AWWA Water Operator Certification Exam Prep 2024 With 520 Questions and Answers

AWWA Water Operator Certification Exam Prep 2024 With 520 Questions and Answers What is the most common disinfection by product when adding chlorine to water containing natural and inorganic matter? - ANSWER Chloroform What will most probably cause taste and odors, slime, and filter clogging? - ANSWER Blue-green Algae Why can rapid sand filters handle higher filtration rates compared to slow sand filters? - ANSWER Coarser sand Iron bacteria can interfere with ___________ because the bacteria produce _____________that prevents the stabilization chemicals from reaching the pipe surface. - ANSWER stabilization, a slime layer Hypochlorous acid is favored over hypochlorite ion when the pH is _____________and the temperature is ___________. - ANSWER low, low What filter has an unstratified media distribution? - ANSWER slow sand filters What is (are) the combine chlorine residual(s) at pH values ranging from 6.5 to 8.5? - ANSWER Monochloramine and dichloramine When iron alone is treated using manganese greensand filters, the chlorine feed rate should be about _________________. - ANSWER 1.0 to 1.2 times the iron concentration chlorination of water that has high concentrations of natural organic matter will produce - ANSWER THMs When disinfecting with chloramines, when can the ammonia be added to the process? - ANSWER Before, same time as, or after the chlorine What will settle out of the water in a short period of time? - ANSWER Very fine silt Point- of-use activated carbon filters are most effective for removing _________________. - ANSWER Chlorine Potassium permanganate is used as an oxidant for control of ____________________. - ANSWER Iron and manganese, organic precursors, and taste and odors What must an operator periodically check regarding the cyclone separator system? - ANSWER Storage bin or hopper to empty of sand and grit These types of chemicals chemically tie up scale-forming ions and are eventually ingested by consumers. - ANSWER Sequestering agents An operator should record filter ______________ measurements, condition, and depth of media on a ________ basis. - ANSWER bed expansion, quarterly Lime will precipitate noncarbonate hardness from the water, but it also orms noncarbonate salts that cause noncarbonate hardness. What are these salts? - ANSWER CaSO4 and CaCl2 What are absolute ratings based on with regard to membranes? - ANSWER Largest pore opening How ar manganese greensand beds regenerated? - ANSWER Backwashed with permanganate solution The most effective process for removing radon gas, when considering cost and footprint, would be ____________. - ANSWER packed tower aeration What is the primary advantage of placing a properly sized anthracite coal layer over manganese greensand? - ANSWER Longer filter run times What factor will cause problems for chlorination? - ANSWER Foreign substances In the lime-soda ash softening process, smaller plants find that ________ is less expensive to purchase; regardless of the size of the plant, ___________ needs to be mixed long enough because it dissolves rather slowly. - ANSWER calcium hydroxide, lime What does the optimal pH establish when applied to iron and manganese oxidation? - ANSWER Detention time A water plant using chloramines as a disinfectant has allowed sizable amounts of turbidity to enter the distribution system. If this occurs over a period of years, what will occur at the far end of the distribution system? - ANSWER Taste and odor will develop, Bacterial growth will be supported, and Nitrification The reduction of color would most likely occur after - ANSWER coagulation, flocculation, and sedimentation To eliminate hydrogen sulfide (H2S), the pH of the water should be lowered to ____________ or less before beginning aeration. - ANSWER 6.0 Permanganate reactions are largely dependent on ___________. - ANSWER pH What are the primary reasons that more small water stems are installing pressure filters? - ANSWER Because installation and operating costs are low Because lime slurries have a _________ and a ___________ in water, calcium carbonate will ____________ on anything the slurry touches. - ANSWER high pH, low solubility, preciptate It is recommended that the free chlorine residual at a customer's tap should be at least ________. - ANSWER 0.2 mg/L Microfiltration is considered to be intermediate between ___________ based on pore size. - ANSWER ultrafiltration and multimedia granular filtration After microscreening, there should be a significant reduction in ______________. - ANSWER Turbidity How can the problem of poorly formed floc be solved? - ANSWER Use of coagulant aid What chemical used in corrosion control gives off large quantities of CO2 when it comes in contact with an acid? - ANSWER Soda ash Alum requires _____________ to be present naturally or added fro proper coagulation, and about _____________ is required for each milligram of alum added per liter. - ANSWER alkalinity, 0.5 mg/L