Q - If the average sewage from a city is 40×106 l/day and the average 5-day BOD is 200 mg/l against a standard of 80 mg/day per capita at 20°C, then what will be the population equivalent of the city.

An industry generates 4 million gallons per day (MGD) (that is 15,000 m^3/ day) of liquid industrial wastewater having BOD5 of 1000 mg/L and first order reaction rate constant of 2.0/day. Because of the high BOD, there is a plan to build an industrial pre-treatment system at an industrial park. Effluent from the pre-treatment will be discharged into the city sewer for final polishing at the city wastewater treatment plant.  Determine: a. Percent BOD removal if the wastewater is treated in one 5000 m^3 continous flow stirred tank reactor. b. Percent BOD removal if the wastewater is treated in one 5000 m^3 plug flow reactor. c. Percent BOD removal if the wastewater is treated in one 2500 m^3 continous flow stirred tank reactor followed by one 2500 m^3 plug flow reactor. d. Percent BOD removal if the wastewater is treated in one 2500 m^3 plug flow reactor followed by one 2500 m^3 continous flow stirred tank reactor. e. Percent BOD removal if the wastewater is treated in one 2500 m^3…

The density of water at 4°C is 1000 kg/m3 at atmosphericpressure. The gravity acceleration constant (g) is 9.81 m/s2. Thespecific gravity of an industrial wastewater (SGww) is 1.32. Whatis the specific weight of this wastewater?

A city of 20,000 people disposes of 1.05 m3/s of treated sewage that still has an ultimate BOD of 28.0 mg/L and 1.8 mg/L DO into a river.  Upstream from the outfall, the river has a flow rate of 7.08 m3/s and a velocity of 0.37 m/s.  At this point, the ultimate BOD and the DO in the river are 3.6 and 7.6 mg/L, respectively.  The saturation value of DO (at the temperature of the river) is 8.5 mg/L.  The deoxygenation coefficient is 0.61/day, and the reaeration coefficient is 0.76/day.  Assume complete mixing and the velocity in the river is the same upstream and downstream of the outfall.  What is the oxygen deficit and the ultimate BOD just downstream from the outfall (just after mixing, before any reaction can occur)?