3B2 E2.5 C14 Review
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Questions and Answers

What is the maximum allowable concentration of Benzene in water?

  • 0.01 mg/L
  • 0.1 mg/L
  • 0.005 mg/L (correct)
  • 0.05 mg/L

    • What is the pH range for wastewater before it can be discharged into receiving water?

  • 6.5 to 8.5 (correct)
  • 7 to 10
  • 5 to 9
  • 5.5 to 9.5

    • What is the primary factor affecting oxygen levels in water?

  • pH level
  • Temperature
  • Chemical oxygen demand
  • Number of bacteria and protozoa (correct)

    • What is the purpose of retention ponds in wastewater treatment?

    <p>To cool wastewater</p> Signup and view all the answers

    What is the acronym for the Canadian Council of Ministers of the Environment?

    <p>CCME</p> Signup and view all the answers

    What is the primary concern with high-temperature wastewater?

    <p>It increases oxygen demand</p> Signup and view all the answers

    What is the purpose of cooling towers in wastewater treatment?

    <p>To expose wastewater to air, increasing dissolved oxygen content</p> Signup and view all the answers

    What regulates waste water quality in federal government operations in Canada?

    <p>Canadian Environmental Protection Act</p> Signup and view all the answers

    What is the effect of pH levels close to zero on aquatic life?

    <p>It becomes more acidic, potentially harming aquatic life</p> Signup and view all the answers

    What is the purpose of long serpentine channels in wastewater treatment?

    <p>To cool wastewater before discharge</p> Signup and view all the answers

    What is the primary purpose of wastewater treatment?

    <p>To remove and properly dispose of contaminants by the most practical and economic means</p> Signup and view all the answers

    What is one of the factors that affect the quality of water?

    <p>Acidity</p> Signup and view all the answers

    What type of waste liquid is generated from industrial plants?

    <p>Cooling tower blowdown water</p> Signup and view all the answers

    What is the term used to describe the adverse effects of certain chemicals on human life?

    <p>Toxicity</p> Signup and view all the answers

    What is the final step in the wastewater treatment process?

    <p>Disinfecting the wastewater</p> Signup and view all the answers

    What type of water is generated from agricultural activities?

    <p>Agricultural pesticides</p> Signup and view all the answers

    What is the primary reason for maintaining a specific pH range in wastewater?

    <p>To ensure aquatic life can thrive</p> Signup and view all the answers

    Why are retention ponds used in wastewater treatment?

    <p>To cool wastewater to a safe temperature</p> Signup and view all the answers

    What is the effect of high-temperature wastewater on receiving water?

    <p>It deaerates the water and increases oxygen demand</p> Signup and view all the answers

    What is the role of the Canadian Council of Ministers of the Environment (CCME)?

    <p>To establish guidelines for water quality and wastewater discharge</p> Signup and view all the answers

    What is the primary factor affecting the ability of water to retain dissolved oxygen?

    <p>Temperature of the water</p> Signup and view all the answers

    What is the purpose of the Canadian Environmental Protection Act?

    <p>To regulate wastewater quality in federal government operations</p> Signup and view all the answers

    What is the effect of high biochemical oxygen demand on aquatic life?

    <p>It reduces the oxygen levels in the water</p> Signup and view all the answers

    Why are cooling towers used in wastewater treatment?

    <p>To cool wastewater and increase dissolved oxygen levels</p> Signup and view all the answers

    What is the maximum allowable concentration of Cadmium in water?

    <p>0.005 mg/L</p> Signup and view all the answers

    What is the purpose of the Canadian Water Quality Guidelines?

    <p>To establish guidelines for water quality and wastewater discharge</p> Signup and view all the answers

    What determines the maximum allowable concentration of chemicals in wastewater?

    <p>Industry-specific regulations</p> Signup and view all the answers

    Which of the following waste liquids is most likely to contain high levels of pesticides?

    <p>Agricultural wastewater</p> Signup and view all the answers

    What is the primary concern with high levels of acidity in wastewater?

    <p>Toxicity to aquatic life</p> Signup and view all the answers

    Which parameter is most critical in determining the quality of wastewater?

    <p>Toxicity levels</p> Signup and view all the answers

    What is the primary goal of controlling wastewater parameters?

    <p>To minimize environmental impact</p> Signup and view all the answers

    What is the significance of oxygen demand levels in wastewater?

    <p>They impact the aerobic treatment process</p> Signup and view all the answers

    What is the primary purpose of the stabilization lagoon in the wastewater treatment process?

    <p>To remove organic components from the wastewater</p> Signup and view all the answers

    What is the function of the air diffusers in the first stage aeration tank?

    <p>To supply oxygen to the microorganisms</p> Signup and view all the answers

    What is the purpose of the clarifiers in the wastewater treatment process?

    <p>To separate the wastewater from the sludge</p> Signup and view all the answers

    What happens to the sludge in the clarifier?

    <p>A portion of it is sent back to the first stage aeration tank</p> Signup and view all the answers

    What is the final step in the wastewater treatment process?

    <p>Polishing pond</p> Signup and view all the answers

    How long does the wastewater typically remain in the first stage aeration tank?

    <p>Three to six hours</p> Signup and view all the answers

    What is the primary purpose of the oil/water separation pond in the industrial wastewater treatment plant?

    <p>To skim off oil and scum that float to the top</p> Signup and view all the answers

    What happens to the wastewater in the collection system if the plant is not built on a slope?

    <p>Lift pumps are used to raise wastewater from collection tanks to the oil/water separation pond</p> Signup and view all the answers

    What is the purpose of the flare pit in the industrial wastewater treatment plant?

    <p>To burn off waste hydrocarbons</p> Signup and view all the answers

    How long should the wastewater typically remain in the oil/water separation pond?

    <p>Two to four days</p> Signup and view all the answers

    What is drawn off halfway between the surface and the bottom of the oil/water separation pond?

    <p>Effluent</p> Signup and view all the answers

    What is the purpose of the burner system in the flare pit?

    <p>To assist in complete combustion of waste hydrocarbons</p> Signup and view all the answers

    What is the function of the compressed air bubbled into the bottom of the stabilization lagoon?

    <p>Diffuse dissolved oxygen through the liquid</p> Signup and view all the answers

    What happens in the first stage aeration tank of the wastewater treatment process?

    <p>Microorganisms feed on the organic material in the water</p> Signup and view all the answers

    What is the purpose of sending a portion of the activated sludge from the clarifier back to the first stage aeration tank?

    <p>Continue breaking down any remaining organic material</p> Signup and view all the answers

    What best describes the wastewater treatment process taking place in the second stage aeration tank?

    <p>Organic decomposition continues for a much longer time</p> Signup and view all the answers

    Why is clear water from the top of the clarifier sent to the polishing pond?

    <p>To undergo final settling and aeration</p> Signup and view all the answers

    What is the final adjustment that occurs in the polishing pond in the wastewater treatment process?

    <p>Settling and aeration of effluent</p> Signup and view all the answers

    What is the purpose of a grit chamber in wastewater treatment?

    <p>To remove heavy particles like sand and other abrasive materials</p> Signup and view all the answers

    How is grit typically removed from a grit chamber?

    <p>By using a vacuum truck for periodic cleaning</p> Signup and view all the answers

    What type of system may be used to handle a substantial amount of grit build-up in a wastewater treatment plant?

    <p>Screw conveyor or auger</p> Signup and view all the answers

    What is the purpose of a bar screen in wastewater treatment?

    <p>To remove heavy particles like grit</p> Signup and view all the answers

    In the context of wastewater treatment, what does a barminutor do?

    <p>Shreds material that accumulates on the screen</p> Signup and view all the answers

    When is the grit chamber in a wastewater treatment plant usually cleaned with a vacuum truck?

    <p>When the volume of grit is small enough</p> Signup and view all the answers

    What is the purpose of a rotating trash screen in a wastewater treatment system?

    <p>To accumulate and clean off material from the screen face</p> Signup and view all the answers

    Why is material high in organics on a screen less acceptable as landfill material?

    <p>Because it impacts the quality of the landfill</p> Signup and view all the answers

    What is the function of a flotation tank in a wastewater treatment system?

    <p>To cause suspended materials to rise and float to the surface</p> Signup and view all the answers

    In municipal wastewater systems, where is the removal of inorganic material typically carried out?

    <p>In grit chambers and screen sections</p> Signup and view all the answers

    What happens when air and water are combined under pressure and then depressurized in a flotation tank?

    <p>The air escapes as tiny bubbles and attaches to suspended material</p> Signup and view all the answers

    What is the primary purpose of a slow-moving skimmer in a flotation tank of a wastewater treatment system?

    <p>To remove the floating concentrated sludge from the surface</p> Signup and view all the answers

    What is the primary function of a grit chamber in wastewater treatment?

    <p>Allowing heavy particles to settle out</p> Signup and view all the answers

    What is the method used to clean a grit chamber when the volume of grit is small enough that a conveyor system is not needed?

    <p>Utilizing a vacuum truck</p> Signup and view all the answers

    What is the purpose of a bar screen in wastewater treatment for material high in bulky or fibrous content?

    <p>Screening out or shredding material</p> Signup and view all the answers

    How is a bar screen cleaned when the quantity of trapped material is low?

    <p>Manually cleaning the bars</p> Signup and view all the answers

    What is the action taken if a substantial amount of grit builds up in a wastewater treatment plant?

    <p>Handling the build-up online</p> Signup and view all the answers

    Why is the removal of grit important in wastewater treatment processes?

    <p>To minimize wear on equipment</p> Signup and view all the answers

    What happens to the air when air and water are combined under pressure and then depressurized?

    <p>It escapes as tiny bubbles</p> Signup and view all the answers

    Why is material high in organics on a screen less acceptable as landfill material?

    <p>It is more likely to contaminate soil and groundwater</p> Signup and view all the answers

    What is the purpose of the clear effluent from the flotation tank?

    <p>To be returned to the dissolved air tank</p> Signup and view all the answers

    What is the purpose of the jet of water in the rotating trash screen?

    <p>To clean the material off the screen</p> Signup and view all the answers

    What happens to the suspended materials in the flotation tank?

    <p>They are skimmed off the surface</p> Signup and view all the answers

    What is the purpose of adding chemicals to enhance gravity separation?

    <p>To promote settling</p> Signup and view all the answers

    What is the size range of colloidal particles?

    <p>50 to 5000 ångström units</p> Signup and view all the answers

    Why are colloidal materials difficult to filter?

    <p>They are too small</p> Signup and view all the answers

    What is the process that neutralizes charges on colloidal particles?

    <p>Coagulation</p> Signup and view all the answers

    What is formed when colloidal particles attract each other after coagulation?

    <p>Floc</p> Signup and view all the answers

    What is added to water to assist in the flocculation process?

    <p>Coagulants</p> Signup and view all the answers

    Which phenomenon follows coagulation in the wastewater treatment process?

    <p>Flocculation</p> Signup and view all the answers

    What is the purpose of adding flocculants in the water treatment process?

    <p>To enhance sedimentation</p> Signup and view all the answers

    What is the main purpose of the clarifier in the wastewater treatment process?

    <p>To separate and settle out sludge</p> Signup and view all the answers

    What is the function of air bubbled into one leg of the 'U' tube syphon in the clarifier?

    <p>To pump scum or activated sludge back to the aeration tanks</p> Signup and view all the answers

    What happens to the sludge at the bottom of the conical clarifier?

    <p>A portion of it is returned to the aeration tanks</p> Signup and view all the answers

    What is the purpose of the central collection trough in the clarifier?

    <p>To collect and direct clear liquid effluent to the outlet</p> Signup and view all the answers

    What is the final product of the clarification process?

    <p>Clear effluent that can be discharged to the environment</p> Signup and view all the answers

    What is the primary function of a clarifier in the wastewater treatment process?

    <p>Separating sludge from the water</p> Signup and view all the answers

    Which part of the clarifier vessel is responsible for returning scum or activated sludge from the top of the inlet section back to the aeration tanks?

    <p>Internal baffle</p> Signup and view all the answers

    In the wastewater treatment process, what is a common purpose of flash mixers before clarifiers?

    <p>Enhancing flocculation</p> Signup and view all the answers

    What is the primary role of the

    <p>Bubbler in the stabilization lagoon</p> Signup and view all the answers

    What happens to the clear liquid in the clarifier after it rises to the top of the cone?

    <p>Spills over the edge of a central collection trough</p> Signup and view all the answers

    In the context of the wastewater treatment process, what is the main purpose of the flash mixing section?

    <p>To add the coagulant</p> Signup and view all the answers

    Why is a high concentration of colloidal materials in water considered unacceptable?

    <p>Because they form highly insulating deposits in water systems.</p> Signup and view all the answers

    Why do colloidal particles need to be removed from water?

    <p>Because they are too small for effective filtration.</p> Signup and view all the answers

    How does the process of coagulation help in wastewater treatment?

    <p>By neutralizing the charges on colloidal particles.</p> Signup and view all the answers

    What is the role of flocculation in wastewater treatment?

    <p>To form larger particles called 'floc.'</p> Signup and view all the answers

    What is the purpose of adding inorganic salts or organic polymers to water in the coagulation process?

    <p>To decrease the negative charge on the particles.</p> Signup and view all the answers

    Why are colloidal particles difficult to remove without coagulation and flocculation processes?

    <p>Because they are too small to settle due to having the same charge.</p> Signup and view all the answers

    What is the primary purpose of the air injected into the tank in the activated sludge process?

    <p>To provide oxygen for the bacteria to live</p> Signup and view all the answers

    In the activated sludge process, what happens to the biological mass settled at the bottom of the clarifier?

    <p>It contains healthy growing bacteria</p> Signup and view all the answers

    What is the main function of the rotating biological contactor (RBC) in wastewater treatment?

    <p>To reduce the BOD of a liquid effluent</p> Signup and view all the answers

    How does the rotating biological contactor (RBC) work to reduce BOD?

    <p>By using a series of rotating discs with pie-shaped plastic sheets</p> Signup and view all the answers

    What is the role of the cones on the surfaces of the plastic sheets in a rotating biological contactor (RBC)?

    <p>To create space between the discs</p> Signup and view all the answers

    Why is it necessary for the sheets in the rotating biological contactor (RBC) to be spaced apart?

    <p>To facilitate contact between the sheets</p> Signup and view all the answers

    What is the primary function of the biological film in a Rotating Biological Contactor (RBC)?

    <p>Converting organic material in the wastewater</p> Signup and view all the answers

    Why is sludge formed in a Rotating Biological Contactor (RBC) and what happens to it?

    <p>Develops due to the breakdown of organics by microbial growth, then sloughs off</p> Signup and view all the answers

    Why does an Anaerobic Digester need to be heated?

    <p>To optimize the conversion of organics by anaerobic bacteria</p> Signup and view all the answers

    What is the consequence of the anaerobic organisms developing in a Trickling Filter due to thickening of the biological film?

    <p>Outer layer microbial growth falls off in a process called sloughing</p> Signup and view all the answers

    Why does the digested sludge in an Anaerobic Digester become less odorous?

    <p>Organics are converted into stable substances like water and carbon dioxide</p> Signup and view all the answers

    What is the primary role of the open drain system in a Trickling Filter?

    <p>To provide source of air for microorganisms</p> Signup and view all the answers

    Why is flow balancing and management recommended for systems targeting low ammonia nitrogen values?

    <p>To ensure high-quality effluents by regulating the flow</p> Signup and view all the answers

    What is the role of the permeable media bed in a Trickling Filter with regard to the wastewater treatment process?

    <p>To provide a surface for microorganisms to develop a biological film</p> Signup and view all the answers

    What is the significance of the thin biological film formed on the media bed in a Trickling Filter?

    <p>It degrades the organic material present in the wastewater</p> Signup and view all the answers

    Why is recirculation of liquid back to the trickling filter important in the operation of a Trickling Filter?

    <p>To keep the filter moist and dilute incoming wastewater</p> Signup and view all the answers

    What is the primary function of air injected into the tank in the activated sludge process?

    <p>To introduce oxygen required for bacterial growth</p> Signup and view all the answers

    What is the purpose of the rotating biological contactor (RBC) in wastewater treatment?

    <p>To reduce the biological oxygen demand (BOD) of a liquid effluent</p> Signup and view all the answers

    What happens to the biological mass in the secondary clarifiers?

    <p>It settles to the bottom of the clarifier and is collected</p> Signup and view all the answers

    What is the function of the discs in the rotating biological contactor (RBC)?

    <p>To provide a surface area for bacterial growth</p> Signup and view all the answers

    Why is it necessary to provide oxygen for the bacteria in the activated sludge process?

    <p>To facilitate the growth of bacteria</p> Signup and view all the answers

    What is the purpose of the clarifier in the activated sludge process?

    <p>To remove the biological mass from the wastewater</p> Signup and view all the answers

    What is the main difference between the arrangement of discs in a Rotating Biological Contactor (RBC) and a Trickling Filter?

    <p>The RBC discs submerge into wastewater and resurface into the air, while the Trickling Filter has trickling wastewater over a media bed.</p> Signup and view all the answers

    Why are ventilation ports located at the bottom of a Trickling Filter?

    <p>To allow adequate airflow for microbial growth on the media surface.</p> Signup and view all the answers

    What is the primary function of the anaerobic digesters in the wastewater treatment process?

    <p>To biologically break down organic contents into stable substances with the help of anaerobic bacteria.</p> Signup and view all the answers

    How do microorganisms in the biological film of a Trickling Filter contribute to the treatment process?

    <p>They degrade organic material in the wastewater as they attach and grow on the media bed.</p> Signup and view all the answers

    Why does the sludge in the anaerobic digesters become less odorous during the treatment process?

    <p>From the breakdown of organic contents into stable substances like water, carbon dioxide, and methane.</p> Signup and view all the answers

    What is the main outcome of sloughing in a Trickling Filter?

    <p>To allow microorganisms attached to the media to continuously degrade organic material.</p> Signup and view all the answers

    What is the significance of creating a biological film on the Trickling Filter media?

    <p>To support degradation of organic material in the wastewater.</p> Signup and view all the answers

    How does the growth of microorganisms on the media surface of a Trickling Filter impact the treatment process?

    <p>It consumes the organics in the wastewater as they attach to the media bed.</p> Signup and view all the answers

    How does the presence of anaerobic organisms on the media surface of a Trickling Filter affect treatment efficiency?

    <p>By converting organic material into stable substances when oxygen is no longer present.</p> Signup and view all the answers

    What is the purpose of recirculating some of the liquid back to the Trickling Filter from the settling tank?

    <p>To dilute the incoming wastewater and keep the filter moist.</p> Signup and view all the answers

    Why is it important to take inlet samples in a wastewater treatment plant?

    <p>To verify that the desired conditions at the beginning of the process are met.</p> Signup and view all the answers

    What is the role of topographical features around a wastewater treatment plant?

    <p>To introduce stormwater or snowmelt into the wastewater flow.</p> Signup and view all the answers

    How does the introduction of new microorganisms contribute to wastewater treatment?

    <p>By ensuring optimal conditions and matching material quantity in the wastewater.</p> Signup and view all the answers

    What could be a consequence of a sudden decrease in nutrient supply in the water of a wastewater treatment plant?

    <p>The bugs will starve.</p> Signup and view all the answers

    Why are steady-state conditions important in the operation of a wastewater treatment plant?

    <p>To minimize variation in treatment requirements year-round.</p> Signup and view all the answers

    What is the role of nutrients in domestic wastewater for plant growth?

    <p>To nourish the bugs and promote their well-being.</p> Signup and view all the answers

    What do nitrifying bacteria in the aerobic zone convert ammonia (NH3) to?

    <p>Nitrate (NO3)</p> Signup and view all the answers

    What is the primary purpose of the Anoxic zone in the BPNR process?

    <p>Convert nitrite to nitrogen gas</p> Signup and view all the answers

    What is the primary role of settleability testing in the wastewater treatment process?

    <p>Check proper separation of sludge</p> Signup and view all the answers

    What is the biochemical oxygen demand (BOD) test used for in wastewater treatment?

    <p>Calculate oxygen used by microorganisms</p> Signup and view all the answers

    Why might an increase in chemical oxygen demand (COD) indicate an issue in the treatment process?

    <p>Organic compounds remain</p> Signup and view all the answers

    Which action is necessary if the wastewater becomes too alkaline during treatment?

    <p>Add an alkaline solution</p> Signup and view all the answers

    What is the main function of the anaerobic zone in the BPNR process?

    <p>Release stored phosphorus</p> Signup and view all the answers

    How is the oxygen demand of aerobic microorganisms calculated in the wastewater treatment process?

    <p>Through the BOD test</p> Signup and view all the answers

    What happens if the pH of the wastewater flow drops too low during the treatment process?

    <p>Neutralize with an acid</p> Signup and view all the answers

    Why should the pH level be monitored and adjusted as needed throughout the wastewater treatment process?

    <p>To maintain optimal process conditions</p> Signup and view all the answers

    What can be inferred about the wastewater treatment plant if the 'bugs' are happy?

    <p>The plant is operating properly</p> Signup and view all the answers

    Why is it important to take inlet samples at a wastewater treatment plant?

    <p>To confirm if desired conditions have been met</p> Signup and view all the answers

    What is the primary reason for the presence of stormwater or snow melt in a wastewater flow near a treatment plant?

    <p>Increases the organic material in the flow stream</p> Signup and view all the answers

    In the context of the text, why are inlet samples important at a wastewater treatment plant?

    <p>To optimize plant conditions</p> Signup and view all the answers

    What happens if the quantity of the material in the wastewater is not properly matched to the right quantity and type of microorganisms?

    <p>Necessitates a change in the treatment process</p> Signup and view all the answers

    Why are sample points also important at the inlet of a wastewater treatment plant?

    <p>To detect changes that may require a strategy adjustment</p> Signup and view all the answers

    What happens to excess phosphorus carried off by bacteria in the BPNR process?

    <p>It settles at the bottom of the clarifier</p> Signup and view all the answers

    Which zone in the BPNR process converts nitrate to nitrogen gas?

    <p>Anaerobic</p> Signup and view all the answers

    What is the purpose of the BOD test in wastewater treatment?

    <p>To test oxygen demand by microorganisms</p> Signup and view all the answers

    Why is the oxygen demand of wastewater samples tested using the BOD test?

    <p>To measure the amount of oxygen used by microorganisms</p> Signup and view all the answers

    What happens if pH levels in the treatment process drop too low?

    <p>Sodium hydroxide is added to raise pH</p> Signup and view all the answers

    Which parameter is caused by the oxygen demand of aerobic microorganisms in the BPNR process?

    <p>BOD</p> Signup and view all the answers

    What is the role of varying pH levels in different stages of treatment?

    <p>To adjust reaction rates for optimum process conditions</p> Signup and view all the answers

    What is the purpose of the nitrification process in the BPNR system?

    <p>To convert ammonia to nitrate</p> Signup and view all the answers

    How is the oxygen demand of microorganisms in wastewater determined?

    <p>By conducting the BOD test</p> Signup and view all the answers

    What is the process by which BPNR converts ammonia to nitrite and then nitrate in the wastewater?

    <p>Nitrification</p> Signup and view all the answers

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