Centralized Control on Decentralized Wastewater Treatment: The Emerging Role of Membrane Bio-reactors New Horizons in Biotechnology November 22-25, 2015, Trivandrum, India
C. Visvanathan and P. Jacob
Environmental Engineering and Management Program Asian Institute of Technology, Thailand Email:
[email protected] http://faculty.ait.ac.th/visu
What is Membrane Bioreactor (MBR) ? • Combination of 2 basic processes Biological degradation Membrane separation • MBR is a single process where SS and microorganisms responsible for biodegradation are separated from treated water by a membrane separation unit instead of gravity settlement.
MBR System
Influent
+ Effluent
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Centralized Control on Decentralized Wastewater Treatment
History
How it Began – WWT For solid liquid separation
History
1829 - Smith Slow Sand Filtration Water Purification 1899 - Trickling Filter Activated Sludge Sewage treatment C .Visvanathan
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Membrane Separation Bioreactor Principles: Dissolved organic materials converted to: Microbial biomass: Suspended solids entrained in some way Gases: Mineralization end products of respiratory metabolism aerobic systems- CO2, H2O Anaerobic systems - CO2 , CH4 C .Visvanathan
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Conventional WWT Approach
Filtration/ Adsorption
Activated Sludge Process Return Sludge
Sedimentation
Tertiary Treatment
Disadvantages:
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Need for close operational control (SS Removal)
Separation depends on floc characteristics
The large amount of waste sludge Centralized Control on Decentralized Wastewater Treatment
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Technology Evolution- Telephone
Not only a Telephone Anymore C .Visvanathan
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Development of MBR Conventional Approach
Membrane Technology for Tertiary Treatment
Energy Saving Options in Membrane Bioreactor
Tertiary treatment
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Submerged Membrane
Membrane Bioreactor (Crossflow membrane filtration)
Decentralized Wastewater Treatment
Air
Plunging Liquid Jet Aeration
Membrane as Solid/Liquid Separator & Air Diffuser Air
Centralized Control on Decentralized Wastewater Treatment
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Centralized Control on Decentralized Wastewater Treatment
We are already Connected
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Internet of Things (IoT) • Internet of Things (IoT) is a scenario in which objects, devices are provided with a unique identifiers. • Thus ability to transfer data over a network without requiring human-tohuman or human-to-computer interaction. • An ability to learn by constant feedback from centralized servers • Ex. Self learning thermostats. • Ex. Google Nest
Source : http://www.tweaktown.com/news/41530/internet-of-things-market-is-growing-with-industry-deals-accelerating/index.html
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https://nest.com/ Centralized Control on Decentralized Wastewater Treatment
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What are decentralized WWT and MBR’s Role • Decentralized WTP are so called due to their location away from main wastewater treatment facility • They are located close to source, such as homes and businesses. • Currently trends in WWT moving towards Decentralized WTP.
• Small conventional WTP cannot be used as decentralized system • Membrane based bioreactors with its ability to retain 2-4 times the MLSS can treat onsite WW effectively. • Thus source treatment increasing the chances of water reuse. C .Visvanathan
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Centralized Control on Decentralized Wastewater Treatment
•
Decentralized MBR send and receiving data from central control system through internet.
•
Centralized operation control unit can observe and operate individual plants.
•
Operators and technicians will be informed if any, technical issue.
Centralized Control
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Case Study - Gas Station Wastewater Management
Gas Station Overview
Slope
Slope
Slope
Slope
Slope
Slope
Slope
Slope
Slope
Slope
8
3 5
7
4
Slope
Slope
Slope
Slope
Slope
Slope
Slope
6
Slope
Slope
Slope
Slope
Slope
Slope
Slope
9 2
Slope
1
Slope
Slope Slope
Slope
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Premium Gas Station 1 Gas station 2 Toilet 1 3 Office 4 Food court 5 Noodle restaurant 6 Coffee shop 7 Toilet 2 8 MBR system 9 KFC restaurant 10 Convenience store 11 Effluent sump 1 12 Effluent sump 2 Fixed film tank Water pump station Septic tank
12 Slope
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Slope
Slope
Slope
Slope
Slope
Slope
Slope
Slope
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Major Wastewater Source- Gas Station Coffee shop, 3%
~60 m3/month KFC, 10%
~ 180 m3/month
Toilet, 66%
~ 1,200 m3/month
Food Court, 17%
~ 300 m3/month
Noodle Restaurant, 3% ~ 60 m3/month Coffee shop C .Visvanathan
KFC
Food Court
Noodle Restaurant
Toilet Centralized Control on Decentralized Wastewater Treatment
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Wastewater Characterization Parameter
Unit
KFC restaurant
Coffee shop
Noodle restaurant
Food court
Toilet
COD
mg/L
797 ± 48
2448 ± 48
715 ± 35
1578 ± 170
245 ± 5
TKN
mg/L
53 ± 3
31 ± 3
91 ± 21
30 ± 5
182 ± 14
TP
mg/L
10 ± 0.5
8 ± 0.1
6 ± 0.1
7 ± 0.1
15 ± 4
100
100
100
100
100
COD : N : P Ratio
COD
N
100
100 80
P
75 50 25 5 0
1
Suitable ratio
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7
13 1
KFC restaurant
2
0.4
Coffee shop
1 Noodle restaurant
2
6
0.4
Food court
Toilet
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Emerging Issues: Social Concerns Affecting WWT • Gas stations toilets wastewater contained ~1-2 condom/ (Per transfer (5m3)) • In our research: Solids and condoms were skimmed before entering storage units @ 50 C
• Condoms are polymer based material that can easily clog pipes, screens, basic (fixed film) and advance WW (MBR’s) treatment units. • This is a social issue that will severely affect decentralized WWTP’s in automated operations. • Potential for research ? Social Issues affection Environmental Protection C .Visvanathan
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Pilot Scale MBR System
PLC Controller
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PLC Controller on Computer Centralized Control on Decentralized Wastewater Treatment
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Schematic Diagram of Pilot Scale MBR System PG
AB
V4
Influent
V2
V3
P5
V P AB PG FI
Chemical Tank
FI
Wastewater Flow Air Flow Waster Backwash Flow Chemical Flow Valve Pump Air Blower Pressure Gauge Flow Meter
V1 P3
Anoxic Tank
P2
MBR Tank Drainage P4
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Permeate Tank
• Pumps, Pressure gauge, flow meters are connected to computerized control system. • System can control and observe over the internet.
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Flux and TMP Interaction over the MBR Study
20
40
15
30 10 20 10
Flux (LMH)
5
TMP (kPa)
0
TMP (kPa)
Permeate Flux (LMH)
50
0 1
3
5
7
9 11 13 1
SWW (6)
3
5
7
9 11 13 15 17 19 21 23 1 RWW (6)
3
5
7
9 11 13 15 17 19 21 23 RWW (8)
TIME (D)
• Trends of flux and TMP were stable at 32 LMH and 13 kPa. • Membrane fouling has low affected to TMP and permeate flux because of backwash system. C .Visvanathan
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Colour for Acceptable Reuse
Color (CU) in permeate of; AIT MBR vs. Gas station’s MBR 60 vs. 131 Tap Water vs. AIT MBR 28 vs. 60
200
Color (Color Unit))
Treating RWW; • At HRT 6, color in permeate was 111 ± 17 CU. • At HRT 8, color in permeate was 104 ± 12 CU.
150
At HRT 8 with RWW, FeCl3 was add anoxic tank. Color in permeate reduced to 60 ± 6 CU.
100
50
0 2 TW
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GS
6
10
SWW (6)
14
2
6
10
RWW (6)
14
4
6
8
RWW (6-pH) Time (d)
10
2
6
10
RWW (8)
14
2
6
8
10
RWW (8-FeCl3)
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Performances of this MBR study with literatures
This study AIT HRT Wastewater Type MLSS (g/L) Flux (LMH) % COD removal % TKN removal % TP removal Coloreff (CU)
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6h SWW
25 - 36 91 ± 2 82 ± 3 43 ± 5 35 ± 6
8h RWW
RWW
8 - 10 27 - 42 24 - 37 85 ± 4 84 ± 3 81 ± 19 99.4 ± 0.3 9±3 6±4 173 ± 41 104 ± 12
RWW – FeCl3 28 - 38 94 ± 1 99.5 87 ± 8 60 ± 6
Gas Station 4h Toilet Wastewate r 0.6 – 1.1 20 58 83 20 131
21 h
(Abdel-Shafy and El-Khateeb, 2011) 2.4 d
Blackwater
Blackwater
6.3 96 49 -
2-4 92 95
(Hocaoglu et al., 2011)
-
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Energy Consumption Others 22%
Aeration Energy consumption 78%
Synthetic Wastewater (HRT 6)
Others 21%
Others 17%
Aeration Energy consumption 83%
Aeration Energy consumption 79%
Real Wastewater (HRT 6)
Real Wastewater (HRT 8)
Major energy consumption was the aeration The percentages of energy consumption distribution at different HRT were approximately 78, 79 and 83% of total energy consumption. C .Visvanathan
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Concept: Centralized Control Over Decentralized WWTP
Gas station 1
Central Controller Gas station 2
Online data storage Gas station n
Data exchange and analysis
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Concept: Centralized Control Over Decentralized WWTP
Gas Station 1
Gas Station 3
Central Control
Gas Station 2
Gas Station 4
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Concept: Centralized Control Over Decentralized WWTP
MBR Tank C .Visvanathan
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Potential of Decentralized and Automated control : E.g. MBR 45
50
40
40
Stable flux
35
45
Stable
Stable flux
40
30 35 25 30 20
Flux (LHM)
15
TMP (kPa)
25 20
10
TMP Increases
5
Stable TMP
TMP Increases
15
0
10
1
3
5
7
9
11
13
15
17
19
21
23
25
27
29
31
33
37
39
41
43
45
47
49
51
53
55
57
59
61
63
65
67
Time (Min)
•
Sudden flux decline, TMP rises → 40 kPa
•
System automatically back wash to solve problem.
•
During backwash TMP and Flux = 0
•
Stable Flux achieved for few minutes.
•
2nd time sudden flux decline- System sends message to controller and operator fixes problem
•
Problem due to clogging and leak
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TMP ()kPa)
Flux (L/m2.h)
ALERT OPERATOR
AUTOMATIC SYSTEM BACKWASH
Thank You!
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