Wastewater Treatment Fundamentals, Exams of Engineering

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WasteWater Operator Certification Study

Guide Grade 1 Questions with Answers

WasteWater Sources & Characteristics: What is the most common reason for a wastewater to contain intermittent large amounts of sand, gravel, and grit? ✔ storm events WasteWater Sources & Characteristics: Combined wastewater is defined as ✔ sanitary wastewater and stormwater runoff WasteWater Sources & Characteristics: In general, the solids content in wastewater is about ✔ 0.1% WasteWater Sources & Characteristics: In general, what is the % of suspended solids in the total amount of solids ✔ 30% WasteWater Sources & Characteristics: Generally, the % of dissolved solids in the amount of total solids is about ✔ 70% WasteWater Sources & Characteristics: Which type of organisms would most probably be associated with poor treatment or young biomass ✔ amoebas WasteWater Sources & Characteristics: Which type of organisms would most probably be associated with very clear plant effluent. low BOD and low amounts of suspended solids ✔ stalked cilates Basic WasteWater Treatment:

Aerobic bacteria will reproduce and live in an environment that contains only ✔ oxygen Basic WasteWater Treatment: Anaerobic bacteria will reproduce and live only in an environment that completely lacks ✔ free or dissolved oxygen Basic WasteWater Treatment: The biochemical oxygen demand (BOD) test usually has a specific time of ✔ 5 days Basic WasteWater Treatment: An Imhoff cone measures ✔ volume of settleable solids Basic WasteWater Treatment: Septic conditions are caused by ✔ anaerobic bacteria Basic WasteWater Treatment: Scum is usually removed in the _____treatment stage ✔ primary Basic WasteWater Treatment: When domestic wastewater enters natural waters, what species deplete most of the oxygen ✔ aerobic bacteria Basic WasteWater Treatment: Once the oxygen is depleted in a natural body of water, which organisms take over? ✔ anaerobic Basic WasteWater Treatment: The major gas produces by anaerobic decomposition is ✔ methane Wastewater Treatment Facilities:

What is the wastewater velocity range in FPS for grit removal in a grit chamber? ✔ 0.7 - 1.4 ft/s Racks, screens, comminutors and Grit removal: Which one of the following chemicals gives water its greatest capacity to neutralize acids? ✔ hydroxide Racks, screens, comminutors and Grit removal: The bar rack is used ✔ when the bar screen is out of service Primary Sedimentation: Typically, what is the average detention time for wastewater in a primary clarifier? ✔ 2 hr Sedimentation and Flotation: Name one gas this irritates the "eyes" ✔ chlorine Primary Sedimentation: Activated sludge clarifiers accept material to be settled from ✔ an aeration tank Primary Sedimentation: According to CWA, secondary treatment is defines as a wastewater plant producing an effluent that has no more than____total suspended solids and no more than_____BOD ✔ 30 mg/L, 30 mg/L Primary Sedimentation: The color of bio film on a rotating Biological Contactor would appear____under normal operating conditions ✔ gray Activated Sludge: A primary effluent and returned activated sludge mixture is called ✔ waste activated sludge

Activated Sludge: The mixture of organisms and solids in water that is removed from the settling tank is called ✔ mixed liquor Activated Sludge: Under normal operating conditions, what color is activated sludge ✔ dark chocolate brown Activated Sludge: What test(s) could an operator use to make process changes immediately if a problem develops ✔ COD test Activated Sludge: The main "workers" in the activated sludge process are ✔ bacteria Activated Sludge: A yellow gas flame from a digester's waste gas burner may indicate a poor quality gas with a ✔ high CO2 content Waste Treatment Ponds: Ponds used in series after primary wastewater treatment are sometimes called ✔ oxidation ponds Waste Treatment Ponds: The most common type of pond is ✔ facultative pond Waste Treatment Ponds: Which one of the following nuisance organisms is controller simply by the water surface being disturbed by wind or currents? ✔ mosquitoes Waste Treatment Ponds:

Wastewater Solids Processing: The solids treatment method produces methane gas that can be used in other plant processes: ✔ anaerobic digestion Wastewater Solids Processing: This solids treatment method cures the final product and then it may be applied to farmlands ✔ composting Wastewater Solids Processing: The solids treatment method uses evaporation but also requires a great deal of labor. ✔ sand drying beds Wastewater Solids Processing: The solids treatment method uses a partially submerged rotating drum ✔ vacuum filter Wastewater Solids Processing: These solid treatment methods use a coagulant polymer and pressure ✔ belt filter and plate Sampling, testing & reporting Tests such as pH, temperature and dissolved oxygen should always be performed within____after collection ✔ 15 min Sampling, testing & reporting When calibrating a pH meter, the buffers used should bracket the expected pH and

✔ be at least 2 pH units apart Sampling, testing & reporting A test method for determining dissolved oxygen is the______ ✔ azide modification for the Winler titration method Sampling, testing & reporting

How long can a dissolved oxygen sample wait for analysis using the modified Winkler method, if it is preserved with sulfuric acid? ✔ 8 hr Sampling, testing & reporting BOD5 samples can be preserved by ✔ storing them in a refrigerator above freezing and up to 4 degrees C Sampling, testing & reporting The maximum holding time for preserved BOD5 samples is ✔ 2 days Sampling, testing & reporting Which one fo the following tests is least likely to effectively help an operator control a waste plant's process? ✔ BOD 5 Sampling, testing & reporting The maximum holding time for a preserved total suspended solids sample is: ✔ 7 days Sampling, testing & reporting Generally, the state regulatory body must be notified of all unusual or extraordinary discharges by telephone within: ✔ 24 hours Sampling, testing & reporting Generally, the state regulatory body must be notified for any noncompliance that could adversely affect that state's waters or that could endanger public health within: ✔ 24 hours Maintenance: Electromotive force (emf) is also known as ✔ voltage Maintenance: Electron flow is measure in ✔ amps

Safety: Which one of the following gases is least likely to collect in a below-ground vault? ✔ carbon monoxide Safety: When working in a manhole, your vehicle, whenever possible, should be placed ✔ between the manhole and oncoming traffic Safety: OSHA requires that adequate protection, such as shoring, be placed in any trench that is ✔ 5 ft or greater in depth Safety: How far back from the opening of a trench should soil be excavated from that tench be placed ✔ 2 ft at least Safety: In a trench, ladders are required every ✔ 25 ft Safety: How many ladders are required to be in a 5-ft deep trench when 6 people are working down the trench ✔ 6 ladders Safety: which is not an essential ingredient for all ordinary fires? a. ignition source b. fuel c. heat d. oxygen ✔ ignition source Safety: If some clothes are on fire, what class of fire is it?

✔ class D Safety: If some magnesium is on fire, what class of fire is it? ✔ 3 Safety: What is the minimum number of people that should be on-site working at a confined space site? where one of them is entering a manhole ✔ 3 Safety: What type of fire extinguishers should be in pump stations ✔ A-B-C chemical type Basic Chemistry: What piece of laboratory glassware is primarily used to mix checmicals and measure approximately volumes? ✔ beaker Basic Chemistry: The electrical potential between two points is measured in ✔ volts Basic Chemistry: What is the most common use today for a positive-displacement pump ✔ chemical feed pump Basic Chemistry: Which lab glassware will give the most accurate measurements of liquids ✔ burettes Basic Chemistry: Which lab glassware is used for measuring volumes ✔ graduated cylinders Basic Chemistry:

c. acid oxides d. acid hydrates ✔ acid anhydrides Basic Chemistry: Which one of the following is not a hydrate: a. alum b. blue nitrate c. sodium nitrate d. ferrous sulfate ✔ sodium nitrate