THE EFFECT OF FILL MODE ON THE PERFORMANCE OF SEQUENCING-BATCH REACTORS TREATING VARIOUS WASTE-WATER

The performance of sequencing-batch reactors (SBRs) for the treatment of three kinds of wastewater (synthetic phenolic wastewater; synthetic wastewater containing polyvinyl alcohol (PVA), and effluent from a co ke-plant-wastewater treatment system) was investigated. Under low-stre ngth phenol conditions, the performance of the SBR with unaerated fill was superior to the SBR with aerated fill in which filamentous bacter ia developed. However at high influent phenol concentrations, the SBR with unaerated fill accumulated phenol during the fill period to conce ntrations inhibitory to microorganisms. Fill mode had no significant i nfluence on the performance of SBRs treating PVA-containing wastewater For the SBRs treating the effluent from a coke-plant-wastewater treat ment system, fill mode had no significant impact on the performance of SBRs with respect to organic carbon removal and sludge settleability; but an operating mode which incorporated two anoxic periods, one ahea d of the aeration and one after the aeration, was better than other op erating modes in terms of nitrogen removal. Copyright (C) 1996 Elsevie r Science Ltd.