Types of solid waste in urban and rural India, and why the 3Rs and segregation matter

Introduction

Solid waste is the discarded solid and semi-solid material of homes, farms, shops, industries and hospitals. What a place throws away depends on how its people live and work, so the waste of Indian towns and villages differs both in kind and in amount.

Categories of solid waste in urban areas

• Domestic and municipal waste. Household waste has a wet part, mainly kitchen waste that rots easily, and a dry part of plastic, glass, metal and paper that can largely be recycled.
• Commercial and market waste. Shops, offices and markets throw out packaging, paper, cardboard and unsold vegetables and fruit.
• Domestic hazardous waste. Paint drums, pesticide cans, CFL bulbs and tube lights, expired medicines, broken mercury thermometers, used batteries and used needles from homes.
• Hospital (bio-medical) waste. Dressings, bandages, used needles and syringes and tissue can carry germs and need very careful disposal.
• Industrial waste. Factories and mines leave solid wastes from their processes; some of these are toxic chemicals, and mining waste does not break down and stays almost indefinitely.
• Construction and demolition waste. Rubble, concrete and soil from building work.

Towns and cities produce large amounts of plastic, paper, leather, tin cans, bottles and mineral refuse, much more per person than villages.

Categories of solid waste in rural areas

• Agricultural waste. Crop residues such as rice husk, straw and bagasse; this biomass could be used to generate power or make paper.
• Animal waste. Dung, animal excreta and dead animals are mainly rural concerns.
• Agro-chemical residues. Left-over fertilisers and pesticides from the fields are a health hazard.
• Household waste. Mostly biodegradable kitchen and plant waste, though packaged goods now bring plastic into villages too.

Village communities once produced little waste and reused most of it; industrial goods have changed that.

Relevance of the 3R principle

The 3R principle, reduce, reuse and recycle, is meant to be followed in that order. Reducing at source is the best choice, because waste that is never made needs no handling and the pressure on natural resources falls; reusing an article in its present form comes next, since no energy is spent in remaking it; recycling comes last, because although it turns waste into a resource it still uses energy. In India this matters for four reasons. Landfill space near cities is scarce; much of the waste is plastic, glass, metal and paper that can be recovered; materials such as styrofoam and many plastics can take hundreds of years to decompose if they are simply thrown away; and the 3Rs create livelihoods in repair, second-hand markets and recycling. A family that carries a cloth bag, refills water bottles and sells newspapers to the kabadiwala is applying all three.

Relevance of waste segregation

Segregation means sorting waste and storing its components separately: biodegradable waste, recyclable and non-recyclable dry waste, sanitary waste, domestic hazardous waste and construction debris. The Solid Waste Management Rules, 2016 require every generator to keep at least three streams, biodegradable, non-biodegradable and domestic hazardous, and to hand them over separately (rule 4).

• It makes the 3Rs possible: clean dry waste can be sold and recycled, while mixed waste cannot.
• Wet waste kept apart can be composted or turned into biogas instead of rotting in a dump.
• Hazardous items are kept away from people who handle waste and from the soil.
• Only the small reject fraction then needs a landfill, which saves land and money.

A household's quantity of dry waste is a simple measure of how well it follows the 3Rs.

Conclusion

Urban India's waste is large in volume and rich in recyclables and hazardous items, while rural waste is mostly biomass and animal waste. In both, segregating at source and then following reduce, reuse and recycle in order is the most practical way to keep waste out of dumps.