Question

Briefly explain wastewater treatment (biological treatment).

Answer 1

Wastewater treatment is divided into three stages, namely primary, secondary and tertiary treatment.

• Primary treatment consists of temporarily holding the sewage where heavy solids settle down and oil, grease, and lighter solids float to the surface.
• Secondary treatment is the biological treatment. In this, a wide variety of microorganisms are used under aerobic condition. The microorganisms convert biodegradable organic matter present in wastewater into simple substances. Aeration provides the necessary oxygen required by aerobic microorganisms. Aerobic biological treatment processes include activated sludge process, trickling filter, oxidation ponds. Activated sludge process is the most widely used process for domestic and industrial wastewater. Biological treatment is used widely as it is effective and economical than any other chemical processes.
• Tertiary treatment includes chlorination, ultrafiltration.