REQUIREMENT OF PRE-PROCESSING IN A WASTE TO ENERGY (WTE) PLANT BASED ON INDIAN MUNICIPAL SOLID WASTE (MSW)

摘要

Globally, mass incineration is the most commonly used waste-to-energy (WtE) technology for processing of Municipal Solid Waste (MSW). In such plants, the MSW, as received, is kept in a bunker for approximately 7 days for reduction of moisture, and homogenization. The waste is then subjected to controlled combustion in a mass-burn incinerator for the production of heat or electricity. However, in developing countries like India, characteristics of waste are substantially different from those in developed countries. Most projects based on incineration technologies in India have failed and been forced to shut down. The problems encountered with these plants, include low calorific value of MSW, inefficient combustion of waste and environmental pollution concerns. These problems have been attributed to poor source segregation of waste, high moisture content, and mixing of construction and demolition debris, road sweepings, and drain silt in MSW amongst various other reasons. The combination of these problems have made the combustion of raw MSW (mass incineration) challenging. Therefore, this paper recommends that mixed MSW in countries like India should be subjected to extensive mechanical preprocessing, so that the organically rich fraction, combustible fraction and inert materials can be separated. The materials derived through this process (refuse derived fuel or combustibles) have a higher calorific value, high volatile matter, a higher combustion rate, and a lower moisture content as compared with mixed waste. All of these factors aid in more efficient burning, lower environmental pollution and a higher yield per unit. The inert materials left over as a result of this process can be disposed in sanitary landfills, and the organically rich fraction can be used to generate compost or biogas.