Answers:
a) BOD5 = UBOD * ( 1 - e^(-k*t))
17.5 = 92*( 1 - e^(-k*5)
k = 0.042 day^-1
b) UBOD = (Q1*UBOD1 + Q2*UBOD2) / (Q1 + Q2)
1 MGD = 0.043813 m3/s
150 MGD = 0.043813 * 150 m3/s
UBOD =( 0.043813 * 150 * 92 + 250*6 ) / (0.043813 * 150 + 250)
= 8.2 mg/L
DO = ( 0.043813 * 150 * 0.2 + 250*4.5 ) / (0.043813 * 150 + 250)
= 4.39 mg/L
deficit = DOsat - DO
critical travel time = Tc = 4.32 * 1000 / 0.25
= 17280 s
= 0.2
critical deficit = Dt =( kd * UBOD / (ks - kd)) * [ e^(-kd*t) - e^(ks*t) ] + [ Da*e^-ks*t]
assuming initial deficit Da = 0
Dt = ( 0.3 * 8.2 / (0.5 - 0.3)) * [ e^(-0.3*0.2) - e^(0.5*0.2) ]
=- 2 mg/L + Da
The East Hartford WWTP discharges 150 MGD of treated wastewater into the CT river. The treated was tested in the lab and found to have aBOD5 of 17.5 mg/L and an ultimate BOD (Lo) of 92 mg/L at 20oC....
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