Question
With reference to the role of biofilters in Recirculating Aquaculture System, consider the following statements:
1. Biofilters provide waste treatment by removing uneaten fish feed.
2. Biofilters convert ammonia present in fish waste to nitrate.
3. Biofilters increase phosphorus as nutrient for fish in water.
How many of the statements given above are correct?
Explanation
Statement 1 is correct: Biofilters host microorganisms that break down organic waste, including uneaten fish feed, helping keep the water clean.
Statement 2 is correct: Nitrifying bacteria in biofilters convert toxic ammonia first into nitrite and then into less-harmful nitrate, a process central to maintaining water quality in aquaculture systems.
Statement 3 is incorrect: Biofilters are actually used to reduce, not increase, phosphorus levels in aquaculture water — excess phosphorus is a pollutant to be managed, not a nutrient boost for fish.
With statements 1 and 2 correct, the answer is Option B.