Texas Wastewater Class A Exam with Questions and Answers

Texas Wastewater Class A Exam with Questions and Answers 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