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91 Cards in this Set
- Front
- Back
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Floatable solids are easy to measure. |
A. True B. False |
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A well-operated digester normally receives sludge at about ____% volatile solid and reduces it to about ____% volatile solids. |
A. 70-75%, 25-30% B. 90-95%, 45-50% C. 90-95%, 25-30% D. 70-75%, 40-45% |
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According to osha, which of the following oxygen in air concentrations is the lowest safe concentration for humans to breathe in order to avoid the hazard of oxygen deficiency? |
A. 7.5% B. 19.5% C. 21% D. 33% |
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The population equivalent factor for bod is |
A. 0.15 lb/day/bod/person B. 0.17 lb/day/bod/person C. 0.20 lb/day/bod/person D. 0.22 lb/day/bod/person |
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Which of the following groups of microorganisms are found in a good settling mixed liquor? |
A. Rotifers, stalked ciliates and free swimming ciliates B. Flagellates, free swimming ciliates and stalked ciliates C. Stalked ciliates, rotifiers and flagellates D. Nematodes, flagellates and stalked ciliates |
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Which heavy metal is the most stringent for land application? |
A. Copper B. Zinc C. Lead D. Mercury |
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Grit chambers that are designed to remove grit have a velocity of |
A. Less than 0.5 ft/sec B. 0.5 to 1.0 ft/sec C. 1.5 to 4.0 ft/sec D. 2.0 to 4.0 ft/sec |
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The purpose of adding sodium thiosulfate to a microbiological ( such as fecal Coliform) sample bottle is to |
A. Extend the allowable holding time from 6 to 30 hours B. React with nitrates that interfere with the mpn test C. Remove any chlorine residual present D. To insure sterilization of sample bottle |
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Which of the following types of wastewater would settling occur most rapidly? |
A. Cold wastewater B. Old wastewater C. Septic wastewater D. Strong wastewater |
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The disadvantage of using a constant percentage return activated sludge flow control is |
A. Variations in the MLSS concentration are reduced B. F/M varies more than with constant rate RAS control C. MLSS remains in the clarifier to long D. Clarifier is subjected to maximum solids loading when it contains maximum amount of sludge |
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Under which one of the following conditions should sludge wasting normally be increased? |
A. Mixed liquor settles to slowly B. Large pillows of white foam start forming on the aeration tank surface C. A dark brown scummy foam appears on the aeration tank surface D. All of the above |
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The outlet of a forced ventilation system for a chlorinator room should be located |
A. On the roof B. Above the window C. Near the floor D. At the same level as the blower |
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If packing is not maintained properly |
A. Cavitation damage will result B. Impeller will corrode C. There will be a loss of suction from air being allowed to enter the pipe D. Shaft or shaft seal will be damaged |
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Turbidity in wastewater is caused by: |
A. Color B. Dissolved calcium C. Finely divided suspended material D. Hardness |
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One of the primary reasons why air should be excluded from the digester is that |
A. Gas storage capacity is reduced B. The entrance of air mixed with gas produced in the digester could create an explosive mixture C. It interferes with the action of aerobic bacteria D. Harmful bacteria may be brought in with air |
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Barminutors and comminutors are installed for different purposes. |
A. True B. False |
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What are end products of the aerobic biochemical reaction? |
A. H2O and CO2 B. H2O and CH4 C. CH4 and CO2 D. Organic acids |
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Pump maintenance includes |
A. Checking operating temperatures of bearings B. Checking packing glands C. Lubricating the impeller D. All of the above |
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Pump packing should be |
A. Changed every week B. Tightened to a drip C. Greased when smoke is detected D. Tightened to where there is no leakage |
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The fusible plug that is in all chlorine cylinders |
A. Should be removed after the cylinder is emptied B. May be used as a tap for the chlorine source C. Is used for an electrical connection for evaporating coils D. Should never be removed or tampered with |
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A piston or diaphragm pump would be used for pumping |
A. Primary sludge B. Raw wastewater C. Final effluent D. Activated sludge |
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Collection system variables that could upset an activated sludge process include |
A. Activities of collection system maintenance crew B. Chlorination of return sludge flow C. Recycling a digester supernatant D. Decrease in influent flow |
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What type of pump is not seriously damaged if the discharge valve is closed for a short time, while the pump is running? |
A. Centrifugal pump B. Diaphragm pump C. Piston pump D. Plunger pump |
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Which of the following chemicals would be the most effective in achieving a pH adjustment of 8.4 so nitrification can take place in an RBC? |
A. Sulfuric acid B. sodium hydroxide C. Soda ash D. None of the above |
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Acids should never be added to chlorine solutions because they |
A. Cause chlorine gas to be released B. Corrode or eat away the solution tank C. Decrease the disinfection properties of chlorine D. Result in the formation of a chloride precipitate |
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Which of the following is a method for treating flow to the primary settling tank that would increase grease removal efficiency of that unit? |
A. Lower the pH to less than 7 B. Increase the temperature of the wastewater C. Add activated silica D. Preaerate |
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Three water born diseases are |
A. Mumps, measles, cold B. Scarlet fever, pneumonia, hay fever C. Typhoid fever, dysentery, cholera D. Tuberculosis, diphtheria, chicken pox |
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When organic wastes are discharged to receiving water, oxygen is depleted by |
A. Algae during the day B. Bacteria C. Ducks D. Limestone rocks |
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Sludge wasting from secondary clarifiers, are normally required in order to control |
A. Effluent BOD B. Effluent suspended solids C. Aerator mixed liquor solids D. Sludge settleability |
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An application for renewal of an NPDES permit must be submitted ______ days before the previous permit expires |
A. 30 B. 60 C. 90 D. 180 |
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From a public health standpoint, which of the following is the safest sludge for soil conditioning purposes |
A. Sludge dewatered on sand filters or vacuum filters B. Liquid raw sludge C. Heat dried sludge D. Liquid digested sludge |
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The purpose of an inlet baffle in a settling tank is to |
A. Reduce velocity and disperse flow B. Increase velocity to prevent excessive settling near the inlet C. Remove scum from the wastewater D. Protect the scraping mechanism from damage by excessive velocities |
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The primary purpose of force draft ventilation in lift stations is to |
A. Prevent odors B. Remove dangerous gases C. Cool the pumps D. Keep the pressure equalized |
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High- rate anaerobic digestion refers to the fact that the organic waste material is applied to an anaerobic reactor at high ______ loading rates |
A. Gravimetric B. Hydraulic C. Organic D. Volumetric |
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As a digester approaches "sour" conditions |
A. Alkalinity of solids decreases B. Concentration of volatile acids increases C. Amount of methane production decreases D. All of the above |
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The concentration of volatile solids in the feed sludge to a digester is an indirect measure of the |
A. Amount of the sample that will evaporate when standing B. "Food" available for bacteria in the digester C. Number of bacteria in the digester D. Primary effluent suspended solids |
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Typical detention time in a mesophilic digester is |
A. 5 days B. 15 days C. 28 days D. 120 days |
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The presence of white pillowing foam on an aeration tank indicates |
A. The aeration tank is underloaded organically B. The aeration tank is overloaded organically C. The aeration tank is overloaded hydraulically D. None of the above |
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The chemicals that are added to distilled water for BOD test serve what purpose |
A. Assure the presence of DO at all times B. Increase thermal conductivity of the solution C. Adjust the pH within the desirable range and provide essential elements for the growth of biological life actually exerting the oxygen demand D. Satisfy the natural oxygen demand that might exist in the sample |
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An operator runs a winkler by the azide modification of the winkler method. He runs out of standard sodium thiosulfate. Which reagent can be used instead |
A. Calcium hypochlorite B. Phenyl arsenide oxide C. Sodium bicarbonate D. Ferrous ammonium sulfate |
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The best way to control excessive foaming during start-up of a digester is to |
A. Add water to the tank B. Allow the digester content to cool slightly C. Increase the feed rate D. Stir gently to release excess gas |
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The principal function of the zoogleal mass on the trickling filter is to |
A. Filter suspended solids B. Reduce the organic content C. Reduce the nitrogenous BOD D. Control the flow to the following process |
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Which of the following can cause foaming in the anaerobic digesters |
A. Nocardia B. Fluctuating temperature C. Inadequate mixing D. All of the above |
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Which of the following sets of characteristics describes a good quality of activated sludge |
A. Good settling characteristics, some dissolved oxygen present, and brown in color B. Brown color, high in ammonia, and BOD C. Black color, very small particles, which do not settle, and a musty odor D. Zero dissolved oxygen content, brown color, and good gas production |
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Ultra violet radiation kills bacteria by |
A. Heat B. Destroying their cellular material C. Inhibiting their enzymatic system thus starving the bacteria D. Splitting the cell in half |
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Possible techniques for controlling Filamentous organisms in an activated sludge process include |
A. Dosage of return sludge with oxidants such as hydrogen peroxide or chlorine B. Lower DO levels in aeration bans so Filamentous organisms can not breathe or respire C. Lower F/M level to starve Filamentous organisms D. Stop wasting to allow activated sludge bugs to gain control |
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Which pump is best for pumping chemicals |
A. Positive displacement B. Centrifugal C. Screw D. Air lift |
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Low sulfonator injector vacuum could be caused by |
A. Low back pressure B. Missing gasket C. Low flow of injector water D. Wrong orifice |
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A white Filamentous growth on the RBC media is indicative of |
A. High CaC03 levels B. High rotation speed and lime addition C. Treatment of creamery wastes D. Sulfur bacteria present |
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The temperature verses DO relationship is |
A. The higher the temperature then the higher the DO B. The lower the temperature then the higher the DO C. There is no relationship between DO and temperature D. The lower the temperature then the lower the DO |
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An increasing F/M ratio and decreasing MCRT indicates |
A. Excessive solids wasting causing a decrease in solids inventory B. Inadequate solids wasting causing an increase in the solids inventory C. Decreased hydraulic load increasing the sludge detention time D. Operation is normal |
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Bar racks and bar screens have clear spacing respectively of |
A. 0.25 to 2 inches and 2.0 to 4.0 inches B. 0.2 to 1.0 inches and 1.0 to 2.0 inches C. 2.0 to 4.0 inches and 0.25 to 2.0 inches D. 1.0 to 2.0 inches and 0.2 to 1.0 inches |
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On a large scale which is the best method for removing ammonia nitrogen from wastewater |
A. Trickling filter B. Activated sludge C. Breakpoint chlorination D. Ion exchange |
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An increase in plant effluent Coliform level could be caused by |
A. Short circuiting in contact chamber B. A decrease in effluent BOD C. High chlorine residual D. Lack of solids in contact chamber |
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When collecting a fecal sample, it should be |
A. A grab sample preserved with copper sulfate B. A composite sample preserved with copper sulfate C. A composite sample without preservative D. A composite sample preserved with sodium thiosulfate E. A grab sample preserved with sodium thiosulfate |
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The principal difference between step-feed aeration and conventional aeration is that in step-feed aeration the incoming waste load is introduced in slugs at the tank entrance |
A. True B. False |
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The height or energy of water above a point is commonly referred to as the |
A. Flow B. Pressure C. Distance D. Head |
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At what temperature does the muffle furnace have to remain at in the determination of the volatile solids |
A. 103*c B. 500*c C. 550*c D. 600*c |
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Which of the following factors could cause a demand for more oxygen in an aeration tank? |
A. Increase in pH B. Increase in microorganisms C. Increase in inert or organic wastes D. Increase in toxic substances |
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Your maintenance person wants to use general purpose grease in the RBC bearings. The reason for not using general purpose grease is |
A. It does not contain high load capability or moisture inhibitor B. The temperature rating is to low C. The color will not show a rusting condition D. The RBC speed is not right for general purpose grease |
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Which of the following is not an example of a flow-measuring device |
A. Manometer B. Weirs C. Parshall flume D. Magnetic |
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Why does some of the suspended material in wastewater fail to be removed by settling in 1 hour |
A. Because it takes 1.5 hours to settle B. Because it's lighter than water C. Because it's specific gravity is very close to that of water and it is so small in size D. Because it is attached to fine air bubbles |
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The dissolved oxygen concentration should normally ______ as you proceed through the stages of the RBC system |
A. Increase B. Decrease C. Remain the same |
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The most abundant pollutant entering natural water bodies ( rivers, lakes, etc.) is |
A. Domestic waste B. Food processing waste C. Non-point source D. Hospitals |
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How can a toxic waste be discovered in a treatment plant |
A. Decrease in aerator DO B. Increase in aerator DO C. Decrease in secondary effluent floc D. Increase in plant inflow |
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Mesophilic range is |
A. 80 to 100*f B. 120 to 130*f C. 100 to 120*f D. 60 to 80*f |
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The most important factor used to determine the number of samples to be collected is the |
A. Discharge limits of waste being monitored B. Purpose for the sampling C. Flow characteristics of wastestream D. Wastewater characteristics |
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Chlorine applied minus ______ equals chlorine residual |
A. Chlorine dose B. Chlorine demand C. Combined chlorine D. Free chlorine E. Total chlorine |
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Copper sulfate-sulfamic acid solution is added to a sample of mixed liquor on which a DO test is run in order to |
A. Prevent settling of the sludge while the sample is in transit to the lab B. Keep the organic process at a high level while the sample is in transit to the lab C. Kill the bacteria which would continue to use oxygen while the sample is in transit to the lab |
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What temperature does the BOD incubator need to be |
A. 15* c B. 25* c C. 20* c D. 98.6* c |
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BOD is a term that refers to the |
A. Oxygen demand in milliliters per hour per square meter of lagoon surface during the aerobic phase of metabolism B. Oxygen required to neutralize the effects of anaerobic organisms in wastewater effluents C. Oxygen required to stabilize the decomposable organic matter in a wastewater sample by bacterial action D. Phase of the nitrogen cycle known as anabolism or synthesis |
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What information must be on a warning tag attached to a switch that has been locked out |
A. Directions for removing tag B. Time to unlock switch C. Signature of person who locked out switch and who is authorized to remove tag D. Name of nearest physician to call incase of emergency |
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Return activated sludge flow rate may be adjusted or controlled by which of the following |
A. Food/microorganism ratio B. SVI approach C. Mean cell residence time (MCRT) D. Sludge age |
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In order, what are the top three injuries in wastewater |
A. Face, feet and back B. Back, leg and hand C. Back, hand and face D. Hand, back and leg |
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Ideally, the pH meter should be calibrated |
A. Once a day B. Weekly C. Twice a month D. Before each use |
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Sludge blanket depths may be measured by the use of |
A. Bubbler tubes B. Floats connected to cables and pulleys C. Ultrasonic transmitters and receivers D. A hose and an aspirator |
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The discharge of a centrifugal pump |
A. Decreases with an increase in head B. Independent of head C. Increases with an increase of head D. Is not affected by head |
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What test is not run on a raw wastewater |
A. BOD B. Fecal Coliform C. Suspended solids D. pH |
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A piston pump can be damaged if |
A. The suction valve is open and the discharge valve is open B. The discharge valve is closed C. The suction valve is leaking D. The discharge gauge bleed valve is missing |
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Wear rings are installed in pumps to |
A. Keep the shaft stabilized B. Wear instead of the impeller C. Keep the impeller in place D. Plug internal water leakage |
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Facultative ponds |
A. Do not need oxygen B. Are aerobic on top and anaerobic on the bottom C. Completely anaerobic D. Are not found in Wyoming |
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Blue green algae in a stabilization pond is caused by |
A. To much air B. Red algae die off C. Low pH and low DO D. High ph only |
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In a 2 cell lagoon operation it is best to operate the ponds in winter in |
A. Parallel B. Series C. The nitrification mode D. The denitrification mode |
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A parshall flume |
A. Can only be used in plants over 1 mgd B. Measures flow based on its size and shape C. Uses Venturi principle D. Must be adjusted daily for accuracy |
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The space between the bars on a bar screen |
A. 2-4 inches B. 2/3 - 1 inch C. 3/8" to 2 inches D. 3-4 inches |
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In a cyclone separator, the heavier solids are |
A. Forced inward and expel at the bottom B. Forced outside and expel out the top C. Forced outside and go out the bottom D. Forced inward and expel at the top |
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When televising a sewer line, the camera should move |
A. Upstream B. Downstream C. It doesn't matter D. Upstream then down stream |
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A screw pump is a |
A. Centrifugal pump B. Plunger pump C. Positive displacement pump D. Piston pump |
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The main difference between a primary clarifier and a secondary clarifier is |
A. There is no difference B. Flow rate C. Primary sludges are denser D. Secondary sludges are denser |
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Which of the following conditions doesn't affect the operation of a clarifier |
A. Toxic waste B. Flow velocity C. Settleability rate tests D. Septicity from the collection system |
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Surface loading rates for clarifiers are used to indicate |
A. Whether to have a rectangular or circular clarifier B. Effectiveness of solids removal efficiency C. Weir effectiveness D. Solids loading |
