WASTEWATER - By Rick Lallish
Where do the bacteria obtain the necessary oxygen to survive in an anoxic zone?
A. Remaining dissolved oxygen
B. Nitrite and nitrate
C. Carbonaceous oxygen
D. The bacteria in an anoxic zone do not require oxygen
Answer: B. Anoxic zones are generally found in denitrification treatment processes. Anoxic conditions are created when dissolved oxygen has been depleted, leaving oxygen only available in the form of nitrite and nitrate. More information may be found in the Water Environment Federation textbook: Wastewater Treatment Fundamentals I – Liquid Treatment, Chapter 9.DRINKING WATER - By Drew Hoelscher
The raw water to be treated has a
