TEXAS WASTEWATER CLASS A EXAM | ALL QUESTIONS AND CORRECT ANSWERS | ALREADY GRADED A+, Exams of Water and Wastewater Engineering

Download TEXAS WASTEWATER CLASS A EXAM | ALL QUESTIONS AND CORRECT ANSWERS | ALREADY GRADED A+ and more Exams Water and Wastewater Engineering in PDF only on Docsity! TEXAS WASTEWATER CLASS A EXAM | ALL QUESTIONS AND CORRECT ANSWERS | ALREADY GRADED A+ | VERIFIED ANSWERS | LATEST VERSION 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---------------3,644 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---------------3,525 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 The following scenario is to be used in answering questions 38, 39, and 40. A pump with a 15-inch impeller is running at 1170 RPM s, with pump efficiency of 75%, and is pumping 500 gpm with 75 feet of head. If the RPM of the pump is increased to 1750 RPMS calculate the following: New output in gpm: ------CORRECT ANSWER---------------1750 1770 =F = 1.5 500 x 1.5 = 750 gpm 750 New head in feet: 75 x 1.5 x 1.5 = 168.75 ------CORRECT ANSWER--------- ------170 New horsepower required: ------CORRECT ANSWER---------------750 x 170 - 43 3960 x 0.75 a. 43 What compound or compounds are formed when Cl, combines with water? ------CORRECT ANSWER---------------Both a and d 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 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---------------6.0 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 What are the dangerous gases a collection system worker might come into contact with? ------CORRECT ANSWER---------------CO2 CO НaS CH4 (all of the above) On a construction job site, equipment booms must maintain at least how many feet of clearance from overhead electric lines? ------CORRECT ANSWER---------------10 How should trench shoring be installed? ------CORRECT ANSWER----------- ----to above the top of the trench 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-------------- -the manhole is completely watertight and tested for no leakage As the population of a collection system increases, the ratio of peak flow to average daily flow will ------CORRECT ANSWER---------------decrease Motivating workers to do a better job is best done by ------CORRECT ANSWER---------------letting workers participate in setting goals One important element of a good communicator is ------CORRECT ANSWER---------------being a good listener Monitoring and reporting records of a wastewater treatment plant shall be kept at the facility site for a period of ------CORRECT ANSWER--------------- d. three years The TCEQ Design Criteria requires that deflection tests be performed on all new installed flexible or semi-rigid pipe after the final backfill has been in place for 30 days. This deflection test is usually performed using a rigid ball or mandrel that has a diameter equal to -percent of the inside diameter of the pipe. ------CORRECT ANSWER---------------c. 95 Seeding of BOD samples is necessary when samples ------CORRECT ANSWER---------------e. all of the above A one-cylinder reciprocating sludge pump with a 10-inch bore and a 5-inch stroke pumps at rate of 50 cycles per minute. How many minutes must the pump be operated to pump 5,000 gallons of sludge? ------CORRECT ANSWER---------------3.14 x0.416 x0.416 x0.416 x 50x7.48 = 84.5 gpm 5000 gal = 59.2min 84.5 gpm d. 60 minutes e. When is blue-green algae the most dominant on a pond treatment system? ------CORRECT ANSWER---------------Summer 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 15. 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 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=117.6 round to 118 A bubbler level control system works off of what principal? ------CORRECT ANSWER---------------differential pressure 67. 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 One of the requirements of the Texas Hazard Communication Act of 1985 is that the employer must hold annual training in which the utilities' written policies and the employee's rights are explained to ------CORRECT ANSWER---------------all employees 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 = 255,000 15 x1500 = 22,500 50x 250 = 12,500 255,000 + 22,500+ 12,500 = $290,000 2000 x 85 = 170,000 12x1500 - 18,000 30x250 =7,500 170,000 + 18,000 + 7,500 = S195,500 195,000/290000 =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 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 What are the hazards of using powered activated carbon? ------CORRECT ANSWER---------------a. fire/explosive b. inhalation c. uncomfortable working conditions Why is lime added to sludge? ------CORRECT ANSWER---------------to raise the pH and assist in pathogen reduction How often must a facility conduct a TCLP on its sludge if its sludge disposal is equal to or greater than 15,000 metric tons annually? ------CORRECT ANSWER---------------monthly If effluent is land applied for irrigation what tests must be run? ------ CORRECT ANSWER---------------CBOD and TSS pH and dissolved solids total nitrogen total phosphorous A cyclone grit separator operates on what principle? ------CORRECT ANSWER---------------centrifugal force Which temperature is more important to the operation of a trickling filter? --- ---CORRECT ANSWER---------------influent temperature What is the MCL for coliform? ------CORRECT ANSWER---------------per b. 1.0 per 100 mls 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