Wastewater Study Guide: Answers on Anaerobic Bacteria, TSS, Sewer Lines, and Treatment, Exams of Water and Wastewater Engineering

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The name of the State Agency responsible for enforcing pollution control laws in Texas is - a. Texas Water Development Board. b. Texas Water Commission. c. Texas Section of EPA. d. Texas Commission on Environmental Quality e. Texas Water Resource and Conservation Commission CORRECT ANSWERS✅ D The term pathogenic means - a. Aerobic Bacteria b. Anaerobic Bacteria c. Fecal Matter d. Coliform Bacteria e. Capable of Causing Disease CORRECT ANSWERS✅ E The minimum separation between sewer lines and potable water lines is - a. 5 feet b. 7 feet c. 9 feet

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d. 11 feet e. 24 feet CORRECT ANSWERS✅ C A licensed wastewater operator is a professional who - a. Consistently does the best job possible b. Practices personal safety c. Strives to improve job knowledge d. Strives to keep the plant and collection system in the best appearance and working order e. All the above CORRECT ANSWERS✅ E An important step in testing a sample for Total Suspended Solids (TSS) is - a. Settling the sample b. Filtering the sample c. Incubating the sample d. Burning the sample e. Evaporating the sample CORRECT ANSWERS✅ B The Biochemical Oxygen Demand (BOD) of a sample is based on -

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a. pH readings b. Measuring Total Suspended Solids (TSS) of a sample c. Measuring the Dissolved Oxygen (DO) used d. Measuring the anaerobic decomposition e. Measuring total detention time CORRECT ANSWERS✅ C The results of a Biochemical Oxygen Demand (BOD) sample taken at a treatment plant tells the operator - a. How the plant is currently operating b. How the plant was operating 5 days ago c. How the plant was operating 10 days ago d. Is of no benefit to the operator e. How the plant will be performing at TCEQ inspection time CORRECT ANSWERS✅ B Which of the following are dangerous gases that are likely to be present in lift stations and or manholes? a. Natural gas and Gasoline fumes b. Hydrogen Sulfide and Carbon Dioxide

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c. Hydrogen, Sulfur, and Argon d. Oxygen, Nitrogen and Helium e. Both a & b CORRECT ANSWERS✅ E A preferred hydraulic method of cleaning sewer lines is - a. Cable & Auger b. Continuous Roding Machine c. Hydro Jet Cleaner d. Bucket & Belt Press e. Both a & d CORRECT ANSWERS✅ C Which of the following are ways to reduce bad odors coming from a collection system? a. Aeration & Air Scrubbers b. Adding Enzymes To The Collection System c. Routinely cleaning slow running or low flow lines d. Adding Chlorine or Hydrogen Peroxide to the Collection System e. Both c & d CORRECT ANSWERS✅ E

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Which of the following types of pipe are commonly used in a wastewater collection system? a. Vitrified Clay b. Poly Vinyl Chloride (PVC) c. Ductile Iron d. Stainless Steel e. Both a & b CORRECT ANSWERS✅ E Before entering a confined space a worker should - a. Use approved monitoring device and check for the presence of dangerous gases b. Ventilate the space with a blower c. Wear a safety harness and attach a life line d. Enter the confined space even if another co-worker in not present e. a, b, & c CORRECT ANSWERS✅ E A properly designed and operated primary sedimentation tank should remove ______ percent of incoming BOD? a. 10 to 15 % b. 20 to 30 % c. 30 to 40 %

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d. 35 to 50% e. None of the above CORRECT ANSWERS✅ C Which device may be used to determine the level of sewage in a lift station? a. Air bubbler tube b. Parshall Flume c. Altitude Valve d. Air Actuated Valve e. All the above CORRECT ANSWERS✅ A What is the most important role of aerobic bacteria in the treatment of wastewater? a. Enhance organic matter b. Decompose organic matter c. Introduce workers to dangerous diseases d. Enhance oxygen production e. Produces Odor and Offensive Smells CORRECT ANSWERS✅ B The hydraulic loading of a trickling filter may be determined by -

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a. BOD and depth of filter media b. Organic loading and filter volume c. Total pounds of BOD removed d. Total pounds of suspended solids applied daily e. Flow rate and filter area CORRECT ANSWERS✅ E Which of the following is typically used to dewater sludge? a. Belt press b. Drying beds c. Solid bowl centrifuge d. Gravity thickener e. All the above CORRECT ANSWERS✅ E Which of the following are the most important to providing adequate sewage treatment in a stabilization pond? a. Protozoa, rotifers and turtles b. Sunlight, algae, bacteria, and Time c. Aeration, Sedimentation, and Chlorine Contact d. Nitrification, Sedimentation, Recirculation, & Detention

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e. Blowers, Diffusers, & Ultraviolet Disinfection CORRECT ANSWERS✅ B Offensive and objectionable odors which sometimes occur in trickling filters usually indicate that - a. The filter should be backwashed b. The flow is too great for the filter area c. Chlorinator is not working properly & algae is growing on the media d. Septic conditions are present e. All the above CORRECT ANSWERS✅ D Dissolved Oxygen (DO) in the aeration tank of an activated sludge plant should be maintained at or about - a. 1 to 2 mg/L b. 2 to 3 mg/L c. 2 to 4 mg/L d. 4 to 6 mg/L e. 0.5 to 0.75 mg/L CORRECT ANSWERS✅ C Which of the following would contribute to infiltration in a collection system?

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a. Breaks in the main lines b. High ground water levels c. Heavy rains d. Hydro jet cleaning plugged mains e. a, b, & c CORRECT ANSWERS✅ E When a centrifugal pump loses prime, which of the following is most likely to result? a. Pump sounds as though it is pumping gravel b. Pump is no longer moving liquid c. Check valve on the suction side of the pump slams closed d. RPM of motor increases to compensate e. a, b, & c CORRECT ANSWERS✅ B A Rotating Biological Contactor (RBC) is - a. Fixed film biological treatment process b. Addition to most Activated Sludge Plants c. New filter media aerobic digester d. Variable speed Recirculating Biological Contact Unit e. Reconditioned Biological Containment Unit CORRECT ANSWERS✅ A

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Which of the following need to be checked regularly to properly operate an activated sludge treatment plant? a. De-foaming agents b. Overflow rate in the primary clarifier c. Aeration equipment and mixed liquor solids d. Aeration equipment, Chlorine concentration, and Suspended solids e. All the above CORRECT ANSWERS✅ C An aeration basin holds 5000 gallons of mixed liquor, the MLSS is 4000 mg/l and the inflow is 200 gallons per hour. Calculate the detention time of the aeration tank in hours. (D.T. = V divided by Q) a. 2 hours b. 4 hours c. 12 hours d. 24 hours e. 25 hours CORRECT ANSWERS✅ E

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Calculate the volume in gallons of a rectangular aeration tank that is 60 feet long, 30 feet wide, and 20 feet deep. (V=L X W X H X 7.48) a. 26, b. 269, c. 36, d. 360, e. 4,812 CORRECT ANSWERS✅ B An operator's flow meter at the plant indicates there was 2.6 MGD flow through the plant. What is the GPM? a. 1805 b. 18, c. 1083 d. 10, e. None of the above CORRECT ANSWERS✅ A Point source discharges are - a. Discharges that show up in the system and at the plant from an

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unidentified or explained source. b. Discharges that come from pipes or ditches that are monitored, controlled and inspected. c. Discharges that have Intermittent, dispersed flows having little or no control. d. Discharges that contribute greatly to the BOD and COD and typically come from dairies and farm related activities. e. None of the above CORRECT ANSWERS✅ B Non-Point Source Discharges are - a. Discharges that have Intermittent, dispersed flows having little or no control. b. Discharges that come from pipes or ditches that are monitored, controlled and inspected. c. Discharges that come from municipalities, or industry. d. Discharges that are high in BOD & typically come from food establishments. e. None of the above CORRECT ANSWERS✅ A

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The Texas Water Code establishes the protection of water quality and quantity of the state by - a. Limiting what farmers can use for irrigation. b. Establishing minimum standards for how close cattle or dairy operations can be to a lake or receiving stream. c. Setting stream standards, issues permits for discharges, identifies non-point source controls, and establishes water reuse. d. Making it almost impossible to meet effluent discharge standards. e. None of the above. CORRECT ANSWERS✅ C The wastewater plant operator is primarily responsible for - a. Treating potable water to Safe Water Standards b. Treating wastewater discharged from the community c. Developing, implementing, and complying with budget d. Collection and Containment of all non-point source water e. Traffic law compliance while vehicles are on plant property CORRECT ANSWERS✅ B

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Chapter ____ of the Texas Water Code is the state law controlling water pollution and _____ authority to control discharges in Texas. a. Chapter 30 & Texas Commission on Environmental Quality b. Chapter 30 & Texas Water Commission c. Chapter 26 & Texas Commission on Environmental Quality d. Chapter 26 & Texas Water Commission e. Chapter 290 & Texas Commission on Environmental Quality CORRECT ANSWERS✅ C The Texas Commission on Environmental Quality can revoke an Operator's license if the operator - a. Causes a permit violation, Falsifies records, or Neglects their duty b. Causes a permit violation, is convicted of a Felony, or DWI c. Knowingly violates plant permit under authority of the mayor d. Causes an environmental impact event under direction of supervisor e. TCEQ cannot revoke a license once it has been issued CORRECT ANSWERS✅ A If an accidental discharge, bypass, or spill (SSO) of wastewater occurs the responsible party MUST notify TCEQ regional offices within ______ hours.

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a. 12 hours b. 24 hours c. 36 hours d. 48 hours e. 72 hours CORRECT ANSWERS✅ B Aerobic Bacteria require _______ in the water for their metabolism a. Nitrogen b. Hydrogen c. Oxygen d. Either aerobic or anaerobic conditions e. Cannot live with O2 present CORRECT ANSWERS✅ C Anaerobic Bacteria require _______ in the water for their metabolism a. Nitrogen b. Hydrogen c. Oxygen d. Either aerobic or anaerobic conditions

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e. Cannot live with O2 present CORRECT ANSWERS✅ E Facultative Bacteria require ________ in the water for their metabolism a. Nitrogen b. Hydrogen c. Oxygen d. Either aerobic or anaerobic conditions e. Cannot live with O2 present CORRECT ANSWERS✅ D Chemical characteristics of sewage include - a. Solids, Grease, Dissolved Oxygen, O2 Demand, pH, & gases b. Liquids, Grease, BOD, Oxygen, pH, & gases c. Solids, Grease, Oxygen, pH, & Organics d. Water, Dissolved solids, Organics, Suspended Solids, & gases e. Varies from system to system therefore there is no uniformity CORRECT ANSWERS✅ A ________ removes Total Suspended Solids (TSS) a. Chemicals

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b. Aeration c. Sedimentation d. Detention e. Filtration CORRECT ANSWERS✅ E Inorganic Solids include - a. Sand, Grit, & Minerals b. Sand, Grease, & Organics c. Grease, Grit, & Organic Solids d. Organic materials from Plants, Animals, or Humans e. Both a & d CORRECT ANSWERS✅ A Organic Solids Include - a. Sand, Grit, & Minerals b. Sand, Grease, & Inorganics c. Grease, Grit, & Minerals d. Organic materials from Plants, Animals, or Humans e. Both a & d CORRECT ANSWERS✅ D

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A good plant influent pH is about _______ a. 6. b. 7. c. 7. d. 7. e. 8.0 CORRECT ANSWERS✅ C Dangerous gases are produced during bacterial decomposition of organics in wastewater. The main gases are - a. Hydrogen Sulfide, Carbon Dioxide, & Methane b. Hydrogen Sulfide, Carbon Monoxide, & Methane c. Natural gas, Methane, & Hydrogen Sulfide d. Ammonia, Methane, & Hydrogen Sulfide e. Carbon Dioxide, Methane, & Ammonia CORRECT ANSWERS✅ A The majority of Dissolved Oxygen in raw sewage come from _________ a. Inorganic Decomposition

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b. Facultative Decomposition c. Organic Decomposition d. Organic Solids e. Potable Drinking Water CORRECT ANSWERS✅ E Each person contributes approximately ______ lbs of BOD to the system daily. a. 0. b. 0. c. 1. d. 17 e. 17.4 CORRECT ANSWERS✅ A Sources of wastewater include - a. Domestic, Storm Water, Commercial, Food Processing, Agricultural, & Industrial. b. Domestic, Storm Water, Commercial, Agricultural & Hazardous c. Domestic, Commercial, Agricultural, & Industrial

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d. Commercial, Storm Water, Food Processing, & Industrial e. Domestic, Commercial, Agricultural, & Industrial CORRECT ANSWERS✅ A A sewer manhole provides access into the system for cleaning or service. A manhole is located - a. At changes in pipe composition, grade, direction & intersection b. At changes in pipe composition, grade, direction, & intersection c. At changes in alignment, diameter, grade, direction, & intersection d. At the discretion of the engineer & public works director e. Where a sewer clean out is not feasible CORRECT ANSWERS✅ C New manholes must have an inside diameter of at least _______ feet and the entry access must be at least ______ inches. a. 3 feet and 24 inches b. 4 feet and 24 inches c. 4 feet and 30 inches d. 5 feet and 30 inches e. There is no current standard or requirement CORRECT ANSWERS✅ B

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In the past _____ was used to construct manholes. This product is prohibited for construction or grading today. a. Concrete b. Fiberglass c. Poly Vinyl Chloride (PVC) d. Brick & Mortar e. Ductile Iron or Cast CORRECT ANSWERS✅ D Vitrified clay and Poly Vinyl Chloride (PVC) are the most common pipe materials used for sewer lines but other materials are available such as - a. Ductile Iron, Cast Iron, Acrylonitrile Butadiene Styrene(ABS) Concrete, Polyethylene & Asbestos Concrete b. Stainless Steel, Galvanized, Fiberglass, Orangeburg & Copper c. Ductile Iron, Cast Iron, Stainless Steel, & Galvanized d. Poly, SDR-35, Orangeburg, C-900, & Schedule 80 PVC e. Both a & b CORRECT ANSWERS✅ A

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In order to maintain two (2) feet per second velocity in a six (6) inch main line, the fall per 100 feet of pipe will be - a. 0.25 percent or 3 inches b. 0.33 percent or 4 inches c. 0.50 percent or 6 inches d. 0.75 percent or 8 inches e. 1.00 percent or 10 inches CORRECT ANSWERS✅ C Whenever wastewater cannot flow to the treatment plant by _______ a _______ is typically used. a. Gravity / Lift Station b. Pressure / Pressure Pump c. Gravity / Booster Pump d. Pressure / Lift Station e. Gravity / Positive Displacement Pump CORRECT ANSWERS✅ A The primary cause of stoppage in a collection system is _____ and ______ a. Line breakage / Roots

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b. Grit / Roots c. Grease / Roots d. Poor Construction / Roots e. Customer Abuse / Grease CORRECT ANSWERS✅ C The ________ pump is most commonly used in a lift station a. Positive Displacement b. Diaphragm c. Vertical Shaft Turbine d. Centrifugal e. Roller CORRECT ANSWERS✅ D A centrifugal pump must be ______ or it will not pump. a. Vented b. Flushed Periodically c. Primed d. Phased to proper rotation e. Properly Packed CORRECT ANSWERS✅ C

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You are instructed to install 1,000 feet of 8-inch diameter main line. The percent of fall is 0.33 %. How many feet of fall will there be in the 1,000 feet? a. 2.3 feet of fall b. 3.3 feet of fall c. 4.3 feet of fall d. 30.3 feet of fall e. Not enough information to compute CORRECT ANSWERS✅ B ________________ gas is very toxic and deadens the sense of ________. a. Hydrogen Sulfide / Smell b. Hydrogen Peroxide / Smell c. Hydrogen Sulfide / Taste d. Chlorine / Taste e. Methane / Smell CORRECT ANSWERS✅ A _____________ gas is colorless, odorless, and heavier than air

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a. Hydrogen Sulfide b. Chlorine c. Methane d. Nitrogen e. Petroleum CORRECT ANSWERS✅ C _____________ gas is greenish-yellow, pungent, heavier than air and highly toxic a. Hydrogen Sulfide b. Chlorine c. Methane d. Nitrogen e. Hydrogen Peroxide CORRECT ANSWERS✅ B One common type of weir design for measuring flow is - a. B-Knotch b. C-Knotch c. Z-Knotch