Answer:
(i) 5-day BOD of the waste is 120 mg/l.
(ii) The ultimate carbonaceous BOD (Lo) is 20 mg/l.
Explanation:
The dilution factor D is 0.05.
The initial DO is 8.0 mg/L and the DO after 5 days is 2.0 mg/L.
The BOD of the waste for an unseeded mixture is
[tex]BOD_5=(DO_5-DO_0)/D=(8-2)/0.05=6/0.05=120mg/l[/tex]
The ultimate carbonaceous BOD (Lo) can be calculated as
[tex]L = L_o*10 ^{- k_1t} \\L_o=L/10^{- k_1t}=2/10^{- 0.2*5}=2/10^{- 1}=2*10=20mg/l[/tex]
