Solid Waste
Introduction: Solid waste is the unwanted or useless solid materials generated from human activities in residential, industrial or commercial areas. As per report by the planning commission in 2014 , India produced 62 million tonnes of MSW annually and its is expected to increase to 165 million tonnes by 2030.
In India, solid waste collection efficiency is around 70% while this is around 100 % for developed countries.
- 43 million tonnes per annum is collected.
- 9 million tonnes are treated
- 31 million tonnes are dumped in landfill sites.
- 75-80% municipal wastes are collected and only around 20% are treated
- Around 80% of solid waste produced in India is not treated and goes into dumping sites.
Treatment and Disposal of Municipal Solid Waste :
- Open Dumping and landfills : It is the controlled disposal of waste on land in such a way that contact between waste and the environment is significantly reduced and the waste is concentrated in a well-defined area.
Dumps are open areas where waste gets exposed to natural elements, stray animals and birds. This can contribute to air pollution, water pollution as well as soil pollution.
- Thermal treatment :
- Incineration plants (Waste to Energy method) Incineration is combustion of waste in the presence of oxygen. Waste gets converted into CO2, water vapour and Ash along with heat.
Advantages : Reduction in the waste volume, kills many diseases causing organisms etc.
Limitations: Air pollution, climate change, health issues.
Pyrolysis: Here, material is exposed to very high temperatures in an inert (oxygen less) environment. The material decomposes due to the limited thermal stability of chemical bonds of material, which disintegrates.
Pyrolysis is thus a thermo chemical treatment, which can be applied to any carbonic (carbon based) product. It produces volatile products and leaves a solid residue enriched in carbon char.
- Plasma Arc Gasification (PAG) process: It is a waste treatment technology that uses a combination of electricity and high temperature to turn municipal waste (garbage or trash) into usable by-products without combustion.
It should not be confused with incineration. This technology doesn’t combust the waste as happens in incineration. It converts the organic waste into gas that contains all its chemical and heat energy and converts the inorganic waste into an inert vitrified glass called slag. This process reduces the volume of waste reaching the landfills and also generates electricity.
- Biological Treatment Methods (Use of microorganisms) :
- Bio gasification : It is a waste to energy technique where biological decomposition of organic matter of biological origin under aerobic conditions would be done to produce methane and other secondary gases.
- Composting : In this process, the organic waste is converted into compost through decomposition. Compost is rich in nutrients and can be used as soil conditioner, a fertiliser addition of vital humus and humic acids and as a natural pesticide in soil.
It can also be used for erosion control ,land and sea reclamation, wetland construction and as landfill cover.
- Vermiculture / Vermicomposting : It is the process of making compost through the decomposition process.
But here, decomposition is done by using various species of worms, usually red wigglers, white worms, and other earthworms.
- Bioremediation : It invokes use of bio culture or microorganisms to degrade organic waste and contaminants that pose environmental and human risks. Here the environment is altered to simulate the growth of microorganisms and degrade pollutants. The organic waste is eventually converted into soil.
A widely used approach to bioremediation involves stimulating naturally occurring microbial communities, providing them with nutrients and other needs to break down a contaminant. This is termed biostimulation.
Another bioremediation approach is termed bioaugmentation where organisms selected for high degradation abilities are used to inoculate the contaminated sites. These two approaches are not mutually exclusive; they can be used simultaneously.
- Biomining : Biomining involves use of separator machines or large sieves to separate waste material of different sizes , thereby obtaining soil, plastic ,wood and metal components in isolation for appropriate processing.
| The three landfills in Delhi:
Why in the news? The three municipal corporations in the city are targeting to flatten main garbage dumps by September 2024. There are three main landfills in Delhi- Bhaswati in north, Ghazipur in east and Okhla in South. According to an estimate, together they have around 28 million tonnes of waste. Several studies have shown that leachate from these landfills are not contaminating groundwater but are also reaching Yamuna river. There are traces of heavy metal in ground water and other parameters are several times beyond the permissible range. Other concerns due to landfills: ● Air pollution >= landfills fires are common because of the emission of methane by these landfills. ● Indoor pollution>= the bad smell emanating from these landfills makes the life of people living and working around it very difficult. ● Groundwater and River pollution. ● Wastage of resources >=land resources as well as resources dumped onto the sites. ● Breeding ground for diseases.
In 2019, NGT dismissed the plan to cap landfills and directed the Delhi government and civic bodies to follow the “Indore Model” of Biomining and Bioremediation. |
Solid Waste Management Rules, 2016:
In 2016, The environment ministry had revised the solid waste management rules after 16 years.
Salient features:
Beyond Municipal Areas : The rules are now applicable beyond municipal areas and extend to Urban agglomerations, census towns, notified industrial townships, areas under the control of Indian Railways, airports, airbase, port and harbour, defence establishment, SEZs, state and central government organisations, places of pilgrims, religious and historical importance.
Source segregation of waste has been mandated to channelize the waste to wealth by recovery, reuse and recycle.
Responsibility of Generators have been introduced to segregate waste in three streams :
- Wet (Biodegradable)
- Dry (plastic, paper, metal, wood etc.)
- Domestic hazard wastes (diapers, napkins, empty containers of cleaning agents, mosquito repellents etc.)
Integration of waste picker’s/rag picker’s/ waste dealers in the formal system should be done by the state governments and SHGs or any other group to be formed.
Ban on open throwing, burning or burying : No person shall throw, burn, bury the solid waste generated by him, on streets, open public space outside his premises or drain or water bodies.
User free and spot fine : Generator will have to pay User Fee to the waste collector and for Spot Fine for littering and Non Segregation.
Provisions for Bulk and institutional generators : Bulk and institutional generators, market associations, event organisers and hotels and restaurants have been made directly responsible for segregation and sorting the waste and managing in partnership with local bodies.
All resident welfare and market associations, gated communities and institutions with an are > 5000sq.m should segregate waste at source in to valuable dry waste like plastic , tin, glass, and handover recyclable material to either the Authorised waste picker’s or authorised recyclers, or to urban local body.
The biodegradable waste should be processed, treated and disposed through composting or bio methanation within the premises as far as possible. The residual waste shall be given to the waste collectors or agency as directed by the local authority.
New township and group housing societies have been made responsible to develop in house waste handling and processing arrangements for biodegradable wastes. Street vendors keep separate containers for separate wastes.
The developers of SEZs, industrial estate, industrial parks etc. to earmark 5% of the total area of the plot or minimum 5 plots/sheds for recovery and recycling facility.
Sanitary napkins and diapers manufacturers or brand owners explore the possibility of using recyclable material in the product and shall provide a pouch or wrapper for disposal of each napkin or diaper along with a packet of their sanitary products. Educate masses in wrapping and disposal of their products.
Industrial units using fuel and located within 100 km from a solid waste based RDF plant shall make arrangements within 6 months of notification of these rules to use at least 5% of their fuel requirement by RDF so produced.
Non-recyclable waste having calorific value of 1500k/cal/kg or more shall not be disposed of on landfills and shall only be utilised for generating energy either or through refuse derived fuel or by giving away the feedstock for preparing refuse derived fuels. High calorific wastes shall be used for co-processing in cement or thermal power plants.