4 Stages of Wastewater Treatment Process

4 Stages of Wastewater Treatment Process

October 26, 2018 0 By Naveen

The wastewater treatment is required for removing waste and other unwanted material from sewage. The process involves several stages for removing harmful water substance and producing safe water that is no a threat to the environment. In the wastewater treatment process systems, effluent from factories, homes, and businesses drains into pipes. The effluent then leads to a treatment center, and then it passes through the wastewater treatment process.

The wastewater treatment process generally involves four noteworthy stages. These four states are preliminary treatment, primary treatment, auxiliary or secondary treatment, and sterilization.

Continue reading this blog to get insights into these four states.

Preliminary treatment

Preliminary treatment is the screening stage of the treatment process. At this stage, the wastewater is pumped through screens that comprise bars a few inches apart. The screens eject bits of junk such as wood, clothes, paper, glass, plastics, and other comparable things. These items are removed from the water for the safety of the pumps and other gear in the next stages. After the successful removal of the materials, the wastewater is pumped to the sedimentation tanks.

Primary treatment

In this stage, the wastewater comes to the sedimentation tanks. The water remains in the tank for two to three hours. This lets the lighter junk such as oil and small plastic material to float. On the other hand, heavier solids reach the base of the tank. This way, the floating junk is skimmed from the highest point of the tanks.

The filtration methods that are applied to the industrial application include oils waste removal, ultra-filtration, Nano-filtration, pulp, and paper removal – paper industry, color removal – textile factories, laundry effluent removal, and ultra-filtration.

After the filtration of small junk, primary sludge (also known heavier solids) are pumped through gadgets that are pumped through devices that use radiating power for isolating granules of different sizes which are then expelled. The treated wastewater (to some extent) from this stage streams to the secondary treatment framework.

Auxiliary treatment

In auxiliary treatment stage, sludge and air are pumped in the tanks for the purpose of further wastewater separation. The air pump blends the muck and wastewater by fortifying the growth of oxygen-utilizing microbes and other bacteria that are usually found in the sewage.

These bacteria or microorganisms ingest much of the organic substance that still contaminates the water. This stage of the Wastewater Treatment Process Systems may usually consume five to seven hours.

After this, the last sedimentation tanks that are much like the ones in the primary stage are used to settle relatively bigger particles at the base as auxiliary much. The rest of the auxiliary muck is removed from the sedimentation tanks.


Sterilization is the fourth stage of the wastewater treatment process. It is typically the use of a chemical or physical procedure for eliminating all microorganisms. It also includes the infusion of a chlorine process into the wastewater in a contact that lasts around half an hour. Despite connecting propelled wastewater treatment necessities, a chlorine contact time may span two hours to remove high levels of solids. It is now again required for employing specific water system for wastewater. The chlorine measurement depends on the quality of the wastewater and the different variables, yet doses of 6 to 20 mg/l are basic.

These are the four stages of the wastewater treatment process.

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