Wastewater III Study Exam Latest Update Already Passed

Wastewater III Study Exam Latest Update Already Passed First action for a polymer spill ✔✔Apply an absorbent to the spill such as sand or kitty litter and then sweep up the materials. Total discharge head includes ✔✔ ...

Wastewater III Study Exam Latest Update Already Passed First action for a polymer spill ✔✔Apply an absorbent to the spill such as sand or kitty litter and then sweep up the materials. Total discharge head includes ✔✔Discharge pressure head + static discharge head + Velocity head (outlet) + Friction Head (discharge line) Where is the best location to collect a sample? ✔✔A location that represents the entire waste stream or basin. What are the preservation and hold times for BOD samples? ✔✔48 hours at < or = to 6 degrees C. Define BOD. ✔✔The rate at which organisms use the oxygen in water or waste water while stabilizing decomposeable organic matter under aerobic conditions. What is the purpose of a dessicator? ✔✔To allow residual samples to control moisture prior to weighing. What will happen if the flow to the grit chamber is too low? ✔✔Too much organic material will be deposited. How does an operator control the suspended solids in an activated sludge basin? ✔✔By wasting and returning activated sludge. Chlorine combines with ammonia to form what ✔✔Chloramines What can the operator control with the activated sludge process? ✔✔Wasting and return rates. What is the best way to control filamentous bacteria? ✔✔Addition of chlorine to the (RAS.) Called return on some tests. A 5.2 acre lagoon with an in-fluent of 47000 gallons per day is dropped 3 inches a day from a depth of 5 feet to a depth of 2 feet. How many gallons are discharged each day? ✔✔470,577 gallons per day (exact problem) Define endogenous respiration. ✔✔A situation where living organisms oxidize some of their own cellular mass instead of new organic matter they absorb or absorb from their environment. What should the velocity of the sewage in a gravity sewer line be coming into the waste water plant? ✔✔At least 2.0 Feet per second. What does hydrogen sulfide do in a collection system? ✔✔It causes corrosion. What must be on the warning tag attached to a switch that has been locked out? ✔✔The signature of the person who locked out the switch and who is the only person authorized to remove the tag. Primary clarification generally removes what percentage of TSS? (Total Suspended Solids) ✔✔40 to 60% How is the flow of the chlorine controlled from the chlorinator? ✔✔With a rotometer. Chlorine is corrosive when it mixes with? ✔✔Moisture What is the acceptable leak rate of a mechanical seal? ✔✔Mechanical seals should not leak. What piece of equipment is required to enter a confined space? ✔✔Oxygen meter. What should be worn to enter a space with a large chlorine leak? ✔✔SCBA Why is waste water disinfected? ✔✔To destroy or disable pathogenic organisms. The rakes in a primary clarifier jerk, skips or hangs, what should be done? ✔✔Drain clarifier and determine the source of the problem. What is the predominant organism responsible for stabilizing the waste in the trickling filter? ✔✔Bacteria Where should the air relief valve be located in a forced main in the collections system? ✔✔At the highest elevation in the line. What hazardous gases would an operator be potentially exposed to? ✔✔Hydrogensulfide, methane. What is the ratio of methane to carbon dioxide in a properly operating anaerobic digester? ✔✔65-70% methane and 30-35% carbon dioxide. You have an inflow of 100 gallons of storm water into your collections system. How many people does this represent? ✔✔100-200 gallons per day per person. The best test to perform to determine the stabilization of waste in aerobic digestion is? ✔✔Volatile solids. What are three physical factors that determine facultative pond efficiency? ✔✔Temperature, short-circuiting, depth. Organisms that are both aerobic and anaerobic are called what? ✔✔Facultative. When the DO drops to <1 or <2 nitrification. ✔✔Decreases remain the same. The conversion of ammonia to nitrate is called what? ✔✔Nitrification. Most nitrogen entering a plant is in the form of what? ✔✔Ammonia and organic nitrogen. What is the purpose of for adding seed to a BOD sample? ✔✔To add organisms to stabilize the organic material in the sample. What is the first thing that should be done prior to performing a PH analysis? ✔✔Calibrate the meter. You have 60lbs of material that is 21% chemical by weight. How many lbs of chemical do you have? ✔✔12.6 lbs of chemical. How long must sludge records be maintained? ✔✔5 years. What material is added to waste water in the form of slurry? ✔✔Lime Disease causing organisms are called what? ✔✔Pathogenic What is coning? ✔✔Development of a cone shaped flow of liquid, like a whirlpool, through sludge. This can occur in a sludge hopper during sludge withdrawal when the sludge becomes too thick.Part of the sludge stays in place while liquid rather than sludge flows out of the hopper. Know all types of positive displacement pumps. ✔✔Plunger, Rotary,Lobe, Diaphram, Screw, Poog, cavity, Auger A piston or reciprocating pump should be operated when? ✔✔When the suction and discharge valves are open. The flow of sludge is generally determined by using what device? ✔✔Magnetic velocity meter. Which way does an electric current flow in cathodic protection? ✔✔From anode to tank or from anode to pipe What is the purpose of the "air relief valve" on an anaerobic digester? ✔✔Pressure relief valve or vacuum relief valve. What gases are formed during anaerobic digestion? ✔✔Initially hydrogen sulfide at start up and the methane and carbon dioxide. The term for the protection of potentially hazardous material from entering the waste water plant is called what? ✔✔Pretreatment The best tool to have during a hazardous material spill is? ✔✔MSDS or SDS A pump and motor should be? ✔✔Aligned What is the definition of a submersible pump? ✔✔A pump which is combined with a motor and mechanical seals and totally sealed to keep out water. The best way to record when maintenance is done is? ✔✔Work order. What is the purpose of a thermal control circuit on a motor? ✔✔Opens the circuit when the motor overheats. You have an influent COD of 620mg per liter and an effluent COD of 26mg per liter. What is your % removal of COD? ✔✔96% What is the incubation time and temperature of a 5 day BOD? ✔✔5 day incubation at 20 degrees celsius. A centrifugal pump that loses efficiency is most likely due to what? ✔✔Cavitation,debris When receiving deliveries you should do what for security purposes? ✔✔Check all credentials of the driver. How does the operator know when air filters need to be replaced? ✔✔When the differential pressure increases between the inlet side and the outlet side. For safety purposes what should be installed on the gears and other moving parts of clarifiers? ✔✔Guards must be installed on the gears and other moving parts that could be contacted accidentally. Why are some chemicals/reagents stored in amber bottles? ✔✔The chemical or reagent may be sensitive or reactive to light. The best way to prevent accidental release of untreated waste is to? ✔✔Clearly mark all pipes and valves. You have a receiving stream flow of 500 million gallons a day and a discharge of 700,000 gallons per day. What is the ratio of dilution? ✔✔... When potable water and waste water are used within close proximity what should you have? ✔✔Air gap device. Note: Backflow device is not one of the choices. The natural biological progression in an anaerobic digester is the? ✔✔Acid formers and then the methane formers. The most important physical characteristic of pump lubricant is? ✔✔Viscosity Why are chlorine rooms segregated from everything else? ✔✔... Maintenance of a V-notch weir involves what? ✔✔Clean and brush off deposits that accumulate in the weir. Keep weir and upstream and downstream channels clear of foreign bodies and interference. What does a GFCI switch do? ✔✔The GFCI monitors the current flowing from hot to neutral and opens or trips the circuit if an imbalance is detected. Why is a motor allowed to run temporarily without a relief plug after lubrication? ✔✔To allow excess grease to drain out. Which of the following problems is /are caused by hydrogen sulfide gas? ✔✔Corrosion of sewers, structures and equipment. At what time of day would the DO levels in apond be the lowest? ✔✔Early morning, algae consumes O2 at night Define as-built plans. ✔✔A set of drawings or maps that indicates structures as the are currently built. If changes to these structures are made then the "as-built" plans need to be updated to reflect these changes.