American Water College Practice Test

These questions are part of the practice quiz. Start practicing

• What characterizes an oxidation pond in waste water treatment?
• What may indicate inadequate mixing in a digester?
• What effect do aerobic bacteria have on dissolved oxygen in water bodies if domestic wastewater is untreated?
• What temperature range is suitable for refrigerating samples collected for BOD analysis?
• How does aerating wastewater prior to primary clarification affect grease removal?
• What is formed when water combines with chlorine in the chlorine feed system?
• Under normal conditions, how long do solids remain in an anaerobic digester?
• Under normal operating conditions, what color is activated sludge expected to have?
• Which gas is primarily generated along with carbon dioxide during anaerobic digestion?
• What is the role of coagulants in wastewater treatment?
• Which of the following describes the relationship between colloids and electrical charge in water?
• What defines a flow proportional sample in wastewater collection?
• In wastewater treatment, what form is chlorine usually applied?
• What is the typical percentage of BOD reduction achieved without chemical addition in primary clarification?
• What can occur if ammonia levels increase in the primary clarifier?
• What can be a consequence of prolonged exposure to hydrogen sulfide gas?
• Which substance can be added to a sour digester as a remedial measure?
• What is the actual weight of a 150-pound chlorine gas cylinder when including the tank?
• What percentage of total solids in wastewater is characterized as dissolved solids?
• What classification do trickling filters and their various forms fall under?
• Why is it important to maintain adequate mixing in an anaerobic digester?
• Which of the following is a common cause of a sour digester?
• What is hydraulic loading in wastewater treatment?
• What is the primary function of the secondary clarifier in wastewater treatment?
• Which two parameters should an operator monitor to ensure proper settling in a primary clarifier?
• What advantage does an Aire Drive unit provide on an RBC?
• What is a common concern in anaerobic waste treatment environments?
• What is the ideal thickness of healthy biomass on the RBC disks in the first stage?
• What is one method to address a sour anaerobic digester?
• Why do viruses not increase in number while in wastewater?
• What happens to inorganic materials in a grit channel during wastewater treatment?
• Do viruses increase or decrease in wastewater?
• How do warmer temperatures affect the biological activity in a trickling filter?
• What should be ensured to help maintain a functioning digester?
• What is defined as groundwater entering the collection system through leaking joints, cracks, or holes in the pipes?
• When operating a trickling filter, what should operators aim for regarding recirculation rate?
• Which statement is true about virus reproduction in wastewater?
• How can an operator cure a sour anaerobic digester?
• What type of process is a trickling filter?
• What reaction helps operators identify chlorine leaks?
• What is the importance of the recirculation rate in a trickling filter?
• Why is wastewater treated?
• What is the purpose of trickling filter media?
• What does a brown foam on the surface of an aeration tank indicate?
• What is a proper response if a hydrogen sulfide gas leak occurs?
• In what type of facilities is the food-to-microorganism (F:M) ratio used as a primary control parameter?
• What is the main purpose of anaerobic digestion in wastewater treatment?
• How should ton cylinders of chlorine gas be positioned during transportation?
• What is one cause of foaming in an aeration basin?
• Why is grease removal from wastewater more difficult when the pH is below seven?
• What percentage of total solids in wastewater is characterized as suspended solids?
• What is a potential use of a trickling filter in wastewater treatment?
• What happens when the pH of wastewater is controlled above seven regarding grease?
• What happens to the solids during flocculation?
• What potential issue arises from a thick zoogleal mass in trickling filters?
• Which process involves adding chemicals to enhance coagulation and sedimentation?
• How is recirculation of affluent performed in a trickling filter?
• What is the primary function of a trickling filter?
• Which body system is primarily affected by hydrogen sulfide gas exposure?
• Why is hydrogen sulfide gas considered particularly dangerous?
• What can result from inadequate dissolved oxygen (DO) levels in an aeration tank?
• Which element is NOT typically associated with enhanced primary treatment?
• In anaerobic digestion, what is a common technique used to prevent explosive conditions?
• What is a characteristic of a ton cylinder for chlorine gas?
• When should chlorine residual be analyzed after sample collection?
• What is the purpose of notches in weirs?
• What is a common requirement of NPDES permits regarding wastewater treatment?
• In the process of treating a sour anaerobic digester, what is a last resort method?
• What does surface loading help determine for treatment tanks?
• Why is it critical to manage sludge bulking in wastewater treatment?
• What characterizes the sludge in the bulking process?
• Which of the following is considered fixed media in wastewater treatment?
• What is the primary treatment process designed to do in wastewater management?
• What can excessive biological activity in wastewater lead to during treatment?
• What is the ideal consistency of sludge being pumped to a digester?
• What is bulking in the context of waste water treatment?
• What is the function of a grit channel in wastewater treatment?
• What is the primary outcome of the nitrification process?
• Which material serves as the media for microbial growth in trickling filters?
• How does nitrification affect alkalinity in waste water?
• Approximately how much surface area does a normal RBC disk design have?
• In waste water treatment, why is denitrification important?
• What is a key characteristic of the drive unit in a mechanical RBC?
• What can correct the high solids concentration indicated by foam in an aeration tank?
• What effect does excess nitrogen in water have?
• How does temperature affect dissolved oxygen levels in water?
• What is specific gravity?
• What is the main challenge of grease management in wastewater treatment?
• Filamentous bacteria are often a problem in waste water treatment when...
• What action can help ensure that methane formers are adequately fed in an anaerobic digester?
• If the sludge is going septic, what action should be taken?
• What is the definition of flocculation?
• What is the recommended total solids concentration for primary sludge before being pumped to an anaerobic digester?
• What is the term for surface runoff entering through leaking manhole covers or illegal connections?
• What process takes place in a sealed unit without any dissolved oxygen?
• Excess filamentous bacteria growth on an RBC is indicated by what color of slime?
• What is a characteristic odor associated with hydrogen sulfide gas?
• What can result from not effectively maintaining hydraulic and organic loading in trickling filters?
• What is a method to manage zoogleal mass in trickling filters?
• Why do operators need to monitor hydraulic retention time?
• How does hydrogen sulfide affect the sense of smell over time?
• What is an effect of overfeeding in an anaerobic digester?
• What types of organisms are present in the aerobic microbial population of a trickling filter?
• What does surface loading indicate in a treatment process?
• What type of bacteria will dominate a natural body of water that lacks dissolved oxygen?
• What is a notable physical property of hydrogen sulfide gas?
• What does the Clean Water Act require from wastewater treatment plants regarding total suspended solids (TSS) and biochemical oxygen demand (BOD)?
• What is one of the primary functions of a laboratory's chlorine residual analysis?
• What purpose does primary sludge fermentation serve in wastewater treatment?
• How much incoming BOD can be removed by the primary treatment process when chemical coagulants are used?
• What type of microorganisms are primarily involved in the trickling filter process?
• Which two criteria are used to control trickling filter operations?
• What is the primary role of activated sludge in waste water treatment?
• What is a potential consequence of storm events at a treatment plant?
• How does warmer water temperatures affect biological activity in a collection system?
• What is a common cause of inflow into a collection system?
• What hazardous condition can occur when an anaerobic digester is dewatered for maintenance?
• What is commonly analyzed to assess the organic matter content in water bodies?
• Under what conditions is hydrogen sulfide gas typically produced?
• What does a foul odor from a trickling filter typically indicate?
• What is the primary role of phosphorous in wastewater ecosystems?
• What does enhanced primary treatment achieve in waste water management?
• What color of biomass indicates a problem in the RBC process?
• What does a yellow flame indicate in a digester gas burner?
• What condition is created when methane is mixed with air?
• What process occurs when there is an adequate combination of carbon and nitrogen in an anaerobic digester?
• At what temperature should a sample be stored when cooling is used for preservation?
• In what state should a healthy biomass on RBC disks appear?
• Which two parameters are essential for ensuring proper settling in primary clarifiers?
• To convert Fahrenheit to Celsius, which mathematical operation should you perform first?
• How much time is typically required for a BOD test to complete?
• What does monitoring surface overflow rates help maintain in a clarifier?
• What percentage of suspended solid removal can be achieved without chemical addition in primary clarification?
• What is the primary purpose of a stabilization pond?
• To cure a souring digester, what action should the operator take?
• For how many days can preserved BOD samples typically be held?
• Which of the following describes the flammable characteristics of hydrogen sulfide?
• What happens to the food-to-microorganism ratio (F:M) as mean cell residence time (MCRT) increases?
• Where is floatable scum typically removed in the wastewater treatment process?
• For what reasons is wastewater typically sampled?
• What is required for the RBC process to operate properly?
• Which process is enhanced when recirculation rates are optimized in a trickling filter?
• What primarily contributes to algae blooms in water bodies?
• What should be prioritized in the management of a sour anaerobic digester?
• What is the total solids concentration typically found in most wastewater?
• What is the common practice to ensure safety during the maintenance of anaerobic digesters?
• What is the sum of total nitrogen components in water?
• A decrease in nitrate and nitrite concentrations indicates what process?
• What consequence may arise if the recirculation rate is too low in a trickling filter?
• What defines infiltration within the context of a wastewater collection system?
• What type of odor typically masks the presence of hydrogen sulfide, making it particularly hazardous?
• What does an increase in secondary nitrate and nitrite concentrations indicate?
• Why should the under drain channel be drained in a trickling filter during periods of shut down?
• What can cause foaming in an anaerobic digester?
• What is produced as a byproduct in an anaerobic digestion process?
• What are colloids?
• What can excessive filamentous bacteria lead to in a secondary clarifier?
• What are the two types of composite samples used in wastewater analysis?
• What is the primary role of coagulants in water treatment?
• In typical primaries sludge, how much of the total solids are usually volatile?
• What does detention time refer to in wastewater treatment?
• What does the RBC process primarily deal with?
• Why is phosphorus removed prior to discharge to receiving waters?
• Which element is NOT typically monitored in trickling filter operations?
• Which process is primarily responsible for the separation of suspended solids from wastewater?
• What is the primary function of a coagulant?
• How is enhanced primary treatment primarily defined?
• What must be done to prevent a digester from becoming sour?
• What happens to dissolved oxygen levels as water temperature increases?
• Which benefit does a mechanical drive on an RBC offer?
• An increase in primary ammonia levels indicates what condition?
• What type of wastewater collection system carries both sanitary wastewater and stormwater runoff?
• What substances can be used to neutralize the electrical charge of colloidal particles?
• What does BOD stand for in the context of wastewater treatment?
• What byproduct can indicate a severe imbalance in an anaerobic digester?
• What color indicates healthy biomass on an RBC disk in the downstream stage?
• How does increasing the recirculation rate affect the affluent BOD from a trickling filter?
• What dangerous byproduct is produced due to increased biological activity in the collection system?
• How soon must lab analysis of pH, temperature, and dissolved oxygen be performed after sample collection?
• What is the primary role of bacteria in an activated sludge treatment plant?
• What is the appearance of a healthy first-stage biomass on a rotating biological contactor (RBC)?
• How does cooler water temperatures affect the ability to hold dissolved oxygen?
• Why are BOD samples generally not used for process control?
• What is the primary purpose of a pipette in a laboratory?
• In a properly functioning anaerobic digester, which two formations occur at approximately the same rate?