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Wastewater Operator Class 1 & 2
Practice Test Exam 2024 Update
Questions and Correct Answers Rated
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Flow measurement system where flow stream contents are collected in container for fixed period of time - ANSWER-Timed gravimetric Uses a strong oxidizer to break down organic material - ANSWER- Chemically Oxidizable Carbon (COD) a measure of carbon dioxide given off when material is heated to 550° - ANSWER-Total Organic Carbon (TOC) What is the recommended detention time for a primary clarifier? - ANSWER-1 1/2 - 2 hours What would be added to a lagoon/pond to subdue a strong odor and increase oxygen (O2)? - ANSWER-Sodium Nitrate What is the maximum holding time for fecal coliform alanyses? - ANSWER- 6 hours What sort of system do lagoons/ponds form for the wastewater organix population? - ANSWER-Aerobic, Anaerobic, Facultative What is the primary function of a brush aerator? - ANSWER-To produce great dissolved oxygen (DO) If the first pond in a series operation is organically overloaded, how should the flow be controlled? - ANSWER-They should be switched to parallel operation
What should the operator do with plants/weeds growing along the water's edge with respect to ponds? - ANSWER-Remove them as they appear to avoid the establishment of a deep root system How should lantern rings be installed on the stuffing box as part of a pump unit? - ANSWER-Completely filled with grease before all the rings of packing are in place. What are the pH parameters outlined by KPDES in the process of wastewater treatment? - ANSWER-6.0 - 9.0 ppm The explosive range of the main product of anaerobic digestion, methane, is in the range of: - ANSWER- 5 - 15% Recirculation in a tricking filter operation is sometimes used with trickling filters to: - ANSWER-Keep the media wet during low flow periods, dilute the organic strength of the influent, and smooth out diurnal flow fluctuations Small quantities of sludge should be pumped often in primary clarifiers to: - ANSWER-To prevent hydraulic & organic overloading of the digester and to keep sludge blankets down so that the septic "floating" sludge will not result. In an active oxidation ditch, how long should a measured amount of wastewater treated before going to the next stage? - ANSWER- 18 - 36 hours Fish such as salmon and trout cannon tolerate more than trace amounts of chlorine. therefore, a total residual chlorine monthly limits for zero flow streams are set at: - ANSWER-0.01 mg/L The most severe penalties an operator can be subjected to for negligence and violation of EPA regulations are: - ANSWER-Civil or criminal penalties
When visitors are touring your plant your greatest concern should be: - ANSWER-Their safety Where are lantern rings installed on a pump? - ANSWER-Between the water supply line and the stuffing box What must be checked for when using a float type influent gage? - ANSWER-Grease and/or rag buildup on the float The pretreatment area of a plant is equipped with a comminutor and large solids are getting into the primary clarifier. What might be the problem? - ANSWER-Misaligned teeth or worn teeth What is the standard design criteria for Total Suspended Solids? - ANSWER-0.20 lbs/capital/day A newly created pond/lagoon will establish a thriving biological population for waste reduction in about how many days? - ANSWER-60 days The grit removal process is so important because of why? - ANSWER-It protects downstream equip,emt You arrive at a manhole where strong gas fumes are detected. What should you do? - ANSWER-Do not enter and call the police/fire department What type of sample indicates the character of the wastewater over a period of time, eliminates short duration effects, evens out high and low flows, and is a representative sample? - ANSWER-Composite sample What is the actual EPA directed maximum Cl2 residual allowed in the efflluent? - ANSWER-0.019 ppm A sudden increase in organic loading on the biological treatment system, with an acidically low pH, is known as a what? - ANSWER-Shock load
At what VA/TA ration would an anaerobic digester be under stress from volatile acids/compounds? - ANSWER-0.3-0. Metal plating wastes may be treated with: - ANSWER-Sodium Sulfide Effluent disinfection is necessary in order to do what? - ANSWER-Kill pathogenic bacteria Denitrification and rising sludge in the final clarifier may be an indication of:
- ANSWER-Low dissolved oxygen A spill or dump of unknown origin, which could be harmful to the treatment process or the operator(s), is known as what? - ANSWER-Slug load A grab sample is taken: - ANSWER-at "maximum" conditions such as high flow Before working on electrical wires, circuits, control boards, or motors the operator should do what? - ANSWER-ensure that all power sources are locked out and tagged out Sulfur dioxide is the dechlorinating chemical of choice because it reacts almost instantaneously with chlorine on a theoretical basis of what? - ANSWER-1 ppm SO2 to remove 1 ppm Cl What is the process for running the total suspended solids test? - ANSWER-Weigh dry filter, filter sample, dry at 103° C for hour, place in desiccator 15 minutes, weigh Foam coming out of the top valve of a newly filled anaerobic digester is an indication of: - ANSWER-Normal conditions Sludge floating to the surface of a clarifier is an indication of what? - ANSWER-Denitrification
The detention time in a final clarifier for a facility utilizing a fixed film reactor is: - ANSWER- 2 - 3 hours Collection system construction requirements, an infiltration or exfiltration test must be performed with a minimum positive head of: - ANSWER-2 ft Wastewater is composed of what? - ANSWER-99.9% water and 0.1% solids The nutrient requirements for biological stabilization of organic matter result in the following ratio for Carbon/Nitrogen/Phosphorus - ANSWER-100/5/ Plastic media in a super high-rate trickling filter system should be at what depth? - ANSWER- 10 - 40 ft deep Beggiatoa is a - ANSWER-filamentous organism At what point in the treatment process should a fecal sample be grabbed? - ANSWER-At the last point of the treatment process There are three general types of grit chambers. In the horizontal channel, velocities are reduced to ______ fps so that the grit will settle while the organics remain in suspension. - ANSWER- 1 - 1. Which is a type of diffuser: a ball, a bubbler, or electrical? - ANSWER-A ball A two stage trickling filter system is designed for a minimum BOD5 removal efficiency percentage of: - ANSWER-85% What type of foam should be seen at the initial start-up of aerators - ANSWER-Crisp, white Flow into an RBC should not exceed the design flow by more than what percentage? - ANSWER-50%
Which of the following does not cause filamentous: low dissolved oxygen, toxicity, low f/m (food to microorganism ratio), chlorination - ANSWER- Chlorination It takes ___________ ppm of alkalinity to convvert 1 ppm nitrate (NO3). - ANSWER-7. Sludge blanket depth in a final clarifier should be maintained at what feet? - ANSWER-1.0-3.0 ft The lethal dose of chlorine with a few breaths is: - ANSWER-1000 ppm or .1% by weight An approved method of measuring chlorine residual is: - ANSWER- Amperometric Titration What percentage of BOD is soluble? - ANSWER-50% Heavy metals, Phenols & Toxins would be classified as what kind of pollutant? - ANSWER-Non-conventional How much oxygen is needed to oxidize 1 ppm Ammonia to Nitrate? - ANSWER-4. Cadmium, Lead, Nickel and Zinc are classified as what kind of pollutant? - ANSWER-Priority pollutants To improve disinfection by chlorination, it is recommended that the detention time be: - ANSWER-Increased How much chlorine is required to oxidize 1 ppm ammonia, assuming adequate pH. alkalinity, and temperature? - ANSWER-9.
Microorganisms/bacteria make up about ______ of the activated sludge biomass. - ANSWER-95% Synthesis: - ANSWER-production of new cells ***can not work without respiration Respiration: - ANSWER-Process of deriving energy from carbonaceous organic matter, BOD5, aka food. *** can not work without synthesis Synthesis needs ______ and respiration needs a ______ - ANSWER- energy, living cell Biochemical Oxygen Demand (BOD) - ANSWER-Uses bacteria and oxygen used to estimate biologically useful carbon Binary fission - ANSWER-reproduce by splitting in two What happens during the lag phase? - ANSWER-Bacteria become acclimated to their new surrounding, they are digesting food, developing enzymes, and other things required for growth. What happens during the log phase? - ANSWER-Accelerated growth - the bacteria are growing as fast as they can since there is an excess of food - cells are mostly dispersed not sticking together. Phases of bacteria in order - ANSWER-Lag, log, stationary, declining growth, death What happens during stationary phase? - ANSWER-The bacteria have lost their flagella and have secreted the "slime", allowing them to stick together into floc. The floc get big enough, that if aeration and mixing were stopped, the floc could settle to the bottom. What happens during the declining growth phase? - ANSWER- Reproduction slows down because there is not enough food for cell
preproduction to continue. There are now a large number of bacteria to complete for remaining food. What happens during the death phase? - ANSWER-The total number of living bacteria keeps falling. The bacteria starts to eat each other or itself just to stay alive. Dead bacteria now providing food to sustain remaining bacteria. What is the typical f/m ratio? - ANSWER-0.05 to 0. Population equivalent of water? - ANSWER-100 gallons per day Population equivalent of TSS? - ANSWER-0.2 lbs per day Population equivalent of nitrogen? - ANSWER-0.02 lbs per day Population equivalent of phosphorus? - ANSWER-0.0048 lbs per day IN addition to Carbon, Nitrogen, and Phosphorus, you also need trace amounts of what 6 elements? - ANSWER-Sodium (Na), Potassium (K), Calcium (Ca) and Magnesium (Mg), Iron (Fe), and Sulfur (S) If CNP ratio has deficiencies how will the bacteria respond? - ANSWER- Will create more slime, resulting in slime bulking, making floc not settle well. The level of oxygen in the water is dependent on what? - ANSWER-The temperature of the water When water has the highest concentration of DO, the water is _________ - ANSWER-saturated What is toxic to anaerobic bacteria? - ANSWER-oxygen
What is a detention time? - ANSWER-The time required to fill a tank at a given flow or the theoretical time required for a given flow of wastewater to pass through a tank. Organisms are attached to the media by the slime layer, biofilm. As the biofilm thickens, microorganisms fall off the media, these are called ______
- ANSWER-slough solids. What three processes are used for secondary treatment? - ANSWER- Activated sludge process, aerated lagoons, sequencing batch reactors. Factors that affect activated sludge process - ANSWER-Nutrients (carbon, nitrogen, phosphorus), dissolved oxygen, temperature, mixing, and other factors (pH, toxics, and hydraulics) Increasing sludge wasting will also increase what? - ANSWER-F/M ratio What is MLSS? - ANSWER-mixed liquor suspended solids - microorganisms, food and non biodegradable solids What is MLVSS? - ANSWER-mixed liquor volatile suspended solids - represents the biomass present in the sample (bacteria) What does a centrifuge test measure? - ANSWER-Solids in system Excessive white billowy foam is an indication of what? - ANSWER-Young sludge (Will always get on new plants initial start up) An overabundance of dark, brown greasy looking foam is an indication of what? - ANSWER-Old sludge or filamentous organisms Denitrifying bacteria uses ___________ rather than organic carbon for the synthesis of new cells. - ANSWER-Carbon Dioxide
Bacteria use ______________, not oxygen, in the process of making energy - ANSWER-nitrate What is the downfall of chemical removal of phosphorus? - ANSWER- Increase creation of sludge Ponds vs lagoons - ANSWER-Ponds are up to 8 ft and typically aerobic while lagoons are greater than 8 ft and can be aerobic or anaerobic. Ponds and lagoons are basically the same thing. Pond that receives waste with little or no prior treatment - raw wastewater (sewage lagoons) - ANSWER-Stabilization ponds Ponds that often are arranged in series following primary treatment - extra clarification and BOD5 removal - ANSWER-Oxidation ponds Ponds that often are in series after secondary treatment to provide tertiary treatment - ANSWER-Polishing ponds What is the most common type of pond? - ANSWER-Facultative How does bacteria get energy in anaerobic pond? - ANSWER- Fermentation Algae are microscopic plants that require what three things? - ANSWER- Sunlight, carbon dioxide, nitrogen and phosphorus What percentage of cell tissue is broken down into carbon dioxide, ammonia, and water? - ANSWER- 75 - 80% Methane fermenters function best at a pH range of what? - ANSWER-6.6-
Chlorine disinfection has a recommended minimum detention time of what?
What is the purpose of wearing rings? - ANSWER-Used to plug the space between the impeller and the casing to prevent internal liquid leakage What is the purpose of lantern rings? - ANSWER-To provide water seal connection between the water supply line and the stuffing box Pump that has flow parallel to the axis of the impeller - normally used in wet well applications - ANSWER-Axial Flow Pump Pump used for wide unobstructed passages - normally used in dry well applications - ANSWER-Mixed Flow Pumps Pump used by moving piston back and forth - normally used to handle sludge - ANSWER-Reciprocating or piston pumps Auger type pump housed in trough or on an incline - commonly used on influent or effluent - ANSWER-Incline screw pumps ____________________ pumps work on the principle of a decrease in overall specific weight of a confined column of gas and water mixture. - ANSWER-Air Lift 5 types of pathogenic organisms - ANSWER-viruses, bacteria, protozoa, fungi, and helminths/worms Exposure to pathogens can occur through contact with what six things - ANSWER-Wastewater, aerosols, compost, foam, sludge, work surfaces What three events have to happen for disease to be transmitted? - ANSWER-Pathogens must leave an infected body, pathogens must come in contact with the operator, pathogens must enter the operator 4 avenues of exposure - ANSWER-Ingestion (fecal/oral transmission), Inhalation (breathing), Injection (needles), invasion (cut or any break of the skin)
Hazardous gas that is produced by the anaerobic biological reduction of sulfur containing materials in wastewater. - ANSWER-Hydrogen sulfide
