<span;>The Only source of BOD in a river is untreated wastes that are being discharge from a food processing plant. The characteristics of untreated waste is not reported for the environmental protection agency of the town . To identify the waste water property from the processing plant the authority measured the DO of the river at 10km and 40km away from the plant and found 5mg/l and 2.5mg/l respectively. The average flow rate of the river is 0.25m/s and average depth is 4.5m with bed activity coefficient of 0.2.assume saturation DO 10mg/l
<span;>Parameter river waste water
<span;>Flow,m3/s 0.7 0.23
<span;>BOD @ 18°C 2.5 N/A
<span;>DO, mg /l 8 N/A
<span;>Temperature 20 20
<span;>K @ 20°c - 0.23
<span;>a. What is the DO and BOD of the untreated waste form the processing plant?
<span;>b. What is the critical DO and where downstream does it occur?
<span;>c. If the state requirement for minimum DO is 2mg/l is assimilative of the river restricted or not ?