Question

Which of the following compound is broken down by the microbial biofilms in the waste water?

(a) Iron

(b) Nitrogen

(c) Sodium

(d) Potassium

This question was posed to me in an international level competition.

This intriguing question originated from Microbial Biofilm and Wastewater Treatment in chapter Biological Treatment of Waste Water of Environmental Biotechnology

Answer 1

Right option is (b) Nitrogen

To explain I would say: Phosphorus and Nitrogen compounds are present in the waste water and those need to be degraded to get better quality of water which is done by microbial biofilms, Iron, sodium and potassium are treated as highly toxic compounds.