Exam

for water quality management in environmental engineering

 

1. 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

1. 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

Parameter            river     waste water  

Flow,m3/s         0.7            0.23

BOD @ 18°C        2.5           N/A

DO, mg /l             8             N/A

Temperature       20            20

K @ 20°c             -                  0.23

a. What is the DO and BOD of the untreated waste form the processing plant? 

b. What is the critical DO and where downstream does it occur?

c. If the state requirement for minimum DO is 2mg/l is assimilative of the river restricted or not ?

<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 ?