Study On High-load Biological Treatment Of Acetone-phenol Wastewater

A three-phase biological fluidized bed reactor was used for the pretreatment ofacetone-phenol wastewater which contained high salinity and high chemical oxygendemangd(COD). The effects of influent concentration, hydraulic retention time(HRT) andmulti-stage treatment on pollutant removal were investigated. A coagulation-sedimentationmethod was developed for the removal of high suspended organics in the effluent of thefluidized bed reactor. The main conclusions were as follows.Microorganism acclimation for organic degradation at high salinity was achieved inabout one month with a conventional activated sludge seed from a petrochemical wastewatertreatment plant. Both influent organic concentration and reactor HRT had siginificant effecton effluent quality. The effluent COD of the reactor decreased to about400mg/L meetingnational Integrated Wastewater Discharge Standard （GB8978-1996） under followingconditions: influent COD of about2000mg/L, total disolved solid(TDS) of about50g/L,HRT=48h. The effluent suspended COD was200~250mg/L, which was a main part ofeffluent COD. Accoding to the results of GC-MS and fluorescence excitation-emission matrix,aromatic organics were removed effectively by the reactor. According to the results ofscanning electronic microscope, biofilm attached on modified polyurethane biomass carrierswas good. The microorganisms in the biofilms were dominated by bacters.Coagulation-sedimentation method was used for the further treatment of the effluent ofthree-phase fluidized bed reactor. Aluminum sulfate(Al2(SO4)3) and aninic poly acrylamide(APAM) were found to suitable coagulant and flocculation aid for the removal of suspendedorganics。Under optimized conditions(pH7, Al2(SO4)3dosage of250mg/L， APAM dosage of30mg/L, coagulation mixing rate of300r/min for2min, flocculation mixing rate of50r/minfor5min), effluent COD after coagulation-sedimentation was below150mg/L， wheninfluent COD was400mg/L.