Q4) A town of discharges 15,000 m'd of treated wastewater into a Creck. The treated wastewater has The treated wastewater has a BOD, of 10 mg/L and a ko of 0.12 d'. The creek has a flow rate of 0.6 m's and an ultimate BOD of 6 mg/L. The DO of the creek is 7 mg/L and the DO of the waste water is 1 mg/L. The creek has the temperature of 7 °C while the wastewater has a temperature of 20 °C. The creek stream flows at 0.03 m/s average speed. The depth of the creek water is 5 m and the bed-activity coefficient is 0.3. 1) Determine the water temperature after the creek and wastewater mix. 2) Calculate the critical DO and the distance downstream at which it occurs Q4) A town of discharges 15,000 m'd of treated wastewater into a Creck. The treated wastewater has The treated wastewater has a BOD, of 10 mg/L and a ko of 0.12 d'. The creek has a flow rate of 0.6 m's and an ultimate BOD of 6 mg/L. The DO of the creek is 7 mg/L and the DO of the waste water is 1 mg/L. The creek has the temperature of 7 °C while the wastewater has a temperature of 20 °C. The creek stream flows at 0.03 m/s average speed. The depth of the creek water is 5 m and the bed-activity coefficient is 0.3. 1) Determine the water temperature after the creek and wastewater mix. 2) Calculate the critical DO and the distance downstream at which it occurs