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What is the typical BOD removal efficiency in a primary clarifier? A) 10 to 15% B) 40 to 60% C) 20 to 50% D) 95 to 99% C) 20 to 50% (v.1 pg 129) What does the "F" in F/M ratio represent? A) The microorganism population in the aeration tank B) The amount of filamentous bacteria in the activated sludge process C) The MLVSS in the aeration tank D) The food for the microorganisms flowing into the aeration tank, in lbs/day D) The food for the microorganisms flowing into the aeration tank, in lbs/day (v.2 pg 58) Which of the following describes the appearance of healthy activated sludge? A) Thick, greasy, dark tan foam B) Brown with a moderate amount of crisp, white foam C) Clear liquid with clear foam D) Gray liquid with no foam B) Brown with a moderate amount of crisp, white foam What is used to control filamentous organisms? A) Polymer B) Sulfur Dioxide C) Coagulant D) Chlorine
D) Chlorine (v.1 pg 399) What are commonly used to control chlorine feed rate for disinfection? A) BOD and MLVSS B) pH and temperature C) Flow and chlorine residual D) DO and TSS C) Flow and chlorine residual (v.1 pg 356) Which toxic gas is commonly found in septic wastewater and smells like rotten eggs? A) Hydrogen Sulfide B) Carbon monoxide C) Hydrogen D) Carbon Dioxide A) Hydrogen Sulfide (v.2 pg 299) What is the permissible exposure limit for chlorine gas vapor during a normal 8 hour workday and a 40 hour work week? A) 0.1 ppm B) 0.5 ppm C) 1 ppm D) 15 ppm B) 0.5 ppm (v.2 pg 268) What is a vulnerability assessment? A) Assesses the impact of hydrogen sulfide to a concrete structure B) Analyzes the impact of flow and infiltration problem to the plant hydraulics C) Estimates the vulnerability of aquatic wildlife to excessive algae growth D) Contingency planning to determine the vulnerability of the utility during various types of emergencies and identify corrective actions to reduce the risks
D) Microorganisms become more active B) Modify operations to increase solids under aeration to provide more microorganisms to treat the BOD (v.2 pg 71) What type of sludge would you expect in an aeration tank if the content is dark and has low DO? A) Sludge that is heavy B) Chlorinated Sludge C) Septic Sludge D) Healthy Sludge C) Septic Sludge (v.2 pg 75) What could have happen if the volatile acid/alkalinity ratio starts to increase, and corrective action is not taken immediately? A) Carbon dioxide content in the digester gas will decrease B) Carbon monoxide content in the digester gas will fluctuate C) pH of the digester sludge will increase D) Carbon dioxide content in the digester gas will increase D) Carbon dioxide content in the digester gas will increase (v.2 pg 191) What are screenings? A) Colloids B) TDS C) Pieces of wood, roots, rags, and other large debris D) COD C) Pieces of wood, roots, rags, and other large debris (v.1 pg 41) What happens when there is more food in the influent to the aeration tank?
A) Less oxygen is required in the aeration tank B) More oxygen is required in the aeration tank C) Less organism activity takes place D) Less oxidation takes place B) More oxygen is required in the aeration tank (v.2 pg 19) What impact does temperature have on the reaction rate of microorganisms in wastewater? A) Reaction rate doubles with every 18 degree Fahrenheit increase in temperature until higher temperature inhibits biological activity B) Reaction rate decreases by 20% with every 10 degree Fahrenheit increase in temperature C) Reaction rate of microorganism is not impacted by temperature D) Reaction rate goes to zero A) Reaction rate doubles with every 18 degree Fahrenheit increase in temperature until higher What is commonly used to control the odor of hydrogen sulfide? A) Carbon Dioxide B) Methane C) Chlorine D) Hydrogen C) Chlorine (v.1 pg 398) What is used to determine the amount of microorganisms in the aeration tank? A) Mixed Liquor Suspended Solids (MLSS)
D) Dissolved and non settable organic material D) Dissolved and non settable organic material (v.1 pg 46) Which document is a written record that accurately traces the custody of wastewater samples through all phases of a monitoring program? A) Wastewater Lab Analysis form B) NEPA C) Chain of Custody form D) Diagnostic form C) Chain of Custody form (v.2 pg 498) What could cause a sudden drop in pH of the influent? A) Acidic chemical in the influent B) A strong base was dumped into the collection system C) Ammonia from a factory was discharged into the sewer D) The influent contained sodium hydroxide A) Acidic chemical in the influent (v.2 pg 579) What is the recommended daily maintenance activity for a clarifier? A) Dewater the clarifier by draining the wastewater B) Repaint metal surfaces that have lost their protective coating C) Hose down walls, floor and equipment inside the clarifiers D) Inspect chains, sprockets, and flights. D) Inspect chains, sprockets, and flights (v.1 pg 118)
Which of the following could be the cause of ponding in a trickling filter? A) Hydraulic loading is too low B) Clogging of distributor orifices C) Excessive organic loading D) Denitrification C) Excessive organic loading (v.1 pg 192) What could happen if the dissolved oxygen content in the aeration tank is too low? A) Pinpoint floc will develop B) Filamentous organisms could thrive and prevent the sludge sludge floc from settling properly in the secondary clarifier C) Settling will improve in the secondary clarifier D) Sludge bulking will be eliminated B) Filamentous organisms could thrive and prevent the sludge sludge floc from settling properly in the secondary clarifier (v.1 pg 254) What is the expected BOD removal efficiency in a facultative pond? A) Mostly between 40 to 50% B) Mostly between 30 to 40% C) Mostly between 20 to 30% D) Mostly between 70 to 80% D) Mostly between 70 to 80% (v.1 pg 317)
A) Sense of smell B) Atmospheric monitoring C) Color titration D) Lab test B) Atmospheric monitoring (v.2 pg 271) What is sludge age? A) An expression of the average time that a microorganism will spend in the activated sludge process, and calculated using total suspended solids removed from the process B) A measure of food provided to bacteria in an aeration tank C) The theoretical time required for water to pass through a tank at any given flowrate D) A rough indicator of the length of time a pound of solids is maintained under aeration D) A rough indicator of the length of time a pound of solids is maintained under aeration (v.2 pg 519) What is one of the benefits of a COD test over a BOD test? A) COD test does not require any chemicals to perform the test B) COD test will easily predict the effects of an effluent on the DO in receiving waters C) Shorter test period D) COD test is capable of measuring the biodegradability of matter C) Shorter test period (v.2 pg 541) What is the typical detention time for a primary clarifier?
A) 3 to 4 hours B) 30 minutes C) 6 hours D) 1.5 to 2 hours D) 1.5 to 2 hours (v.1 pg 43) If you are testing the pH of a wastewater sample, what is the maximum recommended holding time? A) 5 days B) It must be tested immediately C) 24 hours D) 36 hours B) It must be tested immediately (v.2 pg 502) What could cause short circuiting in a clarifier? A) Sludge composition B) Reduction in flowrate C) Uneven weir settings D) Broken sludge pump C) Uneven weir settings (v.1 pg 125) What could cause the slime growth on a rotating biological contactor to appear black? A) It could indicate solids or organic overloading B) High DO in the plant effluent
B) Remove soluble or finely divided suspended materials (v.2 pg 16) What is the carbon dioxide content of a properly functioning anaerobic digester? A) 65 to 70% by volume B) 1 to 2% by volume C) 30 to 35% by volume D) 40 to 60% by volume C) 30 to 35% by volume (v.2 pg 158) Which of the following is a collection of individual samples obtained at regular intervals? A) Grab B) Culmination C) Comprehensive D) Composite D) Composite (v.2 pg 499) What is the most common piece of laboratory equipment, which is used mainly to mix chemicals and measure approximate volumes? A) Beaker B) Graduated cylinder C) Pipet D) Flask A) Beaker(v.2 pg 479)
What are colloids? A) Solids that settle rapidly B) Dissolved solids C) Solids found in the grit channel D) Very small, finely divided solids that remain dispersed in a liquid for a long time D) Very small, finely divided solids that remain dispersed in a liquid for a long time (v.1 pg 22,144) What is the most common type of grit collector? A) Deflectors B) Weirs C) Chain driven scrapers called "flights" D) Parshall flume C) Chain driven scrapers called "flights" (v.1 pg 87) What is true about surface loading and detention time? A) They stay fairly constant throughout the day B) They are impacted by the influent BOD C) They are indirectly related to flow D) They are directly related to flow D) They are directly related to flow (v.1 pg 118) What is the slime growth on a trickling filter called?
A) In atmosphere where oxygen content is less than 19.5% by volume B) In atmosphere where oxygen content is less than 23.5% by volume C) In atmosphere where oxygen content is less more than 23.5% by volume D) In atmosphere where oxygen content is less than 29.5% by volume A) In atmosphere where oxygen content is less than 19.5% by volume (v.2 pg 267) Which of the following is not true about chlorine gas? A) 2.5 times heavier than air B) Extremely toxic C) Common chlorine gas concentration at the treatment plants is 12.5% D) Corrosive in moist atmosphere C) Common chlorine gas concentration at the treatment plants is 12.5% (v.1 pg 375) What is a "dead spot" in an activated sludge process? A) An area in the secondary clarifier with rising sludge B) An area in the aeration tank that has insufficient mixing C) An area in the aeration tank that has high concentration of DO D) An area in the secondary clarifier with may dead viruses B) An area in the aeration tank that has insufficient mixing Which of the following is an improper way to control an anaerobic digester? A) Control the loading rate or food supply B) Control the volatile acid/alkalinity relationship
C) Control mixing D) Control the acid formation so that it is larger than the methane formation D) Control the acid formation so that it is larger than the methane formation (v.2 pg 148) Which of the following is not true about permitted confined space entry? A) Wear an approved harness with an attached line B) If the entry is made through a top opening, use a hoisting device with a harness that suspends a person in an upright position C) Testing for atmospheric hazards is not required as long as a blower is in use D) Wear protective clothing when entering a confined space that contains corrosive substances or other substances harmful to the skin C) Testing for atmospheric hazards is not required as long as a blower is in use (v.2 pg 270) What is a MSDS? A) A federal law that is designed to protect the health and safety of workers B) A condition in which a persons nose is no longer able to detect odor from a chemical C) A document that contains important information about a chemical, such as safe exposure level, flammability rating, and first aid procedures D A publication written by the federal government that contains all regulations, including those that affect safety and the environment C) A document that contains important information about a chemical, such as safe exposure level, flammability rating, and first aid procedures (v.2 pg 728) How often should grit be removed from the grit channel? A) Weekly
D) Total and Fecal D) Total and Fecal (v.2 pg 552) Which of the following is true about the extended aeration process? A) Wasting is not necessary to maintain proper control of the process B) It produces more waste than conventional activated sludge process C) It has low F/M ratio D) It has low MLSS concentration C) It has low F/M ratio (v.1 pg 257) What type of disinfection is gaining popularity, and expected to become a practical alternative to chlorination? A) Sulfur dioxide B) Ultraviolet (UV) disinfection C) Aqueous ammonia D) Caustic soda B) Ultraviolet (UV) disinfection (v.1 pg 303) Where is the proper sampling location for an effluent from a wastewater treatment plant? A) Next to the chlorinator equipment B) At the end of a solids handling facility C) Prior to discharge into receiving waters D) At the head of a chlorine contact chamber C) Prior to discharge into receiving waters
What is true if the F/M ratio increases? A) Less DO is required B) Less BOD is available C) DO will not be affected by an increase in F/M ratio D) More DO is needed D) More DO is needed (v.2 pg 53) Who must be included in a hearing conservation program to prevent hearing loss? A) Employees whose normal noise exposure equals or exceeds 65 decibels B) Employees whose normal noise exposure equals or exceeds an 8 hour time weighted average of 85 decibels C) Employees whose normal noise exposure exceeds 45 decibels at any time D) Employees whose normal noise exposure exceeds and 8 hour time weighted average of 25 decibels B) Employees whose normal noise exposure equals or exceeds an 8 hour time weighted average of 85 decibels (v.2 pg 277) What is a major cause of repeated sludge bulk? A) High pH B) High DO C) High food to mircoorganism loading rates D) High nutrient concentration C) High food to mircoorganism loading rates (v.2 pg 71)
