Wastewater Treatment: Questions and Answers for 2024-2025, Exams of Water Resources Planning and Management

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2024-2025 Ga Wastewater Class 2

Questions and Correct Verified Answers.

Graded A

________ can be used to break the emulsion when using emulsion-type polymers.

• ANSStatic Mixers a cation typically used to precipitate phosphorus from wastewater is - ANSaluminum A chemical commonly used for controlling hydrogen sulfide and its odors is __________? - ANSChlorine Acetic Acid(Reagent) - ANSto lower the pH to between 3- An ideal carbon to nitrogen ratio for composting sludge is __________ - ANS30: An operator notices that some of the secondary clarifiers have rafts of sludge floating on the liquid surface of the clarifiers. What is the problem? - ANSThe sludge is not being removed quickly enough from the clarifiers, causing denitrification to occur in the tanks As a last resort, what situation might require an operator to chlorinate the RAS? - ANSExcessive Filamentous Organsisms

Breakpoint Chlorination - ANSFree Chlorine + Combined Chlorine = Total Chlorine Dominance of flagellates in your mixed liquor indicate? - ANShigh F:M, low SRT Excessive organic material is being removed from a grit system. This situation can be corrected by - ANSincreasing the velocity Gor pH meters. a pH of 7 corresponds to how many millivolts? - ANS Grit is washed in order to _______. - ANSremove organic matter H2SO4 - ANSsulfuric acid High-rate activated sludge processes typically have a mean cell residence time of?

• ANS1 to 5 days How does an increase in effluent water temperature impact chlorine disinfection?
• ANSdemand increases; residual decreases If an activated sludge is not settling or compacting well there may be _____________________ - ANSexcessive filamentous organisms If there is insufficient alkalinity in your wastewater initially, the _____ of an aerobic digester tends to _____ over time - ANSpH, decrease

If your calculated F:M value is significantly higher than your target, which of the following actions could help to correct the situation. - ANSdecrease the wasting rate Impellers are a component of ______ pumps - ANSCentrifugal In an electrical circuit an ________ is used to measure current. - ANSammeter In anaerobic digestion, what explosive gas is formed? - ANSmethane In general biological sludges require __________ polymer for coagulation and flocculation. - ANScationic In typical domestic wastewater, what are the typical percent removals of BOD and TSS during primary treatment? - ANSBOD: 20- TSS 50- MLVSS is used for SOUR testing rather than MLSS because - ANSthe MLVSS does not include inert solids Most of the major odorous gases contain which element? - ANSSulfur (S) Most often the WAS rate for an activated sludge process is based on _______. - ANSMRCT or SRT NaOH - ANSSodium Hydroxide

(caustic soda) NH3 - ANSAmmonia Normal Sodium Thiosulfate(Reagent) - ANSStock Solution/Chloroform is added in order to decrease bacterial decontamination Normal Sodium Thiosulfate(Reagent) - ANSTitrant. Prepared from 0.1 Normal solution above. Oxidation Reduction Potential (ORP) is most often associated with _______. - ANSChlorine Control Potassium Bi-lodate or Potassium Dichromate(Reagent) - ANSUsed to standardize the Sodium Thiosulfate Potassium Iodine(KI)(Reagent) - ANSreacts with the chlorine Rotary drum screens are typically classified as _________ - ANSFine screens Slime slakers convert quicklime(CaO) to __________ - ANSCalcium Hydroxide Sludge cake is moved through a multiple-heart furnace by an action called? - ANSrabbing Solid-bowl describes which type of dewatering equipment? - ANSCentrifuges

Starch Solution(Reagent) - ANSIndicator The air-to-solids ration for a DAF unit is always - ANSless than one The bioassay test measures the ________ of a plant's effluent sample - ANStoxicity The differential speed of of a centrifuge results in ___________. - ANSSolids being transported from the feed zone to the beach The First indicator of a high organic load coming into an activated sludge process is a decease in ________. - ANSDissolved Oxygen The first step in shutting down a centrifuge is to? - ANSturn of the feed sludge The hydraulic loading rate to a trickling filter is based on - ANSflow to the filter and surface area of the filter The lack of acid preservation and digestion of a filtered phosphorus sample will measure only ________ - ANSOrthophosphate The last step to starting a gravity belt thickener is _________. - ANSStarting polymer and sludge feed pumps

The microorganisms typically involved in the activated sludge treatment are bacteria and metazoa such as? - ANSRotifers The most common type of wastewater treatment pond used is the ______ pond. - ANSfacultative The precise amount of polymer used to settle sludge in a thickener is termed the _____. - ANSOptimal Dosage The primary indicator of an upset in your anaerobic digester is _________ - ANSvolatile acids increase The process of adding water to quicklime is termed________ - ANSSlaking The purpose of a turnbuckle on the stay rod on a trickling filter is to ________. - ANSpermit the adjusting and leveling of the distributer arm The target SRT is 12 days. Currently, the MLSS concentration is 2800 mg/L. Tourist season begins this weekend and the influent BOD load is expected to increase by 25% in the next few days. What should the operator do to maintain the SRT? - ANSincrease the wasting rate Typically the presence of light, stiff, billowy foam on the surface of an aeration tank is an indication of _______________. - ANShigh F:M ratio What condition/situation might require an operator to chlorinate the RAS? - ANSFilamentous Organisms

What is the maximum safe level of ammonia a worker can be exposed to during an 8-hour workday? - ANS50 ppm What type of unit removes grit from wastewater? - ANSVortex Separator Which of the following chemicals is commonly used for chemical phosphorus removal? - ANSAluminum Sulfate Which of the following chemicals is used to precipitate phosphorus from wastewater - ANSAluminum Sulfate Which of the following chemicals would be used to aid in precipitating phosphorus? - ANSFerric Chloride Which of the following influent constituents cannot be removed through bioflocculation? - ANSTotal Dissolved Solids Which of the following is a probable cause for excessive sloughing in a rotational biological contactor? - ANSpH below 5. Which of the following is true of the pressure dewatering zone in the belt filter press? - ANSSludge passes from the low-pressure zone created by large-diameter rollers to the high-pressure zone created by small-diameter rollers

Which of the following thickening processes mixes incoming sludge with a pressurized recycle stream as it enters the thickener? - ANSDissolved Air Flotation Thickener (DAF) Which of the following units is used for the final washing and dewatering of grit? - ANSGrit Classifiers Which two compounds are formed during nitrification? - ANSnitrate and nitrite Which type of bacteria use chemically bound oxygen? - ANSanoxic You conducted a jar testing on one liter samples of sludge. The best results came from the jar that received 26mL of 0.5 percent polymer solution. What is the polymer concentration in this jar? - ANS130 mg/L