A domestic wastewater with BOD5 of 205 mg/L is treated by a secondary treatment plant that removes 85% of the BOD. You are to run a five-day BOD test with a standard 300-ml bottle on the treated sewage without seed. Assume the initial DO is 9.2 mg/L. (a) What maximum volume of treated sewage should you put in the bottle if you want to have at least 2.0 mg/L of DO at the end of the test (filling the rest of the bottle with water)? (b) If you make the mixture half water and half treated sewage, what DO would you expect after five days?
please explain while solving
Given:- BOD5= 205 mg/L, the Secondary Treatment Plant removes 85% of BOD.
Initial Do (Doi) =9.2 mg/L, (Dof) Final DO= 2mg/L,
Biological Oxygen Demand (BOD) is a measure of the amount of dissolved oxygen consumed by microorganisms in the process of breaking down organic matter in water. BOD is an important indicator of water quality and is used to determine the amount of organic pollution in water.
The BOD test involves adding a measured amount of oxygen to a water sample and then measuring the amount of oxygen remaining after a certain period of time, usually five days. The difference between the initial and final oxygen levels is a measure of the amount of oxygen consumed by microorganisms during that time period, and is reported as the BOD value.
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