Class C Water Plant Operator 451-500 Exam Questions With Correct Answers

451. When collecting iron samples, what chemical is added as a preservative? - Answer HNO3 to Ph < 2 452. Physical factors that affect coagulation include? - Answer Ph, alkalinity, temperature, turbidity 454. When dealing with disciplinary situations, a supervisor should be? - Answer Calm, flexible, and open minded 453. While the filter influent valve is shut, the water level in the filter drops 6" in 90 seconds. The filter is 12' long and 8' wide. what is the filtration rate in gpm/sq ft? - Answer 2.5 455. A community water system serving 350 or more persons, or having 150 or more service connections must provide auxiliary power for operation of source treatment units and pumps at a rate equal to? Average daily flow. - Answer 456. How many pounds of dry polymer must be added to a 10 gal tank to produce a .30 strength solution? - Answer 2.5 lbs 457. How many gallons of water must be added to a gallon of 6% NaOCl solution to produce a .06% solution? - Answer 99 gal 458. The V/V test indicates 2% sludge. what change should you make in plant process? - Answer Blow off less sludge 459. A WTP is having difficulty maintaining a sludge blanket. What action must be taken? - Answer Adjust recirculation rate 460. Gaseous chlorine is being withdrawn at a rate faster than liquid can be evaporated. what is likely to happen? - Answer Freezing of the cylinder. 461. When backwashing a filter, how do you determine when the filter is clean? - Answer Backwash water is clear. 462. A positive L.I. will _____ the rate of _____. - Answer Decrease / Corrosion 463. What process methods are used to reduce the volume of sludge? - Answer Thickening, conditioning, dewatering 464. How is water removed from a sand drying bed? - Answer gravity 465. Accurate maps of the distribution system are necessary in order to? - Answer Locate valves and mains quickly in an emergency