Philadelphia Pilots—Builds Oxygen Activated Sludge

The 13-month pilot program was conducted to establish sound design criteria for the City's expanded plants. Analyses of the testing program is broken down into the program of study and presentation of results. The testing program included such variables as waste source, organic loading, oxygenation time, and diurnal flow. Results cover oxygen consumption, excess sludge production, sludge settleability, and organic removals as a function of organic loadings. An economic comparison between conventional air and oxygen activated sludge is presented. From these results specific design criteria are developed in a step-wise fashion. Criteria include mixed liquor suspended solids level, reactor detention time, oxygen required, in tons per day, F/M, percentage of return sludge, and excess sludge production. Specific design criteria are then converted into preliminary plans.