Assuming that in all the following scenarios the MLSS concentrations in the comp
ID: 83487 • Letter: A
Question
Assuming that in all the following scenarios the MLSS concentrations in the completely-mixed aeration tank remains the same at 3500 mg/L. Indicate whether the following
changes in wastewater characteristics or operation require an increase, decrease or no change in the aeration tank volume required. Explain your answer. For the base case, no nitrification is occurring, the influent BOD and TKN are at 500 and 35 mg/L, respectively. The SRT is at 6 days and the temperature is at 20 oC. Treat each of the following scenarios independently.
(a) Influent BOD concentration increases by 50%.
(b) Influent non-biodegradable VSS concentration increases by 30%.
(c) The influent wastewater flow rate decreases by 40%.
(d) Nitrification is required now and the effluent ammonia concentration design goal is changed to 0.5 mg N/L.
(e) The average ambient temperature decreases to 10 oC in the winter.
Explanation / Answer
MLSS mixed liquor solid substances concentration of suspended solid particles in aeration tank during activated sludge process during waste water treatment. MLSS is an important part of the activated sludge process to ensure that there is a sufficient quantity of active biomass available to consume the applied quantity of organic pollutant at any time. This is known as the food to microorganism.