4. When the soluble BOD in the influent to the treatment plant rises from 133 mg/L to 222 mg/L, the operator called to ask your advice on a new MLVSS value for the plant. It has been operating with a F/M ratio of 0.31 mg/mg. d and the operator would like to continue using the same F/M. The plant data are as follows: aeration tank volume = 1270 m3;mixed liquor volatile suspended solids 2,600 mg/L.