Texas Wastewater A ( Test 2) Latest Update 2024-2025 250+ Questions and 100% Verified Correct Answers Guaranteed A+
- What type of wastewater treatment operates in the endogenous bacteria growth
phase? - CORRECT ANSWER: Extended air
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: 2.27
- 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
- The biomass on a normal functioning RBC has what appearance? - CORRECT
ANSWER: Grey to brown and 0.05 to 0.1 inch thick
- 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 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
57. The most common pump used in the collection system is - CORRECT ANSWER: d.
centrifugal
67. The major cause of wastewater line stoppages is - CORRECT ANSWER: roots and
grease
- One of the most important factors affecting the slope of a gravity wastewater line is
- CORRECT ANSWER: pipe bedding
A 24-inch wastewater interceptor is observed to be flowing half-full at 3 fps. The
approximate volume of wastewater flowing through the line is - CORRECT ANSWER:
3.14 x1x1x3 = 9.42 = cfs 9.42 x 449 = 4229.58 gpm 4229.58 = 2114.79 2,115 gpm
A 30 ml wastewater sample, is incubated 5 days at 20 degrees C. The DO before was 6.0 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
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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 bubbler level control system works off of what principal? - CORRECT ANSWER:
differential pressure
A chemical element is a - CORRECT ANSWER: atom
A collection system that averages 1.0 mgd or more must employ . - CORRECT
ANSWER: a. at least one Class III Collection operator or a Class B Wastewater
operator
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
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
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
A cyclone grit separator operates on what principle? - CORRECT ANSWER: centrifugal force
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
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.
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 2 / 3
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%
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 pneumatic ejector is - CORRECT ANSWER: a. a lift station pumping device
A predominance of filaments in an activated sludge plant indicates what? - CORRECT
ANSWER: low DO poor settling nutrient imbalance
a wastewater pipe has a slope of 4 feet in 200 feet, it is referred to as - CORRECT
ANSWER: c. 0.02 feet per foot d. two percent
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? - CORRECT 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
A"Racetrack" is what type of Activate Sludge treatment? - CORRECT ANSWER: Extended air
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
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
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
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