Wastewater D License Exam Study Questions and Answers

How many PPB equals one PPM? - One thousand parts per billion equals one part per million If the bubbler system air supply line at the wet well is clogged, what will this cause the pump to do? - Pressure build up in the supply line would signal more water column then there really was, causing the pump to run longer than necessary, possibly not kick off and run continually If the bubbler system air supply line at the wet well has a hole in it above the water level, what will this cause the pump to do? - It would cause a low pressure reading showing a lower water level then there really is, or possible not even kicking on the pump What is the best way to keep within the operating budget? - keep list of purchases and expenses to date during fiscal year comparisons should be made with budget allocations to avoid excess purchases review purchases monthly and compare to budget If a diaphragm pump has 2 check valves open, what will the pump do? - It would not pump properly because 1 check valve should be shut while the other is open A suction lift pump on the inlet side normally reads 2in of mercury on the psi vacuum gauge but not reads 3in of mercury. What is the problem with the pump? - A higher vacuum than normal may indicate a partially plugged or restricted suction line. A lower vacuum may indicate a higher wet well level or a worn pump impeller or wearing rings. One mg per L equals how many pounds per 1 MG? - 8.34 What is the proper way to put packing in a pump? - cut the packing rope about 45 degree angle, place around shaft, be sure to offset/stagger the next joint from the previous How many drips of water should you have coming out of a packing seal? - no drip on a mechanical seal How many drips of water should you have coming out of a packing seal? 2 - what the operation and maintenance manual recommends A one horsepower motor that runs on 110 volts using 10 amps has what efficiency? - most motors run from 80-95% efficiency A motor that has 440 volt supply is usually what phase of power? - 3 phase NPDES - National Pollutant Discharge Elimination System the regulatory agency document issued by either a federal or state agency which is designed to control all discharges of pollutants from point sources into US waterways - NPDES permit What is the name of our operating permit? - NPDES What is the best way to promote safety in the workplace? - the supervisor needs to be safe and promote safety in such a manner to get the employees involved What is normally used to raise the pH in sludge? - lime What is the common device used to measure the effluent of a lagoon? - v notch weir What concentration of H2S is unsafe to humans? - death in a few minutes at 0.2%. Paralyzes respiratory center What is the minimum O2 concentration that is safe for workers to enter a manhole? - If O2 is less than 19.5%, do not enter space without respiratory protection. Normal air contains 20.93% of O2. Normal air contains ______% of O2 - 19.5%