Wastewater treatment contributes to environmental protection, human health protection, and water supply relief. After primary treatment, secondary wastewater treatment uses biological processes to further purify the water.
Organic materials that can be biodegraded can be dissolved and suspended after further treatment. It is also possible to use secondary treatment to get rid of dissolved phosphorus and nitrogen components from a wastewater stream.
Why is secondary treatment of wastewater necessary?
Before wastewater is sent to a disposal field for final treatment, secondary treatment is required to lower the number of organic compounds in the wastewater.
Primary goal of secondary wastewater treatment
The primary objective of secondary wastewater treatment is to substantially reduce the amount of fine suspended and dissolved organic matter, which is still present after primary treatment so that the effluent can be discharged.
It is permitted when standard secondary treatment lowers BOD and suspended solids, to less than 20 mg/l and 30 mg/l, respectively.
Secondary goal of biological or secondary wastewater treatment
The second objective of secondary wastewater treatment is to lessen ammonia toxicity, and nitrification oxygen demand in the stream. The majority of the ammonia is transformed into nitrate during this treatment (nitrification).
The process of nitrification involves turning ammonia into nitrate. The units must be larger than those required for carbonaceous matter oxidation alone, if they are operating at low organic load rates.
Also, sedimentation, the first step in the wastewater treatment process, typically removes 60 to 70 percent of the suspended particle matter, which contains 30 to 40 percent of the BOD present in municipal wastewater. This leaves the primary effluent with 150 to 200 mg/l BOD and about 100 mg/l SS. This is why, secondary treatment of wastewater is necessary.
Chemical unit processes, such as chemical oxidation, coagulation-flocculation and sedimentation, chemical precipitation, and so on, as well as biological (aerobic or anaerobic) processes, in which bacteria act as a catalyst for pollutant removal, can be used for the secondary treatment of wastewater. Thus, the removal of organic components from wastewater is a common goal of biological treatment processes.
As a result, a biological reactor, either single-stage or multi-stage, will typically be utilized for the treatment of wastewater such as sewage, and various agro-based enterprises and food processing industrial wastewaters, depending on the needs to satisfy discharge laws.
What can we offer?
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Contact us if you require assistance with the design of an effective onsite wastewater treatment system or water treatment system. We can assist you with design calculations, financial planning, rough layouts, and lifetime cost analyses. For further information, contact us at +91 9650608473 or email at email@example.com.