Minnesota Class D Water Exam Questions with Complete Solutions 2023/202 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: - Correct Answer 15 service connection or over 25 persons for over 60 days a year What federal law regulates public water supplies? - Correct Answer Safe Drinking Water Act What cause water to move through pores in soil and rocks ? - Correct Answer Gravity What are disease producing bacteria called? - Correct Answer Pathogenic A presence/absence coliform test utilizes - Correct Answer color change What are two main causes of harness in water? - Correct Answer Calcium and magnesium Which source of water has the greatest natural protection from bacterial contamination?
- Correct Answer deep 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. - Correct Answer water hammer What are the two most important safety concerns when entering a confined space? - Correct Answer hazardous gases and oxygen deficiency what piece of safety equipement must an operator wear when entering a confined space? - Correct Answer Harness Which document provides a profile of hazardous substances? - Correct Answer MSDS What safety measure must ab operator follow prior to working on electrical equipment? - Correct Answer Lock out Tag out all electrical switches what is the correct procedure for mixing acid an water - Correct Answer Acid is ADDED SLOWLY to water The major source of error when obtaining water quality information is improper - Correct Answer Sampling Polyphosphates should be fed at which point? - Correct Answer Before the addition of chlorine 1 / 2
After a new water main is installed and pressure is tested, it should be? - Correct Answer Filled 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 - Correct Answer 10 feet The health department requires a minimum of how much free chlorine residual at distant points of the ditribution system? - Correct Answer 0.2 ppm
A PH reading of 2 means the water is: - Correct Answer Acidic
vent openings on reservoirs and clear wells should be: - Correct Answer Screened How many pipe diameters should a meter be located in relationship to elbows or fittings? - Correct Answer Three pipe diameters upstream, five pipe diameters downstream chlorine leaks can be detected around a chlorine cylinder by the use of: - Correct Answer Ammonia The intake of a forced ventilation system for a chlorinator room should be located: - Correct Answer Near the floors If an operator hears a pinging sound coming from a pump what is the probable cause? - Correct Answer Cavitation A main break may cause low pressure in the distribution system which in turn may
result in: - Correct Answer Contamination of the system by backsiphonage
Chemicals added to groundwater supply should be added - Correct Answer after the check valve What is the minimum pipe diameter for fire protection is: - Correct Answer 6 inches Sodium thiosulfate is used to - Correct Answer Neutralize chlorine residuals distribution system pressure during a fire should never drop below: - Correct Answer 20 PSI
High nitrates contents in water can affect: - Correct Answer Infants
The state agency that regulates public water systems is: - Correct Answer Minnesota department of Health
- / 2