Mechanism And Effect Study Of Fenton And UV-Fenton Oxidation Of Sewage Sludge

In recent years, the productivity of municipal sewage sludge has a great increasein our country. Sludge treatment and disposal have become an important problem facedin the process of sewage treatment. Mechanism and effect of Fenton and UV-FentonOxidation of sewage sludge are studied in this paper. Main conclusions include:（1） In the process of sludge treatment with Fenton, the optimum conditions ofFenton experiment are: H2O2dosage=6g/L, Fe2+dosage=4g/L, initial pH3andreaction time=60min. SRF (Specific resistance to filtration) and MC (Moisture Contentof Filter Cake) decrease from7.05×109s2/g and83.19%to1.51×109s2/g and76.31%respectively, degree of reduction are78.58%and8.27%.（2） IntheprocessofsludgetreatmentwithUV-Fenton,theoptimumconditionsof UV-Fenton experiment are: H2O2dosage4g/L, Fe2+dosage2g/L, initial pH3,reaction time60min and UV radiation intensity8w. SRF and MC decrease from6.92×109s2/g and83.34%to0.75×109s2/g and76.07%respectively, degree ofreduction are89.16%and8.72%. UV can improves the efficiency of reaction andreduces SRF obviously.Meanwhile H2O2dosage drops more than half, Fe2+dosagedrops more than a third and reaction time reduces more than30min.（3） Sludge composition has an obvious change after treated by UV-Fenton.SCOD (Soluble COD) and SP (Soluble protein) can rise from32.0mg/L and12.3mg/Lto691mg/L to204.1mg/L respectively.（4）The maximum degree of sludge disintegration by UV-Fenton is11%. Andsludge disintegrating degree is positive index-related with sludge dewateringperformance improvement. In other words, sludge dewatering performanceimprovement is better when sludge disintegrating degree is bigger.（5）AquadraticpolynomialregressionmodelwassetbySRFR(SRFReduction),H2O2dosage, Fe2+dosage and initial pH.（6）RSM (Response Surface Methodology) analysis indicates that H2O2dosage,Fe2+dosage and UV intensity have significant impacts on SRFR. And the impact extentof H2O2dosage and Fe2+dosage are basically equal while which of UV intensity issmaller. Significant interactions exist not only between H2O2dosage and Fe2+dosagebut also between H2O2dosage and UV intensity. The more the H2O2dosage is, thebigger the impacts of Fe2+dosage and UV intensity are. When the initial pH is3and reaction time is60min, the optimum operating conditions of UV-Fenton Oxidation ofsludge are: H2O2dosage4.32g/L, Fe2+dosage2.21g/L and UV intensity8w. Thecorresponding SRFR is90.75%.