Wastewater class C Exam Questions With Verified Answers.

Wastewater class C Exam Questions With Verified Answers. What device(s) can be used as an emergency shut-off for the drive unit of a circular clarifier? - answerShear Pins You are the operator-on-duty. The alarm for the fire detector in the Belt Filter Press Control Room goes off. What type of fire extinguisher would you take to respond to this alarm? - answerClass C When working in an area with two or more floor coverings (for example, grating and checker- plate), be sure that they are always _____. - answerSecured together When working in confined spaces where flammable gases may be present, use only toolsmade of - answerA non sparking alloy A treatment plant should have a valve exercise program in which all plant valves are exercised (opened and closed) - answerOnce a year Immediate first aid for burns is to? - answerFlood with cold water Recommended personal hygiene practices to minimize the risk of being infected by wastewater pathogens include - answerChanging out of your work clothes and showering before leaving work What is the best protection against the risk of exposure to infections and disease at a wastewater plant? - answerPersonal Hygenie Regarding fire extinguisher training in the workplace. The employer must provide what? - answerA written and practiced emergency action plan. The combination of methane and which other gas can be very combustible? - answerOxygen In what location of the sewer manhole would methane gas be found? - answerAt the top Which type of fire is safe for a pressurized water extinguisher or water hose to be used on? - answerBrush Mixing dry granular chlorine (HTH) with petroleum products can cause which of the following? - answerCreate a fire or explosive condition The fusible plugs found on a 150lb cylinders and one-ton chlorinecontainers are designed to melt at what temperature range? - answer158-165 degrees Fahrenheit In the event of a large leak of chlorine is occurring, what is the first action the operator should take? - answerImmediately notify local fire and police departments A Class C type fire involves? - answerElectrical equipment A common fire extinguisher is AB or ABC type. What is the media contained inside these fire extinguishers? - answerDry Powder This toxic gas impairs one's sense of smell rapidly at high concentrations as it paralyses the respiratory organs. At lower concentrations it has a rotten egg odor. - answerHydrogen Sulfide Gas Coliform bacteria are: - answerMore resistant to chlorination than pathogenic bacteria Coliform bacteria are: - answerIndicators E. Coli results must always be higher or lower than fecal coliform results? - answerLower Waterborne diseases and illnesses common to the wastewater industryinclude dysentery, hepatitis, polio, typhoid, and what other disease? - answerCholera How many fusible plugs are in a 1 ton chlorine container? - answer6 What is the proper amount of oxygen to enter a confined space? - answer19.5% - 23.5% Which safety procedure can prevent accidental re-energizing of electrical energy while maintaining a piece of equipment? - answerUse proper LO/TO procedures If a leak of liquid chlorine occurs, one part of the liquid chlorine can expand to how many parts of gaseous chlorine at room temperature and average barometric pressure? - answer457 parts of gas. Chlorine gas is how many times heavier than air? - answer2.5 times Methane gas is lighter than air - answerTrue A pump's seal water pressure should be set at - answer5 to 10 psi more than the pump operating discharge pressure What does a gradual increase in the bearing temperature of a centrifugal blower indicate? - answerThere is a problem with the bearing lubrication or connection How often should the packing on a gate valve be replaced? - answerAs required What is surging in a centrifugal blower? - answerWhen the blower's discharge pressure is less than the aeration system's backpressure Pumps are often required to bring wastewater into a treatment plant. What types of pumps are typically used to lift influent wastewater? - answerCentrifugal If a centrifugal pump loses its prime after starting, what is the most probable cause? - answerAir leaks into the pump through stuffing boxes The casing surrounding a pump impeller that collects the water discharged by the impeller is called a __________. - answerVolute A _____ is installed on the pump discharge piping to prevent water from flowing back across a pump when it is off. - answerCheck Valve Why are check valves used in conjunction with centrifugal pumps? - answerTo prevent water in the suction line from flowing back into the wetwell What separates the impeller from the volute and prevents backflow in a centrifugal pump? - answerWear Rings Cavitation is the formation and collapse of a gas pocket or bubble on the blade of a pump's impeller. - answerTrue Bar screens must be cleaned frequently to prevent (choose the most correct answer) - answerExcess head loss (slowing down the water moving through the pipe) What is an air-gap device used for? - answerBackflow prevention Flow - answerThe amount of fluid to be pumped Head - answerThe extent or distance to which fluid is to be exported. The discharge of a centrifugal pump: - answerDecreases with the increase of head, and increases with the decrease in head In a centrifugal pump, leakage is prevented by - answerWear rings Valves should be closed slowly to prevent: - answerWater Hammer The purpose of racks or screens is to remove which of the following? - answerlarge solids Which of the following indicates that the impeller of a centrifugal pump may be worn or damaged? - answerPump is not delivering the design flow How often should inactive valves be exercised? - answerQuarterly A positive-displacement sludge pump should never be placed into operation - answerWith the discharge valve closed A device that causes the wastewater in a vertical riser pipe to rise to an outlet using compressed air is called an - answerAir lift pump If packing is not maintained properly, - answerIf packing is not maintained properly, If bearings on a centrifugal pump are running hot, over- or under-lubrication should be checked. If lubrication is satisfactory, the next preventative maintenance check would be to - answerInspect the alignment of the pump and motor A water-filled mechanical pump seal not only helps to prevent leaks but also - answerActs as a lubricant for the pump shaft and keeps gritty material from entering the packing box The formation and collapse of gas pockets or bubbles when water reaches boiling point on the blade of a centrifugal pump's impeller are kno