Water that is affected and contaminated by human use is called wastewater. It is nothing but the water that has been used for various purposes such as domestic, industrial, commercial or agricultural activities or any sewer infiltration.

It is important to treat such water so that it can be reused and recycled for other purposes. The process of treating this water and removing harmful pollutants & contaminants is what wastewater treatment is about. The wastewater is converted to effluent that can be returned to the water cycle or maybe directly reused for other purposes. This treatment process takes place in a wastewater treatment plant or a Sewage Treatment Plant (STP). The pollutants are either removed or broken down.

Disposal or Reuse of Wastewater:

Reuse or the disposal of water occurs generally after the wastewater treatment, but it must be considered in the beginning itself since that is the ultimate objective of wastewater treatment. The most common reason to reuse wastewater after treating is to identify it as a new water sources as there is an increased demand for water and the need for a dedicated source of water supply.
Benefits of Reusing Wastewater:
• There is an increase in water availability
• Can reserve drinking water for drinking needs and treated wastewater for other purposes
• There will be a reduce in over abstraction of groundwater
• The energy consumption associated with production & distribution of water will be less
• Increase in agricultural production
• Protection of environment by way of restoration of streams, wetlands & ponds

Wastewater Treatment Plants:

1. Sewage Treatment Plants:
A sewage treatment plant may include a primary treatment method to remove solid material, and a secondary treatment to digest suspended organic material. The terms Sewage Treatment Plant and Wastewater Treatment Plant are sometimes used interchangeably. Sewage can also be treated by nature-based solutions processes.

2. Industrial wastewater treatment plants:
Disposing off the wastewater from industrial plants is comparatively difficult and a costly affair. Most of the petroleum, chemical & petrochemical industries have an onsite facilities to treat their wastewaters so that the pollutants from untreated wastewater do not mix up with the local rivers, lakes & oceans directly. The industrial wastewater treatment plants may help & reduce the raw water costs by converting the wastewater into useable recycled water that can be used for other purposes.

3. Agricultural Wastewater Treatment Plant:
This treatment plant for the continuously narrowed animal operations like egg and milk production may be performed in plants using automatic treatment units similar to those described under industrial wastewater treatment plants, but when land is available for ponds & rivers may have less operational costs or seasonal use conditions from breeding or harvest cycles.

4. Leachate Treatment Plant:
A leachate is any fluid that, which over the course of passing through matter, removes solvent or suspended solids, or some other part of the material through which it has passed through.
Leachate treatment plants are utilized to treat leachate from landfills. Treatment choices include natural treatment, mechanical treatment by ultrafiltration, treatment with dynamic carbon channels, electrochemical treatment including electrocoagulation by different restrictive advances and switch assimilation film filtration utilizing plate tube module innovation.

To sum up, a wastewater treatment plan is necessary as the treated water can be reused for various purposes other than drinking water. This can help us maintain the water levels and avoid excess use of surface & groundwater.