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Indian Journal of Fertilisers, November 2018. 47. Indian Journal ..... Management Manual 2016 and the. Report of the Task ... Municipal Handling) Rules 2016;.
Indian Journal of Fertilisers, Vol. 14 (11), pp.47-69 (23 pages)

Municipal Solid Waste Management vis-a-vis Sustenance of Soil Health Dipak Ranjan Biswas and Avijit Ghosh Division of Soil Science and Agricultural Chemistry, ICAR-Indian Agricultural Research Institute, New Delhi Abstract Enormous amount of organic wastes is generated as municipal solid waste (MSW) because of burgeoning urban population, substantial part of which remains unutilized. It is either burnt or dumped in the nearby sites resulting in environmental pollution and diseases. This can be recycled back to soil as a potential source to meet the nutritional requirements of crops. In this paper, an attempt has been made to evaluate the major parameters of MSW management in terms of its comprehensive review of generation, characterization, environmental degradation and pollution dimensions, collection and composting options for converting MSW into precious nutrient source and amendment as an integrated soil management strategy for sustenance of soil health. Government of India initiatives under Swachh Bharat Abhiyan in popularization of use of MSD compost and its challenges and possible solutions have also been discussed. Improvement in use of MSW as such or through composting offers excellent opportunity in this regard. Conditions for harnessing optimal benefits from the possibilities for public private partnership and challenges thereof for MSW compost and possible solutions are discussed. Paper also reports on installation of decentralized solid waste processing units in metropolitan cities/towns and development of formal recycling industry sector as the need of the hour in the country. Key Words: Municipal solid waste, potential nutrient source, environmental pollution, soil health, composting options, integrated soil management strategy, Government initiatives, Swachh Bharat Abhiyan

Introduction Enormous quantities of organic wastes are generated from plant, animals and industrial activities in our day-to-day life. Most of these organic wastes are generated as municipal solid waste (MSW) catalysed by burgeoning urban population. Substantial part of this MSW generated remains unutilized and is either burnt or dumped in the nearby sites which poses severe problem of disposal, causes pollution, and harbours pathogen for diseases. Instead of disposing, it can be used as source of organic manure and effectively recycled for the production of MSW compost, which can be used to meet the nutritional requirement of crops. The MSW compost is being currently used by farmers and researchers as a soil conditioner as well as an organic fertilizer. Application of MSW improves physical, chemical and biological properties of soil through improvement in soil organic matter (SOM). However, potential ecological and health risks may arise due to nutrient transport to [email protected]

ecologically-sensitive receptors and accumulation of trace elements in the soil profile and their entry into food chain. To mitigate the environmental impacts and optimize compost use in agriculture, these issues need to be carefully addressed. Deterioration in soil health due to low and continuously decreasing soil organic carbon (SOC) is one of the major concerns. Inadequate and imbalanced use of fertilizers and lack of availability of sufficient organic manure have compounded the problem of soil health degradation. Improvement in use of MSW as such or through composting offers excellent opportunity. In this article, the potentiality of MSW as source of nutrients vis-a-vis sustenance of soil health; environmental degradation and pollution dimensions associated with MSW use; composting as an option for converting MSW into precious nutrient source and amendment as an integrated soil management strategy; Government of India initiatives under Swachh Bharat Abhiyan in popularization of use of MSD compost has been summarised. Further, challenges Indian Journal of Fertilisers, November 2018 47

facing MSW utilization and possible solutions have been discussed.

Health of Indian Soils - Cause of Concern Soil health is defined as the continued capacity of soil to function as a vital living ecosystem that sustains plants, animals and humans. This definition lays emphasis on importance of managing soils with long-term goal of sustaining soil resource for future generations. Soil health is a state of a soil meeting its range of ecosystem functions and depends on soil biodiversity. Soil health has, partly if not largely, replaced the expression “soil quality”. The primary difference between the two i.e., soil quality and soil health is that whereas soil quality is focused on individual traits within a functional group, soil health is the condition of the soil in a defined space and at a defined scale relative to a set of benchmarks that encompass healthy functioning. Soil health might also be defined as an assembly of some physical, chemical and biological soil

parameters at optimum level that lead to optimization of native or acquired production capacity and performance of ecologically important roles. Any deviation from normal functioning of soil leads to ill health. Though soil health has experienced decline since time immemorial, its rate of deterioration has accelerated in the post-Green Revolution era. It is abundantly clear that the soils are becoming progressively sick due to population pressure, deforestation, land use changes, intensive soil farming, use of high yielding varieties, excessive and imbalance application of fertilizers, use of pesticides, over-irrigation, switching over to fossil fuel energy, and modern intensive soil management practices, etc.

Status of Soil Physical, Chemical and Biological Health In India, about 120 million hactare (Mha) land is affected by different kinds of degradation. Researchers have confirmed that the rational and sustainable use of water, fertilizer and energy is directly related to soil physical health. In India. About 95% soils are deficient in available nitrogen (N), while 51 and 40% soils are low and medium in phosphorus (P) and 9 and 42% soils are low and medium in potassium (K) (Muralidharudu et al., 2011). Similarly, reports from All India Coordinated Research Project on Micro- and Secondary Nutrients and Pollutant Elements in Soils and Plants have reported that 24.7, 43.4, 14.4, 6.1, 7.9 and 20.6% of the total soil samples analysed across the country to be deficient in available sulphur (S), zinc (Zn), iron (Fe), manganese (Mn), copper (Cu), and boron (B), respectively. The underlying principle in the use of the term “soil health” is that soil is not just an inert, lifeless growing medium. It is rather a living and dynamic entity. It indicates that soils, highly fertile from the point of view of crop productivity, are also lively from a biological point of view. Soil biological health decides on soil quality through maintaining fertility and nutrient supplying

capacity.

Soil Organic Carbon - The Central Spectrum of Soil Health Soil organic carbon controls availability of plant nutrients. Poor SOM and extensive tillage cause breakdown of SOC into CO 2 leading to poor retentive capacity, enhanced nutrient leaching, and accelerated global warming. Pursuance of fertilization practices devoid of matching addition of organic manures to the soil have been responsible for observed decline in soil health since 1960s, era of Green Revolution. Decrease in SOC content may lead to erosion, decline of native fertility, deterioration of physical state of soils, loss of useful soil biodiversity, and accelerated emissions of CO2. Loss of SOC also leads to (a) compaction which leads to deviations in normal aeration, structure, bulk density, root penetration; (b) loss of fertility which disrupts normal supply of essential nutrients in sufficient amounts and right proportion needed for optimum crop growth; (c) higher erodibility; (d) deviations in normal state of native useful soil biology, which is responsible for mobilization of nutrients, sustenance of natural nutrient/water cycles and regulation of climate; and (e) altered chemical composition. Waste to Wealth - A Recent Initiative Due to increasing deficiencies of plant nutrients in field crops, and higher cost and poor use efficiency of chemical fertilizers, the organic wastes recycling for plant nutrient supply is assuming centrality with respect to replenishment of plant nutrients, sustenance of soil health, abatement of environmental pollution, and generation of employment opportunities. Alternative sources of nutrients, including carbon-based materials like composts and manures, have historically been used in agriculture in the past and new types of wastes are being considered/explored/evaluated for their potential as fertilizer Indian Journal of Fertilisers, November 2018 48

replacements. These wastes come from industrial processes like manufacturing of paper or municipal sources such as sewage sludge, food waste, or yard waste. The advantage of waste amendments as an alternative to chemical fertilizers is that, in addition to plant nutrients, these also provide carbon, a major component of SOM. In addition, waste amendments may be inexpensive because of many being locally available, and might help in cutting down on the expenses on transportation. The use of wastes as agricultural amendments cuts down on the need to landfill or incinerate them, sequesters carbon in the soil and recycles nutrients that would otherwise have got lost. Organic wastes improve soil physical, chemical and biological properties because of their high organic matter (OM) and lower load of pollutant elements. Therefore, use of wastes could be a cheap alternative to costly chemical amendments; in addition it has potential to reduce reliance on chemical fertilizers without causing any dent on sustainability in crop productivity. Municipal Solid Waste Generation in India - Past, Present and Future Indian urban population is 377 million (Census of India, 2011a); population in the urban regions increased from 18% in 1961 to 31.2% in 2011 (Census of India, 2011b). Rapid urbanization and uncontrolled growth rate of population are the main reasons for generation of large quantities of MSW (Table 1). Prediction statistics reveal that Indian land would have to accommodate about 1,823 million people by 2051 which will generate about 300 million tonnes (Mt) per annum of MSW. According to Planning Commission Report (Planning Commission, 2014) about 70 million tonnes (Mt) of MSW per annum currently is being produced by 377 million people of urban area and it will rise to 165 and 436 Mt by 2031 and 2050, respectively. But, in India, due to lack of

Table 1. Per capita waste generation rate Population size

>20 lakh

10 lakh -20 lakh

0.43 0.55

0.39 0.46

Waste generation* (kg capita-1 day-1) Waste generation** (kg capita-1 day-1)

5 lakh -10 lakh 0.38 0.48

1 lakh -5 lakh

75 °C), organisms and enzymes get deactivated and the rate of activity may decrease.



Particle size: The optimum particle size should have enough surface area for rapid microbial activity with enough void space to allow air to circulate for microbial respiration. The feedstock composition can be manipulated to create the desired mix of particle size and void space.

Table 6. Important parameters and environmental concerns on windrow composting Parameters Type of waste Organic waste (All type of wet-biodegradable waste) Suitability (t day-1) Min: 100 Max: 1000 Approx. area requirement (m2) Min: 12500 Max: 185000 Approx. capital investment (Rs.) Min: 650 lakh Max: 5,500 lakh Approx. operational cost Min: 70 lakh Max: 250 lakh (Rs./annum) Compost generation Resource: Compost Min: 15 t day-1 Max: 175 t day-1 Approx. operational cost (Rs.) 750 t-1 of compost Processing period 60 days Type of labour requirement Skilled + semi-skilled + unskilled Suitability Large quantity of waste Large piece of land Agriculture and horticulture activity in the surroundings Environmental Concerns Landfill (Whether there is a need of landfill for the technology/ process) Emissions (Whether the technology/ process is associated with emitting gases) Leachate (Whether the technology/ process generates leachate)

Yes, for inert residue Yes Yes

Different Composting Processes Windrow composting: Windrow composting is the production of compost by piling biodegradable waste, in long rows (windrows). This method is suited for producing large volumes of compost. These rows are regularly turned over to improve porosity/voids and oxygen content, mix in or remove moisture, and redistribute cooler and hotter portions of the pile. Windrow composting is a commonly used composting method. The environmental concerns and important considerations related to windrow composting are presented in Table 6. Vermicomposting: Vermicompost is the product of the composting process using various species of earthworms, which feed on mixture of decomposing vegetable or food wastes, and release droppings called vermin-cast (also called worm castings, worm humus or worm manure). It is the end-product of the breakdown of organic matter by an earthworm. The environmental concerns and important considerations related to vermicomposting are presented in Table 7.

Table 7. Important parameters and environmental concerns on vermicomposting Parameters Type of waste Suitability (t day-1) Approx. area requirement (m2) Approx. capital investment (Rs.) Approx. operational cost (Rs./annum) Energy/Resource generation Approx. Production cost (Rs.) Type of labour requirement

Only organic waste Min: 0.1 Max: 2 Min: 100 Max: 2500 Min: 0.25 lakh Max: 2.5 lakh Min: 1.80 lakh Max: 16.80 lakhs Resource: Compost Min: 0.04 t day-1 Max: 0.80 t day-1 5000 t-1 of compost Unskilled

Environmental Concerns Landfill (Whether there is a need of landfill for the technology/process) Emissions (Whether the technology/ process is associated with emitting gases) Leachate (Whether the technology/ process generates leachate)

Aerated static pile composting: Aerated static pile composting refers to the system used to biodegrade organic materials without physical manipulation (turning) during composting. The blended waste is usually placed on perforated piping, providing air circulation for controlled aeration. It may be in windrows, open or covered, or in closed containers. With regard to complexity and cost, aerated Indian Journal of Fertilisers, November 2018 53

No No No

systems are most commonly used by larger, professionally managed composting facilities, although the technique may range from very small, simple systems to very large, capital intensive, industrial installations. Aerated static piles offer process control for rapid biodegradation, and works well for processing saturated wet waste and large volumes. The aerated static piles facilities can be under

Table 8. Important parameters and environmental concerns on aerated static pile composting Parameters Type of waste Suitability (t day-1) Approx. area requirement (m2) Approx. capital investment (Rs.) Approx. operational cost (Rs./annum) Energy/Resource generation

Pure organic waste Min: 0.10 Min: 300 Min: 2.50 lakh Min: 1.80 lakh Resource: Compost

Approx. Production cost (Rs.) Type of labour requirement

1800 t-1 of compost Semi-skilled + unskilled

Environmental Concerns Landfill (Whether there is a need of landfill for the technology/process) Emissions (Whether the technology/ process is associated with emitting gases) Leachate (Whether the technology/ process generates leachate)

Max: 10 Max: 1000 Max: 11.0 lakh Max: 5.50 lakhs Min: 0.04 t day-1 Max: 3.50 t day-1

Yes, for inert residue No Yes

Table 9. Important parameters and environmental concerns for in vessel composting Parameters Type of waste Suitability (t day-1) Approx. area requirement (m2) Approx. capital investment (Rs.) Approx. operational cost (Rs./annum) Energy/Resource Generation

Pure organic waste Min: 0.50 Min: 200 Min: 2.50 lakh Min: 2.16 lakh Resource: Compost

Approx. production cost (Rs.) Type of labour requirement

1700 t-1 of compost Semi-skilled + unskilled

Max: 5 Max: 500 Max: 60 lakh Max: 9.00 lakh Min: 0.15 kg day-1 Max: 1.5 t day-1

Environmental Concerns Landfill (Whether there is a need of Yes, for inert residue landfill for the technology/process) Emissions (Whether the technology/ No process is associated with emitting gases)

roof or outdoor windrow composting operations, or totally enclosed in-vessel composting, sometimes referred to as tunnel composting. The environmental conditions and other important considerations related to aerated static pile composting are presented in Table 8. In-vessel composting: In-vessel composting is a method that confines the composting materials within a building, container, or vessel. In-vessel composting systems can consist of metal or plastic tanks or concrete bunkers in which air flow and temperature can be controlled, using the principles of a “bioreactor ”.

Generally, the air circulation is metered via buried tubes that allow fresh air to be injected under pressure, with the exhaust being extracted through a bio-filter, with temperature and moisture conditions monitored using probes in the mass to allow maintenance of optimum aerobic decomposition conditions. This technique is generally used for municipal scale organic waste processing, including final treatment of sewage bio-solids. It can also refer to aerated static pile composting with the addition of removable covers that enclose the piles. The environmental concerns and important considerations related to in-vessel composting are Indian Journal of Fertilisers, November 2018 54

presented in Table 9. Pit composting: Pit or trench composting is the process of burying organic waste directly into pit or trench. Trenching is an excellent method to use in combination with growing annual plants, especially plants like cabbage, maize, etc. It encourages the development of deep, water conserving root systems. Trenching utilizes anaerobic (without oxygen) decomposition to create an underground band of nutrient-rich humus for plants. This is a slower composting process than that occurs in a well-managed windrow, but the trenched materials will retain more N during the process. This method can be done by digging a hole or trench deep and as wide and long as practical. Filling of trench is done with nutrient-rich food and organic wastes layer-wise (15 cm or 6 inches). It has to be ensured that the materials are quite moist before burying them. The environmental concerns and important considerations related to pit composting are presented in Table 10. Mechanized organic waste composter: Mechanized organic waste composter is designed to make composting easy and convenient. It is fully automatic and has very compact and aesthetic design. The organic waste composter is equipped with intuitive technology which maintains the right temperature, air flow and moisture. A special bacterial strain which is heat, salt and acid resistant is used. Once the bacteria are introduced in the machine, they reproduce at a rapid pace under ideal internal conditions. The environmental concerns and important considerations related to mechanized organic waste composting are presented in Table 11. Quality of Compost Compost which is to be used as fertilizer for crop production should abide by the specifications of Fertiliser (Control) Order 1985

Table 10. Important parameters and environmental concerns on pit composting Parameters Type of waste Suitability (t day-1) Approx. area requirement (m2) Approx. capital investment (Rs.) Approx. operational cost (Rs./annum) Energy/Resource Generation

Pure organic waste Min: 0.10 Min: 100 Min: 0.25 lakh Min: 1.86 lakh Resource: Compost

Max: 2 Max: 2500 Max: 3.00 lakh Max: 3.00 lakh Min: 0.04 t day-1 Max: 0.80 t day-1

of high organic and moisture content. Biomethanation Process The overall process of biomethanation can be divided into four stages: a)

Pre-treatment: Pre-treatment or pre-processing involves separation of non-digestible material either through source segregation or through mechanical sorting at the biogas plant facility to remove undesirable or recyclable material such as glass, metals, stones, etc. The waste is shredded before it is fed into the digester for better fermentation.

b)

Anaerobic fermentation (Digestion): Anaerobic fermentation happens in three steps brought about by different groups of microbes namely, hydrolysis (hydrolytic bacteria), acidogenesis (acidogenic bacteria), and finally biomethanation (methanogenic bacteria).

c)

Gas recovery: The biogas obtained is stored and may be scrubbed to ensure automotive quality CNG-like gas (CO 2