Daily Question 2015.10.8 (EIA Discussion): 3 Wealth points for replies, plus 5 Wealth points for correct answers (single-choice question)
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This post was last edited by Zhang Xiaopeng on 2015-10-8 at 10:27. On the opposite side of the discharge outlet for a proposed project, there is already an existing discharge outlet with a sewage discharge volume of 36,000 tons per day, and a COD discharge concentration of 100 mg/L. The design flow rate during the dry season in the upper reaches of the river is 10 m3/s, and the background COD concentration is 15 mg/L. The design wastewater volume for this project is 100,000 t/d, with a COD discharge concentration of 50 mg/L. The initial COD concentration at the discharge point, as calculated using a **single-state water quality model, is ( ). A. 21.56 mg/L B. 24.95 mg/L C. 42.80 mg/L D. 55.00 mg/L Correct answer: A. Explanation: (864000*15*10^3 + 36000*100*10^3 + 100000*50*10^3) / (864000*10^3 + 36000*10^3 + 100000*10^3) = 21.56 mg/L
On the opposite side of the discharge outlet for a proposed project, there is already an existing discharge outlet with a sewage discharge volume of 36,000 tons per day, and a COD discharge concentration of 100 mg/L. The design flow rate during the dry season in the upper reaches of the river is 10 m3/s, and the background COD concentration is 15 mg/L. The design wastewater volume for this project is 100,000 t/d, with a COD discharge concentration of 50 mg/L. Then, the initial COD concentration at the discharge point, as calculated using a **single-state water quality model, is (A) A、21.56 mg/L B、24.95 mg/L C、42.80 mg/L D、55.00 mg/L
The answer is A. Explanation: (3.6×100 + 86.4×15 + 10.0×50) ÷ (3.6 + 86.4 + 10.0) = 21.56. The units need to be standardized; the key to solving this problem is to convert the design flow rate during the dry season upstream from 10 m3/s to 86.4 t/d.
On the opposite side of the discharge outlet for the proposed project, there is currently another discharge outlet with a sewage discharge volume of 36,000 tons per day, and a COD discharge concentration of 100 mg/L. The design flow rate during the dry season in the upper reaches of the river is 10 m3/s, and the background COD concentration is 15 mg/L. The design wastewater volume for this project is 100,000 t/d, with a COD discharge concentration of 50 mg/L. Then, the initial COD concentration at the discharge section calculated using a **-state water quality model is (A)
Option A, 21.56~~~~~~~~~~~~~
On the opposite side of the discharge outlet for a proposed project, there is already an existing discharge outlet with a sewage discharge volume of 36,000 tons per day, and a COD discharge concentration of 100 mg/L. The design flow rate during the dry season in the upper reaches of the river is 10 m3/s, and the background COD concentration is 15 mg/L. The design wastewater volume for this project is 100,000 t/d, with a COD discharge concentration of 50 mg/L. Then, the initial COD concentration at the discharge point, as calculated using a **single-state water quality model, is (A) A. 21.56 mg/L B. 24.95 mg/L C. 42.80 mg/L D. 55.00 mg/L
On the opposite side of the discharge outlet for a proposed project, there is already an existing discharge outlet with a sewage discharge volume of 36,000 tons per day, and a COD discharge concentration of 100 mg/L. The design flow rate during the dry season in the upper reaches of the river is 10 m3/s, and the background COD concentration is 15 mg/L. The design wastewater volume for this project is 100,000 t/d, with a COD discharge concentration of 50 mg/L. Then, the initial COD concentration at the discharge point, as calculated using a **single-state water quality model, is ( ). A. 21.56 mg/L
A、21.56mg/L
On the opposite side of the discharge outlet for a proposed project, there is already an existing discharge outlet with a sewage discharge volume of 36,000 tons per day, and a COD discharge concentration of 100 mg/L. The design flow rate during the dry season in the upper reaches of the river is 10 m3/s, and the background COD concentration is 15 mg/L. The design wastewater volume for this project is 100,000 t/d, with a COD discharge concentration of 50 mg/L. Then, the initial COD concentration at the discharge section calculated using a **-state water quality model is (A)