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What is the equivalent in total percent solids of a sludge sample that has a concentration of 15,000 mg/l?
1.57%
Which aeration foam may indicate an old sludge condition?
Which is a common type of level control system?
Which type of sewer system contains both sanitary wastewater and storm water?
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What is the formula that defines chlorine residual?
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What happens to the trickling filter effluent D.O. when the recirculation rate increases?
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Why should air be prevented from entering an anaerobic digester tank?
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Which component in the chlorination process is responsible for creating a vacuum condition?
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Where does the D.O. come from in an unrated lagoon?
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What does H2S smell like at high concentrations?
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Which chemical is typically used for conditioning the sludge feed applied to a gravity thickener process?
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What is the relationship of gas chlorine to air?
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What should be done if a neighbor complains about the plant odor?
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Where does denitrification primarily occur?
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Where does nitrification primarily occur?
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What should a supervisor do if he or she finds an employee sleeping on the job?
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Which is the physical process that follows an aeration tank?
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What is a typical RAS to Q ratio for an extended aeration activated sludge process?
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What does it mean if gas and rising sludge is occurring in a gravity thickener?
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What is generally required when the sludge blanket is too high on the floor of a gravity thickener?
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Associated with primary clarifier scum, what does FOG mean?
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What is it called when all of the demand for chlorine has been satisfied?
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What is a typical percent solids in the thickener sludge product of a gravity belt thickener?
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What may be the recommended action to perform if the top belt of a belt filter press was flooded?
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Which term is most related to vector attraction reduction in an aerobic digester?
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Which test is better to use for process control of an anaerobic digestion process?
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What does it mean when there is a lack of any odor coming from a lift station manhole?
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Which gases may be found in a sewer collection system?
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What is a typically accepted D.O. in an aerobic digester?
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What should management do if they see a large increase in the facility's monthly power bill?
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What two laboratory analyses are necessary to calculate the F/M ratio?
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What is the term when ammonia-N and organic-N are added together?
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Which group of bacteria are strictly aerobic and responsible for nitrification in the activated sludge process?
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Which time of day will generally produce the highest D.O. in an unaerated stabilization pond?
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Which test is not used to indicate the performance of an anaerobic digester?
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What percentage of settleable solids are typically removed in a primary clarifier?
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What is the top blanket of sludge called in the DAF process?
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How many lbs/day of WAS are removed each day from a plant with a volume of 14,000 gpd and a concentration of 1% Total Solids?
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Which bar screen will capture more debris on its screen?
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What does this formula represent associated with primary clarifier performance? IN - OUT ÷ IN x 100 = ?
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What is the term for water seeping into a sanitary sewer line?
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What is it called when sludge and polymer plug the belts of a belt filter press?
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Which chemical is used to identify a chlorine leak?
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What does the '5' mean in the BOD5 test?
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What happens to the activity rate of activated sludge microorganisms when the temperature increases?
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What is the makeup of typical screenings debris?
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What form of chlorine comes in one-ton containers?
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What is the organism growth on the media of a trickling filter called?
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Which of the following materials is not commonly used in the construction of a collection system?
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What does the production of foam indicate in an anaerobic digester?
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What is a common volume make-up of gases in a properly operated anaerobic digester?
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Which type of bacteria is responsible for stabilization of organic material (CBOD5) in wastewater?
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Which best describes the nitrification cycle?
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What is a common method of determining the quantity of chlorine used each day?
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What is the weir overflow rate for the secondary clarifier?
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What does this formula represent? π r2 x depth, ft x 7.48
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What happens to the pH and alkalinity of the sludge after lime is added to it?
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What is the surface area of the secondary clarifier?
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What adjustment may be the best to make if the secondary clarifier, and the settleometer test, show an abundance of small pin floc in the effluent?
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What does the unit parts per million (ppm) mean?
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What are the two major zones of a belt filter press called?
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Which lab test requires the use of an analytical balance, a drying oven, filter papers, and a desiccator?
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What is the makeup of typical grit debris?
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Which factors affect the operation of an aerobic digester?
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What color should digested sludge be in a properly operated anaerobic digestion process?
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What happens to the alkalinity in wastewater during the denitrification process?
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What is an acceptable surface loading rate for a primary clarifier?
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What process test can be performed in about 10 minutes and identifies the amount of oxygen being consumed by the microorganisms?
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What component is used to convert liquid chlorine into chlorine gas?
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What is the system called that requires proper documentation associated with sampling?
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What is the volume of 1 cubic foot of water?
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What is the best adjustment to make if the RAS in a secondary clarifier is black and the sludge blanket depth is high?
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What term is most related to free chlorine residual?
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What adjustment should be made if solids are rising in the secondary clarifier accompanied by large, smelly gas bubbles?
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What does an open circuit mean in electrical terms?
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What percentage of total suspended solids (TSS) is typically removed in a primary clarifier?
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What is another term for inorganic solids?
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What is the term for the collection of one (1) sample in which an analysis is performed?
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What component of a pump keeps the material in the discharge pipe from emptying out through the pump suction when the pump is off?
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What percentage of CBOD5 is typically removed in a primary clarifier?
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Why is flooding of trickling filter media sometimes recommended?
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What are the two major gases produced in a properly operated anaerobic digestion process?
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What is the solids loading rate on the secondary clarifier?
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What is a common spacing between the bars for a fine bar screen?
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What is the purpose of an Imhoff cone test?
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Which problem is the more likely cause of pumps and pipes clogging and requiring cleaning to restore normal flow rates?
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Given the provided data, what is the SRT of this activated sludge plant? - Plant flow = 0.575 mgd - MLSS = 3,500 ppm - Aeration tank dimensions = 100 ft long, 25 ft wide, and 14 ft deep - WAS volume = 14,000 gpd - WAS concentration = 1% total solids - Effluent TSS = 2.5 ppm
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What does the term aliquot mean?
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What is the main purpose of a trickling filter?
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What is the main purpose for a comprehensive maintenance program?
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What is a common problem associated with trickling filters?
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What type of maintenance is performed on a piece of equipment before it breaks?
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What item is important in the development of a maintenance program?
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Which dangerous gas will be more likely to rise near the surface of a manhole?
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What is the amount of oxygen required to convert 1 ppm of ammonia-nitrogen?
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What does a recirculation rate of 1:1 mean in a trickling filter process?
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What type of maintenance is performed on a piece of equipment after it breaks?
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What piece of equipment is used in the volatile solids test?
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What is the equivalent in gpm of a pipe that has 1 mgd flowing through it?
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Which activated sludge growth phase is considered to have the lowest F/M ratio?
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Study Notes
Sludge and Wastewater Treatment
- Total percent solids of sludge with a concentration of 15,000 mg/l is 1.57%.
- Black-colored aeration foam indicates old sludge conditions.
- Level control systems commonly use bubblers.
Sewer Systems and Waste Treatment Processes
- Combined sewer systems carry both sanitary wastewater and stormwater.
- The formula for chlorine residual is Supply - Demand = Residual.
- Increasing the recirculation rate of a trickling filter effluent results in higher dissolved oxygen (D.O.).
Anaerobic Digestion
- Air should be prevented from entering anaerobic digesters to avoid explosion risks.
- Gas injectors create vacuum conditions for mixing chlorine gas with solution.
- Algae growth generates D.O. in unrated lagoons.
Chemical and Physical Properties
- Hydrogen sulfide (H2S) has no smell at high concentrations.
- Polymer is commonly used for conditioning sludge feed in gravity thickening.
- Gas chlorine is 2.5 times heavier than air.
Odor Management and Biological Processes
- Neighbor complaints about plant odor should prompt an evaluation of the odor source and use of management practices.
- Denitrification primarily occurs in anoxic zones; nitrification occurs in aerobic zones.
- The presence of pin floc in secondary clarifier effluent indicates a need to decrease the solid retention time (SRT).
Clarifiers and Solids Management
- RAS to influent flow ratio for extended aeration activated sludge processes typically ranges from 75% to 100%.
- Rising sludge in gravity thickeners suggests insufficient sludge withdrawal.
- Increasing sludge withdrawal rate is required when sludge blankets are too high in gravity thickeners.
Chlorination and Chemical Measurements
- Breakpoint occurs when all chlorine demand is satisfied.
- Typical percent solids in gravity belt thickener sludge product ranges from 4% to 8%.
- Algae contribute to the D.O. levels in water bodies, enhancing water treatment processes.
Solids Management and Microbial Activity
- SOUR (Specific Oxygen Utilization Rate) is related to vector attraction reduction in aerobic digesters.
- Analysis of acid/alkalinity is critical for anaerobic digestion process control.
- The pH and alkalinity of sludge increase when lime is added.
Measurement and Testing
- Total suspended solids (TSS) analysis requires analytical balances, drying ovens, and desiccators.
- Settling tests like the Imhoff cone tests identify settleable solids.
- The SRT can be calculated using volumes of aeration and waste activated sludge.
Equipment and Process Adjustments
- Flooded belt filter press belts indicate the need to adjust sludge feed rate or belt speed.
- Bar screens with timer or level control capture more debris.
- Proper documentation in operations is ensured through chain of custody procedures.
Gas and Safety Considerations
- Methane and carbon dioxide are the primary gases produced in well-operated anaerobic digesters.
- Dangerous gases, such as methane, tend to rise near the surface of manholes.
Maintenance Practices
- Preventive maintenance is executed before equipment failure; corrective maintenance follows failures.
- A comprehensive maintenance program includes tracking equipment data, frequencies, and emergency contacts.
Operational Parameters and Ratios
- Secondary clarifiers' surface loading rates are acceptable between 800 to 1,200 gpd/ft².
- The oxygen required to convert 1 ppm of ammonia-nitrogen is typically 4.6 pounds.
- The extended aeration phase in activated sludge processes features the lowest food-to-microorganism (F/M) ratio and highest SRT.
Environmental and Treatment Outcomes
- The production of foam in anaerobic digesters signals high acid production levels.
- Screening debris typically comprises organic materials, while grit debris is mainly inorganic.
Conclusion
- Continuous monitoring and maintenance of operational parameters in wastewater treatment processes are essential for effective management and compliance with environmental standards.
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Description
Test your knowledge on wastewater treatment concepts and terms with these flashcards. From sludge concentration to level control systems, this quiz covers essential topics crucial for understanding wastewater management.