Texas Wastewater Class A Exam {2024} Questions with Complete Solutions, Exams of Physics

Download Texas Wastewater Class A Exam {2024} Questions with Complete Solutions and more Exams Physics in PDF only on Docsity! Texas Wastewater Class A Exam {2024} Questions with Complete Solutions Seeding of BOD samples is necessary when samples - 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? - 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 - 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 - 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 - Answer - 95 percent When must TCEQ be notified about expansions of a treatment facility? - Answer - Before construction In an anaerobic digester, the percentage of methane and carbon dioxide gas content should be - Answer - 70% methane, 30% carbon dioxide The temperature of an anaerobic digester should be maintained at a minimum of - Answer - 95° F What type of wastewater treatment operates in the endogenous bacteria growth phase? - Answer - Extended air the pipe. - Answer - c. 95 Seeding of BOD samples is necessary when samples - 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? - 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? - Answer - Summer What is the purpose of biomonitoring of a plant's effluent? - Answer - d. Test for toxicity Technology The management function of selecting and training employees of an organization is called - Answer - staffing e. controlling When must TCEQ be notified about expansions of a treatment facility? - Answer - Before construction In an anaerobic digester, the percentage of methane and carbon dioxide gas content should be - Answer - b. 70% methane, 30% carbon dioxide The temperature of an anaerobic digester should be maintained at a minimum of - Answer - 95° F 13. What type of wastewater treatment operates in the endogenous bacteria growth phase? - Answer - Extended air Why is recirculation needed in a trickling filter? - 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? - Answer - f. a class a and d class c Disinfection with chlorine is the most effective at a pH of - Answer - 6.0 17. The biomass on a normal functioning RBC has what appearance? - Answer - Grey to brown and 0.05 to 0.1 inch thick The sludge from a primary clarifier should contain what percent solids? - Answer - b. 4% to 6% What is eutrophication in a pond system? - Answer - Enrichment with nitrogen and phosphorous Causes algae blooms 20. 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 What is the standard chlorine residual and contact time on Texas discharge permits? - Answer - e. None of the above organization increases, As the complexity of an organization increases, what management function becomes most important? - 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: - 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 - Answer - 170 New horsepower required: - Answer - 750 x 170 - 43 3960 x 0.75 a. 43 What compound or compounds are formed when Cl, combines with water? - Answer - Both a and d When chlorinating treated wastewater, what chlorine residual do we test for? - Answer - Chloramine and Total What is the standard pH range on Texas effluent discharge permits? - Answer - b. 6.0 to 9.0 A wastewater treatment plant has a clarifier that is 80 feet in diameter and is 12 feet deep. The flow is 2.5 mgd. The single weir is two feet inside the outer wall and is 3 feet deep. What is the clarifier detention time in hours? - Answer - What is the clarifier detention time in hours? 2,500,000 gpd - 104,167 gph 24 hrs/day 3.14 x 40 x 40 x 9 x 7.48 gal 3.14 x 36 x 36 x 3 x 7.48 = 91,318 338,216 + 91,318 429,534 gallons 429,534 gals = 4.1 hrs 104,167 gph 4.1 What is the hydraulic loading on the clarifier in gal/sq ft/day? - Answer - 3.14 x 38 x 38 = 4,534 sq ft 2,500,000 gpd = 551 gal / sq ft I day 4,534 sq ft 551 What is the weir loading in gal/linear ft/day? 3.14 x 76 = 239 ft of weir 2,500,000 gpd = 10,460 gal / lin ft / day 239 ft weir - Answer - 10,460 In Texas, an oxidation ditch treatment plant is referred to as - Answer - Racetrack In Texas, pH meters are required to be calibrated on how many buffers? - Answer - two An industrial complex has a BOD discharge to the POTW of 500 pounds per population equivalent of this industry is - Answer - 500 lbs - 2,941 0.17 lbs BOD/ person 2941 What substance will interfere with a DPD chlorine test? - Answer - Manganese The parameters of the BOD test are - Answer - 5 days at 20° Centigrade An Imhoff tank is what type of treatment process? - Answer - Primary Standard Dimension Ratio in pve pipe is defined as - 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? - Answer - c. 30 A pneumatic ejector is - Answer - a. a lift station pumping device How should shoring be removed from a trench? - Answer - d. from the bottom up 57. The most common pump used in the collection system is - 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 - Answer - Part of the collection system and the responsibility of the utility Effective communication depends on - Answer - being a good listener A construction site safety evaluation checklist must include - 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? - 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 - Answer - 150 The minimum velocity of flow in a wastewater line should be - Answer - 2.0 fps At a construction job site, as the roadway speed increases, the spacing barricades should - 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? - Answer - 5x5x0.0408x0.833x60 = 51 gpm 6,000 gal/51 gpm=117.6 round to 118 Septic wastewater has what properties? - Answer - a. dark in color b. offensive odor e. Jacks dissolved oxygen d. is harder treat than fresh wastewater e. all of the above 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 - Answer - all employees The Federal Clean Water Act - 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 - 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 - 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 - 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 - 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 - 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, - 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 - Answer - 185 gpm H,SO, is a(n). - 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 - Answer - 0.02 fps A chemical element is a - Answer - atom Chemical dechlorination can be accomplished with? - 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? - 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 - Answer - 12 How would an operator increase the degree nitrification in an activated sludge plant? - Answer - increase D0 and increase sludge age What processes are used to check an upset activated sludge plant? - Answer - BOD loadings, F/M ratio, SV 30, MCRT, DO When chlorine used, the effective disinfectant is - Answer - HOCI Aerobic digestion is a(n) process. - Answer - endogenous Distilled water used for the BOD analysis should not exceed mg/L oxygen depletion. - Answer - 0.2 Chlorine disinfects the best at - Answer - low pH The inside diameter of a manhole must be at least wide. - Answer - 48 inches What does biomonitoring test for? - Answer - effluent toxicity Why is recirculation needed in a trickling filter plant? - Answer - a. to keep the zoogleal mass wet during low flow periods b. to assist in flooding the filters and to increase sloughing The sludge from a primary clarifier should contain what percent solids? - Answer - 4% to 6% The Federal Clean Water Act: - Answer - a, requires a permit for disposal of sludge b. requires a permit for ocean discharges of wastewater c. requires a permit for disposal of dredge material d. creates a national permit system for all wastewater The effectiveness of an activated sludge process depends on? - Answer - amount of activated solids in the system type and health of organisms in the solids acration basin detention time influent characteristics A predominance of filaments in an activated sludge plant indicates what? - Answer - low DO poor settling nutrient imbalance What is dissolved air floatation in a wastewater plant usually used for? - Answer - grease removal What are the hazards of using powered activated carbon? - Answer - a. fire/explosive b. inhalation c. uncomfortable working conditions Why is lime added to sludge? - 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? - Answer - monthly If effluent is land applied for irrigation what tests must be run? - Answer - CBOD and TSS pH and dissolved solids total nitrogen total phosphorous A cyclone grit separator operates on what principle? - Answer - centrifugal force