Study On Advanced Treatment Of Chemical Mechanical Pulping Wastewater By Ozonation/Catalytic Ozonation

Chemical mechanical pulping wastewater had become the focus of attentionbecause of its composite complexity，large production and seirous pollution. It wasdifficult to achieve emission standards after treatment by traditional physical，biological methods due to some of its technical limitations. Recently ozonation/catalytic ozonation technology get developed because of normal temperature andpressure operation condition, no secondary pollution and simple ozone gas treatmentprocess. The degradation of single ozonation, ozone/activated carbon and FeMn-ACcatalysts were studied in this paper by self-made ozone reactor. The chemicalmechanical pulping wastewater and coagulant pre-treated water were selected aspollutants. The chemical mechanical pulping wastewater ozonation results showedthat the removal of COD would increase along with the amount of ozone input; Theinfluence of temperature, pH and the doses of H2O2overthe removal of COD wassmall. The removal of COD would increase along with moderate amount of AC，whereas excessive dosage would cause the negative influence. The optimal removaleffect came on the condition of lg/L. AC adsorption had little influence on theremoval rate of COD. Powdered AC was more active than granular AC. pH hadobvious influence on the removal of COD. The removal effect of COD increased withhigher pH. Powdered activated carbon and FeMn-AC catalysts were prepared byimpregnation method from manganese nitrate and ferric nitrate. Compared with initialAC，the Hpzc ofFeMn-AC catalysts was lower； The specific surface and total porevolume decreased，but the average pore size increased; The results of XRD showedthat the FeMn-AC catalysts were all undefined structure. The results of XPS indicatedthat the speciation of Fe might be Fe2C>3、Fe304and FeOOH，and the speciation of Mnmight be M112O3and Mn304.Experiment showed that the catalyst were more activewhen the ratio of Fe and Mn was1:1and1:2, as there were acid pHpzc，larger loadings，Fe304and FeOOH with good activityTh. e results showed that the degradation ofpollutants by the three systems above followed the pseudo first-order kinetics. Theactive rates between the first15min(20min) and the last time are different, for the ozonation and AC catalytic ozonation system. The effect of color degradation：ozonation>AC catalytic ozonation>F eMn-AC catalytic ozonation； mineralizationeffect： FeMn-AC catalytic ozonation〉AC catalytic ozonation>ozonation;Biodegradability： FeMn-AC catalytic ozonation〉AC catalytic ozonation>ozonation.The results of the molecular weight distirbution in treated wastewater atferdegradation showed the treatment effect of FeMn-AC catalytic ozonation waseffective. There was a large proportion of small molecular; The chemical mechanicalpulping wastewater before and atfer three ozonation reaction was proved by GC-MSanalysis that its organic compounds are relative complex，the detected organiccompounds were PAEs and long chain normal parafifn. Atfer ozonation process，mostof the organic species and content in chemical mechanical pulping wastewater werereduced.