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CWEA ECI Grade 1 practice questions

Number of questions: 150

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About the CWEA ECI Grade 1 exam

The CWEA Environmental Compliance Inspector (ECI) exams are for people working or who want to work as Environmental Compliance Inspectors in California.

The exams are run by the California Water Environmental Association (CWEA), an organization for wastewater professionals in California.

The CWEA ECI exams has four grades: Grade 1, Grade 2, Grade 3, and Grade 4. Grade 1 is the easiest exam and is for entry-level positions. Grade 2 is more difficult and is for supervisor positions. Grade 3 is more difficult still and for middle-management positions. Grade 4 is the hardest exam and is for upper-management positions.

While CWEA certification isn't mandatory for a job as an Environmental Compliance Inspector, it can help you get a job and it can also lead to a pay raise and other benefits.

Practice questions

1) Calculate the density of a liquid that has a mass of 40 mL, a weight of 50 grams, and a boiling point of 110°C.
  1. 0.8 g/mL
  2. 0.9 g/mL
  3. 1.25 g/mL
  4. 1.5 g/mL
Answers are locked. Please click here to buy them. 2) 0.5 mol of solute is dissolved in 250 cm³ of solution. What is the concentration in mol/dm³?
  1. 0.002
  2. 2
  3. 12.5
  4. 125
Answers are locked. Please click here to buy them. 3) A hydrogen chloride solution has a concentration of 0.5 mol/dm³. Given that the molar mass of hydrogen chloride is 36.5, what is the solution's concentration in g/dm³?
  1. 0.01825
  2. 18.25
  3. 36.55
  4. 73
Answers are locked. Please click here to buy them. 4) Calculate the volume of a 0.5 mol/dm³ solution that contains 1 mol of solute.
  1. 0.5 dm³
  2. 0.75 dm³
  3. 1 dm³
  4. 2 dm³
Answers are locked. Please click here to buy them. 5) 8.0 g of magnesium oxide contains 4.8 g of magnesium and 3.2 g of oxygen. If the atomic mass of magnesium is 24 and the atomic mass of oxygen is 16, what is the empirical formula of magnesium oxide?
  1. MgO
  2. MgO₂
  3. MgO₃
  4. Mg₃O
Answers are locked. Please click here to buy them. 6) What is the concentration, in ppm, of 0.001 g of lead dissolved in 1 kg of water?
  1. 1 ppm
  2. 10 ppm
  3. 100 ppm
  4. 1,000 ppm
Answers are locked. Please click here to buy them. 7) Calculate the amount of solute dissolved in 4 dm³ of a 0.2 mol/dm³ solution.
  1. 0.05 mol
  2. 0.8 mol
  3. 3.8 mol
  4. 4.2 mol
Answers are locked. Please click here to buy them. 8) If a dilution ratio of 7:10 is used to make an acetic acid solution and the final volume of the solution is 950 mL, what is the volume of the solute?
  1. 58 mL
  2. 101 mL
  3. 391 mL
  4. 559 mL
Answers are locked. Please click here to buy them. 9) Parts per million (ppm) can also be expressed as:
  1. cm³
  2. dm³
  3. mL/billion
  4. mg/L
Answers are locked. Please click here to buy them. 10) A pH of 2 is how many times more acidic than a pH of 5?
  1. 3
  2. 6
  3. 256
  4. 1,000
Answers are locked. Please click here to buy them. 11) 200 microliters is how many milliliters?
  1. 0.2 mL
  2. 2 mL
  3. 20 mL
  4. 2,000 mL
Answers are locked. Please click here to buy them. 12) What is 10 mg in micrograms?
  1. 0.0001 mcg
  2. 0.001 mcg
  3. 10,000 mcg
  4. 100 mcg
Answers are locked. Please click here to buy them. 13) In the equation KOH + CO₂ → K₂CO₃ + H₂O, which molecule needs a coefficient for the equation to be balanced?
  1. CO₂
  2. H₂O
  3. KOH
  4. K₂CO₃
Answers are locked. Please click here to buy them. 14) Balance the equation Ag + H₂S → Ag₂S + H₂.
  1. 2Ag + H₂S → Ag₂S + H₂
  2. 4Ag + 2H₂S → 2Ag₂S + H₂
  3. 2Ag + 2H₂S → Ag₂S + 4H₂
  4. 4Ag + H₂S → 2Ag₂S + H₂
Answers are locked. Please click here to buy them. 15) How many gallons of a 0.1 M KOH solution will neutralize 30,000 gallons of 0.5 M HCl?
  1. 15,000
  2. 75,000
  3. 150,000
  4. 450,000
Answers are locked. Please click here to buy them. 16) If 25 mL of LiOH is needed to neutralize 20 mL of 0.500 HBr, what is the concentration of the LiOH?
  1. 0.4 M
  2. 0.5 M
  3. 0.6 M
  4. 0.75 M
Answers are locked. Please click here to buy them. 17) 50 mL of a 0.02 N sulfuric acid solution neutralizes 200 mL of a NaOH solution. What is the normality of the NaOH solution?
  1. 0.005 N
  2. 0.045 N
  3. 0.15 N
  4. 0.2 N
Answers are locked. Please click here to buy them. 18) What does 3% v/w mean?
  1. 3 grams of solute dissolved in 100 grams of solution
  2. 3 grams of solute dissolved in 100 mL of solvent
  3. 3 mL of solute dissolved in 100 grams of solution
  4. 3 mL of solute dissolved in 100 mL of solvent
Answers are locked. Please click here to buy them. 19) The TLV-C is the concentration of a substance that:
  1. a worker can be exposed to for one hour without adverse effect
  2. a worker can be exposed to over a working lifetime without adverse effects
  3. a worker can be exposed to up to 4 times per day
  4. should never be exceeded
Answers are locked. Please click here to buy them. 20) During an eight-hour shift, an employee is exposed to zinc oxide fumes at a concentration of 150 ppm for two hours, 75 ppm for another two hours, and 50 ppm for four hours. Calculate the 8-hour time-weighted average.
  1. 81.25 ppm
  2. 88.515 ppm
  3. 91.75 ppm
  4. 95 ppm
Answers are locked. Please click here to buy them. 21) If a dangerous gas has an 8-hour TWA of 50 ppm and a STEL of 200 ppm, what would be an appropriate gas detector alarm set point?
  1. 25 ppm
  2. 50 ppm
  3. 150 ppm
  4. 300 ppm
Answers are locked. Please click here to buy them. 22) What is the lower flammability limit of carbon monoxide?
  1. 2%
  2. 4%
  3. 7%
  4. 12%
Answers are locked. Please click here to buy them. 23) What is the lower flammability limit of methane?
  1. 1%
  2. 5%
  3. 10%
  4. 17%
Answers are locked. Please click here to buy them. 24) Under OSHA and GHS, which category of liquids has flashpoints between 23°C and 60°C?
  1. Category 1
  2. Category 2
  3. Category 3
  4. Category 4
Answers are locked. Please click here to buy them. 25) What is the upper flammability limit?
  1. The amount of fuel that will burn before the fuel burns itself out
  2. The highest concentration of a chemical that can catch fire
  3. The highest temperature at which a chemical can be stored safely
  4. The lowest temperature at which a chemical will ignite
Answers are locked. Please click here to buy them. 26) In 2015, OSHA adopted the Globally Harmonized System (GHS) for classifying and labeling of chemicals, which resulted in flammable liquids being redefined as liquids with a flashpoint lower than:
  1. 37.8°C
  2. 67.3°C
  3. 93°C
  4. 100°C
Answers are locked. Please click here to buy them. 27) In the context of occupational health and safety, what does STEL stand for?
  1. Short-term exposure limit
  2. Standard task exposure limit
  3. Standard task equipment list
  4. Short-term emergency lighting
Answers are locked. Please click here to buy them. 28) Safety goggles fall under which of the four levels of PPE?
  1. Level A
  2. Level B
  3. Level C
  4. Level D
Answers are locked. Please click here to buy them. 29) A substance with the potential to produce cancer in humans or animals is called a:
  1. carcinogen
  2. caustic substance
  3. nosocomial substance
  4. pathogenic substance
Answers are locked. Please click here to buy them. 30) Which pH buffer solution is typically used first when calibrating a pH meter?
  1. pH 1
  2. pH 4
  3. pH 7
  4. pH 10
Answers are locked. Please click here to buy them. 31) What is the chemical formula for methane?
  1. CH₄
  2. C₂H₈
  3. C₈H₂
  4. C₈H₈
Answers are locked. Please click here to buy them. 32) Complete the following reaction: HCl + Mg(OH)₂ → MgCl₂ + _______
  1. CO₂
  2. H₂O
  3. O₂
  4. O₃
Answers are locked. Please click here to buy them. 33) What is the chemical formula for hydrogen sulfide?
  1. HS
  2. HS₂
  3. H₂S
  4. H₂S₂
Answers are locked. Please click here to buy them. 34) What is the purpose of a custody seal on a sample container?
  1. To help identify the sample if the container is misplaced
  2. To prevent air from entering the container
  3. To show whether the container has been tampered with
  4. To show who currently has custody of the container
Answers are locked. Please click here to buy them. 35) A courier delivers a chain-of-custody sample to a technician at a laboratory. Who needs to sign and date the chain-of-custody form?
  1. Only the courier
  2. Only the laboratory technician
  3. The courier and the laboratory technician
  4. The laboratory manager and the laboratory technician
Answers are locked. Please click here to buy them. 36) Class 8 hazardous materials are:
  1. corrosive
  2. explosive
  3. poisonous
  4. radioactive
Answers are locked. Please click here to buy them. 37) Class 1 hazardous materials are:
  1. explosive
  2. infectious
  3. poisonous
  4. radioactive
Answers are locked. Please click here to buy them. 38) OSHA action levels are set for what type of hazard?
  1. Ergonomic hazards
  2. Hazardous substances
  3. Psychosocial hazards
  4. Slips, trips, and falls
Answers are locked. Please click here to buy them. 39) According to OSHA standard 40 CFR 136, wastewater samples for organic tests must be stored below what temperature?
  1. −5°C
  2. 2°C
  3. 6°C
  4. 10°C
Answers are locked. Please click here to buy them. 40) OSHA's Hazard Communication standard requires employers to inform workers about the workplace dangers of:
  1. bloodborne pathogens
  2. dangerous chemicals
  3. general safety hazards
  4. miscommunication
Answers are locked. Please click here to buy them. 41) Most OSHA permissible exposure limits (PELs) are time-weighted averages of how many hours?
  1. 1
  2. 2
  3. 4
  4. 8
Answers are locked. Please click here to buy them. 42) OSHA considers a confined space as oxygen-deficient if its oxygen level is below:
  1. 19.5%
  2. 20.1%
  3. 20.4%
  4. 20.9%
Answers are locked. Please click here to buy them. 43) According to OSHA standard 1910.95, employers must implement a noise monitoring program when an employee's noise exposure equals or exceeds an 8-hour time-weighted average of how many decibels?
  1. 85 dB
  2. 90 dB
  3. 95 dB
  4. 100 dB
Answers are locked. Please click here to buy them. 44) pH is a measurement of which ion?
  1. Carbon
  2. Hydrogen
  3. Nitrogen
  4. Oxygen
Answers are locked. Please click here to buy them. 45) A pH of 6.6 is:
  1. very acidic
  2. slightly acidic
  3. neutral
  4. slightly alkaline
Answers are locked. Please click here to buy them. 46) Which pH is considered neutral?
  1. 0
  2. 1
  3. 3
  4. 7
Answers are locked. Please click here to buy them. 47) Which device is typically used to separate grit from organics in grit slurries?
  1. Aerated grit chamber
  2. Air lift
  3. Clarifier
  4. Hydrocyclone
Answers are locked. Please click here to buy them. 48) A wastewater treatment plant has 150,000 lbs of mixed liquor volatile suspended solids (MLVSS) in the aeration tank. The primary effluent has a BOD of 75,000 lbs per day. Given this information, calculate the F/M ratio.
  1. 0.5
  2. 1
  3. 1.5
  4. 2
Answers are locked. Please click here to buy them. 49) Which of these water indicators is reported in μg/L?
  1. Temperature
  2. Total toxic organics
  3. Turbidity
  4. pH
Answers are locked. Please click here to buy them. 50) Which dye is used to detect the presence of anionic surfactants in water samples?
  1. Methylene blue
  2. Nile red
  3. Oil red
  4. Thymolphthalein
Answers are locked. Please click here to buy them. 51) An environmental inspector collects a sample of water for a BOD₅ test but cannot start the test until tomorrow morning. How should the sample be stored in the meantime?
  1. At room temperature
  2. In a freezer
  3. In a refrigerator
  4. In a vacuum flask
Answers are locked. Please click here to buy them. 52) An aeration tank has a volume of 100 m³ and an influent flow rate of 10 m³/hour. Calculate the hydraulic retention time of the aeration tank.
  1. 0.1 hours
  2. 10 hours
  3. 100 hours
  4. 1,000 hours
Answers are locked. Please click here to buy them. 53) What are the three characteristics of a confined space?
  1. Has a restricted entry and exit, contains serious safety hazards, and is large enough to work in
  2. Has a restricted entry and exit, contains serious safety hazards, and is too small to work in
  3. Has a restricted entry and exit, is not meant for continuous occupancy, and is large enough to work in
  4. Has a restricted entry and exit, is not meant for continuous occupancy, and is too small to work in
Answers are locked. Please click here to buy them. 54) An aeration basin has a dark brown, almost black sudsy foam that covers the entire basin. The foam smells sour. What is the most likely cause?
  1. Anaerobic conditions in the aeration basin
  2. Filamentous organisms are present
  3. The RAS flow is too low
  4. The aeration basin has excessive solids due to insufficient wasting
Answers are locked. Please click here to buy them. 55) Which stage of wastewater treatment separates readily settleable and floatable solids from the wastewater?
  1. Primary
  2. Secondary
  3. Tertiary
  4. Quarternary
Answers are locked. Please click here to buy them. 56) Which of these units is a typical unit used to measure flow?
  1. CFS
  2. MPH
  3. liters
  4. mg/L
Answers are locked. Please click here to buy them. 57) Total Kjeldahl nitrogen (TKN) is the total concentration of:
  1. nitrate and ammonia
  2. nitrate and nitrite
  3. organic nitrogen and ammonia
  4. organic nitrogen and nitrite
Answers are locked. Please click here to buy them. 58) Which section of the Code of Federal Regulations sets the standards for the use and disposal of sewage sludge?
  1. 20 CFR Part 136
  2. 20 CFR Part 1910.1450
  3. 40 CFR Part 403
  4. 40 CFR Part 503
Answers are locked. Please click here to buy them. 59) Workers can warn traffic of their presence in the street with signs, cones, and:
  1. banners
  2. billboards
  3. chairs
  4. flagmen
Answers are locked. Please click here to buy them. 60) What is the typical unit for reporting water alkalinity?
  1. mEq OH−
  2. mEq/kg
  3. mg/L CaCO₃
  4. mol NaOH
Answers are locked. Please click here to buy them. 61) An industry has three sewer connections with the following discharge rates: 1) 100 gpd 2) 300 gpd 3) 600 gpd. A flow-weighted composite sample of 2 liters is needed. How many milliliters of sample from each connection should be composited?
  1. 0.1, 0.3, 0.6
  2. 100, 300, 600
  3. 200, 600, 1200
  4. 500, 750, 750
Answers are locked. Please click here to buy them. 62) Which of these wastewater components takes the longest to biodegrade?
  1. Carbohydrates
  2. Fats
  3. Glucose
  4. Proteins
Answers are locked. Please click here to buy them. 63) Why is chlorine added during water treatment?
  1. To accelerate sedimentation
  2. To destroy microorganisms
  3. To enhance water taste and odor
  4. To reduce water hardness
Answers are locked. Please click here to buy them. 64) A rectangular pond has a length of 500 feet, a width of 200 feet, and a depth of 10 feet. Calculate the surface area of the pond in acres.
  1. 1.7 acres
  2. 2.3 acres
  3. 3.8 acres
  4. 4.5 acres
Answers are locked. Please click here to buy them. 65) PSI is a unit of:
  1. distance
  2. energy
  3. pressure
  4. time
Answers are locked. Please click here to buy them. 66) What does the unit MGD refer to?
  1. Milligallons per day
  2. Milligrams per day
  3. Million gallons per day
  4. Thousand gallons per day
Answers are locked. Please click here to buy them. 67) VCP stands for ________ ________ pipe.
  1. vacuum channel
  2. verified capacity
  3. vinyl chloride
  4. vitrified clay
Answers are locked. Please click here to buy them. 68) As per 40 CFR 403.5, what is the maximum holding time for wastewater samples intended for salmonella testing?
  1. 30 minutes
  2. 8 hours
  3. 28 hours
  4. 7 days
Answers are locked. Please click here to buy them. 69) Grab samples are also known as __________ samples.
  1. composite
  2. discrete
  3. sequential
  4. time-proportional
Answers are locked. Please click here to buy them. 70) What is the difference between nitrate and nitrite?
  1. Nitrate has three hydrogen atoms while nitrite has two
  2. Nitrate has three oxygen atoms while nitrite has two
  3. Nitrate has two hydrogen atoms while nitrite has three
  4. Nitrate has two oxygen atoms while nitrite has three
Answers are locked. Please click here to buy them. 71) What is the term for the liquid between the sludge and scum in a digester?
  1. Filtrate
  2. Sewage
  3. Slush
  4. Supernatant
Answers are locked. Please click here to buy them. 72) The following copper results, in mg/L, were taken throughout the day: 4.7, 5.1, 5.4, 6.2, 6.1, 5.9, 4.2, 3.5, 3.5, 3.4. Calculate the mean of these results.
  1. 4.5
  2. 4.6
  3. 4.7
  4. 4.8
Answers are locked. Please click here to buy them. 73) What is graywater?
  1. Water from sinks, showers, bathtubs, and washing machines
  2. Water that contains soil
  3. Water that has been cleaned at a water treatment plant
  4. Water that has come into contact with feces
Answers are locked. Please click here to buy them. 74) 40 CFR 136 of the Federal Code of Regulations contains:
  1. guidelines establishing test procedures for the analysis of pollutants
  2. hazardous waste injection restrictions
  3. state UIC program requirements
  4. toxic pollutant effluent standards
Answers are locked. Please click here to buy them. 75) Denitrification is the ____________________ to nitrogen gas.
  1. oxidation of ammonia
  2. oxidation of nitrate
  3. reduction of ammonia
  4. reduction of nitrate
Answers are locked. Please click here to buy them. 76) Which wastewater treatment process is typically accomplished by adding sulfur dioxide?
  1. Dechlorination
  2. Digestion
  3. Disinfection
  4. Thickening
Answers are locked. Please click here to buy them. 77) What do the terms "Schedule 40" and "Schedule 80" refer to?
  1. Employer workplace rights
  2. The storage of dangerous chemicals
  3. The thickness of pipes
  4. Wastewater legislation
Answers are locked. Please click here to buy them. 78) Which of these types of waste is found in food industry effluents?
  1. BOD
  2. Cyanide
  3. Nitrates
  4. Polychlorinated biphenyl
Answers are locked. Please click here to buy them. 79) What is the first step of wastewater treatment?
  1. Grit removal
  2. Screening
  3. Sedimentation
  4. Trickling filters
Answers are locked. Please click here to buy them. 80) What is 100 feet of head in PSI?
  1. 2.91 PSI
  2. 14.01 PSI
  3. 28.23 PSI
  4. 43.29 PSI
Answers are locked. Please click here to buy them. 81) Which of these is required on an inspection report for a wastewater treatment plant?
  1. Contact details of the maintenance contractor
  2. HHE-200 septic permit number
  3. Name of the inspector
  4. Signature of the plant manager
Answers are locked. Please click here to buy them. 82) A clarifier has a volume of 200,000 gallons and a flow rate of 2.4 MGD. Calculate the detention time of the clarifier.
  1. 2 hours
  2. 2.5 hours
  3. 3.5 hours
  4. 3 hours
Answers are locked. Please click here to buy them. 83) Calcium hydroxide is also known as:
  1. caustic soda
  2. lye
  3. quick lime
  4. slaked lime
Answers are locked. Please click here to buy them. 84) Which agency is responsible for administering and enforcing the General Pretreatment Regulations?
  1. Department of Energy (DOE)
  2. Environmental Protection Agency (EPA)
  3. Food and Drug Administration (FDA)
  4. Occupational Safety and Health Administration (OSHA)
Answers are locked. Please click here to buy them. 85) A wastewater sample of 100 mL is diluted to 300 mL with water. The initial DO of the sample is 50 mg/L. After 5 days, the DO has fallen to 10 mg/L. Calculate the BOD₅ of the sample in mg/L.
  1. 120 mg/L
  2. 245 mg/L
  3. 500 mg/L
  4. 600 mg/L
Answers are locked. Please click here to buy them. 86) Which of these is a conventional pollutant?
  1. Ammonia
  2. Chromium
  3. Cyanide
  4. Oil
Answers are locked. Please click here to buy them. 87) What are field blanks?
  1. Bottles of clean water
  2. Collection systems of unknown water quality
  3. Disposable, single-use sampling devices
  4. Water samples taken upstream from incoming pollutants
Answers are locked. Please click here to buy them. 88) A developer anticipates that a new site will produce 500 gallons of wastewater per day. The sewer impact fee is $31.23 per gallon of wastewater per day. Calculate the total daily sewer impact fee.
  1. $10,835
  2. $15,615
  3. $20,935
  4. $25,815
Answers are locked. Please click here to buy them. 89) Electromagnetic flowmeters measure flow by measuring the _________ created by the movement of water.
  1. area
  2. depth
  3. pressure differential
  4. voltage
Answers are locked. Please click here to buy them. 90) Goggles, earplugs, and gloves are needed when using a:
  1. gas detector
  2. pH meter
  3. power grinder
  4. sampling pump
Answers are locked. Please click here to buy them. 91) What is the most oxidized form of nitrogen found in wastewater?
  1. Ammonia
  2. Nitrate
  3. Nitrite
  4. Organic nitrogen
Answers are locked. Please click here to buy them. 92) A factory generates 0.12 MGD of wastewater. The treatment system can treat 200 GPM. How many hours would it take the treatment system to process one day’s wastewater?
  1. 2
  2. 6
  3. 10
  4. 14
Answers are locked. Please click here to buy them. 93) Which of these items of safety equipment is NOT required in an inspector's vehicle?
  1. Fire extinguisher
  2. First aid kit
  3. Spill control pillows
  4. Stop signs
Answers are locked. Please click here to buy them. 94) What organization enforces the pretreatment requirements of the Clean Water Act?
  1. EPA
  2. NOAA
  3. The Department of Energy
  4. The Department of Health and Human Services
Answers are locked. Please click here to buy them. 95) What is the main difference between primary clarifiers and secondary clarifiers?
  1. The density of the sludge handled
  2. The flow rate through the clarifiers
  3. The number of clarifiers required
  4. The sludge removal systems
Answers are locked. Please click here to buy them. 96) An industrial discharger has a wastewater flow of 10,000 liters per day containing 4.5 mg/L of copper. What is the mass emission rate of copper in grams per day?
  1. 12.5 g/day
  2. 15.8 g/day
  3. 4.5 g/day
  4. 9.2 g/day
Answers are locked. Please click here to buy them. 97) What is the most common toxic gas encountered during sampling work?
  1. Carbon monoxide
  2. Hydrogen cyanide
  3. Hydrogen sulfide
  4. Methane
Answers are locked. Please click here to buy them. 98) The following calcium results, in mg/L, were taken throughout the day: 200, 241, 231, 242, 192 What is the range of these results?
  1. 50
  2. 100
  3. 150
  4. 200
Answers are locked. Please click here to buy them. 99) Which of these has the lowest BOD?
  1. Rainwater
  2. Treated municipal water
  3. Unpolluted river water
  4. Untreated municipal water
Answers are locked. Please click here to buy them. 100) A circular spill has a radius of 10 feet and an average depth of 2 feet. Estimate the volume of the spill in gallons.
  1. 2,100
  2. 3,800
  3. 4,700
  4. 5,300
Answers are locked. Please click here to buy them. 101) Composite samples are collected by combining two or more __________ samples.
  1. time-proportional
  2. discrete
  3. aggregate
  4. flow-proportional
Answers are locked. Please click here to buy them. 102) What is Manning's formula?
  1. V = (1.49/A) × n²ᐟ³ × S × √R
  2. V = (1.49/n) × A × R²ᐟ³ × √S
  3. V = (A/1.49) × n × R²ᐟ³ × √S
  4. V = (n/1.49) × A²ᐟ³ × S × √R
Answers are locked. Please click here to buy them. 103) What is the term for a chemical that lowers the surface tension of a liquid?
  1. Liquefactant
  2. Liquescent
  3. Surfactant
  4. Tensile
Answers are locked. Please click here to buy them. 104) Water hardness is a measure of the amount of which two minerals in water?
  1. Calcium and magnesium
  2. Iron and phosphorous
  3. Nitrogen and oxygen
  4. Sodium and fluoride
Answers are locked. Please click here to buy them. 105) What is the main purpose of the General Pretreatment Regulations?
  1. Ensure safe drinking water
  2. Prevent damage to POTWs
  3. Promote wildlife conservation
  4. Regulate air quality
Answers are locked. Please click here to buy them. 106) What is the term for a sample collected at a single location at a single point in time?
  1. Composite
  2. Flow-proportional
  3. Grab
  4. Time-proportional
Answers are locked. Please click here to buy them. 107) What is the Venturi principle?
  1. Fluid pressure reduces when the fluid flows through a constricted section of a pipe
  2. Fluids have constant densities, regardless of pressure variations in the flow
  3. Fluids passing from higher to lower elevations maintain a steady velocity
  4. In a steady flow, the sum of all forms of energy in a fluid along a streamline is the same at all points on that streamline
Answers are locked. Please click here to buy them. 108) Which of these industry types generally produces a very high suspended solids content?
  1. Breweries
  2. Laundries
  3. Oil fields
  4. Textile dyehouses
Answers are locked. Please click here to buy them. 109) How should an inspector be able to activate emergency response procedures?
  1. By calling the police and fire departments
  2. By contacting local TV and radio stations
  3. By making one call to a person in the home office
  4. By phoning the collection system and treatment plant superintendents
Answers are locked. Please click here to buy them. 110) Which of these items should an inspector examine at high-risk industrial facilities with regard to emergency response?
  1. Chemical ordering plan
  2. Future expansion plan
  3. Spare parts inventory plan
  4. Spill prevention plan
Answers are locked. Please click here to buy them. 111) The EPA recognizes what types of dischargers in its efforts to control the flow of pollutants into water?
  1. Direct and indirect
  2. Municipal and industrial
  3. Raw and treated
  4. Sanitary and storm
Answers are locked. Please click here to buy them. 112) A calcium carbonate solution contains 25% calcium carbonate and has a density of 2 g/mL. How many grams of calcium carbonate are in one liter of the solution?
  1. 0.5 grams
  2. 2 grams
  3. 500 grams
  4. 2,000 grams
Answers are locked. Please click here to buy them. 113) Which of these chemicals may cause explosions in sewers?
  1. Acetic acid
  2. Carbon tetrachloride
  3. Gasoline
  4. Hexavalent chromium
Answers are locked. Please click here to buy them. 114) A flow rate of one cubic foot per second is equal to how many gallons per hour?
  1. 26,928
  2. 37,818
  3. 42,470
  4. 58,915
Answers are locked. Please click here to buy them. 115) A POTW must retain Industrial user records for a minimum of how many years?
  1. 2
  2. 3
  3. 5
  4. 10
Answers are locked. Please click here to buy them. 116) What is the average detention time for a 100,000 GPD flow going through a 3,000-gallon interceptor?
  1. 12 minutes
  2. 28 minutes
  3. 37 minutes
  4. 43 minutes
Answers are locked. Please click here to buy them. 117) The reason inspectors must keep notes during an emergency is because they will be useful in preparing:
  1. a briefing for public officials
  2. a case for court if enforcement action is initiated
  3. a meeting for reporters
  4. an informational pamphlet for the public
Answers are locked. Please click here to buy them. 118) What is the best method to determine the pollutants that industrial dischargers are placing in collection systems?
  1. Field test kits
  2. Laboratory chemical tests
  3. Results of industrial self-monitoring
  4. Visual observations
Answers are locked. Please click here to buy them. 119) A batch tank has a water depth of 8 ft, a diameter of 6 ft, and a discharge rate of 10 GPM. How many hours will it take for the batch tank to empty?
  1. 2.8 hours
  2. 4.2 hours
  3. 7.4 hours
  4. 9.6 hours
Answers are locked. Please click here to buy them. 120) A representative sample is:
  1. collected during minimum flows
  2. obtained when industrial representatives are present
  3. similar to the larger body of the waste stream being sampled
  4. transported to a laboratory for analysis
Answers are locked. Please click here to buy them. 121) What is meant by chain of custody?
  1. A record of criminal action against an industrial discharger
  2. A record of each agency action leading to a notice of violation
  3. A record of every person who has access to a sample
  4. A record of every sample submitted to the laboratory
Answers are locked. Please click here to buy them. 122) BOD is a measure of the amount of _______________ in water.
  1. biological organisms
  2. bound oxygen
  3. dissolved oxygen
  4. organic material
Answers are locked. Please click here to buy them. 123) Which type of water stabilization pond has an aerobic zone at the top and an anaerobic zone at the bottom?
  1. Facultative
  2. Aerobic
  3. Anaerobic
  4. Maturation
Answers are locked. Please click here to buy them. 124) In the context of wastewater treatment, what does FOG mean?
  1. Fats, oils, and grease
  2. Filamentous organisms
  3. Free oxygen grade
  4. Fully organic grade
Answers are locked. Please click here to buy them. 125) The focus of pollution prevention is to ______________ waste generated.
  1. dispose of
  2. minimize
  3. recycle
  4. treat
Answers are locked. Please click here to buy them. 126) Which Federal Act introduced the concept that waste generators are responsible for their waste from cradle to grave?
  1. Comprehensive Environmental Response, Compensation and Liability Act
  2. Resource Conservation and Recovery Act
  3. Superfund Amendments and Reauthorization Act
  4. Toxic Substances Control Act
Answers are locked. Please click here to buy them. 127) Industrial wastewater discharge permits grant permission to discharge wastewater into:
  1. a pretreatment facility
  2. the centralized waste treatment facility
  3. the environment
  4. the wastewater collection system
Answers are locked. Please click here to buy them. 128) Which of these is a danger of hydrogen sulfide in sewers?
  1. Pipe corrosion
  2. Pathogen growth
  3. Carcinogenicity
  4. Toxic gas
Answers are locked. Please click here to buy them. 129) The wastewater discharge of a factory is sampled every 300 gallons. What is the term for this type of sampling?
  1. Continuous
  2. Discrete
  3. Flow-proportional
  4. Time-proportional
Answers are locked. Please click here to buy them. 130) The figure below shows the horizontal cross-section of a water tank in the shape of a rectangle with a semi-circle at one end. If the water in the tank is 7 meters deep, then what is the volume of water in the tank in gallons?
  1. 110,547 gallons
  2. 222,938 gallons
  3. 319,937 gallons
  4. 483,885 gallons
Answers are locked. Please click here to buy them. 131) Lead acetate paper is used to determine the presence of which dangerous gas?
  1. Carbon monoxide
  2. Hydrogen sulfide
  3. Methane
  4. Nitrogen dioxide
Answers are locked. Please click here to buy them. 132) The main pollutants from the production of printed circuit boards are organic matter, ammonia, and:
  1. copper
  2. mercury
  3. silicon
  4. steel
Answers are locked. Please click here to buy them. 133) For how long is the BOD₅ test run?
  1. 5 minutes
  2. 5 hours
  3. 5 days
  4. 5 weeks
Answers are locked. Please click here to buy them. 134) A pretreatment system has a capacity of 100 gallons per minute. In how many hours can the facility process 60,000 gallons?
  1. 10 hours
  2. 12 hours
  3. 14 hours
  4. 16 hours
Answers are locked. Please click here to buy them. 135) Maturation ponds are:
  1. aerobic on the top and anaerobic on the bottom
  2. anaerobic on the top and aerobic on the bottom
  3. wholly aerobic
  4. wholly anaerobic
Answers are locked. Please click here to buy them. 136) In the context of water treatment and purification, MLSS is the:
  1. amount of solids removed from an activated sludge reactor
  2. concentration of suspended solids in mixed liquor of an aeration tank
  3. mixture of wastewater and microorganisms returned to the head of an aeration tank
  4. underflow from a secondary sedimentation tank
Answers are locked. Please click here to buy them. 137) In the context of wastewater treatment, what does SSO stand for?
  1. Sanitary sewer overflow
  2. Single source outlet
  3. Surface-to-surface outfall
  4. Suspended solids and organics
Answers are locked. Please click here to buy them. 138) In the context of wastewater treatment, what does F/M ratio mean?
  1. Fat-to-mineral ratio
  2. Flotsam-to-mixture ratio
  3. Flow-to-mass ratio
  4. Food-to-microorganism ratio
Answers are locked. Please click here to buy them. 139) Who is responsible for holding and maintaining an SPCC (Spill Prevention, Control, and Countermeasure) Plan for a facility?
  1. The Environmental Protection Agency
  2. The facility's safety officer
  3. The local government
  4. The owner or operator of the facility
Answers are locked. Please click here to buy them. 140) Calculate the total storage capacity, in gallons, of the following three tanks. Tank I: Cuboid tank measuring 5 feet on all sides. Tank II: Rectangular tank measuring 30 × 10 × 3 feet. Tank III: Cylindrical tank measuring 18 feet in diameter and 10 feet in height.
  1. 21,308 gallons
  2. 22,839 gallons
  3. 24,810 gallons
  4. 26,703 gallons
Answers are locked. Please click here to buy them. 141) An inspector needs to enter an area where a hazardous chemical is in use. How can the inspector find out which protective gear they need to wear?
  1. Ask a supervisor
  2. Ask an employee who works there
  3. Check the PPE policy
  4. Check the SDS
Answers are locked. Please click here to buy them. 142) An environmental compliance inspector records the following pH values at five locations of a wastewater influent: 9.1, 9.5, 8.9, 9.5, 10.0 What is the average of these five results?
  1. 9.4
  2. 9.5
  3. 9.6
  4. 9.7
Answers are locked. Please click here to buy them. 143) What is the main danger of polychlorinated biphenyls (PCBs)?
  1. Carcinogenicity
  2. Combustibility
  3. Flammability
  4. Toxicity
Answers are locked. Please click here to buy them. 144) What is the psi of a column of water with a height of 110.8 inches?
  1. 1
  2. 2
  3. 3
  4. 4
Answers are locked. Please click here to buy them. 145) What is the purpose of unannounced industrial inspections?
  1. To check the effluent quality
  2. To meet with a POTW's normal contact person
  3. To review paperwork
  4. To test the response of the industry
Answers are locked. Please click here to buy them. 146) Which of these chemicals can be used to neutralize acidic wastewater?
  1. CH₃COOH
  2. Ca(OH)₂
  3. HCl
  4. HNO₃
Answers are locked. Please click here to buy them. 147) The effluent from Significant Industrial Users should be sampled at least every _____ months.
  1. 2
  2. 4
  3. 6
  4. 12
Answers are locked. Please click here to buy them. 148) If three pounds of sodium bisulfite are needed to reduce one pound of hexavalent chromium, then how many pounds of sodium bisulfite are needed to reduce 10,000 kg of hexavalent chromium?
  1. 10,001
  2. 28,376
  3. 48,103
  4. 66,138
Answers are locked. Please click here to buy them. 149) Which preservative is needed when collecting a sample for TKN (Total Kjeldahl Nitrogen) analysis?
  1. HCl to pH < 9
  2. HNO₃ to pH > 9
  3. H₂SO₄ to pH < 2
  4. Zinc acetate + NaOH to pH < 2
Answers are locked. Please click here to buy them. 150) Which preservative is needed when collecting a sample for total phosphorus analysis?
  1. HCl
  2. H₂SO₄
  3. KOH
  4. NaOH
Answers are locked. Please click here to buy them.

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