FIELD TESTS AND PHYSICAL MODELING OF THE SACRAMENTO WWTP

The wastewater treatment plant for Sacramento uses high purity oxygen for biological treatment. The Oxidation Tanks (OT) operate under a small positive pressure of 2–4 inches of water. The plant has 12 OTs with 8 located on the south side of the RAS channel and 4 on the north side (see Figures 1 and 2). The tanks are nearly identical with the inflow regulated by fixed finger weirs with nearly the same crest elevations. The main difference in the finger weir arrangements is that the south finger weir chambers are separated from the Stage 1 of the OTs by a curtain wall partition that extends from the roof to below the water line; these partitions do not exist at the north finger weirs (see Figures 3). The most important hydraulic different between the north and the south is that the MLSS from the north passes over a large hump in the West MLSS channel. The plant operators have reported difficulty in balancing the flow amongst the north and south OTs with disproportionately higher flow than the north OTs. This paper will present the major findings from the model studies.