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CWEA ECI Grade 2 practice questions

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1) Primary treatment of wastewater typically removes what percentage of total suspended solids?
  1. 0–10%
  2. 20–40%
  3. 50–70%
    Typically, primary treatment removes 25–40% of the biological oxygen demand and 50–70% of the total suspended solids before the water goes to secondary treatment.
  4. 80–100%
2) If the settled sludge volume is 30 mL/L and the mixed liquor suspended solids (MLSS) is 3,000 mg/L, what is the sludge volume index in mL/g?
  1. 0.01 mL/g
  2. 0.1 mL/g
  3. 1 mL/g
  4. 10 mL/g
    The formula for calculating the sludge index number is: settled sludge volume (in mL/L)/MLSS (in g/L) The question tells us the settled sludge volume is 30 mL/L and the MLSS is 3,000 mg/L. Before we can use the formula, we need to convert MLSS from mg/L to g/L. To do this, divide by 1,000: 3,000/1,000 = 3 g/L Now insert the values in the formula: 30/3 = 10 mL/g
3) What is flocculation?
  1. The biochemical decomposition of organic matter
    The biochemical decomposition of organic matter is called "digestion".
  2. The process of bringing a liquid into contact with air
    The process of bringing a liquid into contact with air is called "aeration".
  3. The process of particles joining together to form larger particles
    Flocculation is a water treatment process where solids form larger clusters, or flocs, which can then be removed from the water more easily.
  4. The separation of liquids from solids
4) In the context of wastewater treatment, what does the abbreviation IU stand for?
  1. Incoming undercurrent
  2. Industrial user
    Industrial users (IUs) are industrial or manufacturing companies that discharge wastewater to publicly-owned treatment works.
  3. Intelligent user
  4. Intermediate user
5) Which of these is a physical wastewater treatment method?
  1. Ion exchange
  2. Neutralization
  3. Oxidation
  4. Screening
    Screening is a physical wastewater treatment method and involves the removal of large solids such as rags, papers, plastics, tins, containers, and wood. The other options are all chemical wastewater treatment methods.
6) Which chemical is added to raw wastewater to make dirt particles stick together and coagulate?
  1. Alum
    During the initial coagulation step of wastewater treatment, coagulants such as alum (aluminum sulfate) are added to the untreated water. The coagulants help bind impurities together to form particles.
  2. Chloramine
  3. Hypochlorite
  4. Ozone
7) What is the final step of SARS-CoV-2 wastewater testing?
  1. RNA extraction
  2. RNA measurement
    The four steps of SARS-CoV-2 wastewater testing are sample preparation, sample concentration, RNA extraction, and RNA measurement.
  3. Sample concentration
  4. Sample preparation
8) UV disinfection happens at what stage of wastewater treatment?
  1. Primary
  2. Secondary
  3. Tertiary
    Primary wastewater treatment uses physical processes to remove large particles from the wastewater. Secondary treatment removes smaller particles using biological processes. Tertiary treatment removes pathogens from the water, making water safe to drink. UV disinfection is part of tertiary treatment.
  4. Quaternary
9) What is the sedimentation step of wastewater treatment also known as?
  1. Clarification
  2. Flocculation
  3. Rapid gravity filtration
  4. Slow sand filtration
10) If chlorine is used for water disinfection, then the sewage treatment plant will require a sample measurement of:
  1. chlorinating granules
  2. fecal coliform
  3. total residual chlorine
  4. total suspended solids
11) When testing wastewater samples for viruses, what is used to estimate the amount of virus lost during sample processing?
  1. Matrix recovery control
    Matrix recovery controls (also called process controls) enable estimation of the amount of virus lost during sample processing. This control is important for comparing concentrations resulting from different testing methods and over time.
  2. Phage recovery control
  3. TDS recovery control
  4. Virus recovery control
12) Which of these wastewater treatment methods uses specially modified soil to remove microorganisms and extra nutrients from effluent?
  1. Absorption trenches
  2. Amended soil mounds
  3. Sand mounds
  4. Subsurface irrigation
13) Which emerging technology uses microorganisms to generate electricity from the organic matter in wastewater?
  1. Membrane technology
  2. Microalgae
  3. Microbial fuel cells
    Microbial fuel cells use microorganisms to convert the chemical energy in organic matter into electric current while simultaneously treating the wastewater.
  4. Restriction fragment length
14) If a vertical cylindrical tank has a diameter of 5 feet and a height of 8 feet, what is the capacity of the tank in cubic feet?
  1. 145 ft³
  2. 157 ft³
    Step 1) Calculate the radius of the tank First, find the radius of the tank. The question gives the tank's diameter as 5 feet, so the radius is 2.5 feet (half of 5). Step 2) Calculate the area of the base of the tank Since the base of the tank is a circle, we can find the area of the base using the formula area = π × r²: area = π × r² area = π × 2.5² area = π × 6.25 area = 19.6 Step 3) Calculate the volume of the tank in cubic feet The formula to find the volume of a cylinder is volume = height × base area. So the volume of the tank is: volume = height × area volume = 8 × 19.6 volume = 157 cubic feet
  3. 227 ft³
  4. 290 ft³
15) During the initial stages of water treatment, water mixes gently to form heavier and larger particles called:
  1. clogs
  2. clusters
  3. flocs
  4. sediments
16) A well has a one-meter diameter and its water is ten meters deep. How much water is in the well?
  1. 385 liters
  2. 2,730 liters
  3. 4,890 liters
  4. 7,850 liters
    Step 1) Calculate the radius of the well First, find the radius of the well. The question gives the well's diameter as 1 meter, so the radius is 0.5 meters (half of 1). Step 2) Calculate the volume of the well We know the well's radius and the question tells us the well's height. Now we can calculate the volume of the well. Volume of a cylinder = radius² × π × height Volume of a cylinder = (1/2)² × π × 10 Volume of a cylinder = 0.25 × π × 10 Volume of a cylinder = 7.85 m³ Step 3) Convert from m³ to liters Finally we have to convert from cubic meters to get the answer in liters. To convert from cubic meters to liters, multiply the number of cubic meters by 1,000: 7.85 m³ × 1,000 = 7,850 liters Therefore, the well contains approximately 7,850 liters of water.
17) A river has a flow rate of 50 cubic feet per second. Calculate its flow rate in gallons per second.
  1. 39
  2. 92
  3. 198
  4. 374
    To convert from cubic feet to gallons (or cubic feet per second to gallons per second), multiply by 7.48: 50 × 7.48 = 374 gallons per second
18) Which of these is the preferred way to prevent pollution?
  1. Recycling
  2. Source reduction
    The preferred option for waste management is source reduction, which reduces the amount of waste produced. Then, in descending order of preference, the other options are recycling, treatment, and disposal.
  3. Waste disposal
  4. Waste treatment
19) What does an orifice plate measure?
  1. Flow rate
    An orifice plate is a metal disk with a hole in it. The plate is inserted into a pipe to measure the flow rate.
  2. Salinity
  3. pH
  4. Temperature
20) An industry discharges 5,000 gallons of wastewater per day. The wastewater contains 10 mg/L of magnesium. What is the industry's mass emission rate of magnesium in pounds per day?
  1. 0.31 pounds per day
  2. 0.42 pounds per day
    Step 1: Convert gallons to liters First, convert the volume of wastewater from gallons to liters. We know that 1 gallon is approximately 3.785 liters. &5,000 gallons/day × 3.785 L/gallon = 18,925 L/day Step 2: Calculate the total mass of magnesium in mg Use the given concentration of magnesium to find the total mass in milligrams. mass = volume × concentration = 18,925 L/day × 10 mg/L = 189,250 mg/day Step 3: Convert the mass from milligrams to pounds We need to convert milligrams to pounds. We know that 1 pound is approximately 453,600 milligrams. mass of magnesium (lb) = 189,250/453,600 = 0.42 lb/day Therefore, the industry's mass emission rate of magnesium is approximately 0.42 pounds per day.
  3. 0.58 pounds per day
  4. 0.64 pounds per day
21) Which industry typically produces runoff high in nitrogen?
  1. Agriculture
    Runoff from the agriculture industry is typically high in nitrogen. Agricultural activities often involve the use of nitrogen-based fertilizers, which can contribute to elevated nitrogen levels in runoff.
  2. Metal plating
  3. Petrochemical
  4. Textiles
22) Which of these water treatment methods is a chemical treatment process?
  1. Activated sludge
    The trickling filter process and activated sludge process are both biological aerobic treatments.
  2. Filtration
    Filtration is a type of physical treatment.
  3. Neutralization
    Neutralization is a chemical treatment process. Other chemical treatment processes include chemical precipitation and ion exchange.
  4. Trickling filter
23) What is the best method to determine the chemicals that industrial dischargers are placing in the collection system?
  1. Field test kits
  2. Laboratory chemical analyzes
  3. Results of industrial self-monitoring
  4. Visual observations
24) Which of these is a variable the Manning formula requires to calculate the flow rate in a pipe?
  1. BOD of the water
  2. Hydraulic radius
    To calculate the flow rate in a pipe, the Manning formula requires Manning’s roughness coefficient, the flow area, the hydraulic radius, and the slope of the energy gradient.
  3. Length of the pipe
    The length of the pipe is not needed; only the cross-sectional area (the flow area) of the pipe is needed.
  4. Runoff coefficient
25) What is the purpose of an unannounced industrial inspection?
  1. To check effluent quality
  2. To meet with POTW's normal contact person
  3. To review paper work
  4. To test response of industry
26) Which of the following is a recoverable chemical from textile mill waste?
  1. Caustic soda
    Valuable chemicals can be recovered and recycled from wastewater. Caustic soda is a recoverable chemical from textile mill waste. Textile mills often use caustic soda in processes such as mercerization, which improves the properties of cotton fibers.
  2. Soda ash
  3. Sulfur dioxide
  4. Sulfuric acid
27) What does the term buffer capacity mean?
  1. A measure of the ability of a solution or liquid to neutralize acids or bases
    Buffer capacity is a measure of how much a solution or liquid can neutralize acids or bases. It is used in wastewater treatment when measuring the capacity of wastewater to resist changes in pH due to the addition of an acid or base.
  2. A solution that resists change in pH from the addition of acid or base
    A solution that resists change in pH from the addition of acid or base is called a buffer solution.
  3. The amount of liquid a solid material can absorb
    The amount of liquid a solid material can absorb is called the absorption capacity.
  4. The flow or load that a treatment plant is designed to handle
28) A district charges a sewer impact fee of $2,500 per REC (Residential Equivalent Connection) for new developments, where one REC is 150 gallons per day. Calculate the sewer impact fee for a new office building with 15 employees, assuming each employee will use 20 gallons of water per day.
  1. $2,175
  2. $2,875
  3. $3,000
  4. $5,000
    Step 1) Calculate the number of gallons per day First, calculate the gallons of water the new build will use per day. 15 employees × 20 gallons per employee = 300 gallons per day. Step 2) Convert gallons to RECs Next, convert 300 gallons to RECs. One REC is 150 gallons per day. Therefore 300 gallons per day = 300/150 = 2 RECs Step 3) Calculate the sewer impact fee sewer impact fee = 2 RECs × $2,500 Sewer impact fee = $5,000
29) A developer anticipates that a new site will use 1,100 gallons of water per day. The sewer impact fee is $29.81 per gallon per day. Calculate the total daily sewer impact fee.
  1. $28,198
  2. $29,100
  3. $32,791
    $29.81 × 1,100 = $32,791
  4. $34,814
30) Which of these Acts regulates pollutant discharges into water and the quality standards for surface waters?
  1. Clean Water Act
    The Clean Water Act (CWA) establishes the basic structure for regulating discharges of pollutants into the waters of the United States and regulating quality standards for surface waters.
  2. Comprehensive Environmental Response, Compensation, and Liability Act
  3. National Environmental Policy Act
  4. Safe Drinking Water Act
31) Hydraulic load is the height in inches of the average volume of wastewater introduced into a pond in one:
  1. second
  2. minute
  3. hour
  4. day
32) For protection from effluent splashes and flying debris, workers should use:
  1. fall-detection technology
  2. flame-resistant clothing
  3. respiratory equipment
  4. safety goggles
33) Typically, how often do facilities have to submit discharge monitoring reports (DMRs)?
  1. Weekly
  2. Monthly
    Discharge monitoring reports are usually submitted monthly, by the end of the month after the month in which sampling occurs. Most NPDES permits require facilities to submit monthly DMRs,
  3. Bi-annually
  4. Annually
34) Which of these is a conventional pollutant?
  1. Benzene
  2. Biochemical oxygen demand
    Conventional pollutants are those that are usually found in domestic, commercial, or industrial wastes, and include suspended solids, biochemical oxygen demand, pathogens, and oil and grease. Examples of unconventional pollutants are benzene, beryllium, PCBs, asbestos and vinyl chloride.
  3. Cyanide
  4. Hexavalent chromium
35) Which of these should you never do around a UV system?
  1. Collect samples
  2. Drink bottled water
  3. Look into the lamps without eye protection
  4. Plug a UV system into a grounded electrical outlet
36) What are receiving water standards based on?
  1. Categorical standards
  2. Technology-based standards
  3. The best available technology economically achievable
  4. The tolerance of the stream to pollutants
37) A factory uses 3 cubic feet of copper daily. Assuming the factory operates five days a week, calculate the number of gallons of copper the industry uses every week, to the nearest gallon.
  1. 22
  2. 73
  3. 112
    The factory uses 3 cubic feet of copper daily. To convert this to gallons, multiply the number of cubic feet by 7.48. 3 ft³ × 7.48 = 22.44 gallons The factory operates five days a week. So to work out how many gallons the industry uses per week, multiply the value by 5. 22.44 gallons × 5 days = 112.2 gallons
  4. 157
38) Which law provides increased protection for groundwater systems susceptible to fecal contamination?
  1. Ground Water Rule
    The Ground Water Rule provides increased protection against microbes in community water systems using groundwater resources.
  2. Hydraulic Fracturing Law
  3. Source Water Protection
  4. The Underground Injection Control Program
39) A primary clarifier is 120 feet long, 40 feet wide, and 14 feet deep. The influent flow is 7.5 MGD. Calculate the detention time in hours.
  1. 1.6 hours
    Step 1: Calculate the tank volume volume = length × width × depth volume = 120 ft × 40 ft × 14 ft volume = 67,200 ft³ Step 2: Convert ft³ to gallons To convert from ft³ to gallons, multiply by 7.48. gallons = 67,200 ft³ × 7.48 gallons = 502,656 gallons Step 3: Convert gallons to MG MG means millions of gallons. To convert from gallons to MG, divide the number of gallons by a million. tank volume in MG = 502,656 gallons/1,000,000 = 0.502656 MG Step 4: Calculate the detention time The question tells us the influent flow is 7.5 MGD (millions of gallons per day). From this, and the tank volume in MG, we can work out the detention time. detention time = tank volume/flow rate detention time = 0.502656 MG/7.5 MGD detention time = 0.0670208 days Step 5: Convert days to hours To convert the number of days to hours, multiply by 24. detention time in hours = 0.0670208 × 24 detention time in hours = 1.6 hours
  2. 3.2 hours
  3. 4.8 hours
  4. 6.2 hours
40) Which federal program authorizes the President to take emergency action in the event of the release of hazardous substances into the environment?
  1. Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA)
    The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), also known as Superfund, authorizes the President to respond to releases of hazardous substances into the environment.
  2. Environmental Change and Security Program (ECSP)
  3. National Environmental Policy Act (NEPA)
  4. Resource Conservation and Recovery Act (RCRA)
41) What is brownwater?
  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
42) The provisions of 40 CFR part 433 subpart A apply to six metal finishing operations. These are electroplating, electroless plating, anodizing, coating, chemical etching and milling, and:
  1. electrochemical machining
  2. electron beam machining
  3. printed circuit board manufacture
  4. vapor plating
43) Algal bloom is mostly caused by the presence of large amounts of what in water?
  1. Carbon dioxide
  2. Nitrogen and phosphorus
    An algal bloom is mostly caused by the presence of large amounts of nitrogen and phosphorus in water.
  3. Plastic
  4. Suspended matter
44) In traffic control, which taper requires the longest distance?
  1. Downstream
  2. Merging
    A merging taper requires the longest distance because drivers are required to merge into an adjacent lane of traffic at the prevailing speed.
  3. Shifting
  4. Shoulder
45) A representative sample is:
  1. collected during minimum flows
  2. obtained when industrial representatives are present
  3. similar to the larger body of wastestream being sampled
  4. transported to a laboratory for analysis
46) Which organization administers the Manual on Uniform Traffic Control Devices (MUTCD)?
  1. Environmental Protection Agency (EPA)
  2. Federal Highway Administration (FHWA)
    The Federal Highway Administration (FHWA) is responsible for the construction, maintenance, and preservation of highways, bridges and tunnels. It also administers the Manual on Uniform Traffic Control Devices (MUTCD).
  3. Federal Motor Carrier Safety Administration (FMCSA)
  4. National Transportation Safety Board (NTSB)
47) A battery manufacturing industry discharges 4,000 kg of wastewater per day carrying 6 g/L of benzene. How many kilograms of benzene does the industry discharge per day?
  1. 20 kg
  2. 24 kg
    Step 1: Convert the amount of wastewater from kilograms to liters Since one liter of water weighs one kilogram, 4,000 kg of water = 4,000 liters of water. Step 2: Calculate the mass of benzene discharged per day mass = volume × concentration mass = 4,000 liters × 6 g/liter mass = 24,000 g mass = 24 kg
  3. 28 kg
  4. 32 kg
48) A solution of hydrogen peroxide contains 20% hydrogen peroxide and has a density of 2 g/mL. How many grams of hydrogen peroxide are in one liter of the solution?
  1. 100 g/L
  2. 200 g/L
  3. 300 g/L
  4. 400 g/L
    Step 1: Convert g/mL to g/L To convert from g/mL to g/L, multiply by 1,000. 2 g/mL × 1,000 = 2,000 g/L Step 2: Calculate the amount of hydrogen peroxide The question says that 20% of the solution is hydrogen peroxide. Therefore to find the amount of hydrogen peroxide in one liter of the solution, we need to multiply the density of the solution by 0.20: 0.2 × 2,000 g/L = 400 g/L
49) Which of these is a reason for collecting a water sample in a septum vial?
  1. To keep the sample cool
  2. To prevent infection by possible pathogens
  3. To prevent people from tampering with the sample
    Tamper-evident labels or tape would be used to prevent people from tampering with samples.
  4. To prevent water evaporation
    The septum of a septum vial forms a barrier between the sample in the vial and the outside atmosphere. This barrier protects the sample from contamination and evaporation. Preventing water evaporation from the sample is important for accurate analysis, especially for volatile components.
50) What is the difference between point-source pollution and non-point-source pollution?
  1. Point-source pollution comes from a single place while non-point-source pollution comes from many places
    Point-source pollution enters rivers at a specific point, such as at a discharge pipe. In contrast, non-point-source pollution has no specific point origin. It leaches into surface waters and groundwater as a result of rainfall, soil infiltration, and surface runoff.
  2. Point-source pollution is characterized by continuous discharges while non-point-source pollution occurs in sudden, concentrated releases
  3. Point-source pollution is mainly associated with agricultural runoff while non-point-source pollution is linked to industrial discharges
  4. Point-source pollution results from natural processes while non-point-source pollution results from human activities
51) Which method of pollution treatment uses fungi?
  1. Mycoremediation
    Mycoremediation uses fungi to remove organic contaminants from water.
  2. Phytotransformation
  3. Rhizodegradation
  4. Rhizofiltration
52) Which of these bacteria is an indicator of water pollution?
  1. Azospirillum
  2. Biggiata
  3. E. coli
    E. coli is the most common indicator of water pollution. The presence of E. coli in water indicates fecal contamination.
  4. Lactobacillus
53) What is the main toxic metal in dental amalgam?
  1. Aluminum
  2. Chromium
  3. Lead
  4. Mercury
    Dental amalgam is a mercury, silver, tin, and copper mixture. The most dangerous of these is mercury, which is a potent neurotoxin. The EPA has standards to reduce mercury discharges from dental offices into wastewater.
54) When taking a water sample from a plastic spigot, what is the easiest and most effective way to disinfect the spigot?
  1. Alcohol swab
    Water sampling points should be disinfected before water samples are taken, to ensure samples are not affected by any other impurities. Alcohol swabs are the most effective method of disinfecting sample points.
  2. Flame
    Flames can only be used to disinfect metal spigots, not plastic spigots. (Plastic spigots will melt.)
  3. Ozone disinfection
  4. Peracetic acid immersion
55) New Sources must submit a baseline report to the Control Authority at least _____ days before starting discharge.
  1. 90
    40 CFR 403.12 (Reporting requirements for POTW's and industrial users) says, "At least 90 days prior to commencement of discharge, New Sources [...] shall be required to submit to the Control Authority a report which contains the information listed in paragraphs (b)(1)-(5) of this section."
  2. 180
  3. 270
  4. 360
56) A tank holds 10,000 gallons of cyanide solution with a cyanide concentration of 20 mg/L. Calculate the number of pounds of cyanide in the tank.
  1. 0.84
  2. 1.67
    Step 1) Convert the tank volume to liters To convert from gallons to liters, multiply by 3.785. 10,000 × 3.785 = 37,850 liters Step 2) Calculate the mass of cyanide mass = volume × concentration mass = 37,850 liters × 20 mg/L mass = 757,000 mg Step 3) Convert from milligrams to pounds The final step is to convert milligrams to pounds. We know that 1 pound is approximately 453,600 milligrams. mass (lb) = 757,000 mg/453,600 = 1.67 lb Therefore, the tank holds approximately 1.67 pounds of cyanide.
  3. 2.32
  4. 3.84
57) Which formula calculates the response factor in gas chromatography?
  1. Concentration × detector response
  2. Mass / volume
  3. Mass × slope of the plot
  4. Peak area / concentration
    The general formula for a response factor in gas chromatography is peak area divided by its concentration for a chemical component.
58) Which term means the movement of water through porous materials such as soil?
  1. Percolation
  2. Precipitation
  3. Reticulation
  4. Sedimentation
59) What is the primary goal when attending to a spill?
  1. Keep people safe
    Generally, spill response goals, in order of priority, are:
    1. Ensure human safety
    2. Stabilize the spill to prevent it from worsening
    3. Minimize adverse environmental and socioeconomic impacts
  2. Minimize damage to machinery
  3. Minimize damage to the environment
  4. Prevent the spill from spreading
60) An industry has three sewer connections with the following discharge rates: Connection 1: 500 gpd Connection 2: 150 gpd Connection 3: 350 gpd A flow-weighted composite sample of 3 liters is needed. How many milliliters of sample from each connection should be composited?
  1. 1,000 mL, 1,000 mL, 1,000 mL
  2. 1,200 mL, 800 mL, 1,000 mL
  3. 1,500 mL, 450 mL, 1,050 mL
    Step 1) Sum the discharge rates 500 + 150 + 350 = 1000 gpd Step 2) Calculate the weight of each connection Calculate the proportion of the total discharge rate for each connection.
    1. 500/1000 = 0.5
    2. 150/1000 = 0.15
    3. 350/1000 = 0.35
    Step 3) Calculate the sample needed for each connection Multiply the total sample volume (3000 mL) by the proportion for each connection.
    1. 3,000 mL × 0.5 = 1,500 mL
    2. 3,000 mL × 0.15 = 450 mL
    3. 3,000 mL × 0.35 = 1,050 mL
  4. 500 mL, 150 mL, 350 mL
61) If a water sample is not properly chilled and sealed, which of these water quality indicators would stay the same?
  1. BOD
  2. COD
  3. Dissolved sulfide
  4. Hardness
    If samples are not properly chilled and sealed, then BOD, COD, dissolved sulfide, and pH can change. However, hardness would stay the same.
62) Which Resource Conservation and Recovery Act (RCRA) waste code applies to wastes from nonspecific sources?
  1. F
    The Resource Conservation and Recovery Act (RCRA) assigns codes to different types of hazardous waste. These codes are F, K, P, and U. F codes apply to wastes from nonspecific processes. K codes apply to wastes generated from specific sources or industries, such as pesticides, organic chemicals, and explosives. P and U codes are for wastes from discarded chemical products.
  2. K
  3. P
  4. U
63) What do composite samples measure?
  1. Pollutants of specific concern
  2. The average concentration of pollutants
    A composite sample is a mixture of samples taken at different times or locations and pooled together to provide one sample. This provides a representative picture of the average pollutant concentration.
  3. The maximum concentration of pollutants
  4. The pollutant discharge at a specific time
64) How is the flow depth measured in a Palmer-Bowlus flume?
  1. Channel bottom to water surface at measure point
  2. Channel bottom to water surface at throat
  3. Floor of flume to water surface at measuring point
  4. Floor of flume to water surface at throat
65) How many gallons of water can a 200 cubic-foot tank hold?
  1. 1,017
  2. 1,496
    To convert cubic feet to gallons, multiply the number of cubic feet by 7.48. 200 ft³ × 7.48 = 1,496 gallons
  3. 1,938
  4. 2,432
66) An industry has a wastewater discharge of 40,000 gallons per day containing 15 mg/L of cyanide. What is the industry’s mass emission rate of cyanide in pounds per day?
  1. 5 lb/day
    Step 1) Convert the discharge to liters To convert from gallons to liters, multiply by 3.785. 40,000 × 3.785 = 151,400 liters Step 2) Calculate the mass of cyanide mass = volume × concentration mass = 151,400 liters × 15 mg/L mass = 2,271,000 mg Step 3) Convert from milligrams to pounds The final step is to convert milligrams to pounds. We know that 1 pound is approximately 453,600 milligrams. mass (lb) = 2,271,000 mg/453,600 = 5 lb Therefore, the daily discharge is approximately 5 pounds of cyanide.
  2. 8 lb/day
  3. 10 lb/day
  4. 12 lb/day
67) A wastewater treatment plant exceeds its daily nitrogen discharge limit on 3 days in January, 1 day in March, 2 days in September, and 5 days in December. The penalty is $2,000 for every day the discharge limit was exceeded. Calculate the plant's total penalty for the year.
  1. $18,000
  2. $20,000
  3. $22,000
    Total number of days = 3 + 1 + 2 + 5 = 11 days. Total penalty = 11 days × $2,000 = $22,000.
  4. $24,000
68) How should an inspector respond when an unknown material that is neither flammable nor asphyxiating is found in a collection system?
  1. Assume the unknown material was an accidental spill
  2. Disregard the unknown material until next time
  3. Try to trace the unknown material back to the industrial source
  4. Wait for the unknown material to arrive at the treatment plant
69) Which type of safety system involves a team leader calling their staff periodically (every hour, for example) to make sure they are safe?
  1. Check-call
    Check-call or check-in systems are some of the simplest ways of monitoring staff safety. A check-call usually involves a team leader calling their staff periodically (say every hour) to check that they're safe. Alternatively, it can go the other way; with staff checking in with their supervisors at allotted times
  2. Checklist
  3. Contact-tracing
  4. Dispatch
70) What is dangerous about gasoline in sewers?
  1. It can cause sewage to expand
  2. It can explode
    Gasoline is dangerous in sewers due to its potential for creating fire or explosions.
  3. It can rust pipes
  4. It can thicken sewage and cause blockages
71) In wastewater systems, what does the term "peaking factor" mean?
  1. A value indicating the smoothness of the interior of a pipe
  2. The maximum momentary load placed on a water treatment plant, pumping station, or distribution system
    The maximum momentary load placed on a water treatment plant, pumping station, or distribution system is known as "peak demand".
  3. The ratio of a maximum flow to the average flow
    The peaking factor (PF) is the ratio of the maximum flow to the average daily flow in a water system. It is used to forecast the maximum/peaking flows for wastewater systems.
  4. The ratio of true power to apparent power in an electrical circuit
    The ratio of true power to apparent power in an electrical circuit is known as the "power factor".
72) What is the purpose of ultraviolet light in wastewater treatment?
  1. To improve water taste
  2. To kill pathogens
    Ultraviolet light is a method for destroying disease-causing organisms in wastewater effluent.
  3. To reduce water hardness
  4. To remove suspended particles
73) If the residual chlorine is 2.0 mg/L and the chlorine dosage is 8.0 mg/L, what is the chlorine demand?
  1. 4.0 mg/L
  2. 6.0 mg/L
    The formula for calculating chlorine demand is: chlorine supply − residual chlorine Substituting the values in the formula: 8.0 mg/L − 2.0 mg/L = 6.0 mg/L
  3. 10.0 mg/L
  4. 16.0 mg/L
74) For new developments, a district charges a sewer impact fee of $3,200 per REC (Residential Equivalent Connection), where one REC is 240 gallons per day. If a new build will have 20 employees and each employee will use 15 gallons of water per day, then what is the sewer impact fee?
  1. $1,000
  2. $2,000
  3. $3,000
  4. $4,000
    Step 1) Calculate the number of gallons the new build will use per day 20 employees × 15 gallons per employee = 300 gallons per day. Step 2) Convert gallons to RECs One REC is 240 gallons per day. Therefore 1 gallon per day = 1/240 RECs. Therefore 300 gallons per day = 1.25 RECs (1/240 × 300). Step 3) Calculate the sewer impact fee Sewer impact fee = 1.25 RECs × $3,200 = $4,000.
75) The CWA makes it unlawful to discharge any pollutant from a point source into navigable waters unless a(n) ___________ is obtained.
  1. amendment
  2. demineralization certificate
  3. discrete conveyance
  4. permit
76) What is the maximum residual chlorine dioxide level allowed by the EPA for drinking water?
  1. 0.004 ppm
  2. 0.02 ppm
  3. 0.8 ppm
    The EPA has set the maximum concentration of chlorine dioxide in drinking water at 0.8 ppm (or mg/L).
  4. 5 ppm
77) Which of these is always required when working in a confined space?
  1. Breathing apparatus
  2. Continuous air monitoring
    Anyone working in a confined space must be constantly alert for any changing conditions within the confined space, such as oxygen levels and other air indicators. In the event of an alarm from monitoring equipment, workers should immediately leave the confined space.
  3. Fall arrest tripod
  4. Radio
78) Which of these gases is odorless?
  1. Arsine
    Arsine smells like garlic.
  2. Bromine gas
    Bromine smells like bleach.
  3. Carbon monoxide
    Carbon monoxide is colorless, odorless, tasteless, and highly toxic, making it a highly dangerous gas.
  4. Hydrogen sulfide
    Hydrogen sulfide smells like rotten eggs.
79) Animal slurries are usually treated by:
  1. anaerobic lagoons
    Animal slurry is a mixture of excreta and materials added during application. It is treated by the administration in anaerobic lagoons.
  2. brine treatment
  3. electrochemical coagulation
  4. reverse osmosis membrane filtration
80) What is the normal sampling frequency for water companies carrying out operator self-monitoring (OSM)?
  1. 1 or 2 samples per year
  2. 4 or 8 samples per year
  3. 12 or 24 samples per year
    The normal sampling frequency of operator self-monitoring is 12 to 24 samples per year.
  4. 16 or 28 samples per year
81) What association is devoted to eliminating death and injury due to fire hazards?
  1. CWEA
  2. NFPA
    The NFPA is the National Fire Protection Association. It is a non-profit organization devoted to eliminating death, injury, and property loss due to fire.
  3. NSC
  4. OSHA
82) Before entering an industrial facility for an inspection, why should an environmental compliance officer first visit the sampling points and collect wastewater samples?
  1. To collect an unbiased wastewater sample
    By collecting samples before notifying the facility, the officer ensures the sample hasn't been tampered with. Industrial facilities might be tempted to dilute wastewater or take corrective actions if they know a sample is about to be collected. Collecting samples before notifying the facility ensures the collected sample reflects the actual wastewater characteristics.
  2. To ensure following proper chain of custody procedures
  3. To minimize the time required of the industrial contact
  4. To present the industrial contact with the results of the analysis of sample
83) What are the sources of pollutants in stormwater runoff?
  1. Drag out dripping on the floor
  2. Products which have spilled on the grounds
  3. Rinse waters
  4. Scrubber wastewater
84) Physicochemical wastewater treatment methods, such as coagulation and reverse osmosis, are examples of which level of treatment?
  1. Primary
  2. Quarternary
  3. Secondary
  4. Tertiary
    Physicochemical processes, such as coagulation and reverse osmosis are examples of tertiary treatment. Other examples are filtration and adsorption of organics.
85) What is the purpose of the buffer area in traffic control?
  1. To redirect traffic out of its normal path
  2. To separate traffic from the work area
    The buffer space is an area that separates the traffic from the workspace. It can provide recovery space for errant vehicles.
  3. To store tools and machinery
  4. To warn drivers of work or danger
86) Which of these causes concrete to crack when it reacts with calcium?
  1. Chloride
  2. Chlorine
  3. Nitrate
  4. Sulfate
    Sulfate reacts with calcium compounds in concrete, such as calcium hydroxide and calcium aluminate hydrate, forming expansive products like ettringite. This expansion can cause the concrete to crack and deteriorate. This process is called sulfate attack and is a common cause of concrete degradation in sulfate-rich environments.
87) A containment tank has dimensions of 15×15×2 feet. There is also a cylindrical metal column in the middle of the tank with a diameter of 2 feet and a height of 10 feet. Calculate the number of gallons of water the containment tank can hold.
  1. 3,131 gallons
    Step 1) Calculate the volume of the containment tank Volume = length × width × height Volume = 15 × 15 × 2 Volume = 450 cubic feet Step 2) Calculate the radius of the column The question gives the column's diameter as 2 feet, so the column's radius is 1 foot (half of 2). Step 3) Calculate the volume of the column We know the column's radius and the question tells us the column's height. Now we can calculate the volume of the column. Column volume = radius² × π × height Column volume = (1)² × π × 10 Column volume = 1 × π × 10 Column volume = 31.40 ft³ Step 4) Subtract the space taken up by the column from the volume of the containment tank 450 − 31.40 = 418.6 cubic feet Step 5) Convert cubic feet to gallons To convert cubic feet to gallons, multiply the number of cubic feet by 7.48: 418.6 cubic feet × 7.48 = 3131 gallons
  2. 3,266 gallons
  3. 3,389 gallons
  4. 3,419 gallons
88) When collecting samples to be analyzed for volatile organic compounds, to which point should you fill the vial?
  1. Completely full
    When collecting samples for volatile organic compounds (VOC) testing, the vial should be full, with no air or bubbles. Air allows the off-gassing of certain volatile analytes, causing results that do not accurately represent the conditions at the sampling site.
  2. Filled with about one inch of space at the top
  3. Four-fifths full
  4. Half full
89) For how long is the BOD₅ test run?
  1. 5 minutes
  2. 5 hours
  3. 5 days
    The BOD₅ test measures the biological oxygen demand of a water sample over five days.
  4. 5 weeks
90) What is "direct runoff"?
  1. A discharge from the end of a pipe, often containing pollutants
  2. A pipe that carries stormwater but not domestic and industrial wastewater
    A pipe that carries stormwater but not domestic and industrial wastewater is called a storm pipe.
  3. Wastewater that flows out of a sanitary sewer as a result of an overflow
    Wastewater that flows out of a sanitary sewer as a result of overflow is called sanitary sewer overflow.
  4. Water that flows over the ground surface directly into streams, rivers, or lakes
    "Direct runoff" means the flow of rainwater over the land and into streams, rivers, and lakes. It is also known as storm runoff.
91) What is the minimum number of years a POTW must retain Industrial User records?
  1. 2 years
  2. 3 years
    The relevant regulation for recordkeeping by POTWs is outlined in the Code of Federal Regulations (CFR) Title 40, Part 403. Specifically, 40 CFR § 403.12(e)(2) states that Industrial Users and POTWs must retain records for at least 3 years.
  3. 4 years
  4. 5 years
92) Bubbler systems:
  1. break down foam on the water surface
  2. measure the flow rate of streams
  3. measure the water level
    Bubbler systems measure the water level by detecting the pressure required to force a bubble through a submerged tube.
  4. mix water in stilling wells
93) If a wastewater treatment plant can treat 150,000 gallons of sewage in 1 hour, then how many gallons of sewage can it treat in 8 hours?
  1. 150,000
  2. 400,000
  3. 800,000
  4. 1,200,000
    150,000 gallons × 8 hours = 1,200,000 gallons
94) Which of these is most likely to be a source of catastrophic discharges?
  1. Canneries
  2. Chemical plants
  3. Construction sites
  4. Dairies
95) An industry has a discharge of 16,000 gpd. A composite sample of 1 liter is needed. The sampler takes 125 ml each time it is activated. For a flow proportional sample, at what gallon interval should the sampler activate to take a sample?
  1. 1,000 gallons
  2. 2,000 gallons
    A sampler that takes 125 ml each time it is activated would need to activate 8 times (1000/125) to collect 1 liter of discharge. The total discharge per day is 16,000 gallons. Since the sampler needs to take 8 samples per day to collect 1 liter, then it should take a sample every 2,000 gallons (16,000 gallons/8).
  3. 3,000 gallons
  4. 4,000 gallons
96) The following magnesium results, in mg/L, were taken throughout the day: 0.38, 0.71, 0.47, 0.60, 0.12, 0.11, 0.10, 0.71 Calculate the mean of these results.
  1. 0.25
  2. 0.27
  3. 0.37
  4. 0.40
    Step 1) Sum the results 0.38 + 0.71 + 0.47 + 0.60 + 0.12 + 0.11 + 0.10 + 0.71 = 3.2 Step 2) Divide the sum by the number of results 3.2/8 = 0.4
97) In the rapid infiltration method of land treatment:
  1. collected water is discharged into the stream
  2. effluent is applied on the land by ridge-and-furrow spreading
  3. purification is achieved through biological, physical, and chemical means
  4. wastewater is stored in large ponds
    In the rapid infiltration method of water treatment, water is stored in large ponds called recharge basins.
98) Domestic water generated by small communities can be treated by:
  1. barren land
  2. coastal lands
  3. constructed wetlands
    Constructed wetlands are can treat domestic water generated by small communities.
  4. range land
99) Which of these test papers detects the presence of hydrogen sulfide?
  1. Flame retardant paper
  2. Lead acetate paper
    Lead acetate paper detects the presence of hydrogen sulfide. The paper changes color when hydrogen sulfide is present.
  3. M-9 CAD paper
  4. Peracetic acid test strips
100) COD tests are reported in what units?
  1. mL/mol
  2. mg/L
    The results of chemical oxygen demand (COD) tests are reported in milligrams of O₂ consumed per liter of sample (mg/L).
  3. mol/L
  4. mol/g
101) Which containers are designed exclusively to separate non-polar liquids at oil refineries?
  1. API separator
    API oil-water separator is a container that is exclusively built to separate non-polar liquids.
  2. PE separator
  3. Plastic separator
  4. Polyethylene separator
102) Which term means a conveyance, such as a pipe, ditch, or channel, from which pollutants are discharged?
  1. Effluent
  2. Emergent outflow
  3. Overflow
  4. Point source
103) Which of these tests is reported in mg/L?
  1. Temperature
  2. Total toxic organics
  3. Turbidity
  4. pH
104) What is the flashpoint of car gasoline?
  1. 32°C
  2. 52°C
  3. 82°C
  4. −43°C
    The flashpoint of gasoline is around −43°C. Below this temperature, gasoline freezes,.Above this temperature, gasoline poses a flammability hazard.
105) Facilities do not need to file a Spill Prevention, Control, and Countermeasure (SPCC) plan with the EPA if the oil storage capacity on the facility is less than how many gallons in total?
  1. 10,000
  2. 20,000
  3. 30.000
  4. 40.000
106) What is the most used toxic pollutant in leather tanning?
  1. Chromium
    Tanneries are one of the most polluting activities due to the wide type of chemicals applied during the conversion of animal skins into leather. Chromium is one of the most common tanning agents used in the US.
  2. Copper
  3. Cyanide
  4. Phenol
107) A rectangular containment tank has a length of 15 feet and a width of 10 feet. To the nearest foot, how tall does the tank need to be to hold 10,000 gallons of water?
  1. 6 feet
  2. 7 feet
  3. 8 feet
  4. 9 feet
    Step 1) Convert gallons to cubic feet To convert gallons to cubic feet, divide the number of gallons by 7.48. 10,000 gallons/7.48 = 1,337 cubic feet Step 2) Calculate the required height of the tank The formula to calculate the volume of a cuboid is: volume = length × width × height We know the length, width, and volume of the tank but we do not know the height. We can rearrange the formula to find the height: height = volume/(length × width) Substituting the values in the formula: height = volume/(length × width) height = 1,337/(10 × 15) height = 1,337/150 height = 8.91 feet Therefore, the tank needs to be 9 feet tall to hold 10,000 gallons of water.
108) The Environment Protection Agency provides which web-based tool that calculates and reports facility pollutant discharges based on NPDES permit limit and DMR data?
  1. NPDES E-Reporting Tool
  2. Pollutant Head Tool
  3. Toxics Follow-up Tool
  4. Water Pollutant Loading Tool
    The Water Pollutant Loading Tool, provided by the EPA, helps people determine what, how much, where, and by whom the pollutants are being discharged.
109) Why are septum vials used for samples to be tested for total toxic organics?
  1. To comply with hazardous waste regulations
  2. To prevent cross-contamination with grab samples
  3. To prevent sample contact with air
    The septum forms a barrier between the sample analyte in the vial and the outside atmosphere.
  4. To prevent skin contact with toxic organic compounds
110) Most wastewater is treated through the separation of solids and liquids, typically by:
  1. crystallization
  2. distillation
  3. sedimentation
    Sedimentation is a method of removing suspended solids from water.
  4. stripping
111) Which method of measuring water level uses high-frequency pulses that hit the surface of the liquid and return to the sensor?
  1. Bubbler
  2. Pressure transducer
  3. Sounder
  4. Ultrasound
    Ultrasound uses sensors that transmit ultrasonic pulses. The pulse hits the surface of the liquid and returns to the sensor. The sensor measures the time it takes the sound to return. The time is then used to calculate the distance between the sensor and the water surface. This distance corresponds to the water level in the container.
112) Which instrument measures water turbidity?
  1. Flowmeter
  2. Nephelometer
    A nephelometer is an instrument that measures the turbidity (cloudiness) of a water sample.
  3. Spectrometer
  4. Venturimeter
113) Which of these is a source of dilute solutions that may be discharged to the pretreatment system or POTWs?
  1. Reject products
  2. Spent plating baths
  3. Static drag out solutions
  4. Stormwater runoff
    Stormwater runoff is precipitation (rain or snowmelt) that flows across the land. Stormwater runoff can contain various dilute pollutants like dirt, debris, fertilizers, pesticides, and oil residues from streets and parking lots.
114) Which of these is found on Self-Monitoring Report (SMR) forms?
  1. Air quality index
  2. Child-resistant closures
  3. Hazard pictograms
  4. Laboratory test results
    Federal pretreatment regulations require industrial users to submit periodic Self-Monitoring Reports about the flow, nature, and concentration of pollutants in their effluent. Self-Monitoring Report forms are provided to help industrial users to submit their Self-Monitoring Reports. Self-Monitoring Report forms consist of:
    • Industrial user information
    • Flow and sampling information
    • Laboratory test results
    • Production data
    • Applicable limits
    • Certificates for total toxic organics, cyanide, and zero-discharge
115) What is the main goal of sample storage procedures?
  1. To accumulate a large enough sample for analysis
  2. To allow samples to accumulate before analysis
  3. To efficiently use the analyst's time
  4. To maintain the integrity of the sample until analysis
116) In which temporary traffic control zone does the work take place?
  1. Activity area
  2. Advance warning area
  3. Termination area
  4. Transition area
117) Chemical oxygen demand is reported in what unit?
  1. kg/meq
  2. meq/mole
  3. mg/L
    Chemical oxygen demand is expressed in milligrams/grams per liter, which indicates the mass of oxygen consumed per liter of solution. Older references may express the units as parts per million (ppm).
  4. moles/mL
118) A sulfuric acid solution contains 12% sulfuric acid and has a density of 1.4 g/mL. How many grams of sulfuric acid are in one liter of the solution?
  1. 117 g/L
  2. 168 g/L
    Step 1: Convert g/mL to g/L To convert from g/mL to g/L, multiply by 1,000. 1.4 g/mL × 1,000 = 1,400 g/L Step 2: Calculate the amount of sulfuric acid The question says that 12% of the solution is sulfuric acid. Therefore to find the amount of sulfuric acid in one liter of the solution, we need to multiply the solution's density by 0.12: 0.12 × 1,400 g/L = 168 g/L
  3. 857 g/L
  4. 1167 g/L
119) A wastewater sample is to be analyzed for volatile organic compounds but the water contains chlorine. What can be used to preserve the sample?
  1. 1 mol of nitric acid
  2. 1:2 ratio of 50% ethanol
  3. 2 drops of a 25% ascorbic acid solution
    Water containing chlorine requires a dechlorination agent such as ascorbic acid to neutralize the chlorine.
  4. 5 mL of a 10% mercuric chloride solution
120) In which stage of sewage treatment do microorganisms consume the organic components of the sewage?
  1. Primary
  2. Secondary
    Wastewater and sewage are treated in three phases: primary (removal of solids), secondary (bacterial decomposition of organic components), and tertiary (extra filtration).
  3. Tertiary
  4. Quarternary
121) Temporary traffic control zones generally have five sections: the advanced warning area, the transition area, the buffer area, the work area, and the ___________ area.
  1. controlled
  2. final warning
  3. late warning
  4. termination
    The termination area is the final section of traffic control zones. It alerts drivers that they are leaving the work zone and guides them back into the regular traffic flow.
122) What does the C in COD stand for?
  1. Carbon
  2. Chemical
    COD stands for chemical oxygen demand. COD is the amount of dissolved oxygen that must be present in water to oxidize chemical organic materials, like petroleum.
  3. Chlorine
  4. Combined
123) In water pipes, what is a "springline"?
  1. A line that represents the elevation of energy head of water flowing in a pipe
    A line that represents the elevation of energy head of water flowing in a pipe is called the "energy grade line".
  2. An outlet for overload conditions during peak flows
    An outlet for overload conditions during peak flows is called an "overflow relief line" or "relief line".
  3. The horizontal centerline of a pipe
    The "springline" is the horizontal, mid-height line of a pipe.
  4. The lowest point of the channel inside a pipe
    The lowest point of the channel inside a pipe is called the "flow line".
124) For what purpose do metal plating industries use dragout tanks?
  1. Metal recovery
    Dragout tanks collect the excess plating solution that "drags out" on the surface of the parts being plated. By capturing this excess solution, the metals can be recovered and reused, reducing waste and costs.
  2. Volume reduction
  3. Wastewater equalization
  4. Wastewater segregation
125) Which of these is a method commonly used to thicken activated sludge before treatment?
  1. Aeration
  2. Dissolved air flotation
  3. Sand filtering beds
  4. Vacuum filtration
126) Wastewater from toilets is known as:
  1. blackwater
    Blackwater is wastewater from toilets. This water likely contains feces and urine. Blackwater is distinguished from graywater, which comes from sinks, baths, washing machines, and other kitchen appliances apart from toilets.
  2. brownwater
  3. graywater
  4. whitewater
127) What is the "scouring velocity" of a river?
  1. The average velocity of the river during flooding
  2. The minimum velocity required for zero turbulence
  3. The velocity that prevents particles from settling on the river bottom
  4. The velocity which pulls plants out of the riverbed
128) Lime reacts with carbon dioxide in wastewater to produce which chemical?
  1. Activated carbon
  2. Calcium carbonate
    Lime reacts with carbon dioxide (CO₂) in wastewater to produce calcium carbonate (CaCO₃) and water (H₂O). This process is known as lime softening and is used in water treatment to improve water quality by reducing hardness and alkalinity.
  3. Sodium carbonate
  4. Sodium hydroxide
129) Fees imposed by a local government on a new development project that pay for all or a portion of the costs of providing public services to the new development are called:
  1. buy-in fees
  2. growth-related improvement fees
  3. impact fees
    Impact fees are intended to ensure that the strain on public services, such as roads and utilities, associated with a new development project is borne by the developers rather than the entire community.
  4. reimbursement fees
130) Bacteria used in water treatment plants function optimally at which temperature?
  1. 5–15°C
  2. 15–25°C
  3. 25–35°C
    In most cases, the bacteria used in water treatment plants function optimally at temperatures between 25 to 35°C.
  4. 35–40°C
131) What is a Bronsted-Lowry acid?
  1. A chemical compound with the structural formula HNCO
  2. A salt that produces an acidic solution after being dissolved in a solvent
  3. A substance that donates hydrogen ions during a chemical reaction
    A Bronsted-Lowry acid is any substance that can donate protons (H+) to other molecules.
  4. An organic compound that reacts with alcohols to form uric arid
132) Water samples to be analyzed for bacteria should be kept at what temperature?
  1. 21°C
  2. 37°C
  3. 4°C
    Water samples to be analyzed for bacteria should be kept at refrigeration temperature (4°C). This temperature minimizes bacterial growth during transportation and storage. If water samples are stored at higher temperatures, bacteria can grow rapidly, potentially altering the microbial composition and confounding the results of the bacterial analysis.
  4. −6°C
133) Water samples to be analyzed for cyanide should be kept at what temperature?
  1. −6°C
  2. 4°C
    Generally, water samples to be tested in the laboratory should be kept at 4–6°C. This temperature prevents microbial growth without freezing the sample.
  3. 21°C
  4. 37°C
134) What container and preservative are needed for samples to be analyzed for total or dissolved metals?
  1. Cubitainer, H₂SO₄ to pH < 2
  2. Glass, HCL to pH > 9
  3. Glass, zinc acetate + NaOH to pH > 9
  4. Plastic, HNO₃ to pH < 2
135) What container and preservative are needed for samples to be analyzed for bromide?
  1. Plastic, no preservative
    A plastic container with no preservatives is needed for samples to be analyzed for bromide.
  2. Plastic, NaOH
  3. Glass, HNO₃
  4. Glass, zinc acetate + NaOH
136) Which container and preservative are needed when collecting a sample to be analyzed for sulfides?
  1. Glass, HNO₃ to pH > 9
  2. Glass, H₂SO₄ to pH < 2
  3. Plastic, HCl to pH < 2
  4. Plastic, zinc acetate + NaOH to pH > 9
    Most water samples for laboratory analysis require an acidic preservative. However, sulfide is different because it needs an alkaline preservative, namely sodium hydroxide. Zinc acetate is also needed.
137) What container and preservative are needed for samples to be analyzed for oil and grease?
  1. Glass, HCl to pH < 2
    A glass container with either H₂SO₄ or HCL as a preservative is needed for oil and grease samples.
  2. Glass, zinc acetate + NaOH to pH > 9
  3. Plastic, HNO₃ to pH < 2
  4. Plastic, NaOH to pH > 9
138) A pH of 9 is how many times more alkaline than a pH of 7?
  1. 2
  2. 3
  3. 10
  4. 100
    pH is a logarithmic scale. This means that for each one-digit increase in pH, the alkalinity increases by 10 times. So a pH of 9 is ten times more alkaline than a pH of 8 and a hundred times more alkaline than a pH of 7.
139) On the NFPA hazard diamond below, what do the letters SA mean?
  1. Can shock or cause acid damage
  2. Safety assessed
  3. Simple asphyxiant
    The letters SA on an NFPA hazard diamond stand for "simple asphyxiant". A simple asphyxiant is a gas that displaces oxygen in the air, potentially leading to unconsciousness or death due to lack of oxygen. Simple asphyxiants include helium, nitrogen, neon, argon, krypton, and xenon.
  4. Substance abuse
140) What is 0.05 mL in microliters?
  1. 0.0005 μL
  2. 0.005 μL
  3. 5 μL
  4. 50 μL
    To convert from milliliters to microliters, multiply by 1,000: 0.05 mL × 1,000 = 50 μL
141) Complete this balanced equation: Ca(HCO₃)₂ + Ca(OH)₂ -> _______ + 2H₂O
  1. 2CaCO₂
  2. 2CaCO₃
    In the reaction, Ca(HCO₃)₂ and Ca(OH)₂ react to form CaCO₃ and H₂O. Two moles of CaCO₃ are needed to balance the equation.
  3. CaCO₂
  4. CaCO₃
142) During a titration, 32.20 mL of 0.250 M NaOH neutralizes 26.60 mL of H₂SO₄. What is the molarity of the H₂SO₄ solution?
  1. 0.071 M
  2. 0.083 M
  3. 0.106 M
  4. 0.151 M
    Step 1) Write the balanced chemical equation for the reaction: H₂SO₄ + 2NaOH→Na₂SO₄ + 2H₂O The equation shows that 1 mole of H₂SO₄ reacts with 2 moles of NaOH. Step 2) Calculate the moles of NaOH used in the titration: moles = molarity × volume moles = 0.250 M × 0.0322 L moles = 0.00805 moles Step 3) Calculate the moles of H₂SO₄. Since 1 mole of H₂SO₄ reacts with 2 moles of NaOH, we need to divide the number of moles of NaOH by 2 to find the number of moles of H₂SO₄: 0.00805 moles/2 = 0.004025 Step 4) Calculate the molarity of the H₂SO₄ solution: molarity = moles/volume molarity = 0.004025/0.02660 molarity = 0.151 M Therefore, the molarity of the H₂SO₄ solution is 0.151 M.
143) How many mL of a 0.2 M KOH solution will neutralize 15 mL of 0.4 M HCl?
  1. 10 mL
  2. 20 mL
  3. 30 mL
    The titration formula is M₁ × V₁ = M₂ × V₂ where:
    • M₁ is the molarity of solution 1
    • V₁ is the volume of solution 1
    • M₂ is the molarity of solution 2
    • V₂ is the volume of solution 2
    First, write the balanced equation: HCl + KOH = KCl + H₂O This equation shows that HCl and KOH react in a 1:1 molar ratio. Therefore, we do not need to adjust the stoichiometry in the calculation. Using the titration formula: M₁ × V₁ = M₂ × V₂ 0.4 × 15 = 0.2 × V₂ 6 = 0.2 × V₂ 6/0.2 = V₂ 30 = V₂ Therefore, 30 mL of a 0.2 M KOH solution will neutralize 15 mL of 0.4 M HCl.
  4. 40 mL
144) How many liters of 0.2 M potassium hydroxide are needed to neutralize 25,000 liters of 0.8 M hydrochloric acid?
  1. 25,000
  2. 50,000
  3. 75,000
  4. 100,000
    First, write the balanced equation: HCl + KOH = KCl + H₂O This equation shows that HCl and KOH react in a 1:1 molar ratio. Therefore, we do not need to adjust the stoichiometry in the calculation. Using the titration formula: M₁ × V₁ = M₂ × V₂ 0.8 × 25,000 = 0.2 × V₂ 20,000 = 0.2 × V₂ 20,000/0.2 = V₂ 100,000 = V₂
145) Which document provides written safety information about a chemical or hazardous material?
  1. OSM
  2. SDS
    SDS stands for safety data sheet. It provides information about the hazards, safe handling, storage, and emergency procedures for a chemical or hazardous material.
  3. TOSM
  4. TSM
146) Which section of a safety data sheet gives the flammability of a chemical?
  1. Accidental release measures
  2. Handling and storage
  3. Physical and chemical properties
    The Physical and Chemical Properties section of a safety data sheet tells you a substance's flammability (a substance's ability to ignite and burn). This section also gives information about a substance's color, odor, solubility, and other characteristics.
  4. Transport information
147) Who is responsible for preparing safety data sheets?
  1. The customer
  2. The end-user
  3. The government
  4. The manufacturer or supplier
    The responsibility for creating safety data sheets (SDS) falls on the manufacturer, importer, or distributor of a hazardous chemical.
148) What is NH₃ more commonly known as?
  1. Ammonia
    Ammonia is the name of the compound with the formula NH₃.
  2. Benzene
  3. Hydrazine
  4. Nitrogen hydroxide
149) In the context of gases, what does LEL stand for?
  1. Lead equivalent level
  2. Lower explosive limit
    The Lower Explosive Limit (LEL) is the lowest concentration of a gas in the air that can ignite.
  3. Lowest effective level
  4. Lowest exposure limit
150) 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
    The formula for calculating the average is: average = sum/count In this case:
    • sum is the sum of the ppm for each hour
    • count is the total number of hours (8)
    First, sum the ppm-hours: 2 hours × 150 ppm = 300 ppm-hours 2 hours × 75 ppm = 150 ppm-hours 4 hours × 50 ppm = 200 ppm-hours 300 + 150 + 200 = 650 ppm Then, divide the sum by the total number of hours: 650 ppm-hours/8 hours = 81.25 ppm
  2. 88.515 ppm
  3. 91.75 ppm
  4. 95 ppm

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About the CWEA ECI Grade 2 exam

What is the CWEA ECI Grade 2 exam?

The CWEA Environmental Compliance Inspector (ECI) exams are designed for people currently working as, or aspiring to become, Environmental Compliance Inspectors in California.

The exams are administered by the California Water Environment Association (CWEA), a professional organization dedicated to wastewater professionals in California.

The CWEA ECI exams are categorized into four grades: Grade 1, Grade 2, Grade 3, and Grade 4:

  • Grade 1 is the entry-level exam, ideal for beginners
  • Grade 2 is more challenging and suited for supervisory roles
  • Grade 3 is even more advanced, targeting middle-management positions
  • Grade 4 is the most difficult and is intended for upper-management roles.

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

Applying to take the exam

To apply for the exam, download an application form at cwea.org/certification/apply, fill it in, and email it to memberservices@cwea.org.

The exam costs $224 for CWEA members and $463 for non-members. You can pay this fee by entering your credit card details on the application form.

If the CWEA approves your application, they will send you an approval email. Once you have this email, you can schedule your exam appointment through Pearson VUE's website.

You can take the exam at a test center located throughout the US or at home on your computer. The exam is offered four times a year: in spring, summer, fall, and winter.

Keep in mind that you must have worked as an environmental compliance inspector for at least one year before you can take the CWEI ECI Grade 2 exam. You may also need a certificate or a Bachelor's/Associate degree depending on your years of experience. Refer to the ECI Candidate Handbook for more details.

Exam day

If you take your exam at a test center, arrive at least fifteen minutes early. Bring at least one photo ID. Your photo ID must be current, valid, and government-issued (e.g., state driver’s license or passport).

If you take the exam at home, you will need to check in to the testing system online 15—30 minutes beforehand. During the check-in, an online proctor will ask you to take photos of your testing space to ensure your room is private and secure. You will not be allowed books, paper, calculators, sticky notes, whiteboards, or chalkboards, and the proctor may ask you to remove such material before the exam. The proctor will monitor you throughout the exam.

Whichever method of taking the exam you choose, an onscreen calculator will be available. If you take the exam at a test center, you may also bring your own calculator as long as it is from the CWEA-approved calculator list.

After you finish the exam, your result will immediately appear on the computer screen.

Passing the exam

The exam has 100 questions. To pass the exam, you will generally need a score of at least 75% (although this may vary depending on the exam's difficulty).

Maintaining your certification

If you pass the exam, you will need to meet the following requirements to maintain your certification:

  • Submit 12 hours of continuing education every two years
  • Pay the annual renewal fee

What if I fail the exam?

If you fail the exam, you can retake it after paying the exam fee again.

Cancelling the exam

To reschedule or cancel an exam, contact Pearson VUE at least 24 hours before the exam is scheduled to start.

Exam topics

The CWEA ECI Grade 2 exam covers 25 KSAs (Knowledge, Skills, and Abilities). These are outlined below.

KSA 201: Applications and reports

This KSA is worth 4% of the exam and will test your knowledge of:

  • calculating size requirements of basins and containment structures
  • EPA requirements for discharge permit systems
  • mass limit requirements of national pretreatment standards
  • industrial waste plan checks

KSA 202: Permit generation

This KSA is worth 2% of the exam and will test your knowledge of:

  • the terms "point-source pollution discharge" and "non-point source pollution discharge"
  • the effective control mechanism duration for significant industrial users

KSA 203: Calculations for discharge permits

This KSA is worth 2% of the exam and will ask you to perform calculations related to discharge permitting. You will also need to know about production-based limits and mass-based limits.

KSA 204: Inspections

This KSA will test your knowledge of pretreatment facility inspection and is worth 9% of the exam. You will be tested on:

  • the pollution hierarchy
  • pollution hierarchy assessments
  • typical pollutants from various types of industries
  • substances used in metal finishing procedures
  • organic loading, buffering capacity, and infiltration
  • municipal separate storm sewer system (MS4) permit and requirements
  • ways water can infiltrate sanitary sewers
  • steps an inspector should take when responding to an illicit discharge
  • dental amalgam regulations

KSA 205: Sampling locations

This KSA is worth 2% of the exam and will test your ability to choose appropriate sampling locations and sampling equipment. The exam may also ask you about:

  • open channel flow rate measurement devices
  • flumes and weirs
  • how to clean sampling equipment

KSA 206: Collecting samples

This KSA is worth 4% of the exam and will ask you questions about collecting water samples. You may also be asked about:

  • the various aspects of sampling programs
  • information required for a chain of custody
  • the limitations of split samples in the field
  • the best locations to take wastewater samples

KSA 207: Collection devices, containers, and preservatives

This KSA is worth 4% of the exam. It covers collection devices, collection containers, and sample preservatives. The exam may also ask you about organic chemical analysis test methods as outlined in 40 CFR 136, Appendix A.

KSA 208: Field tests

This KSA is worth 4% of the exam and will ask you questions about basic field tests. You will also need to know about method blanks, turbidity, pH, and temperature.

KSA 209: Recording field conditions

This KSA is worth 4% of the exam and you will need to know how to:

  • take meter readings
  • record field conditions
  • record field test results
  • reduce conventional pollutants using sewage treatment methods
  • calculate flow rates
  • use open channel flow measurement devices
  • take grab samples

KSA 210: Tracing illegal waste discharges

This KSA is worth 4% of the exam and will test your ability to trace illegal waste discharges. You will also need to:

  • identify and calculate illicit discharges in sanitary sewers
  • know the time limit requirements industrial users have to report self-monitoring violations
  • know proper sampling procedures per 40 CFR 136

KSA 211: Noncompliance

This KSA is worth 4% of the exam. You will need to know the correct actions to take when a company fails to comply with industrial waste discharge permit requirements. The exam may also ask you to calculate significant non-compliance violations such as chronic effluent violations and technical review criteria violations.

KSA 212: Assisting collections and operations personnel

This KSA is worth 2% of the exam and will ask you questions about gravity-settling clarifiers and responding to spill incidents.

KSA 213: Safety

This KSA is worth 9% of the exam and will test your knowledge of safety practices, including:

  • opening sewer manholes safely
  • personal protective equipment (PPE)
  • safety data sheets
  • flash point temperatures of liquids
  • traffic control

KSA 214: Explaining environmental compliance regulations

This KSA is worth 6% of the exam and will test your ability to explain environmental compliance regulations, requirements, and policies to business owners/operators, other government agencies, and the public. This KSA will ask you to:

  • recognize examples of various categories of pollutants
  • understand terms and definitions relating to significant industrial users, CERCLA, and RCRA
  • explain the main components of the Clean Water Act
  • identify EPA-regulated industrial categories
  • recall the limitations of a local ordinance and an inspector’s authority to inspect an industrial user

KSA 215: Communication

This KSA is worth 6% of the exam and will test your ability to communicate with customers and the public and give information clearly and concisely. You will need to know:

  • the steps that must be taken before acquiring samples between storm events as outlined in 40 CFR 122.21
  • terms and definitions regarding pollution prevention hierarchy, such as source reduction, refractory materials, precipitation/coagulation treatment, complex metals, and precipitation of metals
  • how to respond to difficult situations during an inspection of a significant industrial user

KSA 216: Preparing notices of requirements and violations of regulations

This KSA is worth 6% of the exam and will ask you about:

  • the preparation of written notices of requirements and regulation violations
  • the procedures a publicly owned treatment works (POTW) must adhere to when responding to non-compliance
  • significant non-compliance requirements
  • record keeping requirements
  • inspectors’ responsibilities when conducting an investigation
  • enforcement response plans

KSA 217: Public outreach activities

This KSA is worth 6% of the exam and will ask you about:

  • terms and definitions relating to ion exchange tanks, water softeners, pollution prevention, waste minimization, and reverse osmosis units
  • benefits for industries that follow pollution prevention strategies
  • stormwater construction permits and waste minimization as outlined in 40 CFR 122.2

KSA 218: Researching the compliance history of facilities

This KSA is worth 2% of the exam and will ask you about:

  • Self-Monitoring Reports
  • how to recognize when a facility is in Significant Non-Compliance

KSA 219: Keeping current

This KSA is worth 2% of the exam and will ask you about keeping current on developments in environmental compliance. You will also be expected to know where to find information about pretreatment regulations for industries.

KSA 220: Legal requirements

This KSA is worth 4% of the exam and will ask you about:

  • the legal requirements to maintain water programs
  • policies and procedures for enforcement actions established by a publicly owned treatment works
  • the National Pollutant Discharge Elimination System (NPDES) and industrial user permits
  • the Control Authorities' responsibility in enforcing the Clean Water Act of 1977 and the levels of pretreatment equipment it required

KSA 221: Reports

This KSA is worth 6% of the exam and will ask you about:

  • compliance monitoring reports, such as:
    • toxic organic management plans (TOMPs)
    • stormwater pollution prevention plans (SWPPPs)
    • spill prevention control and countermeasure plans
    • slug discharge control plans
    • baseline and self monitoring reports
    • 90-day reports
    • periodic reports of continued compliance
    • monitoring reports for compliance with federal, state, and local requirements
  • calculating concentrations of chemicals in illegal loads of wastewater
  • recognizing noncompliance of significant industrial Users
  • the data needed for a baseline monitoring report, timeline reporting requirements for categorical dischargers and essentials that would constitute a sanitary sewer overflow

KSA 222: Prepare written notices of requirements and violations of regulations.

This KSA is worth 2% of the exam and will ask you about:

  • the preparation of written notices of requirements and violations of regulations
  • reporting requirements and the agency that should be notified in the event of a sanitary sewer overflow
  • metal finishing and how it could affect a publicly owned treatment works

KSA 223: Sewer impact fees

This KSA is worth 2% of the exam and will ask you about sewer impact fees. You will also need to know about:

  • tenant occupancy uses and classifications
  • calculating penalties for exceeding discharge limitations
  • the agency that has the authority to change an industrial user's assigned category

KSA 224: Wastewater strength and sewer impact fees

This KSA is worth 4% of the exam and will ask you about:

  • identifying wastewater strength, including calculating sewer impact fees
  • grease interceptors, including sizing requirements and clarifier calculations
  • calculating annual sewer service fees, organic loading, and wastewater strength

KSA 225: Providing management with information and recommendations

This final KSA is worth 2% of the exam and you need to know how to provide management with information and recommendations. You will also be expected to be able to understand policies when dealing with IU's confidential records and to properly identify an IU's category.