Class C Water Operator License Exam With Complete Solution

THM are caused by - Answer Reaction of chlorinated water with humic materials found in surface water sources THMs in finished water can cause - Answer Cancer What is the MCL for Trihalomethanes - Answer 0.1 mg/L Nitrate in levels above ______ mg/L can cause blue baby disease - Answer 10 Water main definition - Answer Any line that passes one property to reach another parcel of property Name three water borne diseases - Answer Typhoid, infectious hepatitis, and cholera How much pressure in one foot of elevation offer? - Answer .433 psi Velocity of flow in a water main is expressed in _________ - Answer Feet per second What is the industry standard for acceptable water loss in a public water supply? - Answer 14% or less The average flow from a 5/8" x 3/4" water meter is _________ gpm - Answer 18-20 gpm How many pounds of water in a cubic foot of water? - Answer 62.4 pounds What is the IDPH required level of fluoride - Answer .6 mg/L - .8 mg/L What type of test is most commonly used for testing fluoride levels? - Answer SPADNS What type of test is most commonly used for testing chlorine residuals in a small system or in a distribution system? - Answer DPD What is added to a bacti sample bottle to remove the chlorine residual? - Answer Sodium thiosulfate Bacti sample bottles should be ___________ - Answer Filled one inch from the top of the bottle Bacti samples must be analyzed no later than ________ hours after collection - Answer 30 What is the minimum "combined" chlorine residual that is required to be in all parts of a distribution system? - Answer 1.0 mg/L What is the minimum "free" chlorine residual that is required to be in all parts of a distribution system? - Answer 0.5 mg/L What does chlorine breakdown into? - Answer hypochlorite ion and hypochlorous acid What is total chlorine? - Answer The amount of chlorine remaining after a given contact period What is the percentage of available chlorine in gas chlorine? - Answer 100% What is the percentage of available chlorine in calcium hypochlorite? - Answer 65-70% What is the percentage of available chlorine in sodium hypochlorite? - Answer 10-15% If calcium hypochlorite and oily rags are allowed to come into contact with each other what will occur? - Answer Ignition and flash fire will occur What is the purpose of poly-pigging a water main? - Answer Progressive poly pigging is a process that involves propelling a "pig" constructed of foam of varied densities through a pipeline. As it travels through the pipe it loosens, removes and transports debris to an access point like a manhole where it can be removed by a vacuum or pump truck and transported away for disposal. What is specific gravity as related to groundwater? - Answer Weight of a particle, substance, or chemical solution in relation to the weight of an equal volume of water What is static water level? - Answer The elevation or level of water table when the well pump is not operating Which component of the well supports the weight of the pumping unit? - Answer Pump pedestal Which component of the well permits measurement of water level by means of air pressure measurements? - Answer Air line water level measuring device Which component of the well permits operator to see level of gravel and add gravel as necessary? - Answer Gravel tube Which component of the well is used to remove first water pumped at start-up? - Answer Pump blowoff Which component of the well allows air to enter well during drawdown to prevent vacuum conditions; vents excess air during well recovery? - Answer Well casing vent Which component of the well permits insertion of water lever measuring device; also used to add cleaning agents? - Answer Sounding tube Which component of the well permits discharge of air in column pipe during start-up and admits air during shutdown? - Answer Air-release vacuum breaker valve Which component of the well provides water tight seal between the motor base and the concrete support pedestal? - Answer Pump motor base seal Which component of the well permits sampling of pumped water? - Answer Sampling taps What is the purpose of a check valve? - Answer Acts as an automatic shut off valve when a pump stops Acts to keep water that has already entered the system from flowing back into the well casing Helps prevent system pressure from decreasing due to backsiphonage If a well pump is wired backward the well pump will _________ - Answer Still pump some water A water plant has a line shaft well. The operator replaces the packing in the packing gland on the motor. After the packing has been replaced there should be _______ - Answer A small trickle of water when the pump is operating A pump housing which obtains its power from a side-shaft electric motor air locks. The pump itself is extremely how to touch. How do you correct this problem? - Answer Leave the motor on, open the spigot, and allow the air to bleed off until water flows from the spigot Pump cavitation is most likely to occur when the top of the water source is ______ - Answer When the water level is changing levels above and below the impeller What is a Ranney well? - Answer A dug well with lateral screens which lay horizontally under a nearby river What is well yield? - Answer The amount of water that can be collected for a given use from wells or surface sources