UNDERSTANDING WASTE

UNDERSTANDING WASTE

• What is waste?
Waste is any material that is thrown away as unwanted. It has other names like garbage, trash and rubbish. What is considered waste by one society may not be considered so by another. For example, in throwaway societies like the US, a good-quality plastic cup may be thrown away as waste. The same cup may be reused several times in India.

• How does nature manage its waste?
In nature, there is no such thing as waste. What is given out by one system is taken in by another. When a tree sheds its leaves, they fall on the ground, get consumed and broken down by soil organisms into simple nutrients. The tree absorbs these nutrients once again to grow new leaves.

• How did we end up in a waste crisis?
Before the industrial revolution, we were largely a biomass civilisation and used natural materials. Production processes were driven by animal, human, water and wind powers, limiting production to just meet the needs of the people. Waste was organic, biodegradable and limited in quantities. After the industrial revolution, we became a mining civilisation. Production processes began to be driven by fossil fuels, resulting in production in excess of human needs. Waste became non-biodegradable and toxic, and began to be generated in huge quantities.

• Modern waste is a mixture of all the following different types of wastes:

1. Municipal Solid Waste: Commercial and residential wastes generated in a municipal area in solid or semi-solid form.
Organic: Degradable wastes like vegetable, vegetarian and non-vegetarian food, coir, cotton, leather, shells, flowers, fish, dead animals and garden waste. When not contaminated with chemicals, organic waste can be composted, turned into resource and safely returned to the earth.
Inorganic: i. Safely recyclable materials like paper, metal and glass; ii. recyclable (but not safe) materials like thermoplastics; iii. non-recyclable materials like thermosetting plastics, thermocol, composite materials (eg. Aluminium coated paper); iv. toxic waste like batteries and electronic waste.

2. Hospital Waste: Infectious waste like soiled bandages, used cotton, pathological and anatomical waste; inorganic waste like tubes, plastics, glass and syringes, generated in hospitals, nursing homes, clinics, blood banks and veterinary hospitals. Hospital waste could pose great health risks when mixed untreated with the general waste stream.

3. Construction Waste: Rubble, wires, pipes, steel and wood from the demolition of existing buildings. Though most of this waste is inert, it is huge in volume and weight and often blocks roads and nullahs.

4. Industrial Waste: Solid waste from industries is in the form of sludge containing toxic heavy metals, oils and bleaches besides other chemicals, usually toxic. These are often mixed with municipal solid waste.

5. Electronic Waste: Used computers and other electrical and electronic gadgets like television sets, refrigerators and cell phones. This highly toxic waste (due to the presence of heavy metals) is on a steep rise.

Others: Rocks, coal waste and other ore-processing residues are mining waste, which, though inert, covers extensive land (usually natural) areas and degrade the environment. Nuclear waste is radioactive and can cause serious environmental and health damages. Human waste, though solid in form, currently gets mixed with fresh water and gets treated as liquid waste.

• Who generates how much?
A person in an industrialised country like the US generates more than twice the amount of waste (2 kgs per person per day) than a person in a less-industrialised country like India. A city dweller in India generates twice the amount of waste than a villager. An Indian with an income higher than Rs. 8,000 generates more waste per day (800 gms) than a person with an income less than Rs. 2,000 (200 gms).

Toxic Waste

Waste is toxic when it contains or releases hazardous chemicals (e.g. heavy metals like lead, arsenic, cadmium, chromium) or releases hazardous chemicals (Persistent Organic Pollutants like dioxins and furans), which are disruptive to the normal functioning of the human organs. Some of the health defects are reproductive and birth defects, nervous disorder, cancer and brain damage, immune and hormonal systems dysfunction. The following are the most common toxic municipal wastes:
• Smelting waste, batteries and electronic waste contain heavy metals.
• PVCs (chlorinated and brominated plastics) release dioxins on burning.
• Tyres and thermocol release harmful gases on burning.

The Worldwatch Institute has listed toxic waste as one of the most serious global issues threatening the humankind. It is not only generated within India, but is also being imported in huge quantities from the Western countries, where toxic waste disposal is very expensive and is required to follow stricter standards.
PLASTICS

This material, which was invented 50 years ago, is manufactured using petrochemicals as raw materials. It is normally inert and does not degrade for thousands of years.

Plastic bags are a menace in India, as they clog the drains and can be swallowed by the cattle and choke them to death. Though thermoplastics can be melted and remoulded again, they lose their original quality and eventually become non-recyclable. Thermosetting plastics (bakelite and melamine used to make switchboards) cannot be recycled.

28% of plastics produced in India is PVC, the most dangerous of all plastics. When disposed by burying, additives leach into the soil and pollute the groundwater, and when burnt, it releases toxic dioxins, a Persistent Organic Pollutant (POP). POPs can stay on in the environment for a long period of time and have been marked for global elimination in the POPs Treaty signed under the UNEP.

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