DECENTRALIZED INTEGRATED ORGANIC WASTE MANAGEMENT FOR URBAN AREAS IN THE DEVELOPING WORLD

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1 DECENTRALIZED INTEGRATED ORGANIC WASTE MANAGEMENT FOR URBAN AREAS IN THE DEVELOPING WORLD Priyadarshini Karve Samuchit Enviro Tech Pvt Ltd, 6, Ekta Park, Law College Road, Pune , India ABSTRACT Several urban municipal authorities in developing countries are increasingly opting for waste-to-energy projects for dealing with the increasing quantities of organic waste being generated in urban habitats. This involves raising awareness among residents about waste segregation or involvement of manual labor for segregation of collected waste, capital investment in space and infrastructure to convert a few tens of tons of organic waste into electricity, running expenses of waste transport and electricity supply to the point of use, etc. We have developed a decentralized integrated waste management system that allows organic waste to be managed at source, while providing an energy service to the local population. For a cluster of 100 houses, an above-ground floating-dome biogas plant is built on community-owned land to process about 50 kg organic waste. The kg biogas produced is supplied to the kitchen of a local restaurant or canteen at a price less than the market price for the equivalent quantity of LPG. The effluent is used for organically fertilized intensive vegetable cultivation on community land, and the surplus slurry is supplied to local nurseries and individual terrace gardeners as liquid organic fertilizer. The operation can be managed by a group of waste pickers (already engaged in collecting and selling recyclable wastes to scrap merchants), with training and technical support provided by us. The economics of the system is attractive for the urban residents. The system also creates an opportunity to enhance income for waste pickers in urban areas. 1. INTRODUCTION Urbanisation is occurring in most parts of the developing world at a rate much faster than the civic administrations can cope with. As a result, most cities in the developing countries are facing problems like escalating prices of housing, scarcity of energy and water, traffic congestions, inadequate systems for sewage treatment and waste management, etc. Specifically the issue of waste management is multidimensional, and its neglect leads to a number of consequences. If India is a typical example of a thriving developing economy, the statistics of urban waste management from India can be considered as indicative of a large part of the developing world. In India between 50 to 90% of urban 1

2 waste produced every year is dumped into open landfill streets or in open drains, or dumped illegally in unmanaged sites. (1) The waste is generally collected and dumped without segregation. Scores of waste pickers, who are the most marginalized section of the urban society, are visible at the garbage dumps, looking for recyclables as a source of income. An estimated 20% of these are children. (2) The civic administrations in urban centers of the developing world have been struggling to look for a solution for a long time. The standard practice that is currently employed in India involves the following steps: 1. Awareness raising among the citizens to segregate the waste. 2. Collection of the segregated waste from door to door. 3. Further segregation of the waste manually or using machinery (as the segregation at source is not happening very efficiently yet). 4. Sale of the recyclables and e-waste to respective recycling facilities. 5. Incineration of biomedical waste. 6. Composting or biomethanation of the organic waste at the garbage dump. In most cities the municipalities are handing over waste collection and management to private contractors, who are employing traditional waste pickers to run the process. In some cities, the waste pickers themselves are forming into co-operatives and are trying to collaborate with the municipalities to manage the urban waste more efficiently than before. However, the municipalities favor the private companies rather than the waste picker co-operatives because the companies are better positioned to invest in large scale machinery to deal with the huge quantities of organic waste being collected on the garbage dump. The trend of handing over waste management to private companies is socially and economically exploitative, costly, and inefficient, for a variety of reasons. In most of the cases, the private contractors are exploiting the waste pickers by paying them less than the legal minimum wages, and not putting in place any systems to ensure safe and hygienic work conditions. The organic waste to compost or organic waste to energy systems being used for processing tens of tons of organic waste at the dump site are not financially sustainable, and therefore the government is being forced to subsidize these operations. The environmental viability of the operations is also questionable considering the huge quantity of diesel burned by the garbage trucks running across the city collecting garbage from door to door. This fleet of trucks is also adding to the traffic congestions and air pollution in densely populated parts of the cities. sites without sorting, while the remainder is left on the We believe that a more efficient, economical and environment friendly mechanism of urban waste management is possible through the co-operatives of waste pickers. 2. TYPICAL OPERATION OF A WASTE PICKERS CO-OPERATIVE A typical waste pickers co-operative is comprised of traditional waste pickers. The structure is democratic, and the waste pickers themselves elect a board of directors to manage the organization. They work in groups assigned to specific clusters, under the direction of a supervisor. They collect waste from door to door, and get paid by the citizens for this door step service. The waste pickers further segregate the waste in some common space within the urban cluster from where the waste has been collected. Thus, the segregation happens in smaller, decentralized locations, with smaller and manageable quantities of waste. The co-operative also ensures use of gloves, masks, and other hygienic practices in segregation. Since the waste pickers know where each bag of waste is coming from, they are better positioned to advocate and educate the citizens in segregation at source. It is therefore expected that in a few years time, the step of waste pickers having to manually segregate the waste can be eliminated totally, with the residents handing over properly segregated waste to them. This has already been achieved in some urban pockets where the waste pickers co-operatives have been in operation for a few years. The typical process followed by one of the pioneering waste pickers co-operative SWaCH, in Pune, India is shown in Fig 1. Waste segregated at source into organic and inorganic collected by SWACH members Inorganic waste further segregated Metal, plastic, glass, paper, e-waste sold to recyling units Biomedic al waste given to collection van Organic waste given to garbage truck Organic waste dumped in open landfills Fig 1 Current waste management scheme by a waste pickers co-operative, SWaCH. 2

3 The recycling mechanisms for paper, glass, plastic, metals, and e-waste are now fairly well established. Working as a co-operative allows the waste pickers to aggregate the recyclables and negotiate better prices from the scrap merchants. The recyclables thus represent another stream of income for the waste pickers, along with the service fee paid by the citizens. At this point of time, the waste pickers are handing over the biomedical and the organic waste to the municipal garbage trucks, to transport to the garbage dumps. In this process, as the segregation is occurring in a decentralized manner, the mass of waste transported through the city streets and dumped in the municipal garbage dump is reduced by about 40 to 50%. The plant is small enough to fit in a typical apartment house balcony. Fig.2 shows a typical household biogas plant based on this technology. We have installed or provided the technical know how for installation of hundreds of such plants across India and in parts of Africa. We propose a system by which the organic waste too can be taken care of in a decentralized manner, practically reducing the waste to be handled by the municipal authorities down to about 10 to 20% of the total waste generated. 3. DECENTRALISED INTEGRATED WASTE MANAGEMENT SYSTEM As explained above, wherever the waste pickers cooperatives are in operation, segregation of the waste into inorganic and organic waste is already happening in a decentralized manner. In addition, in some cities the citizens are being urged to manage their own organic waste, through either legislation or rebates in the annual municipal tax. The process of choice seems to be composting. The primary reason for this is that composting is perceived as an easy process and does not require any capital investment. However, the urban citizens do not themselves have any use for compost, unless they are fond of gardening. Secondly, the process of composting does require some time and effort to be spend in the already busy daily routine of a typical urban citizen. As a result many urban composting projects are failing to sustain, unless there is a committed local champion to keep the process going. In some places, the residents have found a way out by paying extra to the waste pickers to manage the composting system, but the limited market for compost is resulting into the citizens spending money for waste management rather than earning money from it, as they have been initially laid to believe. Actually the waste to energy through biomethanation would be a better approach for decentralized processing of organic waste compared to compost. Our associate organization, Appropriate Rural Technology Institute (ARTI) has developed a technology by which even a single urban household s organic waste can be converted to biogas, by using a floating dome type biogas system constructed out of plastic waste storage tanks. The biogas can partially replace the liquid petroleum gas (LPG) being used in the household s kitchen as cooking fuel. Fig.2 An ARTI biogas plant with digester capacity of 0.5 cubic meter, for processing 500 g of food waste daily. However in this case too, the hassle of managing the system outweighs the benefits, and therefore not many citizens are going for this option at household level. On the other hand, commercial establishments like hotels, hostels, food processing units, industrial canteens, etc., are finding this approach to be more attractive, but are being constrained by space availability. We are proposing to install ARTI type biogas plants at urban cluster level, where the waste pickers who are collecting waste from a particular cluster will also manage the plant, within the cluster itself. The cluster could be a housing colony, or an educational or industrial or business campus, on which collectively substantial quantity of organic waste is being generated, and where there is at least one point of potential use of the biogas thus produced. The biogas system will convert the organic waste into biogas, which will be sold to a commercial kitchen in the cluster, to replace LPG in the kitchen. The effluent from the biogas system is a nutrient rich organic fertilizer. It can be either bottled and sold to neighborhood gardeners, urban farmers, and plant nurseries, or if space is available, the fertilizer can be used for growing organic vegetables within the cluster. For this purpose another technology, also developed by ARTI, for intensive cultivation using raised beds of sand and soil, will be used. The fresh organic vegetables will be sold to the citizens. The waste pickers who are bringing in the organic waste, will also operate the entire system. The revenue generated from the sale of energy and fertilizer and/or organic produce will be used for compensating the waste pickers for their 3

4 labour, and for servicing and maintenance of the system. In addition, the system will also generate sufficient profit to pay back for the initial investment of the client in about 5 to 6 years, while the system life is expected to be at least 15 to 20 years. A schematic of the proposed system is shown in Fig.3. are assuming the market price for these vegetables too. The small vegetable sales outlet operated in the cluster will generate about USD 1500 per year. A 100 sq m vegetable garden will not require all the effluent coming out of the biogas plant daily. We therefore expect an additional revenue stream to emerge through sale of the liquid fertilizer, however it is difficult to estimate its share in the economics at this point as it would be an entirely new product in the urban market. We are already discussing with several educational campuses with residential facilities for installing the system. We believe that this innovation will allow the waste pickers co-operatives to compete for waste management contracts against the private contractors, by providing a total and holistic solution to the problem of urban waste. Going ahead, there is also a possibility of carbon/climate finance to come into the equation in view of the multiple environmental benefits delivered by this decentralized option. Fig.3 Schematic of organic waste management system to be implemented in urban clusters As an example, we have worked out the technoeconomic feasibility for a system for a housing colony with 100 houses. Based on the statistics given to us by a waste pickers cooperative, a typical Indian middle class family generates about 500 g of organic waste in the form of kitchen waste and cooked food, every day. Thus, for a cluster of 100 houses, we require a biogas plant large enough to handle about 50 kg of food waste daily. This will produce about 25 kg of biogas daily, and also about 500 lit of effluent slurry. The biogas can replace about 6 kg of LPG in a commercial kitchen. If the plant is also integrated with a 100 sq m of raised bed system of intensive vegetable cultivation, a part of the effluent can be used for irrigation. This system is expected to generate about 3 tons of organic vegetables annually. The capital investment required for the system is around USD The running expense including labour and other overheads is expected to be about USD 10 per day or USD 3650 per year. We propose to sell the biogas to a commercial kitchen at a price that is 10% less than the price of the commercial LPG that the biogas is replacing. The present price of commercial LPG in India is around USD 1.5 per kg. Thus, the sale price of biogas could be about USD 0.37 per kg. The annual income from sale of biogas is expected to be USD The retail price of most vegetables in urban India at present is about USD 0.5 per kg. In principle, organic produce should sell at a premium, but in view of the general lack of awareness, we 4. CONCLUSION We have put together a number of independently proven concepts to provide a holistic and sustainable solution to the problem of organic waste in urban areas. These ideas are: 1. Active participation of the traditional waste pickers in the urban waste management process. 2. Biogas generation from organic waste, for use as fuel in the kitchen. 3. Use of biogas effluent as an organic fertilizer. 4. Raised bed system of intensive vegetable cultivation. Each concept has separately been tried out under different conditions in the developing world, and has proved successful. We have proposed an integrated model based on a combination of these concepts. Although the preliminary technoeconomic feasibility analysis has been carried out in the Indian context, it should in principle be applicable to any city in the developing world. 5. ACKNOWLEDGEMENTS The author is grateful to Mr. Pradeep Rathi, MBA, University of California, Berkeley, USA, for inputs in developing the business model. 6. REFERENCES (1) International Energy Agency, Turning a Liability into an Asset: Landfill Methane Utilization Potential in India, Aug (2) Chintan, Newsletter: No Child in Trash, Vol 1, Sept

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