Ca Grade 2 Wastewater Treatment Operator Practice Exam 4

Ca Grade 2 Wastewater Treatment Operator Practice Exam 4 1 mg/l is the same as 1 part per billion Ans- F A scada system is capable of monitoring and controlling equipment from where? Ans- remote location A Discharge Monitoring Report is typically submitted to the regulatory agency on daily basis Ans- False = Monthly A mechanical seal is used to prevent leaks between where? Ans- between the pump casing and shaft Alkalinity is the capacity of a liquid to neutralize base Ans- False = Alkalinity neutralizes acids Typical mixed liquor suspended solids concentration is? Ans- 1,000 to 4,500 mg/l Turbidity is caused by... Ans- suspended matters Algae is not essential to the successful operation of both aerobic and facultative ponds Ans- False = Algae supply most of the oxygen to the supernattant The addition of acid and CO2 will do what to wastewater? Ans- lower the pH of wastewater Hydrogen sulfide will deteriorate what kind of structures? Ans- concrete structures The higher the pH, the better the disinfection Ans- False = Maintain a dissolved oxygen concentration of 12 to 14 mg/l in the aeration tank Ans- F What happens when the velocity of the wastewater in a clarifier is greater in some sections than others? Ans- short circuiting The F/M ratio will decrease when the microorganism population____________in the aeration tank? Ans- increases Algae growth will be faster when there is less sunlight Ans- F How do higher temps affection disinfectione rates? Ans- Disinfection increases at higher temps One of the benefits of recirculation for a trickling filter is that it drcreses the contact time of the wastewater with the biological film Ans- F How do you prevent foaming from recurring in a anaerobic digester? Ans- Maintaining a constant temperature Preventative maintenence is a proactive, programmed, and...... Ans- systematic approach to maintenance Abnormal operation in a pond will not occur if it is overloaded with BOD Ans- F Anaerobic decomposition of sweage will release? Ans- hydrogen sulfide Always pour water into acid, and never the other way around Ans- F Scum escaping in the clarifier effluent could be caused by what? Ans- hydraulic overload Operate an activated sludge system at low MCRT if you have what? Ans- limited aeration capacity Chlorine gas is brown in color Ans- False = yellow green Typical suspended solids concentration of domestic influent wastewater is? Ans- 150 to 400 mg/l Poor ventilation of a trickling filter could lead to what? Ans- lead to odor problems Sulfur dioxide is used to dechlorinate the effluent prior to discharge to protect what? Ans- aquatic organisms in the recieving waters MRCT describes the average residence time of the activated sludge particle in the return sludge pipe Ans- F Free chlorine combines with water to form? Ans- hypochlorous and hydrochloric acids The trickling filter can be controlled by changing the loadings based on sludge age F/M ratio or MCRT Ans- F The MPN test for coliform does not test for individual pathegenic microotganism but uses coliform as an indicator organism to estimate the microorganisin population Ans- T Mixed liquor volatile suspended solids MLVSS is used to determine what? Ans- the amount of microorganisms in the aeration tank to treat the incoming waste A manhole, sump, or vault can be entered without following confined space entry procedures...... Ans- if it appears safe An increase in the volatile acids/alkalinity ratio in an anaerobic digester indicates what? Ans- a problem is developing Chain driven scrapers called flights are commonly used as what? Ans- mechanical grit collectors A facultative bacteria is capable of living under an aerobic condition but not in an anaerobic condition Ans- F An impeller is an important part of centrifugal pump that? Ans- spins the liquid at the high speed Hot bearings in a blower could be caused by what? Ans- defective bearings Class A fire extinguisher should be used for an electrical fire Ans- F Scum from primary clarifiers consists mainly of what? Ans- grease and other floatable materials One of the ways to resolve an increase in the volatile acid/alkalinity ratio in an anaerobic digester is to..... Ans- decrease raw sludge feed rates Sludge will not become septic when it remains in a channel or basin for an extended period of time AnsF Shallow ponds that are used to treat wastewater are typically how deep? Ans- 3 to 5 feet deep A slight seal leakage should be observed when a pump is operating for what purpose? Ans- to keep the packing cool Total solids = Volatile solids + suspended solids Ans- F The purpose of sludge wasting in an activated sludge process is to control the amount of solids in the primary treatment process Ans- F Chlorine gas is not flammable Ans- T Screening is a part of the pretreatment process that removes what? Ans- larger debris, such as rocks, cans and bottles The best velocity through a grit channel is 3 foot per second Ans- F What is the main purpose of the activated sludge process? Ans- removal of soluble or finely divided suspended materials that were not removed by previous treament Where is the primary sludge typically pumped to? Ans- sludge digester What problem is caused by denitrification? Ans- rising sludge in secondary clarifier What condition is necessary to perform a BOD test? Ans- 5 days at 20 degrees Celsius What is a fusible plug? Ans- a safety device used to prevent build up of excessive pressure in a chlorine cylinder What is usually the last indicator to change in an anaerobic digester that is becoming sour? Ans- pH What information is needed to calculate the F/M ratio? Ans- BOD and MLVSS Which chemical is commonly used to control hydrogen sulfide gas? Ans- Chlorine What would cause a trickling filter to operate less effectively Ans- Ponding What is MPN? Ans- Most Probable Number of coliform group organisms per unit volume of sample water What is true regarding dissolved solids? Ans- they will pass through a filter Why is chlorine sometimes added at the headworks of the plant? Ans- control order What is the purpose of a launder in a primary clarifier? Ans- collects the primary effluent that flows over the weir and conveys it towards the next treatment process What is the best way to communicate important information to employees? Ans- meeting in person What problem might arise from tightening a gland in a pump? Ans- wear on the shaft or shaft sleeve What could the oxygen uptake rate test be used for? Ans- detect toxicity in the activated sludge process What does anaerobic bacteria require for metabolism? Ans- they obtain oxygen by breaking down chemical compounds that contain oxygen, such as sulfit