration of classes of magnetic devices by installation location (AWWA, 1998)
The operational variations have been mentioned above; illustrations of the latter two types are shown Figure 2.16:
(i)
Magnetic, more correctly a permanent magnet
(ii)
Electromagnetic, where the magnetic field is generated via electromagnets
(iii)
Electrostatic, where an electric field is imposed on the water flow, which serves to attract or repel the ions and, in addition, generates a magnetic field
-
+
Flow
Electromagnetic Device Figure 2.16: Illustration of classes of non-permanent magnet devices (AWWA, 1998)
39 2.4.3
Magnetic Treatment
One of the primary needs of mankind over the next millennium is improved and less expensive water or wastewater treatment methods. Works by Faraday and Maxwell have revealed the effect of electromagnetic fields on the behavior and the properties of matter. Nowadays, more relevant articles and reports are available, so clearly magnetic water treatment has received some attention from the scientific community. The reported effects of magnetic water and wastewater treatment, however, are varied and often contradictory. In many cases, researchers report finding no significant magnetic treatment effect. In other cases, however, reasonable evidence for an effect is provided. Table 2.7 shows the summary of water and wastewater treatment enhanced with magnetic field, respectively.
Table 2.7: Summary of magnetic treatment No.
1.
References
Liburkin et al. (1986)
Types of Influent Ordinary water
Findings •
Magnetic treatment affected the structure of gypsum (calcium sulfate).
•
Gypsum particles formed in magnetically treated water were found to be larger and "more regularly oriented" than those formed in ordinary water. Magnetic treatment changed the mode of calcium carbonate precipitation such that circular discshaped particles are formed rather than the dendritic (branching or tree-like) particles observed in nontreated water.
2.
Kronenberg (1985)
Non-treated water
•
3.
Chechel and Annenkove (1972) Martynova et al. (1967)
Ordinary water
• Magnetic
4.
Joshi and Kamat (1996) Bruns et al. (1966) Klassen (1981)
Ordinary water
•
Magnetic treatment affects the nature of hydrogen bonds between water molecules.
•
They report changes in water properties such as light absorbance, surface tension, and pH.
treatment affects the structure of subsequently precipitated solids. • Scale formation involves precipitation and crystallization. • These studies imply that magnetic water treatment is likely to have an effect on the formation of scale.
40
5.
Lipus et al. (1994)
Types of Influent Ordinary water
6.
Duffy (1977)
Ordinary water
No.
7.
8.
9.
10.
References
Busch et al. (1986)
Donaldson (1988) Lipus et al. (1994) Krylov et al. (1985)
Gehr et al. (1955)
Parsons et al. (1997) Higashitani and Oshitani (1997)
Ordinary water
Calsium carbonate fluid
Calcium sulfate fluid
Calcium sulfate fluid
Findings •
The characteristic relaxation time of hydrogen bonds between water molecules is estimated to be much too fast and the applied magnetic field strengths much too small for any such lasting effects.
•
Provides experimental evidence that scale suppression in magnetic water treatment devices is due not to magnetic effects on the fluid, but to the dissolution of small amounts of iron from the magnet or surrounding pipe into the fluid.
•
Iron ions can suppress the rate of scale formation and encourage the growth of a softer scale deposit.
•
Measured the voltages produced by fluids flowing through a commercial magnetic treatment device.
•
Their data support the hypothesis that a chemical reaction driven by the induced electrical currents may be responsible for generating the iron ions shown by Duffy to affect scale formation.
•
Emerging the effect results from the interaction of the applied magnetic field with surface charges of suspended particles.
•
Found that the electrical charges on calcium carbonate particles are significantly affected by the application of a magnetic field.
•
Further, the magnitude of the change in particle charge increased as the strength of the applied magnetic field increased.
•
Found that magnetic treatment affects the quantity of suspended and dissolved calcium sulfate.
•
A very strong magnetic field (47,500 gauss) generated by a nuclear magnetic resonance spectrometer was used to test identical calcium sulfate suspensions with very high hardness (1,700 ppm on a CaCO3 basis).
•
Two minutes of magnetic treatment decreased the dissolved calcium concentration by about 10%.
•
The magnetic field decreased the average particle charge by about 23%. • These results, along with Gehr et al, imply that application of a magnetic field can affect the dissolution and crystallization of at least some compounds.
41
No.
References
11.
Petruska and Perumpral (1978)
Types of Influent Food processing wastewater
12.
Coey and Cass (2000)
13.
Johan Sohaili (2003)
14.
Wan Salida (2006)
Findings •
High gradient magnetic separation (HGMS) for treating food processing wastewater can cause reductions in TP, SS and chemical oxygen demand.
Calcium carbonat fluid
•
Their study on precipitation of CaCO3, indicate that magnetic effect is maintained for at least 60 hours after exposure to the magnetic field.
Domestic wastewater
•
Revealed the capability of magnetic field is potentially an alternative method in increasing formation and sedimentation rate of suspended particles in wastewater treatment.
•
This capability will help to decrease the retention time, size of sedimentation basin and increase the treatment efficiency.
•
Most of suspended solids are organic matter that contributes to concentration of contamination such as BOD5, COD, SS and nitrate in wastewater.
•
Leachate that is treated with magnetic field would result in decrease of heavy metal and nutrient concentration.
•
Magnetic field enhances the heavy metal removal in the leachate in settling column by accelerating the settlement time for the magnetized leachate.
Landfill leachate
The summary table indicates the acceptance of magnetic treatment as an alternative form of wastewater treatment remains limited because of the lack of a credible mechanism (Baker and Judd, 1996). Magnetism technology is one of the technologies which are favour of cost and easy maintenance. Besides, it does not affect peripheral consequence towards water quality that had being treated (Florestano et al, 1996).
2.5
Conclusion
Concept of using constructed wetlands to treat wastewater is relatively new in Malaysia. However the results achieved so far from international researchers have
42 encouraged great expectations about the technology and what can be achieved further. The wetlands can be used in a sustainable manner, by defining a clear design objective for the wetland system to achieve its ultimate goal and close monitoring to assess the performance of the wetlands to ensure all objectives are fulfilled. Wetlands can be considered a pioneer venture in constructed wetland treatment system in Malaysia.
It is a good example of a wetland to be adapted to treat a variety of wastewaters including landfill leachate. The implementation of constructed wetland in treating leachate can be a low-energy process requiring minimal operational attention. Treatment processes of constructed wetlands are highly effective to treat pollutants from unknown sources and can be accomplished with the least cost compared to other treatment methods (Lim et al.2003). Magnetic treatment is relatively synonym with treated and untreated ordinary water. There were less reported for wastewater including leachate. It is therefore important to ascertain the magnetic treatment of landfill leachate. Due to excellent removal of particle (TSS) and heavy metal, magnetic field treatment can be adapted in treating leachate. Leachate was containing high concentration of heavy metal. With ability to separate positive and negative charge in particle, magnet can form larger floc or colloid and can enhance precipitation process. The flocculation can increased when applying high magnetic strength with low flowrate.
As the conclusion, the concept of treating leachate with constructed wetland enhanced with magnetic field can contribute to higher nutrient and heavy metal removal, hence, also can reduce the time efficiency to reduce or remove the pollutants.
43
CHAPTER 3
METHODOLOGY
3.1
Introduction
This chapter will discuss the methodology applied in order to carry out the tests and analysis on the treatment of leachate using subsurface flow constructed wetland (SSF) enhanced with magnetic field.
There were two systems of subsurface flow constructed wetlands (SSF) and each system was carried out for a period of 18 days. The first system was conducted as vertical flow (VF) while second system was horizontal flow (HF). Each system contained 3 tanks, each performing as a constructed wetland. Tank A was not planted for control purposes whilst tank B and C was planted with 8 clusters of Limnocharis flava. In addition, a sample discharged from tank C was treated with magnetic field for 6 hours;
The performance of the constructed wetland enhanced with magnetic field can be evaluated from the quality of the wetlands effluent. The flow of the overall experiments for each system is shown in Figure 3.1.
44
Experimental Set up -Set up experimental scale constructed wetland systems
Leachate Sample
Vertical Flow System (18 days): (i)
Reactor A (Control)
(ii)
Reactor B (Vegetated)
(iii)
Reactor C (Vegetated with
Horizontal Flow System (18 days): (i)
Reactor A (Control)
(ii)
Reactor B (Vegetated)
(iii)
Reactor C (Vegetated with
magnetic field)
magnetic field)
Effluent Collection
Laboratory effluent analysis • Total suspended solid • Turbidity • Ammoniacal nitrogen • Nitrate • Phosphorus • Ferum • Manganese
Figure 3.1: Flow chart of the experiments
45 3.2
Leachate Collection
Leachate needs to be collected before any experiment can be done. The field techniques used for this study was sample collection. For this study, raw leachate samples were collected from Tanjung Langsat landfill, Johor. Prior to the leachate collection, permission has required from the authorities. The samples were collected in plastic container. Upon collection, the leachate was stored at 4°C to minimize any further change that might occur in its physiochemical and biological properties until the experiments analyses were carried out within a week.
3.3
Experimental Setup
The experiments were carried out in a lab-scaled horizontal subsurface flow constructed wetland (SSF) which consists of (Figure 3.2):
(i)
Three tanks with dimensions 38 cm length x 28cm width x 30 cm depth each for constructed wetland.
(ii)
Three storage tanks 30cm length x 30 cm width x 30 cm depth each.
(iii)
Three collection tanks and
(iv)
Magnetic field 0.55 Tesla magnet strength.
Leachate from storage tank was entering each tanks of constructed wetland at equal time. However, leachate effluent from tank C was treated with magnetic field for 6 hours at interval of 3 days. For each system, all the plants and media were removed and replaced with new plants and media. Leachate effluents were continuously daily return feed from the collection tanks. All systems are operated under gravity flow. Each reactor contained the same quantity of leachate and the experiments were conducted under natural environmental conditions which will be exposed to sunlight and open space. Plant leaves and roots were harvested for each constructed wetland and were analyzed after being treated by each system.
46
Collection Tank
Storage Tank REACTOR A Control (a)
Collection Tank
Storage Tank REACTOR B Vegetated (b)
Magnetic field
CollectionTank
Storage Tank REACTOR C Vegetated with Magnetic Field Treatment (c)
Figure 3.2: Schematic plan of the SFS system used in the experiments; (a) Control; (b) Vegetated and; (c) Vegetated with magnet treatment systems
Samplers of leachate before being treated using constructed wetland were taken for each reactor. Then, after being treated samplers were taken at collection tank (Figure 3.2). Sampling works were done at intervals of 3 days.
47
Figure 3.3: Subsurface flow constructed wetlands for overall experiments
(a)
(b)
(c)
Figure 3.4: Tank (a) Control; (b) Vegetated; and (c) Vegetated with magnet
48 3.3.1
Magnetic Devices
The magnetic devices used in the experiments as depicted in Figure 3.5 was schematically illustrated in Figure 3.6 and Figure 3.7. It consisted of a series of pairs of permanent magnets 0.55 Tesla with north and south poles facing each other, which can be associated alternately. The leachate to be treated passed through a pipe inserted between the polar pieces in opposition of polarity. In this configuration the magnetic induction was perpendicular to the solution flow. Each polar piece is the assembling of two rectangular permanent magnets (42x25mm2 and 6mm thick). The magnetic circuit of each pair of magnets was partially closed by U-shaped pieces of mild steel, to close the magnetic field in the gap. The various pairs were separated by 12 mm.
Figure 3.5: Magnetic devices used in the experiment
49
Magnet
PVC pipe
Figure 3.6: Schematic magnetic devices used in the experiments
Wood block Magnet
Plastic joint
PVC pipe
Figure 3.7: Cross section of magnetic devices used in the experiments
3.3.2
Media
In this study, the media used consists of a 10 cm layer of coarse stone with 15-20mm diameter, followed by a layer of sand with 5-10mm diameter and a layer of soil at the surface.
50 3.3.3
Plant
For the purpose of this leachate treatment, a species of wetland plant called Limnocharis flava (yellow burhead) has been chosen for various reasons. Firstly, it is one of the most common wetland plants available in this region as it is also one of the wetland plants in Putrajaya wetland (Lim et al, 1998). The description of the plant chosen for this study is shown in Table 3.1 and Figure 3.6.
Table 3.1: Description of the plant Item
Description
Scientific Name : Family : Local names : Origin: Brief Description:
Limnocharis flava Buch Limnocharitaceae (Butomaceae) Yellow bur head, yellow sawah lettuce, yellow velvetleaf. Tropical America Perennial, erect, robust marsh herb, rooting in mud and strongly tillering, 20-100 cm tall. Leaves basal, tufted, glabrous, broadly oval-oblong in outline, with long angular leafstalk, 30-75 cm long. Inflorescence stalk as long as the leaves, axillary, glabrous, with 515 flowers. Flowers fairly large, in the axils of membranous bract on 3-7 cm pedicel, pale yellow. Fruit compound, consisting of many follicles, 1.5-2 cm, with numerous seeds. Young inflorescence and flower buds consumed as a vegetable. Common in ditches and shallow rivers. It has the potential of taking over from targetted species, especially in shallow marsh. The fruit capsules split into many follicles and float the water, rendering it rather unsightly.
Potential Threat:
Figure 3.8: Limnochlaris flava (yellow burhead)
51 3.4
Analysis Procedure
All the tests were carried out in Environmental laboratory, Faculty of Civil Engineering. The tests include parameter such as turbidity, suspended solid, tests for nutrients such as nitrate and phosphate and test for heavy metal such as ferum and manganese. The entire tests are carried out using DR-4000 HACH spectrophotometer.
Table 3.2: Method Applied for Parameter Analysis Parameter Method Used Method Code TSS Turbidity Attenuated Radiation 10047 Ammonia nitrogen Nessler 8038 Nitrate nitrogen Cadmium Reduction 8039 Phosphate Molybdovonate 8114 Ferum Ferrover 8008 Manganese PAN 8149
Source *SA DR/4000 DR/4000 DR/4000 DR/4000 DR/4000 DR/4000
*Standard method
3.5
Analysis of heavy metals in plant tissues
The heavy metal uptake by plants was studied. After 18 days of experiment, the plant’s leaves and roots were harvested for each constructed wetland. First, the leaves and roots were washed with tap water and distilled water. After that, the plant samples were dried in an oven at 1050C and ground with mortar and pestle. 0.9 – 3.0 g of the ground plant sample was put inside the conical flask 250 ml and 50 ml of 2 M hydrochloric acid was added in for plant digestion. The sample mixture was centrifuged for 20 minutes and filtered with cellulose acetate membrane 0.45 μm. The filtrate was then analyzed for heavy metal (Fe and Mn).
CHAPTER 4
RESULTS AND DISCUSSION
4.1
Introduction
The results obtained from the experimental analysis of SSF constructed wetlands enhanced with magnetic field will be discussed in details in this chapter. Resultant, all data will be carried out in graphical approach to evaluate the specific analysis processes. Analysis of variance (ANOVA) has been used to reveal significant differences for all treatments. Statistical significance differences were tested at p≤0.05 (95% levels of significance). Thus, an extensive discussion had been concluded in the behavior obtained comparing significant differences between the three tanks (control, vegetated and vegetated with magnet treatment systems) and comparing significant differences between vertical and horizontal SSF systems.
The experimental studies were carried out for about two months from July until September. The effluent was tested for the removal of suspended solid (TSS), turbidity, nitrate (NO3-N), phosphorus (P), ammoniacal nitrogen (NH4-N), ferum (Fe) and manganese (Mn). The removal efficiency from tank A, indicated as control, B indicated as vegetated and C indicated as vegetated with magnet were compared to evaluate the trends for the overall performance.
53 The quality of the raw leachate after being 50% diluted and the effluent quality after the leachate was treated using the SSF constructed wetlands are summarized in Table 4.1.
Table 4.1: Comparison between initial and effluent quality of leachate Leachate concentration(mg/L)a After 18 days of treatment Tank A Tank B Tank C Parameters Initial Control Planted Planted with magnet VF HF VF HF VF HF TSS 73.6 41.30 39.50 38.50 38.00 10.01 7.33 Turbidity 120 42.00 46.00 28.00 21.00 10.00 8.00 26.5 9.00 8.90 8.00 4.80 8.00 3.20 NO3-N P 52.8 26.3 25.2 23.50 20.10 6.00 4.80 NH4-N 136 18.02 28.05 8.01 26.70 8.28 32.20 Fe 0.81 0.08 0.06 0.03 0.03 0.00 0.00 Mn 0.4 0.02 0.03 0.01 0.00 0.01 0.00 a
Except for turbidity = NTU V= Vertical system; H= Horizontal system.
4.2
Treatment Process Mechanisms
Pollutant maybe removed as a result of more than one type of mechanisms at work. The principal pollutant removal mechanisms operative in wetland systems are listed in Table 4.2. Furthermore in this chapter, the performance data of constructed wetland in the removal of all parameters will be discussed in detail.
4.3
Total Suspended Solid Removal
Total suspended solid (TSS) removal is best facilitated through the encouragement of settling in constructed wetlands. Figure 4.1 shows the overall performance of TSS removal for vertical and horizontal subsurface flow (SSF) constructed wetland systems.
54 Table 4.2: Summary of removal mechanisms in wetlands for the pollutants in wastewater (Stowell et al., 1981)
Filtration
Adsorption
BOD
N
P
Heavy metals
Refractory organics
Bacteris & virus
Physical sedimentation
Colloidal solids
Mechanism
Settleable solids
Pollutant affecteda
P
S
I
I
I
I
I
I
S
S
Interparticle attractive forces (van der Walls force).
S
Volatilization of NH3 from the wastewater
S
Chemical precipitation
P
P
Adsorption
P
P
Decomposition
P
P
Plant metabolism
Plant absorption
Natural die-off a b
Formation of or co-precipitation with insoluble compound.
S
S
S
On substrate and plant surfaces.
S
P
P
Gravitational settling of solids in wetland settings. Particulates filtered mechanically as water passes through substrate, and root masses.
Volatillization
Biological bacterial metabolismb
Description
P
Decomposition or alteration of less stable compounds by phenomena such as UV irradiation, oxidation and reduction.
P
Removal of colloidal solids and soluble organics by suspended, benthic and plant supported bacteria.
S
Uptake and metabolism of organics by plant. Root excretion maybe toxic to organisms of enteric origin.
S
Under proper condition, significant quantities of pollutants will be taken up by plant
S
P
Natural decay of organisms in an unfavorable environment
P= primary effects; S= secondary effect; I= incidental effect (effect occurring incidental to removal of another pollutant). The term metabolism includes both biosynthesis and catabolic reactions.
55 On comparing the performance of the two types of wetland systems, greater level of TSS removal was observed in control, vegetated and vegetated with magnet for the horizontal SSF. For vertical system, the TSS removal efficiency is 44% for control, 48% for vegetated and 86% for vegetated with magnet treatment. While for horizontal system, the SS removal efficiency is 46% for control, 48% for vegetated and 90% for vegetated with magnet treatment, respectively
100 90.04 86.40
90 80
TSS removal (%)
70 60 50
43.89
46.33
47.69
48.37
Vertical SSF Horizontal SSF
40 30 20 10 0 Control
Vegetated
Vegetated with magnet
Types of treatment systems
Figure 4.1: Suspended solids removal for vertical and horizontal SSF system
From the results, control and vegetated treatment for both systems were observed lower removal efficiency as compared to vegetated with magnet treatment. This indicated TSS removal due entirely to sedimentation and filtration rather than biological process associated with the plants or microbial community (Gersberg et al., 1986) since the removal efficiencies for the vegetated tanks were not significantly different from the control tank. Most of the suspended solids are filtered out and settled beyond the substrate of constructed wetlands. The accumulation of trapped solids is a major threat for good performance of horizontal systems as the solids may clog at the bed (Vymazal, 2005a). Therefore, the effective pretreatment is necessary for horizontal SSF systems.
56
1.2
Concentration (C/Co)
1.0
0.8 Control
0.6
Vegetated Vegetated with magnet
0.4
0.2
0.0 0
2
4
6
8
10
12
14
16
18
20
Time (Days)
(a) Vertical SSF
1.2
Concentration (C/Co)
1.0
0.8 Control
0.6
Vegetated
0.4
Vegetated with magnet
0.2
0.0 0
2
4
6
8
10
12
14
16
18
20
Time (Days)
(b) Horizontal SSF
Figure 4.2: Comparison of TSS concentration (C/Co) for; (a) Vertical and; (b) Horizontal SSF system with and without magnetic field
Figure 4.2 depicted the concentration of TSS for all treatment systems. The figures shows obviously decreased in TSS for vegetated with magnet treatment. A charged ion in colloidal particles was neutralized through sedimentation and flocculation and when exposed to magnetic field, the efficiency of coagulation and
57 flocculation suspended solids were increased in vegetated with magnet treatment system which obtained the highest SS removal. This trend of using magnetic treatment was similar to what were observed by Vermeiran (1958); Klassen (1981); Johan (2003).
4.4
Turbidity Removal
Figure 4.3 shows the overall performance of turbidity removal for vertical and horizontal subsurface flow (SSF) constructed wetland systems.
100
89.17
Turbidity removal (%)
90
86.67
80
70 64.17 60.00
65.00
Vertical SSF
61.67
Horizontal SSF
60
50
40 Control
Vegetated
Vegetated with magnet
Types of treatment systems
Figure 4.3: Turbidity removal for vertical and horizontal SSF system
As TSS, similar trend was observed in turbidity removal. On comparing the performance of the two types of wetland systems, greater level of turbidity removal was observed in horizontal SSF for control, vegetated and vegetated with magnet treatment. For vertical system, the turbidity removal efficiency is 60% for control, 64% for vegetated and 87% for vegetated with magnet treatment. While for
58 horizontal system, the turbidity removal efficiency is 62% for control, 65% for vegetated and 90% for vegetated with magnet treatment, respectively.
0.9 0.8
Concentration (C/Co)
0.7 0.6 Control
0.5
Vegetated
0.4 Vegetated with magnet
0.3 0.2 0.1 0 0
2
4
6
8
10
12
14
16
18
20
Time (Days)
(a) Vertical SSF
0.8 0.7
Concentration (C/Co)
0.6 0.5 Control
0.4
Vegetated
0.3
Vegetated with magnet
0.2 0.1 0 0
2
4
6
8
10
12
14
16
18
20
Time (Days)
(b) Horizontal SSF
Figure 4.4: Comparison of turbidity concentration (C/Co) for; (a) Vertical and; (b) Horizontal SSF system with and without magnetic field
59 Reduction of turbidity as depicted in Figure 4.4 due to sedimentation and filtration as well as removal of TSS. Typically, a biological process associated with the plants was not contributed to turbidity removal since the percentage between control and vegetated treatment was not significantly different. The effect of magnetic field to colloidal particles as mention primarily was contributed to decreasing of turbidity concentration than other treatments. Thus, magnetic field provided better reduction in TSS and turbidity monitored.
4.5
Nutrients Removal
Three types of nutrients were studied which were ammoniacal nitrogen (NH4-N), nitrate (NO3-N) and phosphorus (P).
4.5.1
Ammoniacal Nitrogen Figure 4.5 shows the overall performance of NH4-N removal and Figure 4.6
shows the concentration for vertical and horizontal subsurface flow (SSF) constructed wetlands. In this study, the high NH4-N content was mainly due to the fact that after NH4-N was formed by ammonification, it was unsuccessfully degraded under anaerobic landfill conditions (Christensen et al., 1997). On comparing the performance of the two types of wetland systems, greater level of NH4-N removal was observed in control, vegetated and vegetated with magnet for the vertical SSF.
Horizontal flow cannot provide nitrification because of their limited oxygen transfer capacity (Vymazal, 2005a). Tanner (1994) pointed out that in terms of land area, the vertical flow wetlands received 2.5 times greater area oxygen dissolved (DO) within the influent wastewater than the horizontal flow. Apart of that, the main sources of oxygen in SSF wetlands are diffusion from the atmosphere through the water surface and via plant shoots into the root zone.
60
100
94.11
NH4-N removal (%)
95
93.91
90 86.75 Vertical SSF
85
Horizontal SSF 80.37
80
79.38 76.32
75
70
Control
Vegetated
Vegetated with magnet
Types of treatment systems
Figure 4.5: Ammoniacal nitrogen removal for vertical and horizontal SSF system The major removal mechanism of NH4-N is nitrification/denitrification (Galbrand, 2003; Vymazal, 2005b). Field measurements have shown that the oxygenation of the rhizosphere of horizontal flow constructed wetlands is insufficient and, therefore, incomplete nitrification is then major cause of limited NH4-N removal (Vymazal, 2005a). Zhu et al., (1994) pointed out that no obvious nitrification could be observed when DO concentration is lower than 0.5 mg/L.
In general, nitrification which is performed by strictly aerobic bacteria, which is called Nitrosomonas bacteria is mostly restricted to areas adjacent to roots and rhizomes where oxygen leaks to the filtration media. The NH4-N will be oxidized by Nitrosomonas to nitrite (NO2-) which is then oxidized to nitrate (NO3-) by Nitrobacter bacteria (Galbrand, 2003). Reduction of NH4-N concentrations as depicted in Figure 4.6 indicated that microorganisms in the humic had transformed the NH4-N to nitrate through nitrification. Nitrate, which is extremely mobile, is usually quickly assimilated by plants or microorganisms, reduced by anaerobic bacteria to nitrogen gas via denitrification or reduced back by ammonium by both aerobic and anaerobic bacteria (Mitsch and Gosselink, 2000).
61
1.0 0.9
Concentration (C/Co)
0.8 0.7 0.6
Control
0.5
Vegetated
0.4
Vegetated with magnet
0.3 0.2 0.1 0.0 0
2
4
6
8
10
12
14
16
18
20
Time (Days)
(a) Vertical SSF
1.0 0.9
Concentration (C/Co)
0.8 0.7 0.6 Control
0.5 Vegetated
0.4 Vegetated with magnet
0.3 0.2 0.1 0.0 0
2
4
6
8
10
12
14
16
18
20
Time (Days)
(b) Horizontal SSF
Figure 4.6: Comparison of NH4-N concentration (C/Co) for; (a) Vertical and; (b) Horizontal SSF system with and without magnetic field The highest NH4-N removal was observed in vegetated vertical SSF system which was 94.11%. Compared to control vertical SSF, the removal was 86.75%, thus indicated that the presence of vegetations (Limnocharis flava) had improved the treatment efficiencies of NH4-N. Vegetation plays a significant role by assimilating
62 NH4-N into plant tissue and providing an environment for nitrification-denitrification in the root zone known as rhizosphere (Brix, 1994; Hammer, 1993; Maehlum, 1999). However, magnetic field does not significantly contribute in NH4-N removal in the wetland since the removal efficiency was similar to vegetated vertical SSF.
4.5.2
Nitrate Figure 4.7 shows the overall performance of NO3-N removal while Figure 4.8
shows the NO3-N concentration for each treatment systems vertical and horizontal subsurface flow (SSF) constructed wetland systems. On comparing the performance of the two types of wetland systems, greater level of NO3-N removal was observed in control, vegetated and vegetated with magnet for the horizontal SSF. All of the tanks in vertical SSF system had the capability in NO3-N reductions, but in low removal efficiencies, ranging from 66% to 70%. Contrary findings for NH4-N, thus indicated that horizontal SSF provide good denitrification by anaerobic bacteria to nitrogen gas (N2). In vertical SSF, the NO3-N removal efficiency for vegetated and vegetated with magnet treatment systems was similar which was 70%. This indicated that the presence of magnetic field does not significantly contribute in NO3-N removal in the wetland. However, the presence of vegetations (Limnocharis flava) had improved the treatment efficiencies of NO3-N as shown by the greater removal efficiency of vegetated compared to control in horizontal SSF system. This finding affirmed the importance of wetland vegetations to provide an environment for nitrificationdenitrification in the root zone (Maehlum, 1999).
63
90
87.92
85
NO3 -N removal (%)
81.89 80
Vertical SSF
75
Horizontal SSF 69.81
70
69.81
66.42
66.04 65
60 Control
Vegetated
Vegetated with magnet
Types of treatment systems
Figure 4.7: Nitrate removal for vertical and horizontal SSF system
0.9 0.8
Concentration (C/Co)
0.7 0.6 0.5 Control
0.4
Vegetated Vegetated with magnet
0.3 0.2 0.1 0 0
2
4
6
8
10 Time (Days)
(a) Vertical SSF
12
14
16
18
20
64 0.9 0.8
Concentration (C/Co)
0.7 0.6 0.5 Control
0.4
Vegetated Vegetated with magnet
0.3 0.2 0.1 0 0
2
4
6
8
10
12
14
16
18
20
Time (Days)
(b) Horizontal SSF
Figure 4.8: Comparison of NO3-N concentration (C/Co) for; (a) vertical and; (b) horizontal SSF system with and without magnetic field
4.5.3
Phosphorus
Figure 4.9 shows the overall performance of P removal for vertical and horizontal subsurface flow (SSF) constructed wetland systems. On comparing the performance of the two types of wetland systems, greater level of P removal was observed in horizontal SSF system for control, vegetated and vegetated with magnet treatment. Generally, it shows that the percentage different for vertical and horizontal SSF systems was not varied significantly. All of the treatment systems had the capability in P reductions, but in lowers removal efficiencies for control and vegetated, ranging from 50% to 62% as compared to vegetated with magnet treatment which resulted highest removal percentage for both systems ranging from 89% to 91%.
65
100 90.91 88.64
90
P removal (%)
80
Vertical SSF
70
Horizontal SSF 61.93
60 55.49 52.27 50.19 50
40 Control
Vegetated
Vegetated with magnet
Types of treatment systems
Figure 4.9: Phosphorus removal for vertical and horizontal SSF system
Although phosphorus is required by plants microorganisms for growth, there is no biological transformation to gas, as there is with nitrogen, and phosphorus will consequently accumulate in wetland systems (Rosolen, 2000). Phosphorus removal in SSF wetland can take place through precipitation and adsorption onto media surface. Furthermore, phosphorus absorbed onto suspended sediments will be filtered out as the suspended solids are removed. Phosphorus has a very low solubility, and is readily moved from solution by several precipitation and adsorption reactions by binding it in an insoluble form (Rosolen, 2000).
Removal of P was higher in horizontal SSF rather than vertical. It is well known that phosphorus can be released under conditions of low dissolved oxygen (Holford and Patrick, 1979; Reddy and D’Angelo, 1997; Nurnberg et al., 1987). This was explained by the lower receivable of dissolved oxygen (DO) in horizontal SSF. DO may be an important factor in phosphorus removal, owing to the typically anaerobic environment and lack of mechanisms for substantial reaeration (Rosolen, 2000). Wetland plants have adapted to low DO conditions by secreting oxygen from their roots, thus forming an aerobic area around the root. This may be important for phosphorus retention, as suggested by Drizo et al., (1997).
66 Kim and Geary (2000) supported that soil substrates are the ultimate sinks for phosphorus. From the result, the variation between control and vegetated P removal shows the wetlands possibility to accumulate P in humic substances, revealed that filtration was a significant P removal mechanism in the treatment. Since P is retained within the wetlands, harvesting the plants and removing the saturated root bed media achieve its ultimate removal from the system, which is not suitable because of the short period for this study.
In spite of that, the low P removal in control and vegetated treatment if compared to vegetated with magnet is due to media used as a substrate in this study (coarse stone, sand and soil) generally have limited surface area for adsorption (Davies and Cottingham, 1993). Deserved to increased surface area, longer retention and better contact time, a finer grained soil has a greater capacity to adsorb phosphorus (Reed et al., 1995; Vymazal, 2005a). However, a finer grained soil not used for SSF system, at present, because of poor hydraulic conductivity.
Greater P removal in vegetated and magnet treatment for both systems were observed. Thus, it appears that the removal of P was primarily caused by the coagulation process. Petruska and Perumpral (1978) explained the system for removing phosphate using magnetically conditioned coagulation is viable. After leachate was exposed to magnetic field, the fluid undergoes coagulation to precipitate P from the fluid to form colloids. It has been found that magnetic field of the fluid allows P to become more readily available for coagulation, allowing the coagulant to become more efficient. The result is that much smaller quantities of coagulant are required. After coagulation, the precipitated P (Reddy et al., 1999) passing through wetlands to undergo filtration.
Ferum and manganese are metals identified as the contaminants of concerns in this study. Zhu et al., (1997) declared that a metal such as Fe and Mn correlates to the ability of a particle to remove phosphorus. Adsorption is dependent on composition of the material, which is oxides of these metals, while the availability of these minerals in the soluble form will direct precipitation reactions.
67 Figure 4.10 shows the P concentration for all treatment systems. The figures depicted substantial different P concentrations in vegetated with magnet treatment rather than others.
1.0 0.9
Concentration (C/Co)
0.8 0.7 0.6
Control
0.5
Vegetated
0.4
Vegetated with magnet
0.3 0.2 0.1 0.0 0
2
4
6
8
10
12
14
16
18
20
Time (Days)
(a) Vertical SSF
1.0 0.9
Concentration (C/Co)
0.8 0.7 0.6
Control
0.5
Vegetated
0.4
Vegetated with magnet
0.3 0.2 0.1 0.0 0
2
4
6
8
10
12
14
16
18
20
Time (Days) (b) Horizontal SSF
Figure 4.10: Comparison of P concentration (C/Co) for; (a) vertical and; (b) horizontal SSF system with and without magnetic field
68 The theoretical aspects and principles of the effectiveness of vertical or horizontal SSF systems in removing P were inconsistent among researchers. With same installation of wetlands systems but differ in vegetation species, Breen (1990) contended that vertical flow format maximized influent-root zone contact and optimized conditions for nutrient absorption by plants. Contrary to the conclusion reached by Breen, Rogers et al. (1991) findings that there was no significant difference in P removal between vertical and horizontal flow format. Comparative study conducted by Tanner (1994) also contrary to conclusion drawn by Breen (1990). The results demonstrated that reduction of P were greater in horizontal flow rather than vertical flow wetlands. Tanner et al., (1997) suggested that vertical flow format itself would not likely increase treatment efficiency per unit of wetland volume but rather the surface to depth ratio would determine the relative importance of plant mediated nutrient uptake and oxygen release.
4.6 Metals Removal
In most circumstances, metals such as Fe and Mn entering wetland systems oxidized and either bind to sediments, particulates or soluble organics, or precipitate as insoluble salts such as sulphides and oxyhydroxides (Galbrand, 2003). Metals in their reduced, soluble forms can also be taken up or transformed by plants and microorganisms (Kadlec and Knight, 1996; Osmond et al., 1995).
4.6.1
Ferum
Figure 4.11 shows the overall performance of Fe removal for vertical and horizontal SSF constructed wetland systems. The performance of the two types of wetland systems was similar in vegetated and vegetated with magnet treatment systems. However, greater level of Fe removal was observed in control for the horizontal SSF which was 93% compared to vertical SSF which was 90%. Generally, it shows that the percentage different for vertical and horizontal SSF systems was not
69 varied significantly. Fe was completely removed in vegetated with magnet treatment while in vegetated treatment recorded 96% removal.
101
100.00
100.00
Fe removal (%)
99 96.30 96.30
97
Vertical SSF
95
Horizontal SSF 92.59
93 91
90.12
89 Control
Vegetated
Vegetated with magnet
Types of treatment systems
Figure 4.11: Ferum removal for vertical and horizontal SSF system. The Fe concentrations observed in the treatment wetland generally decreased as shown in Figure 4.12. Fe is an essential micronutrient element required by both plants and wildlife at significant concentrations (King et al., 1992). The results of vegetated treatment system described that the Limnocharis flava as an emergent plants play a crucial part in the treatment systems. Emergent plants help in reducing heavy metals by retaining it either in the root or in the leaves. Capacity in accumulating and removing heavy metals are varied according to plant species. Uptake and accumulation of elements by plants may follow two different paths which were in the root system and foliar surface (Sawidis et al., 2001). Nevertheless, the result also indicated that the capability of magnetic field in both systems assist Fe removal. The complete removal of Fe indicated the reduction of ion in the leachate due to the aggregation effect by the magnetic fields (Wan Salida, 2005).
70
0.8 0.7
Concentration (C/Co)
0.6 0.5 Control
0.4
Vegetated
0.3
Vegetated with magnet
0.2 0.1 0 0
2
4
6
8
10
12
14
16
18
20
Time (Days)
(a) Vertical SSF
0.8 0.7
Concentration (C/Co)
0.6 0.5 Control
0.4
Vegetated
0.3
Vegetated with magnet
0.2 0.1 0 0
2
4
6
8
10
12
14
16
18
20
Time (Days)
(b) Horizontal SSF
Figure 4.12: Comparison of Fe concentration (C/Co) for; (a) vertical and; (b) horizontal SSF system with and without magnetic field
71 4.6.2
Manganese
Figure 4.13 shows the overall performance of Mn removal and Figure 4.14 shows the concentration for vertical and horizontal subsurface flow (SSF) constructed wetland systems. On comparing the performance of the two types of wetland systems, greater level of Mn removal was observed in vertical SSF for all types of treatment systems. Highest removal was observed in vegetated with magnet treatment which was 93% (vertical SSF) and 88% (horizontal SSF), followed by vegetated treatment which was 88% (vertical SSF) and 83% (horizontal SSF). The lowest removal was observed in control which was 78% (vertical SSF) and 75% (horizontal SSF).
95
92.50
Mn removal (%)
90
87.50
85
87.50
82.50
Vertical SSF Horizontal SSF
80
77.50 75.00
75
70 Control
Vegetated
Vegetated with magnet
Types of treatment systems
Figure 4.13: Manganese removal for vertical and horizontal SSF system
As reported primarily for Fe, Mn removal result also described the capability of Limnocharis flava in the treatment systems. Mn oxidation required oxygen attributed to the higher removal in vertical SSF since it retained higher dissolved oxygen than horizontal SSF. Mn removal in vegetated were significantly high than control tank revealed that the most effective removal mechanism for Mn in treatment wetland systems is settling. The result also indicated that the capability of magnetic field in both systems assist Mn removal.
72
1.0 0.9
Concentration (C/Co)
0.8 0.7 0.6
Control
0.5
Vegetated
0.4
Vegetated with magnet
0.3 0.2 0.1 0.0 0
2
4
6
8
10
12
14
16
18
20
Time (Days)
(a) Vertical SSF
1.0 0.9
Concentration (C/Co)
0.8 0.7 0.6
Control
0.5
Vegetated
0.4
Vegetated with magnet
0.3 0.2 0.1 0.0 0
2
4
6
8
10
12
14
16
18
20
Time (Days)
(b) Horizontal SSF
Figure 4.14: Comparison of Mn concentration (C/Co) for; (a) Vertical and; (b) Horizontal SSF system with and without magnetic field
73 4.7
ANOVA Analysis
Analysis of variance (ANOVA) has been used to reveal significant differences for all types of treatment systems. Statistical significance differences were tested at p≤0.05 (95% levels of significance). Table 4.3 shows the p value when comparing significant differences between control, vegetated and vegetated with magnet treatment systems for vertical SSF while Table 4.4 shows the p value when comparing significant differences between control, vegetated and vegetated with magnet treatment systems for horizontal SSF. Table 4.5 shows the p value between vertical and horizontal SSF systems for the three treatment systems.
Table 4.3: Significant differences between control, vegetated and vegetated with magnet treatment systems for vertical SSF ANOVA Two Factor Without Replication 95% levels of significance p value Parameters Significant p ≤ 0.05 TSS 1.354E-08 Turbidity 1.558E-06 NH4-N 4.234E-06 NO3-N 2.018E-11 P 8.929E-12 Fe 5.798E-10 Mn 2.076E-09
Table 4.4: Significant differences between control, vegetated and vegetated with magnet treatment systems for horizontal SSF ANOVA Two Factor Without Replication 95% levels of significance p value Parameters Significant p ≤ 0.05 TSS 1.354E-08 Turbidity 6.544E-08 NH4-N 1.227E-06 5.525E-08 NO3-N P 2.299E-10 Fe 1.678E-13 Mn 4.532E-07
74 Table 4.5: ANOVA Analysis Comparing Vertical and Horizontal SSF for Control, Vegetated and Vegetated with Magnet Treatment Systems
Parameters
ANOVA Two Factor Without Replication 95% levels of significance p value Control Vegetated Vegetated with Magnet Not Not Not Significant Significant Significant significant significant significant p ≤ 0.05 p ≤ 0.05 p ≤ 0.05 p ≥ 0.05 p ≥ 0.05 p ≥ 0.05 TSS 0.0313 0.0046 0.1768 Turbidity 0.0493 0.3524 0.5931 NH4-N 0.6174 0.2611 0.3173 NO3-N 0.1193 0.3744 0.5918 P 0.0736 0.1160 0.8672 Fe 0.0448 0.2396 0.0395 Mn 0.0076 0.0039
4.8
Uptake by Plant
Wetland plants have been successfully used to phytoremediate trace elements in natural and constructed wetlands (Ying, 2003). In the study, physical uptake of Fe and Mn by plant roots and their subsequent accumulation in leaves was investigated for both vertical and horizontal SSF treatment systems. Figure 4.15 showed the heavy metal uptake by plant’s roots and leaves for Fe while Figure 4.16 showed the uptake for Mn, respectively.
From both systems, the uptake of Fe by plants increased with increasing metal concentration. As a general rule, uptake of metals by plants will only occur if they are bioavailable, which means absorbable by roots. Iron and manganese are metals which tend to moderately bioavailable in wetlands environment (Galbrand, 2003). This study proofs that Limnocharis flava had availability in heavy metal uptake by root and leaves.
75
2000 1785
1800
1716
Fe.conc (ug/g dry weight)
1600 1344
1400 1200 1000
Leaves
800
Root
600 400
313
296
316
200 0 Initial plants
Vegetated
Vegetated with magnet
(a) vertical SSF
2000 1800
Fe conc.(ug/g dry weight)
1600
1406
1403
1344
1400 1200 1000
Leaves
800
Root
600 400
296
310
311
200 0 Initial plants
Vegetated
Vegetated with magnet
(b) horizontal SSF
Figure 4.15: Fe uptake by root and leaves for (a) vertical and; (b) horizontal SSF system. As compared to Fe, uptake of Mn resulted in the similar trend. Accumulation of metals relatively higher in vertical SSF system because vertical flow format retained higher dissolved oxygen than horizontal SSF for Mn oxidation. Heavy metals were accumulated more in roots compared to leaves as mention by Peverly et al., (1995).
76
4.0
3.5
Mn conc.(ug/g dry weight)
3.0
2.5
2.28
2.18 2.0
1.83 Leaves
1.5
1.48
1.47
1.42
Root
1.0
0.5
0.0 Initial plants
Vegetated
Vegetated with magnet
(a) vertical SSF
4.0 3.37
3.5
Mn conc.(ug/g dry weight)
3.0 2.5
2.0
1.5
1.89
1.83 1.42
1.46
1.47
Leaves Root
1.0 0.5
0.0 Initial plants
Vegetated
Vegetated with magnet
(b) horizontal SSF
Figure 4.16: Mn uptake by root and leaves for (a) vertical and; (b) horizontal SSF system
However, it was observed that Limnhocharis flava accumulate more Fe compared to Mn. Study done by Skousen et al. (1994) and Stark et al. (1994) on constructed wetland revealed less successful in removing manganese. This is mostly due to the fact that oxidized manganese does not readily form precipitate unless the
77 pH of waters is at least 7.0 (Galbrand, 2003). In addition, Mn oxidation is sensitive to the presence of Fe2+, which can prevent or even reverse Mn oxidation (Skousen et al., 1994).
Table 4.6: Accumulation of Fe in leaves and roots Accumulation of ferum (%) Vertical SSF Horizontal SSF Leaves Root Leaves Root Vegetated 5.6 27.7 4.6 4.4 Vegetated with magnet 6.7 32.8 5.1 4.6
Table 4.7: Accumulation of Mn in leaves and roots Accumulation of manganese (%) Vertical SSF Horizontal SSF Leaves Root Leaves Root Vegetated 4.0 19.1 2.9 3.1 Vegetated with magnet 4.8 24.6 4.2 4.2
Table 4.6 and Table 4.7 shows the percentage of Fe and Mn accumulated in leaves and roots for both systems. The percentage of accumulation for Fe and Mn in leaves and roots for both systems were relatively low and not exceeded 50% of initial values. Hence, Fe and Mn removal via uptake by Limnocharis flava leaves and roots is typically ineffective and predominant metals removal mechanism to the precipitation-adsorption phenomena in the substrate.
4.9
Physical Appearance of Plants
Both systems were vegetated with equal distributed of plants clusters and leaves. The experiments were carried out with 6 clusters of Limnocharis flava and a 23 pieces of leaves for each vegetated tank. Table 4.8, Figure 4.17, Figure 4.18 and Figure 4.19 showed the physical appearance of plants in vertical SSF constructed wetlands while Table 4.9, Figure 4.20, Figure 4.21 and Figure 4.22 showed the
78 physical appearance of plants in horizontal SSF constructed wetlands for 18 days of experiment.
Table 4.8: Amount or partial and complete wilting of plant’s leaves in vegetated and vegetated with magnet treatment in vertical SSF constructed wetlands Duration of experiment (Days)
6
Treatment systems Vegetated Vegetated with magnet Complete wilting – none Complete wilting – none Partial wilting – none Partial wilting – none
12
Complete wilting – 1 Partial wilting – 2
Complete wilting – 2 Partial wilting – 1
18
Complete wilting – 4 Partial wilting – 3
Complete wilting – 4 Partial wilting – 4
Table 4.9: Amount or partial and complete wilting of plant’s leaves in vegetated and vegetated with magnet treatment in horizontal SSF constructed wetlands. Duration of experiment (Days)
6
Treatment systems Vegetated Vegetated with magnet Complete wilting – none Complete wilting – none Partial wilting – none Partial wilting – none
12
Complete wilting –3 Partial wilting – 3
Complete wilting – 3 Partial wilting – 1
18
Complete wilting –1 Partial wilting – 2
Complete wilting – 4 Partial wilting – 1
(a)
(b)
Figure 4.17: Physical appearance of plants in (a) vegetated and; (b) vegetated with magnet after 6 days of treatment in vertical SSF
79
(a)
(b)
Figure 4.18: Physical appearance of plants in (a) vegetated and; (b) vegetated with magnet after 12 days of treatment in vertical SSF
(a)
(b)
Figure 4.19: Physical appearance of plants in (a) vegetated and; (b) vegetated with magnet after 18 days of treatment in vertical SSF
(a)
(b)
Figure 4.20: Physical appearance of plants in (a) vegetated and; (b) vegetated with magnet after 6 days of treatment in horizontal SSF
80
(a)
(b)
Figure 4.21: Physical appearance of plants in (a) vegetated and; (b) vegetated with magnet after 12 days of treatment in horizontal SSF
(a)
(b)
Figure 4.22: Physical appearance of plants in (a) vegetated and; (b) vegetated with magnet after 18 days of treatment in horizontal SSF
After proceeding with the treatment process, one of the most important aspects to be considered is that, the plants were allowed to climatised with the environment. Though there were fully and partial leaves wilting but at the same time there were some new plant was seen growing. This is because the plant need some time to adapt to the environment and stabilize (Ernest and Andrew, 2002). In spite of that, Rosolen (2000) explained the nutrients are released when the plants die, and the phosphorus cycles back into the system and becomes available for new growth. After about 18 days of experiments the plants were fully adapted to the new environment and leaves were seen growing fertile. Galbrand (2003) elaborated Fe and Mn was micronutrient to plant. Plant will grow fertile until heavy metal exceeded toxic amounts that can be toxic to plant and resulted in inhibited grow by plants.
81 4.10
Conclusion
From the results and analysis, the constructed wetland vegetated with Limnocharis flava have shown their ability to remove suspended solid (TSS), turbidity, nitrate (NO3-N), phosphorus (P), ammoniacal nitrogen (NH4-N), ferum (Fe) and manganese (Mn) from leachate. The leachate concentration used in this experiment was 50%. Study done by Hui (2005) had revealed that 50% leachate concentration will give the highest removal efficiency in removing NO3-N and Mn.
The vegetated with magnetic field treatment also have their capability in treating leachate. TSS, turbidity, NO3-N, P and heavy metals removal have shown that magnetic field posed a great role in their removal. For magnet system, 6 set of permanent magnet was used with strength 0.55 Tesla. The circulation was 1.8 mL/s for duration of 6 hours. Johan (2003) had revealed that the flowrate 1.8 mL/s will give the optimum precipitation of TSS in wastewater. Zulfa et al., (2005) revealed that 6 hours of exposure to the magnetic field was the optimum time to precipitate the TSS in leachate.
The treatability of vertical and horizontal SSF flow regime also shows pros and cons between each others. Horizontal SSF systems cannot provide good nitrification because of their limited oxygen transfer capacity. Vertical SSF systems, on the other hand, do provide a good condition for nitrification but no denitrification occurs in this systems. An overall, horizontal SSF system shows greater removal in all parameters except ammoniacal nitrogen and manganese.
CHAPTER 5
CONCLUSIONS
5.1
Conclusions
The capability of emergent plant Limnocharis flava in the removal of all parameters did show a performance compared to unplanted control. Presence of the vegetation did show there was a substantial removal shown for nutrients (NH4N>80%, NO3-N>70% and P>55%) and heavy metals (Fe>96 and Mn>83%). The macrophyte plays an important role in constructed wetlands by providing microbial attachments, trapping and settlement of suspended components. The capability of emergent plant has lower removal efficiency in TSS (87% for turbidity, >89% for P, complete removal for Fe and for Mn, removal was >88%. Electrically contribute to a greater ionic charge or extra energy when exposed to magnetic field. This energy will make the charged particles to vibrate excessively. Thus more particles are colliding among themselves (Johan et al., 2004). This reaction contributes to additional number of ions (positive and
83 negative charge), which consequently creates a natural magnetic attraction between the opposite charged particles. Particles are then attracted and agglomerated. This phenomenon intensifies coagulation that enables them to flocculate and precipitate when become heavier. As a result particles passing through wetlands were enhanced the removal of mentioned parameters by filtration, sedimentation, adsorption and precipitation.
The effect of different flow format used in this study had shown that vertical flow format do provide a good condition for nitrification but no denitrification. On the other hand, horizontal flow format cannot provide nitrification because of their limited oxygen transfer capacity. The treatability of vertical SSF had showed greater removal in ammoniacal nitrogen (>87%) and Mn (>78%) while horizontal flow had showed greater removal of nitrate (>66%) and phosphorus (52%). Others parameters did not contribute to substantial differences between vertical and horizontal SSF constructed wetlands.
As far as removal mechanisms are concerned, it is generally agreed by this study that uptake of metals by Limnocharis flava is insignificant compared to the other removal pathways. The metals uptake by plant’s leaves and root were relatively low when the percentage accumulation of metals not exceeded 50% when compared to initial value. This situation can be concluded that removal via uptake by Limnocharis flava leaves and roots is typically ineffective and predominant metals removal mechanism to the precipitation-adsorption phenomena in the substrate.
5.2
Recommendations
Magnetic fields had shown great potential in enhancing removal of some parameters. However, there were pro and contras of applying vertical and horizontal SSF system into wetlands. In order for further enhanced the findings of this study, some recommendations are as follows:
84 (i)
Various types of constructed wetlands may be combined in order to achieve higher treatment effect, especially for nitrogen;
(ii)
Arranging vertical SSF and horizontal SSF in a stage manner in order to improved the treatment efficiency;
(iii)
The use of plant types other than Limnocharis flava such as reeds and bulrushes should be investigated to determine if optimum species exists;
(iv)
Longer period of the test is necessary to determine the fullest capacity of the SSF constructed wetlands in pollutant removal.
(v)
To study the effect of pH in the removal of heavy metals in wetlands.
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APPENDIX
99
APPENDIX A Raw Data
Table A1: Initial condition of leachate Parameters
mg/L*
TSS
73.6
Turbidity
120
-
NH4 N
136
NO3-N
26.5
P
52.8
Fe
0.81
Mn
0.4
* Except for turbidity (FTU)
Table A2: Removal of TSS for vertical and horizontal SSF systems Time (Days)
Sample
Effluent (Vertical) mg/L
Removal
Removal efficiency (Vertical)
Effluent (Horizontal) mg/L
Removal
Removal efficiency (Horizontal)
3
C1 P1 M1 C2 P2 M2 C3 P3 M3 C4 P4 M4 C5 P5 M5 C6 P6 M6
70.67 66.50 50.50 66.90 62.90 41.20 62.80 56.30 25.90 59.60 50.20 20.20 49.30 46.80 12.35 41.30 38.50 10.01
2.93 7.10 23.10 6.70 10.70 32.40 10.80 17.30 47.70 14.00 23.40 53.40 24.30 26.80 61.25 32.30 35.10 63.59
3.98 9.65 31.39 9.10 14.54 44.02 14.67 23.51 64.81 19.02 31.79 72.55 33.02 36.41 83.22 43.89 47.69 86.40
69.30 62.80 52.00 66.30 59.60 39.67 60.30 52.60 20.10 52.30 45.80 18.37 44.00 40.70 12.83 39.50 38.00 7.33
4.30 10.80 21.60 7.30 14.00 33.93 13.30 21.00 53.50 21.30 27.80 55.23 29.60 32.90 60.77 34.10 35.60 66.27
5.84 14.67 29.35 9.92 19.02 46.10 18.07 28.53 72.69 28.94 37.77 75.04 40.22 44.70 82.57 46.33 48.37 90.04
6
9
12
15
18
100
APPENDIX A Raw Data
Table A3: Removal of Turbidity for vertical and horizontal SSF systems Time (Days)
Sample
Effluent (Vertical) mg/L
Removal
Removal efficiency (Vertical)
Effluent (Horizontal) mg/L
Removal
Removal efficiency (Horizontal)
3
C1 P1 M1 C2 P2 M2 C3 P3 M3 C4 P4 M4 C5 P5 M5 C6 P6 M6
74.00 66.00 97.00 70.00 63.00 64.00 68.00 56.00 49.00 63.00 46.00 35.00 55.00 44.00 22.00 48.00 43.00 16.00
46.00 54.00 23.00 50.00 57.00 56.00 52.00 64.00 71.00 57.00 74.00 85.00 65.00 76.00 98.00 72.00 77.00 104.00
38.33 45.00 19.17 41.67 47.50 46.67 43.33 53.33 59.17 47.50 61.67 70.83 54.17 63.33 81.67 60.00 64.17 86.67
75.00 62.00 90.00 67.00 57.00 63.00 59.00 51.00 53.00 55.00 49.00 46.00 52.00 47.00 27.00 46.00 42.00 13.00
45.00 58.00 30.00 53.00 63.00 57.00 61.00 69.00 67.00 65.00 71.00 74.00 68.00 73.00 93.00 74.00 78.00 107.00
37.50 48.33 25.00 44.17 52.50 47.50 50.83 57.50 55.83 54.17 59.17 61.67 56.67 60.83 77.50 61.67 65.00 89.17
6
9
12
15
18
Table A4: Removal of NH4-N for vertical and horizontal SSF systems Time (Days)
Sample
Effluent (Vertical) mg/L
Removal
Removal efficiency (Vertical)
Effluent (Horizontal) mg/L
Removal
Removal efficiency (Horizontal)
3
C1 P1 M1 C2 P2 M2 C3 P3 M3 C4 P4 M4 C5 P5 M5 C6 P6 M6
124.50 91.40 99.75 84.60 89.60 90.60 73.80 55.20 68.20 28.26 13.11 21.40 27.70 11.50 15.67 18.02 8.01 8.28
11.50 44.60 36.25 51.40 46.40 45.40 62.20 80.80 67.80 107.74 122.89 114.60 108.30 124.50 120.33 117.98 127.99 127.72
8.46 32.79 26.65 37.79 34.12 33.38 45.74 59.41 49.85 79.22 90.36 84.26 79.63 91.54 88.48 86.75 94.11 93.91
122.60 123.40 109.30 73.80 71.20 69.80 65.40 45.95 59.30 44.15 33.95 47.60 37.15 28.05 39.30 28.05 26.70 32.20
13.40 12.60 26.70 62.20 64.80 66.20 70.60 90.05 76.70 91.85 102.05 88.40 98.85 107.95 96.70 107.95 109.30 103.80
9.85 9.26 19.63 45.74 47.65 48.68 51.91 66.21 56.40 67.54 75.04 65.00 72.68 79.38 71.10 79.38 80.37 76.32
6
9
12
15
18
101
APPENDIX A Raw Data
Table A5: Removal of NO3-N for vertical and horizontal SSF systems Time (Days)
Sample
Effluent (Vertical) mg/L
Removal
Removal efficiency (Vertical)
Effluent (Horizontal) mg/L
Removal
Removal efficiency (Horizontal)
3
C1 P1 M1 C2 P2 M2 C3 P3 M3 C4 P4 M4 C5 P5 M5 C6 P6 M6
15.00 13.60 12.80 11.80 11.20 10.90 15.00 13.50 13.40 9.20 8.00 6.00 9.00 4.80 4.20 9.00 8.00 8.00
11.50 12.90 13.70 14.70 15.30 15.60 11.50 13.00 13.10 17.30 18.50 20.50 17.50 21.70 22.30 17.50 18.50 18.50
43.40 48.68 51.70 55.47 57.74 58.87 43.40 49.06 49.43 65.28 69.81 77.36 66.04 81.89 84.15 66.04 69.81 69.81
18.20 15.10 15.60 21.00 18.30 17.30 17.20 13.20 11.20 11.80 10.20 9.80 8.20 5.60 4.00 8.90 4.80 3.20
8.30 11.40 10.90 5.50 8.20 9.20 9.30 13.30 15.30 14.70 16.30 16.70 18.30 20.90 22.50 17.60 21.70 23.30
31.32 43.02 41.13 20.75 30.94 34.72 35.09 50.19 57.74 55.47 61.51 63.02 69.06 78.87 84.91 66.42 81.89 87.92
6
9
12
15
18
Table A6: Removal of P for vertical and horizontal SSF systems Time (Days)
Sample
Effluent (Vertical) mg/L
Removal
Removal efficiency (Vertical)
Effluent (Horizontal) mg/L
Removal
Removal efficiency (Horizontal)
3
C1 P1 M1 C2 P2 M2 C3 P3 M3 C4 P4 M4 C5 P5 M5 C6 P6 M6
41.50 36.80 26.00 39.60 37.00 20.20 32.50 24.30 13.60 37.60 29.60 14.50 34.20 23.90 13.60 26.30 23.50 6.00
11.30 16.00 26.80 13.20 15.80 32.60 20.30 28.50 39.20 15.20 23.20 38.30 18.60 28.90 39.20 26.50 29.30 46.80
21.40 30.30 50.76 25.00 29.92 61.74 38.45 53.98 74.24 28.79 43.94 72.54 35.23 54.73 74.24 50.19 55.49 88.64
47.20 42.00 23.50 45.00 38.00 27.60 42.30 36.50 14.90 37.80 33.00 11.60 36.50 29.80 9.70 25.20 20.10 4.80
5.60 10.80 29.30 7.80 14.80 25.20 10.50 16.30 37.90 15.00 19.80 41.20 16.30 23.00 43.10 27.60 32.70 48.00
10.61 20.45 55.49 14.77 28.03 47.73 19.89 30.87 71.78 28.41 37.50 78.03 30.87 43.56 81.63 52.27 61.93 90.91
6
9
12
15
18
102
APPENDIX A Raw Data
Table A7: Removal of Fe for vertical and horizontal SSF systems Time (Days)
Sample
Effluent (Vertical) mg/L
Removal
Removal efficiency (Vertical)
Effluent (Horizontal) mg/L
Removal
Removal efficiency (Horizontal)
3
C1 P1 M1 C2 P2 M2 C3 P3 M3 C4 P4 M4 C5 P5 M5 C6 P6 M6
0.55 0.44 0.38 0.43 0.28 0.24 0.27 0.24 0.23 0.17 0.11 0.12 0.09 0.06 0.01 0.08 0.03 0.00
0.26 0.37 0.43 0.38 0.53 0.57 0.54 0.57 0.58 0.64 0.70 0.69 0.72 0.75 0.80 0.73 0.78 0.81
32.10 45.68 53.09 46.54 65.43 70.37 66.67 70.37 71.60 79.01 86.42 85.19 88.89 92.59 98.77 90.12 96.30 100.00
0.35 0.35 0.27 0.33 0.28 0.18 0.15 0.11 0.08 0.11 0.11 0.06 0.10 0.08 0.00 0.06 0.03 0.00
0.46 0.46 0.54 0.48 0.53 0.63 0.66 0.70 0.73 0.70 0.70 0.75 0.71 0.73 0.81 0.75 0.78 0.81
56.79 56.79 66.67 59.26 65.43 77.78 81.48 86.42 90.12 86.42 86.42 92.59 87.65 90.12 100.00 92.59 96.30 100.00
6
9
12
15
18
Table A8: Removal of Mn for vertical and horizontal SSF systems Time (Days)
Sample
Effluent (Vertical) mg/L
Removal
Removal efficiency (Vertical)
Effluent (Horizontal) mg/L
Removal
Removal efficiency (Horizontal)
3
C1 P1 M1 C2 P2 M2 C3 P3 M3 C4 P4 M4 C5 P5 M5 C6 P6 M6
0.27 0.27 0.25 0.24 0.23 0.19 0.18 0.15 0.13 0.16 0.13 0.11 0.11 0.09 0.07 0.09 0.05 0.03
0.13 0.13 0.15 0.16 0.17 0.21 0.22 0.25 0.27 0.24 0.27 0.29 0.29 0.31 0.33 0.31 0.35 0.37
32.50 32.50 37.50 40.00 42.50 52.50 55.00 62.50 67.50 60.00 67.50 72.50 72.50 77.50 82.50 77.50 87.50 92.50
0.33 0.32 0.25 0.30 0.29 0.23 0.29 0.26 0.20 0.20 0.19 0.16 0.19 0.15 0.10 0.10 0.07 0.05
0.07 0.08 0.15 0.10 0.11 0.17 0.11 0.14 0.20 0.20 0.21 0.24 0.21 0.25 0.30 0.30 0.33 0.35
17.50 20.00 37.50 25.00 27.50 42.50 27.50 35.00 50.00 50.00 52.50 60.00 52.50 62.50 75.00 75.00 82.50 87.50
6
9
12
15
18
103
APPENDIX A Raw Data
Table A9: Ferum uptake by plants in roots and leaves
Initial plants Vegetated Vegetated with magnet
Vertical SSF Leaves Roots 296.0 1344.0 312.6 1716.0 315.9 1785.2
Horizontal SSF Leaves Roots 296.0 1344.0 309.6 1403.0 311.2 1406.0
Table A10: Manganese uptake by plants in roots and leaves
Initial plants Vegetated Vegetated with magnet
Vertical SSF Leaves Roots 1.42 1.83 1.47 2.18 1.48 2.28
Horizontal SSF Leaves Roots 1.42 1.83 1.46 1.89 1.47 3.37
104
APPENDIX B Varian Analysis Calculation (ANOVA)
Table B1: Result of ANOVA for TSS in vertical SSF Time Control Vegetated Vegetated with (Days) (%) (%) magnet (%) 3 3.98 9.65 31.39 6 9.10 14.54 44.02 9 14.67 23.51 64.81 12 19.02 31.79 72.55 15 33.02 36.41 83.22 18 43.89 47.69 86.40
Anova: Two-Factor Without Replication SUMMARY Row 1 Row 2 Row 3 Row 4 Row 5 Row 6 Column 1 Column 2 Column 3 Column 4
Count 4 4 4 4 4 4
Sum 48.01358696 73.66304348 111.9891304 135.3695652 167.6494565 195.9755435
Average 12.00339674 18.41576087 27.99728261 33.8423913 41.91236413 48.99388587
Variance 175.5514797 303.858863 637.9152587 733.1851371 846.6625038 795.8630197
6 6 6 6
63 123.6820652 163.5869565 382.3913043
10.5 20.61367754 27.26449275 63.73188406
31.5 228.4743042 201.5792376 481.472388
df
MS 782.2797353 3225.125938 53.58206479
F 14.5996564 60.19040048
ANOVA Source of Variation Rows Columns Error
SS 3911.398677 9675.377814 803.7309718
Total
14390.50746
5 3 15 23
P-value 2.63E-05 1.354E-08
F crit 2.9012945 3.2873821
APPENDIX B Varian Analysis Calculation (ANOVA)
105
Table B2: Result of ANOVA for TSS in horizontal SSF Time
Control
Vegetated
(Days)
(%)
(%)
3 6 9 12 15 18
5.84 9.92 18.07 28.94 40.22 46.33
14.67 19.02 28.53 37.77 44.70 48.37
Vegetated with magnet (%) 29.35 46.10 72.69 75.04 82.57 90.04
4 4 4 4 4 4
Sum 52.86413043 81.04076087 128.2934783 153.7527174 182.486413 202.7418478
Average 13.21603261 20.26019022 32.07336957 38.43817935 45.62160326 50.68546196
Variance 140.3660282 326.5205497 796.9072641 709.7939084 777.5889521 880.4997163
6 6 6 6
63 149.3206522 193.0706522 395.7880435
10.5 24.88677536 32.17844203 65.96467391
31.5 268.9066684 188.6107091 543.6623494
df
MS 844.2746227 3317.667912 62.80170141
F 13.4434992 52.82767564
Anova: Two-Factor Without Replication SUMMARY Row 1 Row 2 Row 3 Row 4 Row 5 Row 6 Column 1 Column 2 Column 3 Column 4
Count
ANOVA Source of Variation Rows Columns Error
SS 4221.373113 9953.003735 942.0255211
Total
15116.40237
5 3 15 23
P-value 4.297E-05 3.31E-08
F crit 2.9012945 3.2873821
APPENDIX B Varian Analysis Calculation (ANOVA)
106
Table B3: Result of ANOVA for Turbidity in vertical SSF Time
Control
Vegetated
Vegetated with magnet (%)
(Days)
(%)
(%)
3 6 9 12 15 18
38.33 41.67 43.33 47.50 54.17 60.00
45.00 41.67 43.33 47.50 54.17 60.00
19.17 46.67 59.17 70.83 81.67 86.67
4 4 4 4 4 4
Sum 105.5 136 154.8333333 177.8333333 205 224.6666667
Average 26.375 34 38.70833333 44.45833333 51.25 56.16666667
Variance 362.7476852 354 447.9699074 589.2291667 752.0833333 805.4444444
6 6 6 6
63 285 291.6666667 364.1666667
10.5 47.5 48.61111111 60.69444444
31.5 67.22222222 50.18518519 628.1712963
df
MS 488.8761574 2831.13696 96.06751543
F 5.088881035 29.47028397
Anova: Two-Factor Without Replication SUMMARY Row 1 Row 2 Row 3 Row 4 Row 5 Row 6 Column 1 Column 2 Column 3 Column 4
ANOVA Source of Variation Rows Columns Error Total
Count
SS 2444.380787 8493.41088 1441.012731 12378.8044
5 3 15 23
P-value 0.0063168 1.558E-06
F crit 2.9012945 3.2873821
APPENDIX B Varian Analysis Calculation (ANOVA)
107
Table B4: Result of ANOVA for Turbidity in horizontal SSF Time
Control
Vegetated
Vegetated with magnet (%)
(Days)
(%)
(%)
3 6 9 12 15 18
37.50 44.17 50.83 54.17 56.67 61.67
48.33 52.50 57.50 59.17 60.83 65.00
25.00 47.50 55.83 61.67 77.50 89.17
4 4 4 4 4 4
Sum 113.8333333 150.1666667 173.1666667 187 210 233.8333333
Average 28.45833333 37.54166667 43.29166667 46.75 52.5 58.45833333
Variance 378.9513889 453.8958333 530.6550926 546.4166667 706.0185185 877.6550926
6 6 6 6
63 305 343.3333333 356.6666667
10.5 50.83333333 57.22222222 59.44444444
31.5 76.94444444 35.74074074 511.2962963
df
MS 456.8888889 3162.604938 66.19753086
F 6.901902275 47.77527042
Anova: Two-Factor Without Replication SUMMARY Row 1 Row 2 Row 3 Row 4 Row 5 Row 6 Column 1 Column 2 Column 3 Column 4
Count
ANOVA Source of Variation Rows Columns Error
SS 2284.444444 9487.814815 992.962963
Total
12765.22222
5 3 15 23
P-value 0.0015744 6.544E-08
F crit 2.9012945 3.2873821
108
APPENDIX B Varian Analysis Calculation (ANOVA)
Table B5: Result of ANOVA for ammoniacal nitrogen in vertical SSF Time
Control
Vegetated
(Days)
(%)
(%)
3 6 9 12 15 18
8.46 37.79 45.74 79.22 79.63 86.75
32.79 34.12 59.41 90.36 91.54 94.11
Vegetated with magnet (%) 26.65 33.38 49.85 84.26 88.48 93.91
4 4 4 4 4 4
Sum 70.90441176 111.2941176 164 265.8455882 274.6544118 292.7720588
Average 17.72610294 27.82352941 41 66.46139706 68.66360294 73.19301471
Variance 203.1849544 215.3985006 487.9302191 1338.985272 1305.407237 1365.619967
6 6 6 6
63 337.5882353 402.3382353 376.5441176
10.5 56.26470588 67.05637255 62.75735294
31.5 948.017474 838.3877739 885.5098183
df
MS 2213.786963 4100.479311 163.2093678
F 13.56409251 25.12404384
Anova: Two-Factor Without Replication SUMMARY Row 1 Row 2 Row 3 Row 4 Row 5 Row 6 Column 1 Column 2 Column 3 Column 4
Count
ANOVA Source of Variation Rows Columns Error
SS 11068.93481 12301.43793 2448.140517
Total
25818.51326
5 3 15 23
P-value 4.076E-05 4.234E-06
F crit 2.9012945 3.2873821
109
APPENDIX B Varian Analysis Calculation (ANOVA)
Table B6: Result of ANOVA for ammoniacal nitrogen in horizontal SSF Time
Control
Vegetated
(Days)
(%)
(%)
3 6 9 12 15 18
9.85 45.74 51.91 67.54 72.68 79.38
9.26 47.65 66.21 75.04 79.38 80.37
Vegetated with magnet (%) 19.63 48.68 56.40 65.00 71.10 76.32
4 4 4 4 4 4
Sum 41.75 148.0588235 183.5220588 219.5735294 238.1617647 254.0661765
Average 10.4375 37.01470588 45.88051471 54.89338235 59.54044118 63.51654412
Variance 47.19296064 429.0014418 640.1885227 835.8656466 894.5668433 923.7416513
6 6 6 6
63 327.0955882 357.9044118 337.1323529
10.5 54.51593137 59.65073529 56.18872549
31.5 639.2503334 756.1747135 419.6656935
df
MS 1528.798479 3240.903297 105.9307538
F 14.43205513 30.59454579
Anova: Two-Factor Without Replication SUMMARY Row 1 Row 2 Row 3 Row 4 Row 5 Row 6 Column 1 Column 2 Column 3 Column 4
Count
ANOVA Source of Variation Rows Columns Error
SS 7643.992395 9722.709892 1588.961307
Total
18955.66359
5 3 15 23
P-value 2.818E-05 1.227E-06
F crit 2.9012945 3.2873821
110
APPENDIX B Varian Analysis Calculation (ANOVA)
Table B7: Result of ANOVA for nitrate in vertical SSF Time Control Vegetated Vegetated with (Days) (%) (%) magnet (%) 3 6 9 12 15 18
43.40 55.47 43.40 65.28 66.04 66.04
48.68 57.74 49.06 69.81 81.89 69.81
51.70 58.87 49.43 77.36 84.15 69.81
4 4 4 4 4 4
Sum 146.7735849 178.0754717 150.8867925 224.4528302 247.0754717 223.6603774
Average 36.69339623 44.51886792 37.72169811 56.11320755 61.76886792 55.91509434
Variance 516.324997 661.4172303 374.2644773 889.6869586 1037.079477 642.077489
6 6 6 6
63 339.6226415 376.9811321 391.3207547
10.5 56.60377358 62.83018868 65.22012579
31.5 120.6977572 175.3079388 199.838614
df
MS 447.9400291 3988.510161 26.46809363
F 16.92377378 150.6912518
Anova: Two-Factor Without Replication SUMMARY Row 1 Row 2 Row 3 Row 4 Row 5 Row 6 Column 1 Column 2 Column 3 Column 4
Count
ANOVA Source of Variation Rows Columns Error
SS 2239.700145 11965.53048 397.0214044
Total
14602.25203
5 3 15 23
P-value 1.07E-05 2.018E-11
F crit 2.9012945 3.2873821
APPENDIX B Varian Analysis Calculation (ANOVA)
111
Table B8: Result of ANOVA for nitrate in horizontal SSF Time
Control
Vegetated
Vegetated with magnet (%)
(Days)
(%)
(%)
3 6 9 12 15 18
31.32 20.75 35.09 55.47 69.06 66.42
43.02 30.94 50.19 61.51 78.87 81.89
41.13 34.72 57.74 63.02 84.91 87.92
4 4 4 4 4 4
Sum 118.4716981 92.41509434 152.0188679 192 247.8301887 254.2264151
Average 29.61792453 23.10377358 38.00471698 48 61.95754717 63.55660377
Variance 341.1914976 164.7944702 462.503471 586.6324908 1022.661534 1004.45556
6 6 6 6
63 278.1132075 346.4150943 369.4339623
10.5 46.35220126 57.73584906 61.57232704
31.5 401.8179661 407.0914916 478.9414976
df
MS 1120.291518 3250.473295 66.35314564
F 16.88377405 48.98747849
Anova: Two-Factor Without Replication SUMMARY Row 1 Row 2 Row 3 Row 4 Row 5 Row 6 Column 1 Column 2 Column 3 Column 4
Count
ANOVA Source of Variation Rows Columns Error
SS 5601.457592 9751.419885 995.2971846
Total
16348.17466
5 3 15 23
P-value 1.085E-05 5.525E-08
F crit 2.9012945 3.2873821
112
APPENDIX B Varian Analysis Calculation (ANOVA)
Table B9: Result of ANOVA for phosphorus in vertical SSF Time
Control
Vegetated
Vegetated with magnet (%)
(Days)
(%)
(%)
3 6 9 12 15 18
21.40 25.00 38.45 28.79 35.23 50.19
30.30 29.92 53.98 43.94 54.73 55.49
50.76 61.74 74.24 72.54 74.24 88.64
4 4 4 4 4 4
Sum 105.4621212 122.6666667 175.6666667 157.2651515 179.2045455 212.3181818
Average 26.3655303 30.66666667 43.91666667 39.31628788 44.80113636 53.07954545
Variance 393.6884135 535.6031527 756.6528543 660.6913979 648.411554 836.3455961
6 6 6 6
63 199.0530303 268.3712121 422.1590909
10.5 33.17550505 44.72853535 70.35984848
31.5 109.2374981 145.8823558 165.4865416
df
MS 385.8960366 3721.042371 22.0701196
F 17.48499979 168.6009155
Anova: Two-Factor Without Replication SUMMARY Row 1 Row 2 Row 3 Row 4 Row 5 Row 6 Column 1 Column 2 Column 3 Column 4
Count
ANOVA Source of Variation Rows Columns Error
SS 1929.480183 11163.12711 331.051794
Total
13423.65909
5 3 15 23
P-value 8.739E-06 8.929E-12
F crit 2.9012945 3.2873821
APPENDIX B Varian Analysis Calculation (ANOVA)
113
Table B10: Result of ANOVA for phosphorus in horizontal SSF Time
Control
Vegetated
Vegetated with magnet (%)
(Days)
(%)
(%)
3 6 9 12 15 18
10.61 14.77 19.89 28.41 30.87 52.27
20.45 28.03 30.87 37.50 43.56 61.93
55.49 47.73 71.78 78.03 81.63 90.91
4 4 4 4 4 4
Sum 89.5530303 96.53030303 131.5378788 155.9393939 171.0606061 223.1136364
Average 22.38825758 24.13257576 32.8844697 38.98484848 42.76515152 55.77840909
Variance 538.1165968 329.4330234 752.1192369 788.9269972 807.7948041 903.8424156
6 6 6 6
63 156.8181818 222.3484848 425.5681818
10.5 26.13636364 37.05808081 70.9280303
31.5 224.0157254 211.327288 268.2901458
df
MS 625.2308621 3937.062579 36.63409904
F 17.06690975 107.4698896
Anova: Two-Factor Without Replication SUMMARY Row 1 Row 2 Row 3 Row 4 Row 5 Row 6 Column 1 Column 2 Column 3 Column 4
Count
ANOVA Source of Variation Rows Columns Error
SS 3126.154311 11811.18774 549.5114856
Total
15486.85353
5 3 15 23
P-value 1.015E-05 2.299E-10
F crit 2.9012945 3.2873821
APPENDIX B Varian Analysis Calculation (ANOVA)
114
Table B11: Result of ANOVA for ferum in vertical SSF Time
Control
Vegetated
Vegetated with magnet (%)
(Days)
(%)
(%)
3 6 9 12 15 18
32.10 46.54 66.67 79.01 88.89 90.12
45.68 65.43 70.37 86.42 92.59 96.30
53.09 70.37 71.60 85.19 98.77 100.00
4 4 4 4 4 4
Sum 133.8641975 188.345679 217.6419753 262.617284 295.2469136 304.4197531
Average 33.46604938 47.08641975 54.41049383 65.65432099 73.8117284 76.10493827
Variance 488.0550094 855.69842 920.8977671 1289.96027 1553.849451 1517.122542
6 6 6 6
63 403.3333333 456.7901235 479.0123457
10.5 67.22222222 76.13168724 79.83539095
31.5 558.9010822 371.6913072 333.2825281
df
MS 1095.378836 6292.256658 66.66536055
F 16.43100445 94.38569905
Anova: Two-Factor Without Replication SUMMARY Row 1 Row 2 Row 3 Row 4 Row 5 Row 6 Column 1 Column 2 Column 3 Column 4
Count
ANOVA Source of Variation Rows Columns Error
SS 5476.894179 18876.76997 999.9804082
Total
25353.64456
5 3 15 23
P-value 1.283E-05 5.798E-10
F crit 2.9012945 3.2873821
APPENDIX B Varian Analysis Calculation (ANOVA)
115
Table B12: Result of ANOVA for ferum in horizontal SSF Time
Control
Vegetated
Vegetated with magnet (%)
(Days)
(%)
(%)
3 6 9 12 15 18
56.79 59.26 81.48 86.42 87.65 92.59
56.79 65.43 86.42 86.42 90.12 96.30
66.67 77.78 90.12 92.59 100.00 100.00
4 4 4 4 4 4
Sum 183.2469136 208.4691358 267.0246914 277.4320988 292.7777778 306.8888889
Average 45.8117284 52.11728395 66.75617284 69.35802469 73.19444444 76.72222222
Variance 836.2742849 1004.518976 1495.098854 1470.664431 1533.603554 1541.722451
6 6 6 6
63 464.1975309 481.4814815 527.1604938
10.5 77.36625514 80.24691358 87.8600823
31.5 237.5654118 240.2072855 174.6176904
df
MS 603.7676485 7748.344652 26.70757972
F 22.60660287 290.1178142
Anova: Two-Factor Without Replication SUMMARY Row 1 Row 2 Row 3 Row 4 Row 5 Row 6 Column 1 Column 2 Column 3 Column 4
ANOVA Source of Variation Rows Columns Error Total
Count
SS 3018.838242 23245.03396 400.6136958 26664.4859
5 3 15 23
P-value 1.713E-06 1.678E-13
F crit 2.9012945 3.2873821
APPENDIX B Varian Analysis Calculation (ANOVA)
116
Table B13: Result of ANOVA for manganese in vertical SSF Time
Control
Vegetated
(Days)
(%)
(%)
3 6 9 12 15 18
32.5 40 55 60 72.5 77.5
32.5 42.5 62.5 67.5 77.5 87.5
Vegetated with magnet (%) 37.5 52.5 67.5 72.5 82.5 92.5
Anova: Two-Factor Without Replication SUMMARY Row 1 Row 2 Row 3 Row 4 Row 5 Row 6 Column 1 Column 2 Column 3 Column 4
Count 4 4 4 4 4 4
Sum 105.5 141 194 212 247.5 275.5
Average 26.375 35.25 48.5 53 61.875 68.875
Variance 248.3958333 409.4166667 719.8333333 773.5 993.2291667 1189.229167
6 6 6 6
63 337.5 370 405
10.5 56.25 61.66666667 67.5
31.5 311.875 434.1666667 400
df
MS 1022.385417 4075.010417 51.71875
F 19.76817724 78.7917422
ANOVA Source of Variation Rows Columns Error
SS 5111.927083 12225.03125 775.78125
Total
18112.73958
5 3 15 23
P-value 4.045E-06 2.076E-09
F crit 2.9012945 3.2873821
APPENDIX B Varian Analysis Calculation (ANOVA)
117
Table B14: Result of ANOVA for manganese in horizontal SSF Time
Control
Vegetated
(Days)
(%)
(%)
3 6 9 12 15 18
17.5 25.0 27.5 50.0 52.5 75.0
20.0 27.5 35.0 52.5 62.5 82.5
Vegetated with magnet (%) 37.5 42.5 50.0 60.0 75.0 87.5
Anova: Two-Factor Without Replication SUMMARY Row 1 Row 2 Row 3 Row 4 Row 5 Row 6 Column 1 Column 2 Column 3 Column 4
Count 4 4 4 4 4 4
Sum 78 101 121.5 174.5 205 263
Average 19.5 25.25 30.375 43.625 51.25 65.75
Variance 200.1666667 224.4166667 290.5625 462.5625 668.75 1039.75
6 6 6 6
63 247.5 280 352.5
10.5 41.25 46.66666667 58.75
31.5 471.875 556.6666667 376.875
df
MS 1224.166667 2531.625 70.91666667
F 17.26204465 35.69858989
ANOVA Source of Variation Rows Columns Error
SS 6120.833333 7594.875 1063.75
Total
14779.45833
5 3 15 23
P-value 9.464E-06 4.532E-07
F crit 2.9012945 3.2873821
118
APPENDIX B Varian Analysis Calculation (ANOVA)
Table B15: Result of ANOVA for TSS in vertical and horizontal SSF Time (Days) 3 6 9 12 15 18
Control (%) v 3.98 9.10 14.67 19.02 33.02 43.89
Control (%) h 5.84 9.92 18.07 28.94 40.22 46.33
Vegetated (%) v 9.65 14.54 23.51 31.79 36.41 47.69
Vegetated (%) h 14.67 19.02 28.53 37.77 44.70 48.37
Vegetated with magnet (%), v 29.35 46.10 72.69 75.04 82.57 90.04
Vegetated with magnet (%), h 31.39 44.02 64.81 72.55 83.22 86.40
P-value 9.42023E-05 0.031349628
F crit 5.050329058 6.607890969
Anova: Two Factor Without Replication for control vertical and horizontal SSF SUMMARY Count Sum Average Variance Row 1 2 9.82337 4.911684783 1.732429259 Row 2 2 19.02174 9.510869565 0.332289698 Row 3 2 32.74457 16.37228261 5.76891836 Row 4 2 47.96196 23.98097826 49.18810551 Row 5 2 73.2337 36.61684783 25.92782668 Row 6 2 90.21739 45.10869565 2.990607278 Column 1 Column 2
6 6
ANOVA Source of Variation Rows Columns Error
SS 2455.74278 54.7780951 31.1620817
Total
2541.68296
123.6821 149.3207
20.61367754 24.88677536
228.4743042 268.9066684
df
MS 491.1485563 54.77809509 6.232416337
F 78.80547924 8.789222692
5 1 5 11
Anova: Two-Factor Without Replication for vegetated vertical and horizontal SSF SUMMARY Row 1 Row 2 Row 3 Row 4 Row 5 Row 6 Column 1 Column 2
Count 2 2 2 2 2 2
Sum 24.32065 33.55978 52.03804 69.56522 81.11413 96.05978
Average 12.16032609 16.7798913 26.01902174 34.7826087 40.55706522 48.0298913
Variance 12.63623878 10.05176335 12.63623878 17.86980151 34.34583235 0.230756734
6 6
163.587 193.0707
27.26449275 32.17844203
201.5792376 188.6107091
119
APPENDIX B Varian Analysis Calculation (ANOVA)
ANOVA Source of Variation Rows Columns Error
SS 1935.61979 72.4406924 15.3299391
df 5 1 5
MS 387.1239588 72.44069244 3.065987811
F 126.2640241 23.62719518
P-value 2.94828E-05 0.004629988
F crit 5.050329058 6.607890969
Total 2023.39043 11 Anova: Two-Factor Without Replication for vegetated with magnet vertical and horizontal SSF SUMMARY Row 1 Row 2 Row 3 Row 4 Row 5 Row 6 Column 1 Column 2
Count 2 2 2 2 2 2
Sum 60.7337 90.12228 137.5 147.5951 165.788 176.4402
Average 30.36684783 45.0611413 68.75 73.79755435 82.89402174 88.2201087
Variance 2.07681061 2.160713758 31.05062618 3.091124911 0.212665406 6.629548677
6 6
395.788 382.3913
65.96467391 63.73188406
543.6623494 481.472388
df
MS 1019.08165 14.95605161 6.053087587
F 168.3573276 2.470813679
ANOVA Source of Variation Rows Columns Error
SS 5095.40825 14.9560516 30.2654379
Total
5140.62974
5 1 5 11
P-value 1.44622E-05 0.17678234
F crit 5.050329058 6.607890969
120
APPENDIX B Varian Analysis Calculation (ANOVA)
Table B16: Result of ANOVA for Turbidity in vertical and horizontal SSF Time (Days) 3 6 9 12 15 18
Control (%) v 38.33 41.67 43.33 47.50 54.17 60.00
Control (%) h 37.50 44.17 50.83 54.17 56.67 61.67
Vegetated (%) v 45.00 47.50 53.33 61.67 63.33 64.17
Vegetated (%) h 48.33 52.50 57.50 59.17 60.83 65.00
Vegetated with magnet (%), v 25.00 47.50 55.83 61.67 77.50 89.17
Vegetated with magnet (%), h 19.17 46.67 59.17 70.83 81.67 86.67
P-value 0.001172006 0.049313088
F crit 5.050329058 6.607890969
Anova: Two Factor Without Replication for control vertical and horizontal SSF SUMMARY Count Sum Average Variance Row 1 2 75.83333 37.91666667 0.347222222 Row 2 2 85.83333 42.91666667 3.125 Row 3 2 94.16667 47.08333333 28.125 Row 4 2 101.6667 50.83333333 22.22222222 Row 5 2 110.8333 55.41666667 3.125 Row 6 2 121.6667 60.83333333 1.388888889 Column 1 Column 2
6 6
ANOVA Source of Variation Rows Columns Error
SS 695.833333 33.3333333 25
Total
754.166667
285 305
47.5 50.83333333
67.22222222 76.94444444
5 1 5
MS 139.1666667 33.33333333 5
F 27.83333333 6.666666667
df
11
Anova: Two-Factor Without Replication for vegetated vertical and horizontal SSF SUMMARY Row 1 Row 2 Row 3 Row 4 Row 5 Row 6 Column 1 Column 2
Count 2 2 2 2 2 2
Sum 93.33333 100 110.8333 120.8333 124.1667 129.1667
Average 46.66666667 50 55.41666667 60.41666667 62.08333333 64.58333333
Variance 5.555555556 12.5 8.680555556 3.125 3.125 0.347222222
6 6
335 343.3333
55.83333333 57.22222222
70.55555556 35.74074074
121
APPENDIX B Varian Analysis Calculation (ANOVA)
ANOVA Source of Variation Rows Columns Error
SS 503.935185 5.78703704 27.5462963
df 5 1 5
MS 100.787037 5.787037037 5.509259259
F 18.29411765 1.050420168
P-value 0.003139664 0.352413195
F crit 5.050329058 6.607890969
Total 537.268519 11 Anova: Two-Factor Without Replication for vegetated with magnet vertical and horizontal SSF SUMMARY Row 1 Row 2 Row 3 Row 4 Row 5 Row 6 Column 1 Column 2
Count 2 2 2 2 2 2
Sum 44.16667 94.16667 115 132.5 159.1667 175.8333
Average 22.08333333 47.08333333 57.5 66.25 79.58333333 87.91666667
Variance 17.01388889 0.347222222 5.555555556 42.01388889 8.680555556 3.125
6 6
356.6667 364.1667
59.44444444 60.69444444
511.2962963 628.1712963
df
MS 1125.05787 4.6875 14.40972222
F 78.07630522 0.325301205
ANOVA Source of Variation Rows Columns Error
SS 5625.28935 4.6875 72.0486111
Total
5702.02546
5 1 5 11
P-value 9.63769E-05 0.593112413
F crit 5.050329058 6.607890969
122
APPENDIX B Varian Analysis Calculation (ANOVA)
Table B17: Result of ANOVA for ammonia nitrogen for vertical and horizontal SSF Time (Days) 3 6 9 12 15 18
Control (%) v 8.46 37.79 45.74 79.22 79.63 86.75
Control (%) h 9.85 45.74 51.91 67.54 72.68 79.38
Vegetated (%) v 32.79 34.12 59.41 90.36 91.54 94.11
Vegetated (%) h 9.26 47.65 66.21 75.04 79.38 80.37
Vegetated with magnet (%), v 26.65 33.38 49.85 84.26 88.48 93.91
Vegetated with magnet (%), h 19.63 48.68 56.40 65.00 71.10 76.32
P-value 0.000316347 0.617418401
F crit 5.050329058 6.607890969
Anova: Two Factor Without Replication for control vertical and horizontal SSF SUMMARY Count Sum Average Variance Row 1 2 18.30882 9.154411765 0.975886678 Row 2 2 83.52941 41.76470588 31.53114187 Row 3 2 97.64706 48.82352941 19.07439446 Row 4 2 146.7574 73.37867647 68.25586613 Row 5 2 152.3162 76.15808824 24.14103049 Row 6 2 166.125 83.0625 27.1953125 Column 1 Column 2
6 6
ANOVA Source of Variation Rows Columns Error
SS 7774.34004 9.17463686 161.998995
Total
7945.51367
337.5882 327.0956
56.26470588 54.51593137
948.017474 639.2503334
df
MS 1554.868008 9.174636858 32.39979906
F 47.99005098 0.28316956
5 1 5 11
Anova: Two-Factor Without Replication for vegetated vertical and horizontal SSF SUMMARY Row 1 Row 2 Row 3 Row 4 Row 5 Row 6 Column 1 Column 2
Count 2 2 2 2 2 2
Sum 42.05882 81.76471 125.625 165.3971 170.9191 174.4779
Average 21.02941176 40.88235294 62.8125 82.69852941 85.45955882 87.23897059
Variance 276.816609 91.52249135 23.13000108 117.4052768 74.04371215 94.43017409
6 6
402.3382 357.9044
67.05637255 59.65073529
838.3877739 756.1747135
123
APPENDIX B Varian Analysis Calculation (ANOVA)
ANOVA Source of Variation Rows Columns Error
SS 7459.99456 164.530389 512.817875
df 5 1 5
MS 1491.998912 164.5303895 102.563575
F 14.54706422 1.604179549
P-value 0.005312177 0.261107281
F crit 5.050329058 6.607890969
Total 8137.34283 11 Anova: Two-Factor Without Replication for vegetated with magnet vertical and horizontal SSF SUMMARY Row 1 Row 2 Row 3 Row 4 Row 5 Row 6 Column 1 Column 2
Count 2 2 2 2 2 2
Sum 46.28676 82.05882 106.25 149.2647 159.5809 170.2353
Average 23.14338235 41.02941176 53.125 74.63235294 79.79044118 85.11764706
Variance 24.65465506 116.9550173 21.41273789 185.5644464 150.9453125 154.6730104
6 6
376.5441 337.1324
62.75735294 56.18872549
885.5098183 419.6656935
df
MS 1200.222596 129.4405998 104.9529159
F 11.43581943 1.233320662
ANOVA Source of Variation Rows Columns Error
SS 6001.11298 129.4406 524.76458
Total
6655.31816
5 1 5 11
P-value 0.009116571 0.317293606
F crit 5.050329058 6.607890969
124
APPENDIX B Varian Analysis Calculation (ANOVA)
Table B18: Result of ANOVA for nitrate in vertical and horizontal SSF Time (Days) 3 6 9 12 15 18
Control (%) v 43.40 55.47 43.40 65.28 66.04 66.04
Control (%) h 31.32 20.75 35.09 55.47 69.06 66.42
Vegetated (%) v 48.68 57.74 49.06 69.81 81.89 69.81
Vegetated (%) h 43.02 30.94 50.19 61.51 78.87 81.89
Vegetated with magnet (%), v 51.70 58.87 49.43 77.36 84.15 69.81
Vegetated with magnet (%), h 41.13 34.72 57.74 63.02 84.91 87.92
P-value 0.054265462 0.119344994
F crit 5.050329058 6.607890969
Anova: Two Factor Without Replication for control vertical and horizontal SSF SUMMARY Count Sum Average Variance Row 1 2 74.71698 37.35849057 72.90850837 Row 2 2 76.22642 38.11320755 602.6343895 Row 3 2 78.49057 39.24528302 34.46066216 Row 4 2 120.7547 60.37735849 48.13100748 Row 5 2 135.0943 67.54716981 4.556781773 Row 6 2 132.4528 66.22641509 0.071199715 Column 1 Column 2
6 6
ANOVA Source of Variation Rows Columns Error
SS 2165.10027 315.284206 447.478343
Total
2927.86282
339.6226 278.1132
56.60377358 46.35220126
120.6977572 401.8179661
df
MS 433.0200546 315.2842055 89.49566868
F 4.838447055 3.522899043
5 1 5 11
Anova: Two-Factor Without Replication for vegetated vertical and horizontal SSF SUMMARY Count Sum Average Variance Row 1 2 91.69811 45.8490566 16.01993592 Row 2 2 88.67925 44.33962264 358.9177643 Row 3 2 99.24528 49.62264151 0.640797437 Row 4 2 131.3208 65.66037736 34.46066216 Row 5 2 160.7547 80.37735849 4.556781773 Row 6 2 151.6981 75.8490566 72.90850837 Column 1 Column 2
6 6
376.9811 346.4151
62.83018868 57.73584906
175.3079388 407.0914916
125
APPENDIX B Varian Analysis Calculation (ANOVA)
ANOVA Source of Variation Rows Columns Error
SS 2502.34959 77.8568886 409.647561
df 5 1 5
MS 500.4699181 77.85688857 81.92951228
F 6.108542626 0.950291127
P-value 0.034414509 0.374416253
F crit 5.050329058 6.607890969
Total 2989.85404 11 Anova: Two-Factor Without Replication for vegetated with magnet vertical and horizontal SSF SUMMARY Row 1 Row 2 Row 3 Row 4 Row 5 Row 6 Column 1 Column 2
Count 2 2 2 2 2 2
Sum 92.83019 93.58491 107.1698 140.3774 169.0566 157.7358
Average 46.41509434 46.79245283 53.58490566 70.18867925 84.52830189 78.86792453
Variance 55.82057672 291.6340335 34.46066216 102.8123888 0.284798861 164.0441438
6 6
391.3208 369.434
65.22012579 61.57232704
199.838614 478.9414976
df
MS 556.9526522 39.91930699 121.8274594
F 4.571651212 0.327670849
ANOVA Source of Variation Rows Columns Error
SS 2784.76326 39.919307 609.137297
Total
3433.81986
5 1 5 11
P-value 0.060391481 0.591810226
F crit 5.050329058 6.607890969
126
APPENDIX B Varian Analysis Calculation (ANOVA)
Table B19: Result of ANOVA for P in vertical and horizontal SSF Time (Days) 3 6 9 12 15 18
Control (%) v 10.61 14.77 19.89 28.41 30.87 52.27
Control (%) h 21.40 25.00 38.45 28.79 35.23 50.19
Vegetated (%) v 20.45 28.03 30.87 37.50 43.56 61.93
Vegetated (%) h 30.30 29.92 53.98 43.94 54.73 55.49
Vegetated with magnet (%), v 55.49 47.73 71.78 78.03 81.63 90.91
Vegetated with magnet (%), h 50.76 61.74 74.24 72.54 74.24 88.64
P-value 0.011188099 0.073623963
F crit 5.050329058 6.607890969
Anova: Two Factor Without Replication for control vertical and horizontal SSF SUMMARY Count Sum Average Variance Row 1 2 32.00758 16.00378788 58.27091942 Row 2 2 39.77273 19.88636364 52.29855372 Row 3 2 58.33333 29.16666667 172.2480487 Row 4 2 57.19697 28.59848485 0.071740129 Row 5 2 66.09848 33.04924242 9.487632002 Row 6 2 102.4621 51.23106061 2.170138889 Column 1 Column 2
6 6
ANOVA Source of Variation Rows Columns Error
SS 1520.36762 148.648536 145.898497
Total
1814.91465
156.8182 199.053
26.13636364 33.17550505
224.0157254 109.2374981
df
MS 304.0735241 148.6485355 29.17969946
F 10.42072159 5.094244914
5 1 5 11
Anova: Two-Factor Without Replication for vegetated vertical and horizontal SSF SUMMARY Row 1 Row 2 Row 3 Row 4 Row 5 Row 6 Column 1 Column 2
Count 2 2 2 2 2 2
Sum 50.75758 57.95455 84.84848 81.43939 98.29061 117.42
Average 25.37878788 28.97727273 42.42424242 40.71969697 49.14530303 58.71
Variance 48.49632691 1.793503214 266.9450184 20.73289715 62.37768049 20.7368
6 6
222.3467 268.3639
37.05777778 44.72732323
211.3091986 145.852516
127
APPENDIX B Varian Analysis Calculation (ANOVA)
ANOVA Source of Variation Rows Columns Error
SS 1541.19213 176.465782 244.616444
df 5 1 5
MS 308.2384258 176.4657824 48.92328874
F 6.30044369 3.60698937
P-value 0.032338482 0.115981188
F crit 5.050329058 6.607890969
Total 1962.27436 11 Anova: Two-Factor Without Replication for vegetated with magnet vertical and horizontal SSF SUMMARY Row 1 Row 2 Row 3 Row 4 Row 5 Row 6 Column 1 Column 2
Count 2 2 2 2 2 2
Sum 106.25 109.4697 146.0227 150.5682 155.8712 179.5455
Average 53.125 54.73484848 73.01136364 75.28409091 77.93560606 89.77272727
Variance 11.20939509 98.212236 3.031020432 15.08336203 27.27918388 2.582644628
6 6
425.5682 422.1591
70.9280303 70.35984848
268.2901458 165.4865416
df
MS 402.4908173 0.968491736 31.28587006
F 12.86493923 0.030956203
ANOVA Source of Variation Rows Columns Error
SS 2012.45409 0.96849174 156.42935
Total
2169.85193
5 1 5 11
P-value 0.007011171 0.867242071
F crit 5.050329058 6.607890969
128
APPENDIX B Varian Analysis Calculation (ANOVA)
Table B20: Result of ANOVA for ferum in vertical and horizontal SSF Time (Days) 3 6 9 12 15 18
Control (%) v 32.10 46.54 66.67 79.01 88.89 90.12
Control (%) h 56.79 59.26 81.48 86.42 87.65 92.59
Vegetated (%) v 45.68 65.43 70.37 86.42 92.59 96.30
Vegetated (%) h 56.79 65.43 86.42 86.42 90.12 96.30
Vegetated with magnet (%), v 53.09 70.37 71.60 85.19 98.77 100.00
Vegetated with magnet (%), h 66.67 77.78 90.12 92.59 100.00 100.00
P-value 0.003586301 0.044822773
F crit 5.050329058 6.607890969
Anova: Two Factor Without Replication for control vertical and horizontal SSF SUMMARY Count Sum Average Variance Row 1 2 88.88889 44.44444444 304.8315806 Row 2 2 105.8025 52.90123457 80.84895595 Row 3 2 148.1481 74.07407407 109.739369 Row 4 2 165.4321 82.71604938 27.43484225 Row 5 2 176.5432 88.27160494 0.762078951 Row 6 2 182.716 91.35802469 3.048315806 Column 1 Column 2
6 6
ANOVA Source of Variation Rows Columns Error
SS 3764.37154 308.704212 217.960931
Total
4291.03668
403.3333 464.1975
67.22222222 77.36625514
558.9010822 237.5654118
df
MS 752.8743078 308.7042118 43.59218615
F 17.27085458 7.081640978
5 1 5 11
Anova: Two-Factor Without Replication for vegetated vertical and horizontal SSF SUMMARY Row 1 Row 2 Row 3 Row 4 Row 5 Row 6 Column 1 Column 2
Count 2 2 2 2 2 2
Sum 102.4691 130.8642 156.7901 172.8395 182.716 192.5926
Average 51.2345679 65.43209877 78.39506173 86.41975309 91.35802469 96.2962963
Variance 61.72839506 0 128.7913428 0 3.048315806 0
6 6
456.7901 481.4815
76.13168724 80.24691358
371.6913072 240.2072855
129
APPENDIX B Varian Analysis Calculation (ANOVA)
ANOVA Source of Variation Rows Columns Error
SS 2916.73017 50.8052634 142.76279
df 5 1 5
MS 583.3460346 50.80526343 28.55255805
F 20.43060498 1.779359431
P-value 0.002428551 0.23975834
F crit 5.050329058 6.607890969
Total 3110.29823 11 Anova: Two-Factor Without Replication for vegetated with magnet vertical and horizontal SSF SUMMARY Row 1 Row 2 Row 3 Row 4 Row 5 Row 6 Column 1 Column 2
Count 2 2 2 2 2 2
Sum 119.7531 148.1481 161.7284 177.7778 198.7654 200
Average 59.87654321 74.07407407 80.86419753 88.88888889 99.38271605 100
Variance 92.21155312 27.43484225 171.4677641 27.43484225 0.762078951 0
6 6
479.0123 527.1605
79.83539095 87.8600823
333.2825281 174.6176904
df
MS 482.6754052 193.1870142 25.22481329
F 19.13494461 7.658610272
ANOVA Source of Variation Rows Columns Error
SS 2413.37703 193.187014 126.124066
Total
2732.68811
5 1 5 11
P-value 0.002828867 0.039485851
F crit 5.050329058 6.607890969
130
APPENDIX B Varian Analysis Calculation (ANOVA)
Table B21: Result of ANOVA for manganese in vertical and horizontal SSF Time (Days) 3 6 9 12 15 18
Control (%) v 32.5 40.0 55.0 60.0 72.5 77.5
Control (%) h 17.5 25.0 27.5 50.0 52.5 75.0
Vegetated (%) v 32.5 42.5 62.5 67.5 77.5 87.5
Vegetated (%) h 20.0 27.5 35.0 52.5 62.5 82.5
Vegetated with magnet (%), v 37.5 52.5 67.5 72.5 82.5 92.5
Vegetated with magnet (%), h 37.5 42.5 50.0 60.0 75.0 87.5
Anova: Two Factor Without Replication for control vertical and horizontal SSF SUMMARY Row 1 Row 2 Row 3 Row 4 Row 5 Row 6
Count
Column 1 Column 2 ANOVA Source of Variation Rows Columns Error Total
2 2 2 2 2 2
Sum 50 65 82.5 110 125 152.5
Average 25 32.5 41.25 55 62.5 76.25
Variance 112.5 112.5 378.125 50 200 3.125
6 6
337.5 247.5
56.25 41.25
311.875 471.875
MS 747.5 675 36.25
F 20.62068966 18.62068966
SS 3737.5 675 181.25 4593.75
df 5 1 5
P-value 0.002376602 0.007605297
11
Anova: Two-Factor Without Replication for vegetated vertical and horizontal SSF SUMMARY Row 1 Row 2 Row 3 Row 4 Row 5 Row 6 Column 1 Column 2
Count 2 2 2 2 2 2
Sum 52.5 70 97.5 120 140 170
Average 26.25 35 48.75 60 70 85
Variance 78.125 112.5 378.125 112.5 112.5 12.5
6 6
370 280
61.66666667 46.66666667
434.1666667 556.6666667
F crit 5.050329058 6.607890969
131
APPENDIX B Varian Analysis Calculation (ANOVA)
ANOVA Source of Variation Rows Columns Error
SS 4822.91667 675 131.25
Total
5629.16667
df 5 1 5
MS 964.5833333 675 26.25
F 36.74603175 25.71428571
P-value 0.000603087 0.00386403
F crit 5.050329058 6.607890969
11
Anova: Two-Factor Without Replication for vegetated with magnet vertical and horizontal SSF SUMMARY Row 1 Row 2 Row 3 Row 4 Row 5 Row 6 Column 1 Column 2
Count 2 2 2 2 2 2
Sum 75 95 117.5 132.5 157.5 180
Average 37.5 47.5 58.75 66.25 78.75 90
6 6
405 352.5
67.5 58.75
400 376.875
MS 758.4375 229.6875 18.4375
F 41.13559322 12.45762712
ANOVA Source of Variation Rows Columns Error
SS 3792.1875 229.6875 92.1875
Total
4114.0625
df 5 1 5 11
Variance 0 50 153.125 78.125 28.125 12.5
P-value 0.000459454 0.016748032
F crit 5.050329058 6.607890969