Explain the strategies which should be adopted to control environmental pollution.
Lots of solid waste is generated in the neighborhood. Apart from household wastes, we also have medical, agricultural, mining and industrial wastes. The improper disposal of these wastes results in environmental pollution. Hence, care must be taken while disposing these wastes to reduce the pollution levels in our surroundings.
Recycling
This is the simplest method of treating the waste. Recycling of materials saves much of the raw materials cost as well as reduces the cost of disposal. Some common examples of recycling by industries are:
- Recycling of Glass
- Using scrap metal to manufacture steel
- Recovering energy by burning down of wastes which are combustible in nature
- The use of waste paper.
Sewage treatment
Sewage treatment involves the following three types of stages
- The first stage known as Primary Treatment involves the removal of large solid particles. This is done by mechanical process consisting of screening and sedimentation. For this, the waste is filtered through different types of screens. In the next step solid waste is separated and then dumped in landfill sites. It is then allowed to flow into sedimentation tanks. This process allows removal solid that settles out (sludge). This process also allows removal of grease which floats to the surface and can be skimmed off.
- The second stage known as secondary treatment involves the biological oxidation of organic content of waste materials by micro-organisms followed by filtration.
- In the third step which is also called as final treatment which includes various specialized physical and chemical processes that help in reducing the quantities of specific pollutants that remain in the sewage even after primary and secondary treatments. The quality of wastewater is improved after this process. The common methods used in this treatment involve reverse osmosis, disinfection by chlorine, treatment with activated charcoal, coagulation, filtration, chemical removal of phosphate, etc.
During these operations sludge is produced which also poses a problem for safe disposal. The sludge is dried and then damped or digested or may be incinerated