The most effective way of separation is manual sorting in households prior to collection.

The municipality generally provides separate, easily identifiable containers into which the householder deposits segregated recyclable materials such as paper, glass, metals, etc.

Usually, separate collections are carried out for the recyclable material. At curbside, separate areas are set aside for each of the recyclable materials for householders to deliver material – when there is no municipal collection system.

In case the separation is not done prior to collection, it could be sorted out through mechanical techniques such as Mechanical component separation, magnetic separation, etc., to recover the wastes

1. Mechanical component separation

Component separation is a necessary operation in the recovery of resources from solid wastes and where energy and conversion products are to be recovered from processed wastes. For example, trammels are now used routinely for the separation of unprocessed waste. Along with trammels, shredders are also used for the separation.

2. Magnetic separation

The most common method of recovering ferrous scrap from shredded solid wastes involves the use of magnetic recovery systems. Ferrous materials are usually recovered either after shredding or before air classification.

When wastes are mass-fired in incinerators, the magnetic separator is used to remove the ferrous material from the incinerator residue. Magnetic recovery systems have also been used at landfill disposal sites.

The specific locations, where ferrous materials are recovered will depend on the objectives to be achieved, such as reduction of wear and tear on processing and separation equipment, degree of product purity achieved and the required recovery efficiency.

Equipment used for magnetic separation Various types of equipment are in use for the magnetic separation of ferrous materials.

The most common types are the following:

2.1. Suspended magnet:

In this type of separator, a permanent magnet is used to attract the ferrous metal from the waste stream.

When the attracted metal reaches the area, where there is no magnetism, it falls away freely.

This ferrous metal is then collected in a container. This type of separation device is suitable for processing raw refuse, where separators can remove large pieces of ferrous metal easily from the waste stream.

2.2. Magnetic pulley:

This consists of a drum-type device containing permanent magnets or electromagnets over which a conveyor or a similar transfer mechanism carries the waste stream.

The conveyor belt conforms to the rounded shape of the magnetic drum and the magnetic force pulls the ferrous material away from the falling stream of solid waste.

3. Screening

Screening is the most common form of separating solid wastes, depending on their size by the use of one or more screening surfaces.

Screening has a number of applications in solid waste resource and energy recovery systems. Screens can be used before or after shredding and after air separation of wastes in various applications dealing with both light and heavy fraction materials.

The most commonly used screens are rotary drum screens and various forms of vibrating screens. Note that rotating wire screens with relatively large openings are used for separation of cardboard and paper products while vibrating screens and rotating drum screens are typically used for the removal of glass and related materials from the shredded solid wastes.

4. Drying and Dewatering

In many solid waste energy recovery and incineration systems the shredded light fraction is pre-dried to decrease weight.

Although the energy requirements for drying wastes vary with local conditions, the required energy inputs can be estimated by using a value of about 4300kJ/kg of water evaporated.