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4 based on 24-hour maximum design flows of 50, 000 GPD. With a calculated BODS loading of 171. 19 lbs BODS/day and a maximum daily BODS and a maximum daily BODS loading capacity of 108. 0 lbs, the aerated buffer tank will pretreat the incoming waste, thus lowering the BOD to a level less than 280 mg/L prior to its entering the main plant aeration chamber. The Bio-Pure process is not subject to upset by flow variations because a constant quantity waste is treated in each batch. For this project, the basic Bio-Pure 500EFO-1 has a hydraulic-flow oversize capacity of 4 , 900 gallons per day. Adding the 11, 655 gallon reserve (safety) capacity, which is designed into the aeration chamber, and the 4 , 900 gallon oversizing effectively gives the system an internal flow equalization and safety factor of 16, 555 gallons per day, which equals 36 . 71% of calculated daily flows, or 33 . 11% of system design flow capacity. Since the system feed pump is located near the bottom of the 20, 000 gallon front-end buffer tank, at least 18, 000 gallons of additional volume are available as flow-equalization capacity. Adding this 18 , 000 gallons to the above 16, 555 gallon safety factor raises the total reserve capacity to 34 , 555 gallons, or 76 . 62% of the calculated daily flows, or 69 . 11% of the system design flow capacity. Under normal sequence of operations, the collection system will deliver the wastewater from the generating facilities to the aerated buffer tank. From the buffer tank, the wastewater is lifted in the aeration chamber. Float controls are used to start and stop the system feed pump in the buffer tank. A major concern is to prevent wastewater from remaining in the buffer tank in an anaerobic state for a long period of time and it is for this reason that the buffer tank is aerated. Under maximum daily flow conditions, the system batch sequencing processes a batch from the aeration chamber at least once every 97 minutes, and the fill rate of the total reserve capacity during the twice-daily peak flows is, on average, less than 111 GPM. The maximum amount of incoming waste over the 97 minute batch in period would total 10, 777 gallons; subtracting that from the total reserve/safety capacity _ leaves a 23 , 778 gallon reserve capacity. Under peak flow conditions, the entire 201000 gallons (400 of daily flows) could be stored in the buffer tank should the aeration chamber be at its . maximum standby level . This arrangement assures that the system cannot overflow. The digestion process in the aeration chamber is carried out with the introduction of air into the incoming wastewater. The soluble material, oxidized material, settleable solids and suspended solids form a mixed liquor. Aeration. chamber residence time for the digestible materials a minimum of 16 hours of combined time and is dependent on the final system timing, which is based on effluent testing. This reduced mean-cell-retention-time is possible due to