Waste

‘This is such a waste of time’ or ‘This food is now a waste’. We use these phrases in our daily life, without giving any thought. Why do we call anything that’s not useful waste? What is Waste? How do you dispose of ‘any’ kind of waste? Let us study about waste below.

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What is Waste?

Trash, garbage, rubbish, junk, worthless-there are so many synonyms for waste; but what makes anything waste? And how does it become so?

‘Waste’ is any unwanted or unuseful material. These are objects that have been discarded since these materials aren’t functioning anymore. Waste can be in any form (liquid, solid or gas), although generally, waste is solid. There are various types of wastes like unwanted food, torn clothes, kitchen waste, etc.

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• Ecosystem
• Effects of Human Activities on Environment

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Types of Waste

There are various types but primarily there are three kinds of wastes:

a. Municipal Wastes:

Municipal Waste commonly consists of items we use on an everyday basis then dump it. Cloths, paints, wires, glasses, unwanted food, etc come under municipal waste. These waste come from schools, factories, but primarily come from our homes.

The composition of municipal waste differs in each municipality and keeps changing with time. Municipal waste divides further into:

a. Household waste:

Materials like unused food, clothes, unwanted paper, damaged batteries, etc come under household wastes. Agricultural wastes also come under household waste.

b. Commercial waste:

Wastes coming from any kinds of businesses, trading factories, schools, etc come under commercial waste.

c. Demolition waste:

As clear from the word ‘demolition’, these wastes come from the destruction of any structure made of concrete, wood, bricks, etc. Although sometimes demolition wastes can also be recycled.  

b. Hazardous Wastes:

Hazardous waste refers to solid, liquid, or gaseous wastes from industries that have either of the properties:

• Corrosiveness
• Ignitability
• Reactivity
• Toxicity

Treatment of these wastes is necessary before the industries dump it. Hazardous wastes are unsafe for human health and the environment at large. Hazardous waste further divides into:

1. Industrial Waste:

Waste produced by industries includes any material that isn’t useful for the industrial manufacturing process. Wastes such are chemicals, pigments, ashes, metals, etc come under industrial waste.

c. Biomedical Waste:

Any waste coming from medical facilities such as hospitals, medical colleges, research centers, etc come under biomedical waste.

Category of Wastes

We just saw types of wastes. Now, these wastes are further divided into various categories i.e. Solid Waste or Liquid Waste.

Solid Waste:

Any kind of garbage coming households, factories or hospitals come under waste. Except solid wastes are only solids or semi-solids. These solids/semi-solids can be dry or wet.

Wet Waste:

Any dissolved liquid based waste or sludge coming from wastewater plants, households, etc come under wet waste.
Examples such as leftover curries, juices, rotten vegetables will come under wet waste

Dry Waste:

Waste which isn’t dissolved in any form or in liquid form come under dry wastes. Examples such as plastics, bottles, etc will come under dry waste.

Biodegradable Waste:

Any organic material that can be synthesized into carbon dioxide, water, methane or organic molecules by organisms in the soil come under biodegradable waste.

Nonbiodegradable Waste:

Any material that cannot be synthesized into CO2, water or CH4 come under non-biodegradable waste.

Methods to Dispose Waste

Dustbins aren’t the only method to throw waste away. Here are few alternatives:

a. Burial Pits/Landfills :

Throwing daily wastes in burial pits or what are also known as landfills is an alternative for dustbins and is the popular waste disposal method.It looks after burying waste in the ground and eliminating foul smell coming from the wastes.

b. Incineration:

Burning of waste at high temperatures and converting them into residue or gaseous products is known as ‘Incineration’. It’s a better alternative to dustbins since the volume of waste here decreases by 20-30%.

c. Recycling:

The process of reusing the discarded materials and converting them into something new is known as ‘Recycling’. It’s the third main element in the process of ‘Reduce, Reuse and Recycle’. Recycling reduces the harmful effect of greenhouse gases and helps in conservation of resources for future.

d. Composting:

When organic wastes are kept in a pit for a long period of time the microbes start decomposing the waste. If the compost is nutrient rich then it becomes a better manure for plants.

Can you think of any more methods?

Solved Example for You

Q. Most harmful environmental pollutants are:

a. Biodegradable items

b. Non-biodegradable items

c. Corrosive Agents

d. Toxic Chemicals

Sol: b. Non-biodegradable items

Waste that cannot be broken down by other living organisms come under non-biodegradable waste. Non-biodegradable substances affect the environment. They may enter the food chain and harm the organisms in the higher trophic levels (by biomagnification), e.g., pesticides, like DDT, non-biodegradable substances like radioactive wastes, lead, mercury etc., affect the health of all living organisms.