Waste management a valuable Resource.

Waste may be defined as material for which no use or reuse is intended. The wastes generated from the natural Processes and anthropogenic activities which pollute the environment and make the earth an unhealthy planet, is termed as environmental wastes, depending upon the physical states of wastes, these are of three types:
●Solid waste
●Liquid waste
●Gaseous waste.

 **Solid waste**  **Liquid waste**  **Gaseous waste**

The accumulation of wastes in different forms causes serious environmental hazards. So, it’s high time for the present society to take appropriate steps for the management of waste, possibly through its recycling. Effective waste management is crucial for conserving resources. For the purpose of today's discussion, I would like to focus specifically on solid waste management?

1. Management of Solid Waste:
   Solid wastes include solid portions of the discarded material such as glass bottles, crockeries, plastic containers, metals and radioactive wastes. The solid wastes may be biodegradable or non-biodegradable. The biodegradable solid wastes are agricultural wastes, food wastes, paper, food processing by products, manure, yard wastes etc. The non-biodegradable wastes include plastics, metals, synthetic materials, polythene, radioactive wastes etc.
   The solid waste management involves disposal of solid waste to land or recovering and reproducing useful substances from the waste through recycling.

The entire methodology of solid waste management is based on:
(A) Collection of Waste.
(B) Disposal.
(C) Resource recovery.

(A) COLLECTION OF WASTE:
Waste collection is the process of gathering and transporting waste from households, institutions, and businesses to a central location for further processing or disposal.The solid wastes are usually collected by a covered truck.

 **Covered truck or Compactor**.

Types of Waste Collection:

1. Door-to-Door Collection: Waste is collected from individual households or businesses.


1. Community Bin Collection/Skip container: Waste is collected from communal bins located in public areas.

 3. *Drop-Off Collection:* Waste is collected from designated drop-off points. .jpg)

(B) DISPOSAL OF WASTE:
After the collection of wastes, the wastes are disposed of by any one of the methods described below;

Dumping: It is a process of controlled and final disposal of waste at landfill sites which must be done using state of the art methods, {base sealing, treatment of percolated water, landfill gas disposal/utilization etc.


Sanitary landfill: It is a method of disposing of the waste without creating nuisances or hazards to public health by using the principles of engineering. In the process, the waste is confined to smallest practical volume by covering it with a layer of earth, at the conclusion of each day’s operation.


Incineration: It is a method of converting the volume of waste to ashes by burning. This method is adopted when the cost of land filling is very high.


Pyrolysis: It is a method of burning waste in absence of oxygen or air. The process reduces volume of the waste and produces stable end products.


Composting: This process involves preparation of refuse and degrading the organic matter in waste in to bio-fertilizer by aerobic micro-organisms. After about 3 to 4 weeks of the operation, the composting product becomes ready for curing, blending with additives, bagging and marketing.

 

Biogas technology: The organic matter present in solid waste is decomposed by putrefactive bacteria in absence of air (anaerobic condition) to biogases in a biogas digestor. The approximate composition of biogas is 60% methane (CH4) and 40% C02 For better yield of biogas, the organic solid waste may be mixed with poultry waste, grass, leaves, straw, kitchen waste etc.


(C) RESOURCE RECOVERY (RECYCLING):
By the process of recycling a number of useful products can be obtained from the solid wastes.
Some important products obtainable from solid wastes are described below:

1. Electricity can be generated from incinerated plastics.
2. Synthetic oil can be produced from plastic wastes.
3. Waste papers and cardboards from sugar cane bagasse can be used for the preparation of unbreakable dolls, packing cardboards etc.
4. Metals can be recycled from the industrial scrap.
5. Ethyl alcohol can be produced from agricultural wastes.
6. Heavy metals can be extracted by bioleaching technology.
7. Waste glasses can be used for the preparation of new glass bottle.
8. Bricks and concretes can be prepared by using ash generated by power plants, slit from water works and red mud from aluminum industry.