MUNICIPAL SOLID WASTE MANAGEMENT SYSTEM

MUNICIPAL SOLID WASTE MANAGEMENT SYSTEM

- CURRENT STATE AND FUTURE CHALLENGES

Due to population growth, industrialization, urbanization and economic growth, a trend of significant increase in municipal solid waste (MSW) generation has been recorded worldwide. MSW generation, in terms of kg/capita/day, has shown a positive correlation with economic development at world scale. Due to rapid industrial growth and migration of people from villages to cities, the urban population is increasing rapidly. Waste generation has been observed to increase annually in proportion to the rise in population and urbanization. The per capita generation of MSW has also increased tremendously with improved life style and social status of the populations in urban centres . As more land is needed for the ultimate disposal of these solid wastes, issues related to disposal have become highly challenging . India, with a population of over 1.21 billion account for 17.5% of the world population (Census of India 2011). According to the provisional figures of Census of India 2011, 377 million people live in the urban areas of the country. This is 31.16 % of the Country’s total population. 

·      MSW Quantity 

The quantity of MSW generated depends on a number of factors such as food habits, standard of living, degree of commercial activities and seasons. Data on quantity variation and generation are useful in planning for collection and disposal systems. Indian cities now generate eight times more MSW than they did in 1947 because of increasing urbanization and changing life styles . The rate of increase of MSW generated per capita is estimated at 1 to 1.33% annually . MSW generation rates in small towns are lower than those of metro cities, and the per capita generation rate of MSW in India ranges from 0.2 to 0.5 kg/ day. It was also estimated that the total MSW generated by 217 million people living in urban areas was 23.86 million t/yr in 1991, and more than 39 million ton in 2001 . 

   

·      Characteristics and composition of MSW

 As compare to the western countries, MSW differs greatly with regard to the composition and hazardous nature, in India. Many categories of MSW are found such as food waste, rubbish, commercial waste, institutional waste, street sweeping waste, industrial waste, construction and demolition waste, and sanitation waste. MSW contains compostable organic matter (fruit and vegetable peels, food waste), recyclables (paper, plastic, glass, metals, etc.), toxic substances (paints, pesticides, used batteries, medicines), and soiled waste (blood stained cotton, sanitary napkins, disposable syringes) . MSW composition at generation sources and collection points ,determined on a wet weight basis, consists mainly of a large organic fraction (40–60%), ash and fine earth (30–40%), paper (3–6%) and plastic, glass and metals (each less than 1%). The C/N ratio ranges between 20 and 30, and the lower calorific value ranges between 800 and 1000 kcal/kg.

·      Collections and Storage of MSW

 In India most of the urban areas are lacking in MSW storage at the source, significantly. For both decomposable and non-decomposable waste common bins are used to collect the waste without any segregation, and disposed off at a community disposal centre. Two types of storage bins are used- movable bins and fixed bins. The fixed bins are more durable but their positions cannot be changed once they have been constructed, while the movable bins are flexible in transportation but lacking in durability .Collection of MSW is the responsibility of corporations/municipalities. In most of the cities the predominant system of collection (through the communal bins) at various points along the roads, and sometimes this leads to the creation of unauthorized open collection points. House-to-house collection is just starting in many megacities such as Delhi, Mumbai, Bangalore, Madras and Hyderabad with the help of NGOs. 

·      Treatments and Disposal of MSW 

India is facing the lacking of resources or the technical expertise necessary to deal with the disposal of MSW. The disposal method trend adopted in India. For the years 2001 and 2005, waste dumps or open burning continue to be the principal method of waste disposal. These methods causes several accidents are continuous source of emission of harmful gases and highly toxic liquid leachate.

·      Composting

 Composting has a long tradition particularly in rural India .Composting is difficult process because the waste arrives in a mixed form and contains a lot of non-organic material. When mixed waste is composted, the end product is of poor quality. The presence of plastic objects in the waste stream is especially problematic, since these materials do not get recycled or have a secondary market.

·      Incineration

 In India the incineration is a poor option as the waste consists mainly high organic material (40–60%) and high inert content (30–50%) also low calorific value content (800–1100 kcal/kg), high moisture content (40–60%) in MSW and the high costs of setting up and running the plants. The first large-scale MSW incineration plant was constructed at Timarpur, New Delhi in 1987 with a capacity of 300 t/day and a cost of Rs. 250 million (US$5.7 million) by Miljotecknik volunteer, Denmark. 

·      Gasification Technology

 Gasification is the solid waste incineration under oxygen deficient conditions, to produce fuel gas. In India, there are very few gasifiers in operation, but they are mostly for burning of biomass such as agro-residues, sawmill dust, and forest wastes.

·       Landfilling 

A landfill is an area of land onto or into which waste is deposited. The aim is to avoid any contact between the waste and the surrounding environment, particularly the groundwater. In India open, uncontrolled and poorly managed dumping is commonly practiced, giving rise to serious environmental degradation.60%- 90% of MSW in cities and towns are directly disposed of on land in an unsatisfactory manner. 

Future Challenges in MSW Management

 A successful long term planning depends on the characteristics of the solid waste and estimation of future quantities. Decisions related to treatment choices and disposal options for solid waste management will get affected by the composition of solid waste in the future. Researchers have been reported for innovative and forward-looking solutions to address the issue of forecasting the quantities of municipal solid waste. Although both planning and design of municipal solid waste management systems require accurate prediction of solid waste generation. Yet achieving the anticipated prediction accuracy with regard to the generation trends facing many fast-growing regions is quite challenging. A long time Forecast will be more meaningful if it gives the most optimistic, most pessimistic values and also the most likely values . Most traditional statistical forecasting models, such as the geometry average method, saturation curve method, least-squares regression method, and the curve extension method, are designed based on the configuration of semi-empirical mathematical models. The structure of these models is simply an expression of cause-effect or an illustration of trend extension in order to verify the inherent systematic features that are recognized as related to the observed database. Traditional forecasting methods for solid waste generation frequently count on the demographic and socioeconomic factors on a per-capita basis. The per-capita coefficients were taken as fixed over time or they may be projected to change with time. Grossman et al., (1974) discussed such considerations by including the effects of population, income level, and the dwelling unit size in a linear regression model. The influence of per capita income, population density, persons per house, GDP and population on the composition of the solid waste using linear regression have been established by Khan and Burney (1989) . For year 2025, using subjective judgment based on a single factor GDP of the nation, Gupta et al. (1998)projected the quantity and characteristics of solid waste. However, the quantitative relationship between waste characteristics and GDP was not been established and a subjective judgement was used for prediction. Buenrostro et al. (2001) reported relationship between solid waste composition and socioeconomic factors of community using expert judgements based on secondary data. Dynamic properties in the process of solid waste generation cannot be fully characterized in those model formulations. Chang et al., (1993)reported the econometric forecasting as one of the alternatives to static models, in which the future forecasts are derived from current forecasts of the independent variables themselves. It covers part of the dynamic features in forecasting analysis. When recycling impact is unparalleled, intervention analysis may account for the varying trends of solid waste generation under uncertainty. The grey dynamic model was developed to resolve the data scarcity issue . It is particularly designed for handling situations in which only limited data are available for forecasting practice and system environments are not well-defined or fully understood. 

·      References

 [1] Sharholy, M., Ahmad, K., Vaishya, R., Gupta, R., 2007. Municipal solid waste characteristics and management in allahabad, India. Waste Management 27 (4), 490–496. 

[2] Idris, A., Inane, B., Hassan, M.N., 2004. Overview of waste disposal and landfills/dumps in Asian countries. Material Cycles and Waste Management 16, 104–110. 

[3] Gupta S., Choudhary N. and Alappat B.J., (2007),”Bioreactor Landfill for MSW Disposal in Delhi” Proceedings of the International Conference on Sustainable Solid Waste Management, Chennai, India. pp. 474-481. 

[4] Jha, M.K., Sondhi, O.A.K., Pansare, M., 2003. Solid waste management – a case study. Indian Journal of Environmental Protection 23 (10),1153–1160.

[5] Rathi, S., 2006. Alternative approaches for better municipal solid waste management in Mumbai, India. Journal of Waste Management 26 (10), 1192–1200. 

[6] Ray, M.R., Roychoudhury, S., Mukherjee, G., Roy, S., Lahiri, T., 2005. Respiratory and general health impairments of workers employed in a municipal solid waste disposal at open landfill site in Delhi. International Journal of Hygiene and Environmental Health 108 (4), 255–262. 

[7] Sharholy, M., Ahmad, K., Mahmood, G., Trivedi, R.C., 2005. Analysis of municipal solid waste management systems in Delhi – a review. In:Book of Proceedings for the second International Congress of Chemistry and Environment, Indore, India, pp. 773–777. 

[8] Sharma, S., Shah, K.W., 2005. Generation and disposal of solid waste in Hoshangabad. In: Book of Proceedings of the Second International Congress of Chemistry and Environment, Indore, India, pp. 749–751. 

[9] CPCB, 2004. Management of Municipal Solid Waste. Ministry of Environment and Forests, New Delhi, India 

[10] Shekdar, A.V., 1999. Municipal solid waste management – the Indian experience.