Reaearch On The Removal Of PPCPs By Coupled SBR And O2xone/Co²⁺ Oxidation Technology

Pharmaceuticals and personal care products（PPCPs） in the environment is a potential hazard to humanhealth and ecological environment, but conventional sewage treatment process can not completely removethem.SBR can effectively remove organic pollutant, and Oxone/Co²⁺oxidation process has a feature of fastand good removal effects of recalcitrant pollutants, so it is meaningful to unite them for the degradation ofPPCPs.This research objects are the widely used antibiotics:metronidazole and ofloxacin.SBR associatewith Oxone/Co²⁺oxidation are applied to treat simulated wastewater with metronidazole and ofloxacin andtheir mixture, and operating conditions and the satisfactory results were achieved.This research provide atheoretical basis for the removal of PPCPs in wastewater by coupled activated sludge process and advancedoxidation technology. The results show that:1: Removal of metronidazole by SBR and Oxone/Co²⁺advanced oxidation technology:（1）The degradation of metronidazole wastewater by SBR: The conditons were:influent concentrationof about4mg/L,the sludge concentration of4000mg/L,nitrifying bacteria existed in the sludge,the reactioncycle of12h（including water5min,4h aerobic,2h aeration,the aerobic3h,2h non-aeration,50minprecipitation and the5min effluent）,hydraulic retention time of2d,no sludge exhausted during the wholeexperiment.After more than three months,the removal rate of metronidazole was about41%.The adsorptionprocess existed.The degradation products had non-toxic to the microorganisms in the reactor.（2）Oxone/Co²⁺oxidation treated SBR effluents:at room temperature, the optimum conditions:pH=5.0,[Co²⁺]=0.015mmol/L,[Oxone]=1.5mmol/L, metronidazole can be completely removed in30min.Metronidazole removal efficiency increased and then reduced with increased pH value, the concentration ofthe oxidant Oxone concentration and catalyst of Co²⁺had threshold for metronidazole removal efficiency.2: Removal of ofloxacin by SBR and Oxone/Co²⁺advanced oxidation technology:（1）The degradation of ofloxacin wastewater by SBR:The conditons were:influent concentration ofabout10.9mg/L,the sludge concentration of4000mg/L,nitrifying bacteria existed in the sludge,the reactioncycle of12h（including water5min,4h aerobic,2h aeration,the aerobic3h,2h non-aeration,50minprecipitation and the5min effluent）,hydraulic retention time of2d,no sludge exhausted during the whole experiment.After more than three months,the removal effect of ofloxacin was about49%, and theadsorption process existed. The degradation products had non-toxic to the microorganisms in the reactor.（2）Oxone/Co²⁺oxidation treated SBR effluents:at room temperature,the optimum conditions: PH=6.0,[Co²⁺]=0.003mmol/L,[Oxone]=1.2mmol/L,ofloxacin can be completely removed in30min.Ofloxacinremoval efficiency increased and then reduced with increased pH value, the concentration of the oxidantOxone concentration and catalyst of Co²⁺had threshold for ofloxacin removal efficiency.3: Removal of metronidazole and ofloxacin by SBR and Oxone/Co²⁺advanced oxidation technology:（1）The degradation of metronidazole and ofloxacin wastewater by SBR:The conditons were:influentconcentration of metronidazole （about5mg/L） and ofloxacin（about10.5mg/L）,the sludge concentration of4000mg/L,nitrifying bacteria existed in the sludge,the reaction cycle of12h（including water5min,4haerobic,2h aeration,the aerobic3h,2h non-aeration,50min precipitation and the5min effluent）,hydraulicretention time of2d,no sludge exhausted during the whole experiment.In the presence of nitrifyingbacteria.After more than three months,the removal effect of metronidazole and ofloxacin was about42%and49%.But their removal effects had not much difference with their single presence.（2） Oxone/Co²⁺oxidation treated SBR effluents:at room temperature,pH=6.0,[Co²⁺]=0.003mmol/L,[Oxone]=1.2mmol/L, metronidazole and ofloxacin can be completely removed in30min.