Question

10. Consider a lake with 10 m' of surface area for which the only source of phosphorus is the effluent from a wastewater treatment plant. The effluent flow rate is 0.4 m/s, and its phosphorus concentration is 10 mg/L. The lake is also fed by a stream have 20 m/s flow with no phosphorus. If the phosphorus settling rate is estimated to be 10 m/yr, estimate the average phosphorus concentration is the lake. What level of phosphorus removal at the treatment plant would be required to keep the average lake concentration below 0.01 mg/L phosphorus?

Answer 1

data- Surface area of the lake A 108 m2 - Efflunt flow rate 2 0.4m/ Concentration of phosphorous Cin= 10.00 lm3 phosphorous settling rate Vs 10mlys. Calculate the concentration of phosphorous in the lako by using the following formula! c = Qcints QtVs A = 0.um/ x 10g P/m3 20.4 m3/s + Tomlys x 108m2 7 3,600s/hrX24 hr/dx 365d/ds = 0.077 g/m3 C = 0.077 mg/L So, the average phosphorous concentration in He lake is 0,77 nghe Calculate the level of Phosphorow removal at the treeatment Planto as Pollow): – To keep phosphorous at less than 0.010 mg/l sowne want = c Want Source have chave Diolo mal L = 0.13 0.0fting/L

input The needs to be reduced by phosphouous 1 - 013 Therefore, the phosphorous removal is 1872)