Solid Waste treatment and disposal utilizing plasma arc gasification process is an option for eco-friendly solid waste management in which large volume reduction of waste up to 95% is possible. The plasma gasification process uses electricity to generate high temperature plasma arc (above 3000°C) inside the plasma reactor which converts the waste into syngas. The produced syngas when passed through a series of gas purification system comprising of catalytic converter, redox reactor, cyclone separator, scrubber and condenser is ready for use in gas engines for generation of electricity.The residual ash can bemixed with cement for preparation of recycled bricks for usage in construction. Thus, Science helps in the creation of ‘Wealth from Waste’.
However, this technology is not economically viable as energy requirements for waste treatment using this technology is very high (~ 1.5 kWh/kg of waste processed for small plants (< 100 MT capacity) and ~ 1.2 kWh/kg of waste processed for plants with greater than 100 MT capacity). In addition, the high rate of electrode consumption (~ 500 mg/kg of waste processed) further leads to an increase in recurring expenses making the process expensive and not an economically-rationalised option.
Studies suggest that the Municipal Solid Wastes generated in India mostly consists of alarge fraction (> 50%) of organic wastes. Unscientific disposal of organic waste produces greenhouse gas (GHG) emissionsand other air pollutants.The ineffective processing of MSWalso is the root cause of many diseases as the dumped landfills transform into Contamination Hubs for Pathogens, Bacteria and Viruses. The most commonly used processing “composting” also does not yield impactful economic returns for the entrepreneurs as it requires more land space, more labour, pasteurization for effective disinfectionand has restricted utilization due to presence of heavy metals. During the rainy season managing composting becomes difficult due to the presence of excessive moisture.
The bio-degradable component of the waste is decomposed in an anaerobic environment popularly known as bio-gasification. In this process biogas is liberated through conversion of organic matter. The biogas can be used as fuel for cooking purpose. The gas can also be utilized in gas engine for generation of electricity. The residual slurry from biogas plant is converted to compost in a natural process known as vermi-composting by introducing earthworms. The vermi-compost is utilized in organic farming.