Solid waste treatment

The different methods adopted for solid waste disposal and treatment are - open dumping, landfilling, sanitary landfilling, ocean dumping, incineration, pyrolysis, composting and vermicomposting.

 

Open dumping

It is the method of dumping the waste in open areas, which is far away from the cities or unmanned areas. This method is not possible in populated areas and it is mostly used in the deserts in the Gulf countries.

Landfilling  

The wastes are carried and dumped in low-lying areas.

Sanitary land filling

As in open dumping and landfilling the decomposed material percolate down to the underground and contaminate the underground water, the third method called sanitary landfilling is used to solve these issues. In this method, specially made garbage pits are lined with plastic or some other material. Thus isolate the sand from the waste material. After filling a layer of garbage it will be covered with sand and again garbage and it will be continued. It is highly costlier.
Ocean dumping
In this method, the solid waste is packed in a particular way and dumped into the ocean. But it has a disadvantage that it will adversely affect the Marine ecosystem.
Incineration
Incineration means burning of the solid waste in properly constructed furnace. This method is applied when suitable dumping places are not available. In this method first of all the combustible and non-combustible materials are separated. The final products will be ashes and clinkers which can be reused for various purposes.

Pyrolysis

As in the incineration process, the burning of waste produces more carbon dioxide and particulate matters which also are a pollutant. So this issue can be solved in this method called pyrolysis. In this method the wastes are heated at 650 degrees Celsius in low oxygen or oxygen free environment. The end products are gas and tar which can be used for either as fuel or it can be used for industrial purposes.

Composting

In this method waste materials are decomposed into humus and stable, mineral compounds by biological process like using fungi and bacteria. This method is considered as best suited for Indian conditions, especially for small and medium-sized towns.

Vermicomposting

In this method, earth worms are added in the compost to make it richer in nutrients.