11/26/2011

What happens to waste

What happens to the rubbish we produce?

How much waste we produce and what we do with it are vital if we wish to live in a sustainable society.
Waste from our homes is generally collected by our local authorities through regular waste collection, or by special collections for recycling. In addition, householders may make special trips to their civic amenity (CA) site, or organise a bulky waste collection in order to dispose of particular items.

Whilst it is difficult to monitor reduction and reuse schemes, councils and waste management companies do collect figures allowing us to note how much of collected waste is intended for recycling (or recovery) and how much for final disposal through landfill. The main methods currently employed are landfilling, recycling, composting and energy from waste plants.

Landfill

At the most basic level landfilling involved placing waste in a hole in the ground and covering it with soil. Today, the engineering of a modern landfill is a complex process, typically involving lining and capping individual "cells" into which waste is compacted and covered to prevent the escape of polluting liquid or gases. Systems are installed to capture and remove the gases and liquids produced by the rotting rubbish.

Household waste recycling

Recyclate from recycling collections are frequently sent to a materials recycling facility (MRF).
At the MRF the materials typically travel along a conveyor belt and the specific fractions are gradually removed. Metals may be extracted using magnets, paper taken off by weight and other screening devises used. Following separation the constituent material are baled prior to sending to reprocessors.

The activities at these plants are specific to the material being processed Ð pulping and shredding of paper, granulation of plastics, melting of metals and glass to name but a few.

Many goods produced with recycled content will end up in the shops as ordinary household products, such as bin bags, stationery, furniture, or even filling for duvets and pillows.

Composting

The biodegradable component of municipal waste that will break down is know as BMW and includes kitchen and garden waste, paper, card and more. Composting allows this material to break down and results in the formation of compost that can be used as fertilizer.

Although compost can be made at home, councils are increasingly developing centralised composting schemes for residents' garden waste to tackle this large and problematic part of the waste stream.
Incineration

Incineration is the burning of waste. Incineration may be carried out with or without energy recovery. The energy released from burning the rubbish is often used to generate electricity.

source:http://www.wasteonline.org.uk/topic?topic=a0gC0000002RwGLIA0

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