Question

Which one is a biological in sewage treatment?

• A. Primary treatment
• B. Secondary treatment
• C. Tertiary treatment
• D. All of the above

Answer 1

The correct option is B Secondary treatment

The sewage treatment unit employs the primary, secondary and tertiary treatment for the complete process. In the primary treatment, filtration of the large and solid waste is done. Then in secondary treatment, the decomposing microbes are used for the breakdown of the organic sewage. So, the secondary treatment is the biological treatment of the waste water. In the tertiary treatment, the chemical treatment is provided to the water.

Hence, the correct answer is 'Secondary treatment'