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CWEA LABORATORY ANALYST CERTIFICATION EXAM LATEST 2025 ACTUAL EXAM WITH COMPLETE EXAM QUESTIONS AND CORRECT DETAILED ANSWERS (100% VERIFIED ANSWERS) |ALREADY GRADED A+| ||PROFESSOR VERIFIED|| The Water Suitability Test (Test for Bacteriological Quality of Reagent Water) determines the toxic or stimulatory effects of the distilled or deionized water system. Which bacteria genera is used for this test? - ANSWER-Enterobacter Short-term toxicity tests are inappropriate for: - ANSWER- determining chronic toxicity. Basic requirements for toxicity tests do not include: - ANSWER- documented re-use of control test organisms. A test in which solutions and test organisms are placed in test chambers and kept there for the duration of the test is called a: - ANSWER-static test. A test in which solution is replaced continuously in test chambers through the test duration is called a: - ANSWER-flow through test.
A preliminary test designed to establish approximate toxicity of a solution is called a: - ANSWER-range finding test. A toxicity test designed to establish concentration at which a particular end point occurs is called a: - ANSWER-definitive test. Which of the following types of control samples may be used to determine accuracy? - ANSWER-Certified reference material Which of the following types of control samples may be used to determine precision? - ANSWER-Duplicate The average flow in a treatment plant is 3.1 MGD. A chlorine residual of 4.0 mg/L is maintained and the effluent must be dechlorinated before discharging. If an excess of 0.5 mg/L of sulfur dioxide is required after dechlorination, how many lbs/day of sulfur dioxide must be added? - ANSWER-106 lbs SO2/day
A waste is considered hazardous if it has at least one of the following properties: - ANSWER-ignitability, corrosivity, reactivity, and toxicity. Performance standards do not place emphasis on which of the following? - ANSWER-Personality characteristics Of the following inquiries during an interview, which one is appropriate? - ANSWER-"By whom were you referred for a position here?" You are asked to determine the cost per test of the COD analysis. Use the following information: The base salary of an analyst is $30,000; employer paid benefits add 35% to the base salary; administrative overhead adds another 45% to the base salary; there are 10 paid holidays, 15 days paid vacation leave, and 12 days paid sick leave per year; the hourly salary is determined by dividing the monthly salary by
- Each COD test requires an average of 20 minutes of labor from sample preparation to cleanup. Costs for chemicals,
glassware, and equipment use average $1.00 per test. Disposal costs average $2000/year for reagents from 1,000 tests. What is the total cost per test? - ANSWER-$11.62 /test The lower warning limit (LWL) on an LCS control chart indicates: - ANSWER-The recovery which is two standard deviations below the average recovery. When two of three successive determinations fall outside the warning limits: - ANSWER-Another determination should be made, and if it is within the warning limits no action is needed. Which of the below statements is NOT correct when collecting samples for the detection of mercury by EPA 245.1 or SM 3112B?
- ANSWER-a. Collect in polyethylene bottle and preserve with nitric acid and measure within 2 weeks. b. Collect in glass bottle and preserve with nitric acid and measure within 28 days. c. Collect in fluoropolymer bottle and preserve with nitric acid and measure within 28 days.
Which of the following is not a major interference in phenol determination? - ANSWER-Hydroxy derivatives of benzene A freshly prepared sodium hydroxide (NaOH) solution is standardized against primary standard potassium acid phthalate (KHC8H4O4). 0.8000 grams of potassium acid phthalate was dissolved into 50 mL CO2-free water. 2-3 drops of phenolphthalein were added. The sample was titrated to a faint pink endpoint with 22 mLs sodium hydroxide. What is the normality of the sodium hydroxide? - ANSWER-0.178 N What does an ICP source consist of? - ANSWER-A flowing stream of argon gas ionized by an applied radio frequency In gas chromatography, electron capture detectors (ECD) are used to detect which of the following compounds? - ANSWER- Chlorinated hydrocarbon pesticides Why is methlyene chloride replaced by hexane in sample preparation for analyses detected by GC electron capture
detection (ECD)? - ANSWER-Chlorine compounds are detected by ECD Which of the following methods is used to determine pesticides? - ANSWER-EPA Method 608 What analysis uses the purge and trap technique? - ANSWER- Volatile organic compound analysis The test for inhibitory residues on glassware and plastic ware determines the toxic or stimulatory effects of dishwashing detergents used for bacterial analysis. Which bacterial genera is used for this test? - ANSWER-Enterobacter Alkalinity - Bottle, Preservation, Hold Time - ANSWER-250mL plastic/glass, unpres, 14 days 1,4 Dioxane - Bottle, Preservation, Hold Time - ANSWER-500ml amber, sulfite/bisulfate, 28 days
Chlorine Demand - Bottle, Preservation, Hold Time - ANSWER- amber, unpres, 24 hr Chlorine, Total Residual - Bottle, Preservation, Hold Time - ANSWER-plastic/glass, unpres, 0.25hr COD - Bottle, Preservation, Hold Time - ANSWER-plastic/glass, H2SO4 pH<2, 28 days Color (Spec) - Bottle, Preservation, Hold Time - ANSWER-amber plastic/glass, unpres, 48 hr Color (Vis) - Bottle, Preservation, Hold Time - ANSWER-amber plastic/glass, unpres, 24 hr Cyanide - Bottle, Preservation, Hold Time - ANSWER-amber plastic/glass, absorbic acid(dechlor) NaOH pH>11, 14 days DOC - Bottle, Preservation, Hold Time - ANSWER-glass/voa, filter & pH<2 H3PO4, 28 days
HAA - Bottle, Preservation, Hold Time - ANSWER-amber glass, ammonium chloride, 14 days Hardness - Bottle, Preservation, Hold Time - ANSWER- plastic/glass, pH<2 HNO3, 6 mo 1664/HEM - Bottle, Preservation, Hold Time - ANSWER-glass, ph<2 HCl/H2SO4, 28 days HexChrom - Bottle, Preservation, Hold Time - ANSWER-plastic, ammonium sulfate/ammonium hydroxide buffer (14 days), unpres (24 hrs) Mercury - Bottle, Preservation, Hold Time - ANSWER- fluoropolymer, HCl, 28 days Nitrate-Nitrite - Bottle, Preservation, Hold Time - ANSWER- plastic/glass, none, 48 hrs
Phthlates - Bottle, Preservation, Hold Time - ANSWER-amber glass, HCl pH<2, 7 days Settleable solids - Bottle, Preservation, Hold Time - ANSWER- plastic/glass, unpres, 48 hr TSS/TDS/TS - Bottle, Preservation, Hold Time - ANSWER- plastic/glass, unpres, 7 days EC - Bottle, Preservation, Hold Time - ANSWER-plastic/glass, unpres, 28 days Sulfide - Bottle, Preservation, Hold Time - ANSWER-clear glass, zinc acetate pH>9 NaOH, 7 days THM - Bottle, Preservation, Hold Time - ANSWER-amber voa, sod thiosulfate, 14 days
TOC - Bottle, Preservation, Hold Time - ANSWER-amber voa, pH>2 H3PO4, 28 days Turbidity - Bottle, Preservation, Hold Time - ANSWER- glass/plastic, unpres, 48 hrs UV254 - Bottle, Preservation, Hold Time - ANSWER-amber glass, unpres, 48 hrs 524 VOCS - Bottle, Preservation, Hold Time - ANSWER-amber voa, HCl pH>2 (abs acid if chlor), 14 days 624 VOCS - Bottle, Preservation, Hold Time - ANSWER-amber voa, unpres / sod thio (if chlor), 3 days Coliform - Bottle, Preservation, Hold Time - ANSWER-sterile plastic/glass, sod thiosulfate, 8 hr (fecal)/ 30 hr (total) HPC - Bottle, Preservation, Hold Time - ANSWER-sterile plastic/glass, sod thiosulfate, 8 hr / 24 hrs
What does SDS stand for? - ANSWER-Safety Data Sheet What does LOTO stand for? - ANSWER-Lock Out Tag Out What does PPE stand for? - ANSWER-Personal Protective Equipment (PPE) What are some examples of PPE? - ANSWER-Safety glasses, hard hat, gloves, ear protection, chemical aprons, respirator, face shield, hazmat suit What does HVAC stand for? - ANSWER-Heating, Ventilation and Air Conditioning What is the definition of an engine? - ANSWER-A machine designed to convert energy into useful mechanical motion In terms of lubrication, what is required for a sealed ball bearing?
- ANSWER-It does not need to be lubricated under normal use
What is the purpose of a breakaway switch? - ANSWER-To apply the breaks on a trailer in the event of a trailer release from a vehicle What type of saw is used to cut metallic materials? - ANSWER- Hacksaw What type of saw is used to cut intricate external shapes and interior cut-outs in woodworking and carpentry? - ANSWER-A coping saw What type of saw is used to cut wood perpendicular to (across) the wood grain? - ANSWER-A Crosscut saw What type of saw is used to cut wood in the direction of the grain?
True or False : When accepting a work order, the need for speedy completion is an integral aspect of your performance as a Maintainenance Technologist - ANSWER-FALSE : It does not matter how long it takes to complete a work order, the most important and integral aspect of your performance when completing a work order is doing it safely and compleately There is an 18" wide red stripe painted on the ground around a tank. The tank is 25' high and 150' in diameter. What is the perimeter on the outer edge of the stripe? - ANSWER-475.71 ft 18" = 1.5' Perimeter = Diameter * pi = (150' + 1.5') * 3.14 = 475. A 12" diameter pipe, 48' long, weighs 35lbs per linear ft. What is the weight of the total load? - ANSWER-1680 lbs/ft 48' * 35lbs = 1680 What is the definition of Arc Welding? - ANSWER-Arc Welding is a welding process that is used to join metal to metal by using
electricity to create enough heat to melt metal, and the melted metals, when cool, result in a binding of the metals How does a centrifugal pump work? - ANSWER-Moves fluid by means of rotational energy from rotor drives/impellers. Fluid enters the rapidly rotating impeller along its axis and is cast out by centrifugal force along its circumference through the impeller's vein tips What is centrifugal force? - ANSWER-An outward force on a mass when it is rotated How does a positive displacement pump work? - ANSWER-Pump moves fluid by repeatedly enclosing a fixed volume of fluid, with the aid of seals or valves, and moving it mechanically (with a piston or a plunger) through a system How does a vacuum pump work? - ANSWER-Vacuum pumps have an inlet and and outlet with a nozzle in between - the nozzle restricts flow of fluids, thereby increasing fluid's velocity and decreases the fluids pressure. A vacuum is created by the lack of
