Sewage treatment plant is essential to free the waters utilized for irrigation or drinking or household purposes from harmful contaminants. In order to make the waste water reusable, the contaminants in it must be significantly reduced by removing bacteria, suspended solids, organic wastes, and phosphates polluting it.

Sewage treatment refers to domestic wastewater treatment and seeks to remove pollutants from household sewage, both domestic and runoff. Environmental engineers are typically responsible for building and designing facilities to treat wastewater. They use chemical, biological, or physical methods to create systems to treat this wastewater and send it back to the environment.

The traditional sewage treatment plant includes three stages- namely primary, secondary, and tertiary. In the first stage, solids are extracted from the wastewater and the dissolved matter gets changed into solid masses using homegrown water-borne microorganisms. These are thereafter neutralized and then discarded or re-used. The water gets disinfected physically or chemically through lagoons or microfiltration.

Finally, the treated water is then discharged into a river, stream, or wetland and may be reemployed for irrigation purposes.

A sewage treatment plant works to remove suspended solids and BOD (biochemical oxygen demanding waste)-this helps to lessen fish kill because of eutrophication or the diminishing oxygen levels which can harm marine life. The different types of treatment are as follows:

* Primary treatment: those substances which can be easily extracted from wastewater are removed like oil and fat, rocks, and trash.

* Secondary treatment: reduces biological contaminants inside the sewage. Here, microorganisms are encouraged to eliminate the unwanted elements in sewage water.

* Tertiary treatment:  helps to better the quality of water before it is returned to the environment. This can be done through artificial filters or natural filters like wetlands and lagoons. Treatment can be given to remove excess phosphorus and nitrogen.

* A sewage treatment plant often undertakes a final stage of chlorination to totally remove the microorganisms before releasing the wastewater-this chlorine is ultimately removed with sulphur dioxide reaction so that is remains safe for life to exist in this wastewater. Finally, this treated wastewater flows into a river.

Reasons to Invest In Sewage Treatment Plants:

* These companies have industry leading expertise in such treatment facilities, wastewater management, and disposal.

* Such plants can solve drainage related problems in the most eco-friendly manner possible.

* Sewage plants provide a range of products like pumping stations, grease traps, etc.

* A sewage treatment plant is likely to enjoy a long list of customers like homeowners, owners of hotels and restaurants, golf clubs, housing associations, and so forth.

The sewage treatment plant needs to be environment friendly, and rust and leak proof. The plant should also be lightweight, long lasting, and easy to install and maintain. Sewage treatment plants can either be aerobic STP where oxygen is continuously being supplied to a biological reactor using impellers driven by pumps or employing air root blowers leading to oxidation of the carbonic substances to water, nitrogen, and carbon dioxide lessening odor.

The other type of STP is anaerobic where the sewage is partly decomposed in closed reactors without air leading to reduction of the organic matter into hydrogen sulphide, methane, and carbon dioxide.