Texas Wastewater Class A Exam Questions and Answers, Exams of Water and Wastewater Engineering

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Texas Wastewater Class A Exam Questions and Correct Answers.

Seeding of BOD samples is necessary when samples - Correct Answer (All of the above) have a chlorine residual, have a previously been chlorinated, have been subjected to high temperatures, contain high or low pH industrial wastes When is blue-green algae the most dominant on a pond treatment system? - Correct Answer Summer A 30 - inch diameter wastewater interceptor is observed to be flowing half-full at about two fps. The approximate volume of wastewater flowing through the pipe is 3.14x1.25 x 1.25 x 2 = 4.9 cfs x 449 = 2,200 gpm - Correct Answer c. 2,200 gallons per minute A one-cylinder reciprocating sludge pump with a 10 - inch bore and a 5 - inch stroke pumps at a rate of 50 cycles per minute. How many minutes must the pump be operated to pump 5,000 gallons of sludge? 3.14x0.416 x 0.416 x0.416 x 50 x7.48 = 84. 5 gpm 5000 gal = 59,2min 84.5 gpm b. 29 - Correct Answer 60 minutes If an existing centrifugal pump motor is replaced with a motor with 25 percent more speed, the motor horsepower required will increase by 1.25 x 1.25 x 1.25 = 1.95 - Correct Answer 95 percent When must TCEQ be notified about expansions of a treatment facility? - Correct Answer Before construction In an anaerobic digester, the percentage of methane and carbon dioxide gas content should be - Correct Answer 70% methane, 30% carbon dioxide The temperature of an anaerobic digester should be maintained at a minimum of - Correct Answer 95° F What type of wastewater treatment operates in the endogenous bacteria growth phase? - Correct Answer Extended air Why is recirculation needed in a trickling filter? - Correct Answer Keep the media wet Further reduce BOD All of the above (a, b, and c) What type of fire extinguisher would be used on an electrical control panel that has been de-energized? - Correct Answer Class A Class C (a and d) Disinfection with chlorine is the most effective at a pH of - Correct Answer 6. The biomass on a normal functioning RBC has what appearance? - Correct Answer Grey to brown and 0.05 to 0.1 inch thick The sludge from a primary clarifier should percent solids? - Correct Answer 4% to 6%

What is eutrophication in a pond system? - Correct Answer Enrichment with nitrogen and phosphorous Causes algae blooms (b and c) How often should pH meters be calibrated? - Correct Answer Daily In Texas, pH meters are required to be calibrated on how many buffers? - Correct Answer two An industrial complex has a BOD discharge to the POTW of 500 pounds per day. The population equivalent of this industry is 500 lbs = 2,941 0.17 lbs BOD person - Correct Answer 2941 The parameters of the BOD test are - Correct Answer 5 days at 20° Centigrade Standard Dimension Ratio in pvc pipe is defined as - Correct Answer Ratio of OD pipe diameter to wall thickness How should shoring be removed from a trench? - Correct Answer up from the bottom up In low pressure sewer systems where each tap must have a grinder pump lift station, station is considered to be - Correct Answer part of the collection system and the responsibility of the utility Effective communication depends on - Correct Answer being a good listener When designing a wastewater collection system, the engineer considers the population for how many years in the future? - Correct Answer 50 According to 30 TAC Chapter 317, all pipe and fittings used in wastewater pressure shall have a minimum psi pressure rating of - Correct Answer 150 The minimum velocity of flow in a wastewater line should be - Correct Answer 2.0 fps At a construction job site, as the roadway speed increases, the spacing between cones and barricades should - Correct Answer increase The major cause of wastewater line stoppages is - Correct Answer roots and grease Carbon monoxide (CO) poisoning symptoms are - Correct Answer tightness in the chest nausea drowsiness and headache (all of the above) The smallest pipe size for air recirculation of a self-priming centrifugal pump is - Correct Answer 1 inch

What is the purpose of biomonitoring of a plant's effluent? - Correct Answer d. Test for toxicity Technology The management function of selecting and training employees of an organization is called - Correct Answer staffing e. controlling When must TCEQ be notified about expansions of a treatment facility? - Correct Answer Before construction In an anaerobic digester, the percentage of methane and carbon dioxide gas content should be - Correct Answer b. 70% methane, 30% carbon dioxide The temperature of an anaerobic digester should be maintained at a minimum of - Correct Answer 95° F

13. What type of wastewater treatment operates in the endogenous bacteria growth phase? - Correct Answer Extended air Why is recirculation needed in a trickling filter? - Correct Answer a. Keep the media wet b. Further reduce BOD c. Flood the filter to control ponding and filter flies
14. What type of fire extinguisher would be used on an electrical control panel that has been de-energized? - Correct Answer f. a class a and d class c Disinfection with chlorine is the most effective at a pH of - Correct Answer 6.
15. The biomass on a normal functioning RBC has what appearance? - Correct Answer Grey to brown and 0.05 to 0.1 inch thick The sludge from a primary clarifier should contain what percent solids? - Correct Answer b. 4% to 6% What is eutrophication in a pond system? - Correct Answer Enrichment with nitrogen and phosphorous Causes algae blooms
16. A wastewater stabilization pond has 130,680 sq. ft. It has a three to one slope on the embankment and has an average depth of 5 ft. Approximately how many people will this pond provide wastewater treatment for? 130,680 sq ft = 3 acres x 35 lbs / BOD/ acre = 105 lbs BOD =618 0.17 lbs BOD/ person 43,560 sq ft l acre - Correct Answer d. 600 A"Racetrack" is what type of Activate Sludge treatment? - Correct Answer Extended air Which form of activated sludge must have primary clarifiers? - Correct Answer Conventional

What is the relationship between F/M ratio and MCRT? - Correct Answer Indirect; if one goes up, the other goes down Which activated sludge process does not achieve complete nitrification? - Correct Answer Contact stabilization Which form of activated sludge does the better job of handling shock or toxic loads? - Correct Answer Complete mix Which of activated sludge has two aeration basins per single treatment unit? - Correct Answer Contact stabilization

27. A complete mix activated sludge plant has a fast settling sludge and high amounts of pin floc leaving the clarifier. One method of correcting the problem is to - Correct Answer Increase F/M ratio by wasting more problem is Testing of mixed liquor indicates the MLSS is 2500 mg/L and the settling test shows that a 1000 ml sample settles to 400 mls after 30 minutes. What is the SVI? 400 x 1000 2500 160 - Correct Answer 160 In the problem above, what the sludge quality? - Correct Answer Bulking Which activated sludge process has 18 to 20 + hours detention time in the aeration basin?

• Correct Answer Extended air What is the minimum clearance from the sidewall of a pipe to the trench wall in an excavation? - Correct Answer 4 inches What is the definition of pH? - Correct Answer The logarithm of the reciprocal of the hydrogen ion concentration The negative logarithm of the hydrogen ion concentration How often should pH meters be calibrated? - Correct Answer Daily trench is 4,100 feet long, four 4 wide and 6 feet deep. There is a 12 - inch diameter pipe in the bottom of the trench. How many cubic yards of material were removed from the trench? 4x6x4,100 3,644 27 - Correct Answer 3, In the problem above, how many cubic yards of material will be required to fill the trench? 3.14x0.5 x0.5 x 4,100 =119cu yds 27 3,644 - 119 = 3,525 - Correct Answer 3, What is the standard chlorine residual and contact time on Texas discharge permits? - Correct Answer e. None of the above organization increases, As the complexity of an organization increases, what management function becomes most important? - Correct Answer Planning

Standard Dimension Ratio in pve pipe is defined as - Correct Answer Ratio of OD pipe diameter to wall thickness MSDS sheets must be kept for how many years after you have stopped using the chemical? - Correct Answer c. 30 A pneumatic ejector is - Correct Answer a. a lift station pumping device How should shoring be removed from a trench? - Correct Answer d. from the bottom up

57. The most common pump used in the collection system is - Correct Answer d. centrifugal In low pressure sewer systems where each tap must have a grinder pump lift station, the lift station is considered to be - Correct Answer Part of the collection system and the responsibility of the utility Effective communication depends on - Correct Answer being a good listener A construction site safety evaluation checklist must include - Correct Answer a. placement of equipment, vehicles, and spoil bank b. placement of flaggers, barricades, cones and other safety equipment c. use of warning signs When designing a wastewater collection system, the engineer considers the population for how many years in the future? - Correct Answer 50 According to 30 TAC Chapter 317, all pipe and fittings used in wastewater pressure mains shall have a minimum psi pressure rating of - Correct Answer 150 The minimum velocity of flow in a wastewater line should be - Correct Answer 2.0 fps At a construction job site, as the roadway speed increases, the spacing barricades should - Correct Answer increase A piston pump with a 5 - inch piston and a 10 - inch stroke strokes 60 times a minute. How many minutes will operated to pump 6,000 gallons? - Correct Answer 5x5x0.0408x0.833x60 = 51 gpm 6,000 gal/51 gpm=117. round to 118 A bubbler level control system works off of what principal? - Correct Answer differential pressure
58. The major cause of wastewater line stoppages is - Correct Answer roots and grease

What type of valve is usually used for isolation? - Correct Answer gate Carbon monoxide (CO) poisoning symptoms are - Correct Answer a. tightness in the chest b. nausea c. drowsiness and headache d. all of the above Fresh wastewater is desirable because it is much easier to treat. The physical characteristics of fresh wastewater are - Correct Answer dishwater gray in color The smallest pipe size for air recirculation of a self-priming centrifugal pump is - Correct Answer b. 1 inch Dangerous gases in a confined space may not be detected with the physical senses because - Correct Answer a. some gases have no odor b. some gases may deaden the sense of smell c. some gases may displace the oxygen What are the dangerous gases a collection system worker might come into contact with? - Correct Answer a. CO2 b. CO c. H,S d. CH, e. all of the above When designing a wastewater rehab program, the first step is to - Correct Answer d. define the objectives of the program The goal of a sanitary wastewater physical survey is to - Correct Answer Identifying problems in the system need a rehab When should drop manholes be utilized? - Correct Answer wastewater velocities greater than ten fps flows entering the manhole 24 inches or greater above the floor Sewer balls or pigs are what type of wastewater cleaning equipment? - Correct Answer mechanical cleaning equipment On a construction job site, equipment booms must maintain at least how many feet clearance from overhead electric lines? - Correct Answer a. 10 How should trench shoring be installed? - Correct Answer Two above the top of the trench If an existing centrifugal pump motor is replaced with a motor with 20 percent more speed, the motor horsepower required will increase by - Correct Answer 1.2x1.2x1.2=1.728 73 percent When setting work goals for an employee, the goals should be - Correct Answer accompanied by an action plan According to Chapter 317, Design Criteria, a manhole can be installed within 9 feet of an existing waterline if - Correct Answer if a. the manhole is completely watertight and tested for no leakage

The Federal Clean Water Act - Correct Answer requires a permit for disposal of sludge requires a permit for ocean discharges of sewer c. requires a permit for disposal or placement of dredge material creates a national permit system for all wastewater discharge Pretreatment of industrial waste will help minimize - Correct Answer sludge contamination interference to the treatment process safety hazards to workers discharge of industrial pollutants in the effluent If an employee is guilty of misconduct as defined by the utilities personnel policies, the supervisor should - Correct Answer attempt to modify the employee's behavior through training and other forms of assistance inform the employee of the consequences if the behavior is not modified When fighting an electrical fire, you should - Correct Answer Use non-conductive extinguishing methods c. Use Class A or B extinguishers if electricity to the unit has been shut-off d. Either b or e A particular construction project has a total of 3,000 feet of 12 - inch pipe, 15 manholes, 50 wastewater connections. Based upon the contract unit costs shown, if the contractor has completed 2,000 feet of pipe, 12 manholes, and 30 wastewater connections, what percentage of the total project has been completed? 12 inch pipe place $85.00 per linear foot Manholes in place $1,500.00 each Wastewater connections $250.00 each - Correct Answer 3000 x 85 = 255, 15 x1500 = 22, 50x 250 = 12, 255,000 + 22,500+ 12,500 = $290, 2000 x 85 = 170, 12x1500 - 18, 30x250 =7, 170,000 + 18,000 + 7,500 = S195, 195,000/290000 =0.67 = 67% If the float that turns on the lead pump in a wastewater lift station is situated above a gravity influent line, the line will - Correct Answer tend to have a grease problem If an operations company ceases its operation or is sold such that control of the company is transferred to another party, - Correct Answer the company's operations certificate is revoked In 2.5 minutes, a lift station will fill up 18" with no pumps running. In 3.25 minutes, both pumps will drop the level in the lift station 18". In 7 minutes, the large pump will drop the level 18". What is the capacity of the small pump? The lift station is 10' x 10 x 10'.

10x10x1.5x7.48= 1122 gal/2.5=449 gpm inflow Both 1122/3.25=345 gpm + 449 gpm = 794 gpm both Large 1122/7=160 gpm + 449 gpm = 609 gpm large Small 794 gpm - 609 gpm = 185 gpm - Correct Answer 185 gpm H,SO, is a(n). - Correct Answer chemical compound What is the velocity of water flowing through a clarifier that is 16 feet deep x 45 feet wide 135 feet long if the flow is 5,837 gpm? Q- AxV 13=720x fps - Correct Answer 0.02 fps A chemical element is a - Correct Answer atom Chemical dechlorination can be accomplished with? - Correct Answer a. sodium Bisulfite b. sulfur Dioxide A crucible and filter weigh 21.6870 grams. After filtering 50 ml of sample through the filter, and then drying, desiccating and weighing them, the crucible, filter, and sample weigh 21.7250 grams. How many mg/L of suspended solids are in the sample? - Correct Answer b. 760 Three hundred milliliters of 0.02 N H,SO, is needed for a lab test. The lab stocks a standard of 0.5 N. How many ml of the 0.5 N will be needed? 300 x0.02 = V x0.5 300x0.02 0.5 - Correct Answer 12 How would an operator increase the degree nitrification in an activated sludge plant? - Correct Answer increase D0 and increase sludge age What processes are used to check an upset activated sludge plant? - Correct Answer BOD loadings, F/M ratio, SV 30, MCRT, DO When chlorine used, the effective disinfectant is - Correct Answer HOCI Aerobic digestion is a(n) process. - Correct Answer endogenous Distilled water used for the BOD analysis should not exceed mg/L oxygen depletion. - Correct Answer 0. Chlorine disinfects the best at - Correct Answer low pH

Assume that a 12% solution of a substance weighs 10.6 lbs/gal.and a 0.8% solution of the same substance weighs 8.76 lbs/gal. If 10.0 gallons of the 12% solution are mixed with 50 gallons of the 0.8% solution, the percent strength of the mixed solution would be - Correct Answer 3.0% Most gas detection instruments do not latch. This means that - Correct Answer the instrument stops alarming when removed from the contaminated atmosphere An injured person is not breathing, but has a pulse. The correct first aid response is - Correct Answer ventilate Proper employee motivation occurs when - Correct Answer employees participate in developing goals A confined space is defined as - Correct Answer a. a space so configured that an employee can enter and perform work space that is not designed for continuous human occupancy space that has limited entry and exit What can change a non-permit confined space entry into a permit required confined space entry? - Correct Answer a, if an ignition source is identified b. non-sparking tools are required c. a possible source of engulfment is identified d. a hazardous atmosphere is identified e. all of the above What tasks does a manager perform when controlling a utility? - Correct Answer being sure progress being made toward objectives What is the purpose of a capital improvement fund? - Correct Answer replacement fund to keep the utility operating in the future The incubation procedure for fecal coliform in wastewater - Correct Answer 44.5° Centigrade for 24 hours Cartridge respirators provide protection against: - Correct Answer gases Proper safety in the water lab includes: - Correct Answer wearing protective eyewear wearing an apron or lab coat The management function of setting goals, policies, and procedures is called: - Correct Answer planning The organizing management function involves: - Correct Answer deciding who will do what work An operator must measure the current being used by a motor that is operating three phase power. The correct instrument for this measurement is: - Correct Answer clamp-on ammeter

Approved backflow devices in Texas include: - Correct Answer air gap of two times the inlet pipe diameter testable assemblies usually an RPZ The discharge from a centrifugal pump will: - Correct Answer increase with an decrease in head decreases with an increase head The Hazard Communication Act of 1985 is: - Correct Answer Texas law Federal law To be a team player, a person must: - Correct Answer put yourself in the place of other team members to understand their position PL 92 - 500 is known as the - Correct Answer Clean Water Act Water Pollution Control Act In Texas no disinfection of treated effluent is required if - Correct Answer detention time is 21 days + 15,000 gallons of sludge with 4% solids is run through a press to produce a 25% cake. How many dry metric tons of sludge will be disposed of? [Assume a conversion factor of 2200 Ibs per dry metric tons.] - Correct Answer 2. Under the Texas Hazard Communication Act employers must annually report chemicals stored above what limits? - Correct Answer 55 gals/500 Ibs Under EPA regulations utilities that store chlorine gas over what quantity are required to have a "Risk Management Plan"? 2500 Ibs - Correct Answer 2500 Ibs The normal appearance of the biomass on an RBC is - Correct Answer grey to brown and .05 to.1 inch thick shaggy and stringy appearance Wastewater What are the effects of organic pollution on the receiving stream? - Correct Answer Decomposition of organics lowers DO levels adversely affecting aquatic life Nutrients encourage the growth of aquatic organism such as algae c. Lower water quality downstream is more difficult treat for potable use d. All of the above A 30 ml wastewater sample, is incubated 5 days at 20 degrees C. The DO before was 6. mg/L and the DO after was 3.5 mg/L. What is the reportable BOD? - Correct Answer (6-3.5) x 300 30 b. 25