In this section of Solid waste management we will discuss the technologies used for treatment of solid waste to recover some valuable products. But before treatment of waste; it should be processed as per the desired technology.

Waste Processing

Waste processing means the physical alteration in waste to make it best suited for technology adopted for its treatment. The processing of wastes helps in achieving the best possible benefit from every functional element of the solid waste management (SWM) system. It requires proper selection of techniques and equipment for every element to derive maximum economical value. Various methods used in waste processing are baling, shredding, compaction, drying, metal segregation etc.

Objectives of processing techniques:

Three major objectives of any processing done on waste are:-

Improving efficiency of SWM system: the technology should always help in making the waste transport and storage effective.
Example – waste paper is baled to reduce transporting and storage volume requirements, compaction and shredding of waste is done to improve the efficiency of the transportation and disposal.

Recovery of resources: materials with high market value and in sufficient quantity are recovered from mixed waste by various segregation techniques
Example – paper, cardboard, plastic, glass, ferrous metal, aluminium and other residual metals

Recovering conversion products and energy: Combustible organic materials can be converted to intermediate products and ultimately to usable energy. Incineration, pyrolysis, composting or bio-digestion.
Shredding and drying is necessary before the waste material can be used for power generation to reduce moisture content.

At the stage of storage and transportation, it is very important to store maximum waste in one truck and small storage area. This reduces the fright of trucks and storage space thus reduces the investment. Various methods are used to reduce the volume of waste. The most widely used techniques are mechanical, chemical and thermal techniques of volume reduction.

Types of Volume Reduction for SWM

·         Mechanical Volume reduction

·         Thermal Volume reduction

·         Chemical Volume reduction