Advanced Wastewater Treatment Exam Questions with Correct Answers

activated sludge - Answer-Activated sludge is a mixture of sludge particles (floc), bacteria, fungi, protozoa, and rotifers maintained in suspension by aeration and mixing. aerobic (oxic) - Answer-Aerobic is a condition in which free and dissolved oxygen (DO) is available in an aqueous environment. anaerobic - Answer-Anaerobic is a condition in which free, dissolved, and combined oxygen is unavailable in an aqueous environment. anoxic [NO2, NO3, SO4] - Answer-Anoxic is a condition in which oxygen is only available in a combined form such as nitrate (NO3-), nitrite (NO2-), or sulfate (SO4) in an aqueous environment. denitrification - Answer-Denitrification is a biological process where bacteria convert nitrate (NO3-) and nitrite (NO2-) to nitrogen gas (N2) under anoxic conditions. floc - Answer-Floc is clusters of microorganisms and solid particles that form in the activated sludge process and settle in the final clarifier. F/M - Answer-F:M is the amount of food (biochemical oxygen demand (BOD)) provided to the microorganisms (mixed liquor volatile suspended solids (MLVSS) or mixed liquor suspend solids (MLSS)) in the aeration basins. How is F:M determined? - Answer-F:M is determined by dividing the pounds of influent BOD by the pounds of MLVSS or MLSS under aeration. HRT - Answer-HRT is the period of time that wastewater remains in a tank. This is important because treatment processes require sufficient time for the wastewater to be treated. marbling. - Answer-Marbling is the variegated, marble stone like appearance on a quiescent part of an aeration