| Ciprofloxacin is a broad-spectrum antibacterial drugs developed at home and abroad in recent years,and in its production process produce a large number of organic wastewater.Ciprofloxacin wastewater contains high concentration of organic matter,such as antibiotic end product and pharmaceutical intermediates.it has high inhibitory capacity and difficult to biodegrade,wich is hazard to enter the water.Therefore, the investigation of treatment technology on ciprofloxacin wastewater is very urgent and necessary.This paper aimed to study the degradation effect of ciprofloxacin wastewater treatment with combining pretreatment and biochemical technology. With a series of experimental researches carried out, the route and appropriate conditions of process for ciprofloxacin wastewater treatment were preliminarily proved, which would provide theoretical basis and practical guidance for practical engineering design and application.During the investigation for ciprofloxacin wastewater by Fenton oxidation,we mainly studied the effect of dosage of H2O2.initial pH value and Fe2+/H2O2molar ratio,reaction time,carrier gas,feeding number on COD removal.After Fenton reagent oxidation treatment,some refractory organic macromolecular in the wastewater is removed,and the biodegradability of wastewater is improved significantly, which increases from0.08to0.28, reducing the difficulty of treatment on ciprofloxacin wastewater.The results of cipofloxacin wastewater treatment by Fenton oxidation show that,the best dosage of H2O2is15mmol/L,the optimum wastewater’s initial pH value is3.0,the best Fe2+/H2O2molar ratio in the reaction is1:10,the best reaction time is2h,the carrier gas is air,the feeding number is3,and the influent load is6972mg/L.After Fenton oxidation pretreatment,the effluent COD concentration is between5300mg/L and5400mg/L,the removal rate of COD is22.6%.To further improve the biodegradability of wastewater,hydrolysis acidification is use to pretreated cipofloxacin wastewater,and mainly studied the effect of initial pH and hydraulic retention time on the treatment.After hydrolysis acidification,the generation of VFAs in the wastewater is815mg/L,the B/C increases from0.28to0.35,and the biodegradability is improved greatly.lt was found that at pH6.5, the hydrolysis efficiency was upmost, and the VFAs production could reach627mg/L accompanying with11.7%acidification degree and. At HRT12h, the hydrolysis efficiency was optimum, and B/C was improved from0.28to0.35accompanying with815mg/L of VFAs,15.3%acidification degree and12%of COD removal, which were very benefit for the latter biological treatment.To further deal with this high-concentration wastewater,SBR system was used in the further biological treatment for cipofloxacin wastewater which was pretreated by Fenton oxidation,and the COD concentration of the wastewater is decreased rapidly.We mainly studied the effect of the SBR operation cycle,initial pH value,hydraulic retention time on the COD removal,also investigated the COD variation in one cycle after the SBR stable operation.In the research,it was found that the effect of SBR system running was best when the pH of influent was7.0;the best hydraulic retention time of process system was24h, containing0.5h of influent,22h of reaction,1h of precipitation,0.5h of effluent.The effluent COD concentration is about450mg/L,but it is instable because of the water-intermittent SBR system,sometimes above500mg/L which can’t reach the emission standards of the’Integated wastewater discharge’(GB8976-1996).Therefore.activated carbon adsorption process is used to aid processing the effluent water of the SBR system,and the optimum processing conditions through the experiments is that the activated carbon best dosage is300mg/L,best contact time is1.5h.the best reaction temperature is25℃,then the effluent COD concentration of the ciprofloxacin wastewater is388mg/L,which can be able to discharge. |
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