A 500 bed hospital has a small activated sludge plant to treat its wastewater. The average daily hospital discharge is 1,500 L per day per bed, and the average soluble

BOD5 after primary settling is 500 mg/L. The aeration tank has effective liquid dimensions of 10 m wide by 10 m long by 4.5 m deep. The MLVSS for the plant is 2,500 mg/L. Determine the following: aeration period; F/M ratio.5.