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73 Cards in this Set
- Front
- Back
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What would cause a circuit trip on a UV system? |
Ballast failure |
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How do you get rid or prevent mud balls in sand filters |
Backwash more frequently |
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How do you preserve a total phosphorus sample? |
Total phosphorus: pH<2 H2SO4 refrigerate at <6 degrees C |
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What chemical gets rid of struvite? |
Ferric chloride or ferrous chloride (iron salts) added to wastewater flow or digesting sludge. |
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What happens going from conventional to extended aeration in relation to your process? |
F:M decreases |
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What organisms are associated with pin floc in a secondary clarifier? |
Rotifers |
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What filament is gram positive, true in branching and exists in water and foam |
Nocardia |
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Bio tower odor scrubber-snow falls on it, what do you check for? |
Blower discharge pressure |
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Odor scrubber- how many lbs of chlorine per mole of H2s. |
2-4 |
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What’s the best way to treat class A biosolids?? |
Lime slurry |
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What is happening in a centrifuge? |
Sedimentation |
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Pitting on the tips of impellers is caused by? |
Discharge recirculation |
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F:M ratio for conventional treatment |
0.2 - 0.5 |
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The theoretical dosage of sulfur dioxide (so2) when used for de chlorination |
0.9 mg/l so2 per 1.0 mg/l cl2 |
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What type of hepatitis are wastewater workers exposed to? |
Hepatitis A |
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Sludge recirculating line is plugged. |
Back flush with heated digester sludge. |
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Heat exchanger pressure differential is high. |
Check inlet and outlet pressures. Acid flush exchangers. |
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What affects in secondary treatment does lime have? |
Coagulate solids |
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What chemical is used to precipitate phosphorus from wastewater? |
Alum (aluminum sulfate |
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Daft recycle pump increases/decreases based on? |
As the pressure in the tank increases, the flow decreases. |
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Dilution water decreases by .2 Why? |
Bottle is contaminated |
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What should you do first in determining new wastewater rates? |
Determine the total revenue requirements |
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Calcium removal on silica sand filters? |
Soak with muriatic acid |
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Minimum depth of a secondary clarifier? |
11-15ft |
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Temperature of a Mesophilic digester. |
85-100 degrees |
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Temperature of a thermophilic digester. |
120-135 degrees. also read 122-140? |
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35. What filtration system removes salts? |
Reverse osmosis |
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The combination of one or more interconnected instrumentation devices that are arranged to measure, display, and control a process variable. |
Control loop |
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MBR system still not operating properly after backpulsing with chlorine, what should you do next? |
Soak with citric acid |
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Define the stages of bacteria (microorganisms)? |
a. Lag Phase – Bacteria adapts themselves to growth conditions, they start to mature but unable to divide. b. Log Phase aka (exponential phase) cells start to double. Doubling will continue at a constant rate. c. Stationary Phase – where growth rate and death rate are equal, (stagnate). d. Death Phase – decline phase, bacteria start to die. Lack of nutrients, or other changes. |
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What does lime do to the relation to your secondary treatment ie… clarifiers? |
Used to raise PH aids in sludge settling and aid in phosphorus removal. |
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If your ODOR scrubber is treating 25 ppm and your PH below 6 what is your exhaust gas? |
H2s |
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What causes an egglike smell that isn’t H2s? |
Mercaptans |
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What causes an egglike smell that isn’t H2s? |
Mercaptans |
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How do you store an ORP or PH probe? |
In an acidic solution |
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What is the SDS of SO2 (Sulfur Dioxide)? |
a. Contains gas under pressure, non-flammable b. Severe skin burns, c. Toxic if inhaled
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What is the SDS of SO2 (Sulfur Dioxide)? |
a. Contains gas under pressure, non-flammable b. Severe skin burns, c. Toxic if inhaled
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What chemical is used to coagulate metals? |
Alum |
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What is Carbon to Nitrogen to phosphorus ratio? |
100:5:1 |
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What method is used to determine the amount of ammonia using the colorimetric test? |
Nesslerization method |
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What is the ratio between COD/BOD ratio? |
2:1 cod is always double bod |
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What causes pin floc in secondary clarifiers? |
high sludge age (MCRT) or too many solids (darker). Reducing sludge age will often minimize the occurrences of pin floc. |
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Why would a high increase of RAS rate negatively affect the nitrogen and phosphorus removal? |
A high increase in NO3 bound DO can decrease the nitrogen and phosphorus removal rate. |
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Why would a high increase of RAS rate negatively affect the nitrogen and phosphorus removal? |
A high increase in NO3 bound DO can decrease the nitrogen and phosphorus removal rate. |
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What part of optical on a microscope to look at filaments with phase contrast? |
Phase contrast |
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Installed a new pump and motor and notice its using more current then designed on the name plate what is wrong? |
Wired backwards? |
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Installed a new pump and motor and notice its using more current then designed on the name plate what is wrong? |
Wired backwards? |
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Membrane filtration MBR and have a high coliform count how can you fix the problem? |
Backwash |
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White billowy foam in the aeration basin, on the walkways what is this an indication of? |
RAS not returned to aeration, low MLSS, or high organic load from industry. |
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What is the MLVSS concentration in a general treatment process? |
70-80% |
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What is your BOD5 to total phosphorus ratio? |
20:1 |
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What is your BOD5 to total phosphorus ratio? |
20:1 |
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Adding lime to the process how do you lower your PH? |
Recarbonation |
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What is your BOD5 to total phosphorus ratio? |
20:1 |
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Adding lime to the process how do you lower your PH? |
Recarbonation |
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What is Oxygen Uptake? |
a. Is defined as the rate microorganism use oxygen. b. Microorganisms use oxygen when consuming food. c. High oxygen uptake rates indicate high biological activity, DO falls. d. Low oxygen uptake rates indicate low biological activity, DO rises. |
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What is the percentage of oxygen in air? |
21% |
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What is the minimum oxygen concentration a person can breathe. |
19.5% |
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Settleometer sludge settles fast with high effluent resulting in high effluent turbidity? |
Low F/M, high MCRT, high sludge age, high DO, low oxygen uptake rate. |
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Indicators of a slow settling, hard to keep in the clarifier that may turn septic in the return sludge line is? |
High F/M, low MCRT, low sludge age, low DO, High oxygen uptake rate. |
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Centrifugal blower is running and high discharge pressure alarms what happened? |
Fouling on the diffusers which can cause clogging |
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Pin floc is present in the effluent in an activated sludge plant. Settleometer settling rapidly and cloudy supernatant. |
Increase WAS rate |
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Pin floc is present in the effluent in an activated sludge plant. Settleometer settling rapidly and cloudy supernatant. |
Increase WAS rate |
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Straggler floc in clarifier, settles fairly well but sludge doesn’t compact well at the bottom with fairly clear supernatant |
Low MLSS concentration, Decrease Wasting. |
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If you see decrease in phosphorus removal and your taking a mixed liquor sample out of your anaerobic zone what are you going to test for. |
Nitrates |
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What is the benefit of Iron Salts to lime/ferric? |
Costs less, reduces odors and easier on dosage equipment. |
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What is the DO in the anoxic zone? |
< .2 mg/l |
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What is the DO in the anoxic zone? |
< .2 mg/l |
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After having a high ammonia sample in the effluent how long has the downstream been contaminated? |
2-4 days |
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A plant prepares a new ordinance for sewers what three thing used to considered? |
Quantity(flow), quality(strength) and toxicity |
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If there is a significant rise in the volatile acid to alkalinity ratio in your anaerobic digester you should? |
Decrease the sludge withdrawal rate |
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You observe a steady increase in oxygen uptake rate from your aeration tank effluent sample. |
Increase RAS |
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In an anaerobic digester gas pressure is maintained by a controlling mechanism that commonly regulates. |
6-8 inches of water column pressure |
