ABC Wastewater Level 3 - Activated Sludge Questions & Answers Graded A+

ABC Wastewater Level 3 -Activated Sludge Performance problems in the activated sludge process can be caused by ____________. A. Poor solids dewatering B. Inadequate chlorination of effluent C. Consistent influent characteristics D. Insufficient operator training - Answer -D. Insufficient operator training Solids that float to the surface of the clarifier are referred to as ____________. A. Mixed liquor B. Film C. Residual solids D. Scum - Answer -D. Scum Solids that settle to the bottom of clarifiers and are removed from the process are referred to as ___________. A. RAS B. WAS C. TSS D. Total residual chlorine - Answer -B. WAS Large amounts of filamentous bacteria can improve floc structure and speed the settling of the mixed liquor. A. True B. False - Answer -B. False Protozoans are much more abundant than bacteria in activated sludge. A. True B. False - Answer -B. False Under normal conditions, fungi (yeast and molds) are present in activated sludge processes. A. True B. False - Answer -B. False Algae are microscopic plants that can become a nuisance in clarifier launders. A. True B. False - Answer -A. True Which of the following does not result from a pH imbalance in an activated sludge process? A. Power consumption B. Inability to maintain a healthy biomass C. Damage to process equipment D. Increased cost because of chemical addition - Answer -A. Power consumption Because of industrial flows and the nitrification process, pH imbalances may become a concern for activated sludge processes if sufficient __________ is not present. A. TSS B. Alkalinity C. Ammonia D. BOD - Answer -B. Alkalinity Which of the following is NOT a phase of a typical sequencing batch reactor treatment cycle? A. Filter B. Fill C. Decant D. Settle - Answer -A. Filter Because multiple steps occur in a single reactor, the sequencing batch reactor process provides little control over effluent quality. A. True B. False - Answer -B. False Which of the following terms is used to describe biological reactors arranged in a parallel configuration? A. Parallel processors B. Parallel -lined systems C. Multiple process trains D. Reactor chains - Answer -C. Multiple process trains Using portable DO meters can be more economical than using permanently installed, continuous -read units. A. True B. False - Answer -A. True What equipment can be used with surface aerators to aid mixing in deep reactors? A. Draft tubes B. Rotor extensions C. Turbo injectors D. Extended impellers - Answer -A. Draft tubes What type of problem can the splashing of surface aerators cause in or around a reactor? A. Poor oxygen transfer B. Inadequate mixing C. Excessive heat gain D. Biohazards - Answer -D. Biohazards Accelerated respiration rates in high -purity oxygen systems require increased detention times for sufficient treatment of wastewater.