Treatment and Disposal of Solid Waste
Open Dumps
- Open dumps are uncovered; unscientific sites where untreated, unsegregated solid waste is dumped. They become breeding grounds for flies, rats, and insects, spreading diseases. Runoff from these sites contaminates nearby land and water. Open dumping is unhygienic and is being phased out as a method of waste disposal.
Landfills
- Landfills are dug-out pits, usually located in urban areas, where waste is dumped daily and covered with soil to prevent pest breeding. Once full, the site is sealed with mud and converted into parks or parking lots. However, water seepage through the waste contaminates groundwater and soil — a process called leaching.
Sanitary Landfills
- Sanitary landfills are a more advanced and hygienic version of landfills. These sites are lined with impermeable materials like clay and plastic to prevent leaching and contamination of groundwater and soil. They are constructed methodically but are expensive to build.
Incineration
- Incineration involves burning waste at high temperatures in large furnaces. Recyclable materials are separated, while the remaining waste is incinerated, producing ash. However, this method releases toxic ash and pollutes air and water. Due to environmental concerns, incineration is used mainly for infectious waste and as a last resort.
Pyrolysis
- Pyrolysis burns waste in a controlled, low-oxygen environment. It is an alternative to incineration and produces gases and liquids that can be used as fuels. Pyrolysis of carbon-rich waste such as firewood, rice husk, or sawdust also yields charcoal and by-products like tar, methanol, acetic acid, acetone, and fuel gas.
Composting
- Composting is a biological process where microorganisms decompose organic waste into humus-like material, rich in carbon and nitrogen. This improves soil fertility, water retention, and nutrient content. Composting is clean, cheap, and safe, and it significantly reduces disposable garbage.
Vermiculture
- Vermiculture (or earthworm farming) enhances composting by using earthworms. These worms break down organic matter faster, and their nutrient-rich excreta makes the compost highly fertile.
Waste Minimization Initiatives
Four Rs
- The principles of Reduce, Reuse, Recycle, and Recover form the foundation of minimizing waste generation and maximizing resource recovery.
Waste Minimization Circles (WMC)
- WMCs help small and medium industries reduce waste. This program, supported by the World Bank and implemented through the National Productivity Council, promotes education and public awareness, enabling citizens and NGOs to monitor environmental risks cost-effectively.