Study On The Advanced Treatment Technology For High Concentrations Resin Wastewater

Advanced treatment technology, including pretreatment and anaerobic treatment for high concentration of resin water, was investigated in this study. Containing high concentration of refractory organics, resin wastewater should be pretreated firstly with physical and chemical methods, Firstly, an appropriate pretreatment method was adopted for further study after comparing with different methods. Secondly, pretreatment conditions were optimized using response surface analysis (RSA) methodology. Finally, pretreated resin wastewater was further treated anaerobically, especially the substrate stress on anaerobic sludge, and the usage of co-substrate of glucose.The major findings in this study were as follows:1). Firstly, four different pretreatment methods as coagulation, iron-carbon micro-electrolysis, Fenton oxidation and TiO₂ photocatalysis oxidation were compared. The removal rate of COD and phenol reached 32% and 16%, respectively, using coagulation with PAC as coagulant and PAM as flocculant. When mass ratio of iron-carbon in 1:1 and reaction time as 3 h, the removal rate of COD and phenol reached 30% and 16% respectively, with iron-carbon micro-electrolysis method, which was similar to that of the coagulation. While resin wastewater could be pretreated efficiently using Fenton oxidation as the removal rate of COD and phenol reached 60.2% and 55.6% and the B/C ratio reached 0.60, respectively.2). TiO₂ photocatalysis had been widely used as a convenient pretreatment method with less pollution. In this study, max removal rate of COD and phenol was of 38% and 28%, as other conditions when pH at 4, dosage of TiO₂ at 2.5 g/L and initial concentration of COD of 3000 mg/L. In addition, the removal rate of COD and phenol, and B/C ratio could be further increased with the addition of H2O₂. Therefore, TiO₂ photocatalysis was selected for further study.3). Response surface analysis (RSA) methodology was used to optimize pH, dosage of TiO₂ and initial concentration of COD for TiO₂ photocatalytic system, with COD removal rate as response value, and the response surface equation as: (?)As the ANOVA result of the model, i.e., the F-value and the Prob(p)> F-value were 93.92 and less than 0.0001, which indicated that quadratic regression model was significant. Additionally, as the R2 was 0.9918, which means that the model was of high reliability. Moreover, a low cross-validation (CV) value showed that the fitting degree of the model was perfect and the error of the test was small. Finally, as the R2Pred=0.9553, which indicated the high accuracy for predicting the removal rate of COD and TiO₂ photocatalysis in this study. The predicting results as follows: at the pH of 4.06, dosage of TiO₂ of 2.45 g/L, and the initial concentration COD of 2007 mg/L, removal rate of COD reached 41%, which was very close to the highest value 39.8% determined by validation experiments.4). Anaerobic sludge was domesticated using synthetic wastewater containing phenols prior to anaerobic treatment. Comparing with the non-pretreated wastewater, the removal rate of COD of the pretreated resin wastewater reached 80%, which increased by 20-30%. It showed that most of macromolecules in resin wastewater might be destroyed and the biodegradability of wastewater was then improved using TiO₂ photocatalysis. In order to further increase the removal efficiency, usage of glucose as co-substrate was also investigated. In this study, removal rate of pretreated wastewater with and without TiO₂ photocatalysis increased by 15% and 10%, respectively.