Ca Grade 2 Wastewater Treatment Operator Practice Exam 1 Already Passed

Ca Grade 2 Wastewater Treatment Operator Practice Exam 1 Already Passed What is the methane content in a properly operating anaerobic digester? ✔✔65 to 70% by volume What will the addition of chlorine gas do to the ...

Ca Grade 2 Wastewater Treatment Operator Practice Exam 1 Already Passed What is the methane content in a properly operating anaerobic digester? ✔✔65 to 70% by volume What will the addition of chlorine gas do to the pH of wastewater? ✔✔decrease the pH What is the purpose of a Parshall Flume? ✔✔Measure the flow rate What is the typical removal efficency of settleable solids in a primary clarifier? ✔✔95 to 99% Which of the follwing is true about pumoing scum from a primary clarifier? ✔✔scum causes more piping problems than other substances pumped at a wastewater treatment plant What might cause thick billows of white sudsy foam in the aeration tank? ✔✔MLSS is too low What does the M in F/M ratio represent? ✔✔The mixed liquor volatile suspended solids in the aeration tank In general, how will warmer temp affect the settling rate of solids in a clarifer? ✔✔Increase the settling rate What could happen if the digester gas is mixed with air(85 to 95% by volume)? ✔✔Cause an explosion How will algae impact the chlorine demand in the pond effluent? ✔✔increase the chlorine demand Which of the following is true about a positive displacement pump? ✔✔it must never be started with the discharge valve closed What is true about the F/M ratio? ✔✔the volume of the secondary clarifier is not needed to determine the f/m ratio Which of the following is one of the basic rules of lab work? ✔✔never pipet hazardous material with your mouth, even if the pipet has been sterialized What is the recirculation ratio for a trickling filter? ✔✔Qr/Q Which of the following is true about COD and BOD? ✔✔they are indirect measurements of the organic content in the influent What is the purpose of the grit channel? ✔✔remove heavy inorganic waste Which of the following is true about the extended aeration process? ✔✔it does not produce as much waste sludge as other processes What is the correct formula for solids in raw wastewater? ✔✔Non settleable solids + settleable solids = total suspended solids What is freeboard in a waste stabilization pond? ✔✔the vertical distance from normal water surface to the top of the levee What is one of the requirements for a BOD test? ✔✔The BOD bottle should be completely filled to the top What should be scheduled every 3 months for a flamer arrester in an anaerobic digester? ✔✔maintenance What is common practice in an activated sludge process? ✔✔recirculate activated sludge Prior to entering a permit-required confined space, what should you verify? ✔✔a standby person should be located outside the entrance to the confined space, while another person should be within sight or call of the standby person What is a common way to determine the organic strength of wastes in the influent? ✔✔test for the biochemical oxygen demand What should you do if you are mildly exposed to chlorine gas? ✔✔immediately evacuate the contaminated area, remian calm, keep warm. breath lightly, avoid coughing What are the main sources of domestic sewage in the collection system? ✔✔household and commercial establishments Why is it important to maintain a horizontal weir in a clarifier? ✔✔to prevent short circuiting What are mostly removed in the grit channel? ✔✔sand, eggshells, cinders, and heavier particulate matter How often should an anaerobic digester be fed? ✔✔several times a day What is the health effect of carbon dioxide? ✔✔could lead to asphyxiation Which of the following enters the headworks of a treatment plant? ✔✔influent Which gas diminishes your sense of smell? ✔✔hydrogen sulfide What type of microorganism can use nitrate as a source of oxygen? ✔✔facultative bacteria What is the equivalent of 1 mg/l? ✔✔1 ppm Select the most accurate statement about extended aeration? ✔✔an oxidation ditch is usually operated in extended aeration mode, and is used for small flows What is equivalent to organic solids? ✔✔volatile solids What should be done if a large amount of organic matter is found in the grit channel? ✔✔increase the velocity of the wastewater Which flow rate should you use to calculate the hydraulic loading to a trickling filter? ✔✔plant inflow plus recirculated flow What is the differnce between the sludge from a primary clarifier and a secondary clarifier? ✔✔primary sludge is denser than secondary Which process includes a blower? ✔✔activated sludge How does an activated sludge system remove watse from wastewater? ✔✔biological treatment Which of the following best describes pre-chlorination? ✔✔addition of chlorine to wastewater at the entrance to the plant used for odor control, BOD reduction, grease removal, and aid sedimentation When would you expect reduced algae population and less oxygen released into a pond? ✔✔fall and winter, when the weather is cool and sunlight is reduced What is the first step of the lockout/tagout procedure? ✔✔notify all affected employees that a lockout/tagout system is going to be used and the reason why What type of process is the activated sludge system? ✔✔aerobic What will happen if too much raw sludge is added to the digester? ✔✔acid fermenters will predominate and lower the pH What might cause sludge to rise in a clarifier? ✔✔gasification from aging sludge What happens when carbon dioxide is removed from a pond? ✔✔increases pH How much dissolved oxygen should be in a conventional activated sludge system if good effluent is being produced? ✔✔2 to 4 mg/l What is the typical concentration of mixed liquor suspended solids in a conventional activated sludge process? ✔✔1000 to 4500 mg/l The temperature of the plant influent is? ✔✔slighty warmer than tap water The purpose of disinfection is to? ✔✔destruction or inactivation of pathogenic bacteria What must you do before entering a room with harmful concentration of chlorine gas in the air? ✔✔wear self contained breathing apparatus(scba) What does black sludge at the bottom of a secondary clarifier located downstream of a trickling filter signify? ✔✔sludge has stayed in the secondary clarifier too long If the lab results show that the plant influent sample has COD of 100 mg/l and a BOD of 300 mg/l, which of the following is most likey true? ✔✔lab results appear incorrect If a primary clarifier is placed out of service, then how should a plant with at least 2 trickling filters operate the system? ✔✔operate the filters in series What is the main reason for preventing a direct connection between a potable water pipe and a stuffing box(packings) of a wastewater pump? ✔✔cross connection Which of the following is true about algae in a pond? ✔✔during the day time the algae will release oxygen for the aerobic bacteria in the pond Which of the following is not true about hydrogen sulfide? ✔✔hydrogen sulfide is lighter than air What type of treatment is primarily used to thicken sludge instead of dewater the sludge? ✔✔DAF Dissolved Air Flotation Why should sludge at the bottom of a clarifier be removed in a timely manner? ✔✔to prevent sludge gasification which causes the sludge to float What is the purpose of sludge digestion? ✔✔reduce the volume of the sludge and stabilize the solids Which of the following is true about truckling filters? ✔✔the three main parts of a trickling filter are media, distribution system, and underdrain Which of the following could cause foaming in an anaerobic digester? ✔✔organic overload Which of the following parameters should be monitored several times a week in a pond? ✔✔dissolved oxygen, temperature, and pH Which is true about the temperature in an anaerobic digester? ✔✔Temperature in a digester should not be changed by more than 1 degree Fahrenheit per day The effectiveness of disinfection is determined by: ✔✔the coliform concentration in the effluent An increase in the acid/alkalinity ratio for an anaerobic digester means: ✔✔Acid concentration is increasing or alkalinity is decreasing Which of the following will not cause short circuiting in a clarifier? ✔✔flow line of launder is low A grab sample is most suited for these constituents? ✔✔residual chlorine The organic loading to a trickle filter is expressed as? ✔✔lbs BOD/day/1,00ft3(cubed) How often should the sludge at the bottom of the clarifier be pumped? ✔✔frequently throughout the day Which of the following will not affect settling characteristics in a clarifier? ✔✔depth of launder The best way to evaluate the effluent TSS concentration from a plant is to: ✔✔check the composite sample of TSS Which of the following is not assocated with an aeration tank? ✔✔RBC What creates hydrogen sulfide? ✔✔decomposing organic matter under anaerobic condistion A pond with a detention time of less than three days will perform similar to? ✔✔sedimentation tank Which type of bacteria is used for trickling filters? ✔✔aerobic bacteria Which of the following is not associated with a trickling filter? ✔✔filamentous bacteria What is an MCRT? ✔✔an expression of the average time a microorganism will spend in an activated sludge proccess