A. treatment of sewage
B. treatment of water
C. purification of chemicals
D. purification of metals

Correct Answer:

Option A – treatment of sewage

Explanation

There are several wastewater treatment methods based on biotechnology that are used worldwide. It includes Activated Sludge, Oxidation Ponds, Tricking Filters, Bio-filters and Anaerobic treatment. All the methods are part of the biological wastewater treatment and use microbes to treat organic waste in sewage.

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