**Assume that a waste contains 340.0 mg/L of biodegradable CH2O and is processed through a 200000.0 L/day sewage treatment plant which converts 40% of the waste to CO2 and H2O. Calculate the volume of air (at 25 degrees, 1 atm) required for this conversion. Assume that the O2 is transferred to the water with 20% efficiency**© BrainMass Inc. brainmass.com October 24, 2018, 5:50 pm ad1c9bdddf
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Waste water mass balance problem
BOD: Biochemical Oxygen Demand
BOD5 is the total amount of oxygen consumed by microorganisms during the first five days of biodegradation
BOD5 = (DOi - Dof)/(P) this is the five-day BOD of a diluted sample
Where DOi = the initial dissolved oxygen (DO) of the diluted wastewater
DOf = the final DO of the diluted wastewater, 5 days later
P = the dilution fraction = (volume of wastewater)/(volume of wastewater plus dilution water)
A standard BOD bottle holds 300 mL, so P is just the volume of wastewater divided by 300 mL
Consider a lake with 100 X 10^6 m^2 of surface area for which the only source of phosphorus is the effluent from a wastewater treatment plant. The effluent flow rate is 0.4 m^3/s and its phosphorus concentration is 10.0 mg/L (10.0 g/m^3). The lake is also fed by a stream having 20 m^3/s of flow with no phosphorus. If the phosphorus settling rate is estimated to be 10 m/yr, estimate the average phosphorus concentration in the lake. What level of phosphorus removal at the treatment plant would be required to keep the average lake concentration below 0.010 mg/L?