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CSIR-CMERI’s Municipal Solid Waste Processing Facility

Recently, the Council of Scientific and Industrial Research’s Central Mechanical Engineering Research Institute (CSIR-CMERI) has developed a Municipal Solid Waste (MSW) Processing Facility (Decentralised Solid Waste Management Plant) to solve the problem of waste management in India.

MSW Processing Facility:

• It is developed following the Solid Waste Management (SWM) Rules 2016 prescribed by the Ministry of Environment, Forests and Climate Change.
• It has been developed with the potential to scientifically manage the solid waste including the Covid-19 wastes.
• The facility is equipped with special disinfection capabilities to help break the Covid-19 chain through UV-C lights and hot-air convection methods.
• The plant is self-sufficient in terms of energy requirement through the installation of roof-mounted solar panels, which can also feed the surplus energy supply onto a mini-grid.

Objectives:

• To unburden the common households from the segregation responsibilities through advanced segregation techniques.
• To achieve decentralised decimation of solid wastes.
• To help create value-added end-products from abundantly available redundant stuff such as dry leaves, dry grass, etc.

Mechanism:

The mechanised segregation system segregates solid waste into metallic waste (metal body, metal container, etc.), biodegradable waste (foods, vegetables, fruits, grass, etc.), non-biodegradable waste (plastics, packaging material, pouches, bottles etc.) and inert wastes (glass, stones etc.).

Significance:

• It opens up the opportunities to realise the dream of generating 100 GW Solar Power by 2022 and a city with a "Zero-Waste and Zero-Landfill Ecology".
• It may become a source of job creation through both process-engagement and manufacturing, which can help support the Micro Small Enterprises (MSEs) and various start-ups across the nation.

Challenges in Waste Management:

• With an ever-increasing population and rapid pace of urbanisation, India faces a huge challenge of waste management.
• The volume of waste is projected to rise from the present 62 million tonnes to about 150 million tonnes by 2030.
• The ineffective processing of MSW also is the root cause of many diseases as the dumped landfills transform into contamination hubs for pathogens, bacteria and viruses.
• The most commonly used process "composting" also does not yield impactful economic returns for the entrepreneurs.
• Indiscriminate dumping of garbage at the current rate without appropriate scientific treatment would impose a huge requirement of landfill area per year.
• Studies suggest that the MSW generated in India mostly consists of a large fraction of organic wastes and their unscientific disposal produces greenhouse gas (GHG) emissions and other air pollutants like methane (CH4).
• It requires more land space and labour, pasteurisation for effective disinfection and has restricted utilisation due to presence of heavy metals.
• During the rainy season, managing it becomes difficult due to the presence of excessive moisture.

Various Waste Disposal Methods

Bio-degradable Waste Disposal:

• 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 the conversion of organic matter and the biogas can be used as fuel for cooking or can also be utilised in a gas engine for the generation of electricity.
• The residual slurry from the biogas plant is converted to compost in a natural process known as vermicomposting by introducing earthworms. The vermicompost is utilised in organic farming.

Biomass Waste Disposal:

• Biomass waste such as dry leaves, dead branches, dry grass etc. are disposed of by first shredding it to suitable size followed by mixing with the slurry of the biogas digester.
• This mixture is the feedstock for briquette (compressed block of coal dust or other combustible material), which is utilised as fuel for cooking and in gasifier for production of syngas (or synthesis gas), utilised in a gas engine for electricity generation.
• Syngas is a fuel gas mixture consisting primarily of hydrogen, carbon monoxide, and very often some carbon dioxide.

Polymer Waste Disposal:

• The polymer waste consisting of plastics is being disposed of through pyrolysis, in which the polymer waste is heated to a temperature of 400-600°C in an anaerobic environment in presence of a suitable catalyst.
• The volatile matter from the polymer waste comes out as a result of heating which on condensation gives pyrolysis oil.
• The non-condensed syngas and crude pyrolysis oil after purification are reused for heating purposes and it helps in obtaining self-sustainability.
• The solid residue known as char is mixed with the biogas slurry for production of briquette.

Sanitary Waste Disposal:

• The sanitary items including masks, sanitary napkins, diapers etc. are disposed-off utilising high-temperature plasma gasification.
• 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 and the residual ash can be mixed with cement for preparation of recycled bricks.
• However, this technology is not economically viable as energy requirements for waste treatment using this technology is very high.