Minnesota Class D Water Exam Questions & Answers

According to the Safe Drinking Water Act the basic definition of a public water supply system is any water system that supplies water for human consumption that serves: - ANSWERS15 service connection or over 25 persons for over 60 days a year What federal law regulates public water supplies? - ANSWERSSafe Drinking Water Act What cause water to move through pores in soil and rocks ? - ANSWERSGravity What are disease producing bacteria called? - ANSWERSPathogenic A presence/absence coliform test utilizes - ANSWERScolor change What are two main causes of harness in water? - ANSWERSCalcium and magnesium Which source of water has the greatest natural protection from bacterial contamination? - ANSWERSdeep well in gravel Which of the following terms refers to excessive internal pressure which may be several times the normal operating pressure and can seriously damage hydropnematic tanks, valves, and piping network. - ANSWERSwater hammer What are the two most important safety concerns when entering a confined space? - ANSWERShazardous gases and oxygen deficiency what piece of safety equipement must an operator wear when entering a confined space? - ANSWERSHarness Which document provides a profile of hazardous substances? - ANSWERSMSDS What safety measure must ab operator follow prior to working on electrical equipment? - ANSWERSLock out Tag out all electrical switches what is the correct procedure for mixing acid an water - ANSWERSAcid is ADDED SLOWLY to water The major source of error when obtaining water quality information is improper - ANSWERSSampling Polyphosphates should be fed at which point? - ANSWERSBefore the addition of chlorine After a new water main is installed and pressure is tested, it should be? - ANSWERSFilled with a solution of 25 ppm to 50 ppm free chlorine for at least 24 hours before flushing The minimum horizontal distance allowed between waterman and sanitary sewer is - ANSWERS10 feet The health department requires a minimum of how much free chlorine residual at distant points of the ditribution system? - ANSWERS0.2 ppm A PH reading of 2 means the water is: - ANSWERSAcidic vent openings on reservoirs and clear wells should be: - ANSWERSScreened How many pipe diameters should a meter be located in relationship to elbows or fittings? - ANSWERSThree pipe diameters upstream, five pipe diameters downstream chlorine leaks can be detected around a chlorine cylinder by the use of: - ANSWERSAmmonia The intake of a forced ventilation system for a chlorinator room should be located: - ANSWERSNear the floors If an operator hears a pinging sound coming from a pump what is the probable cause? - ANSWERSCavitation A main break may cause low pressure in the distribution system which in turn may result in: - ANSWERSContamination of the system by backsiphonage Chemicals added to groundwater supply should be added - ANSWERSafter the check valve What is the minimum pipe diameter for fire protection is: - ANSWERS6 inches Sodium thiosulfate is used to - ANSWERSNeutralize chlorine residuals distribution system pressure during a fire should never drop below: - ANSWERS20 PSI High nitrates contents in water can affect: - ANSWERSInfants The state agency that regulates public water systems is: - ANSWERSMinnesota department of Health A connection between non potable and potable water supple is called: - ANSWERSCross connection The ______ is the most positive back flow prevention measure - ANSWERSAir Gap The feet of drawdown in a well is the distance between the static groundwater level and the pumping level - ANSWERSTrue A National Secondary Drinking Water Regulation is a legally-enforceable standard that applies to public water systems - ANSWERSfalse The greatest amount of particular contaiminant allowed in drinking water by EPA is known as: - ANSWERSMaximum contaminant Level Water samples collected for coliform bacteria monitoring must be analyzed by the laboratory within: - ANSWERS30 hours Current regulations require that id a routine coliform bacteria sample is positive the water supplier must take _____ more samples - ANSWERSFour- New standard is 5 Increased lead levels in water can cause impaired mental function in children and increased blood pressure or kidney problems in adults - ANSWERSTrue For community water supplies, the well casing vent shall end at least ____ above the finished floor elevation - ANSWERS18 inches Sodium hypochlorite is commonly called: - ANSWERSLiquid bleach A gas chlorine room shall be enclosed and separated from other operating areas. WHAT NINE THINGS MUST IT HAVE? - ANSWERS- Shatterproof glass - vents - eyewash stations - danger signs -emergency Kits -MSDS -Vaccuum ejector -lead gasket - scale - fusible plug - cylinder -main valve