Municipal Solid Waste Research Paper

Abstract - This paper contains the various scientific techniques adopted in the municipal solid waste management system to separate the waste plastic from municipal solid waste. The municipal solid waste contains variety and mixture of wastes including organic and inorganic wastes, biodegradable and non-biodegradable wastes, animal waste, street waste, hazardous waste, etc. There is a need to treat these wastes to reduce their impact on the environment and human beings. The waste needs to be separated and sorted according to their type and nature. The major problem now-a-days is waste plastic which needs to be separated from the municipal solid waste dumps. The waste plastic is firstly separated from the municipal solid waste and further is

In many cases, there is also a need to separate different plastic types (e.g. PVC, PET and polyethylene) from each other. In several cases, plastics are also sorted by color in order to improve the physical appearance of the products derived from post-use material. The following methods can be adopted to separate the waste plastic from other wastes.

3.1.1. Manual sorting

The process of separating waste plastic is based on labor-intensive. The rag pickers and kabari-walas are the media who sort the waste according to the types and characteristics. The workers pick the plastic, paper, cardboards, plastic bottles and collect it for recycling. It is the most common method applicable in all types of areas.

Sorting by density

The overall density of a plastic material can however be altered significantly by the incorporation of fillers or by foaming. Separation of materials by density in float-sink tanks or hydrocyclones is commonly applied to ground waste plastics. The polyolefins most commonly used in packaging applications, PP, LDPE and HDPE, are notoriously difficult to separate efficiently because of the small difference between their densities. [8]

3.1.3. Air classifications

It is possible to sort materials by a combination of density shape using air streams. The technique is called air classification or air sorting. It can be used to sort e.g. film plastics and paper residues from ground plastic flakes. Low velocity air is used to separate lighter materials (e.g., aluminum and plastics) from heavier materials (glass). This can be accomplished by: o Blowing the lighter materials across an air knife to another conveyor at a conveyor tail pulley (heavier materials drop over the tail pulley);