Treatment Study On The High Density And Difficulty Biodegradable Wastewater

Due to the non-biodegradability of heavily contaminated wastewater, the high density wastewater was treated by the promising methd, which included coagulation, advanced oxidation technology and high speed biofilm reactor to reduce its toxicity to microorganisms, improve its biodegradability and decrease a portion of organic loading for subsequent biological treatment unit.During the polyester resin wastewater was pretreated by coagulation—microwave-assisted catalytic oxidation. Single factor method was used to find out the best parameters of coagulation. The results showed that the optimal pretreatment process conditions of polyester resin wastewater by coagulation were using PFS flocculating agent and its dosage =150 mg/L, using PAM coagulation-supporting agent and its dosage=20mg/L, initial pH of wastewater=8.0, water temperature=25℃, mixing time=20min and clarifying time=1h. Under the optimal process conditions, the polyester resin wastewater COD_Cr removal rate could approach 40.1% after coagulation sedimentation, but the BOD₅/COD_Cr level of polyester resin wastewater only increased from 0.17 to 0.19.As the polyester resin wastewater was pretreated by microwave-assisted catalytic oxidation, an orthogonal experimental method was adopted here. Then based on the orthogonal experiment, single factor method was used to find out the best parameters of microwave-assisted catalytic oxidation. The optimal pretreatment process conditions of polyester resin wastewater by microwave-assisted catalytic oxidation were room temperature, microwave time=80s, initial pH=7.0, the hydroxyl radical dosage=40mg/L, O₃ reaction time=4min. Under the optimal process conditions, the polyester resin wastewater COD_Cr removal efficiency could approach 40.78%, and the biodegradable of polyester resin wastewater was improved observably, its BOD₅/COD_Cr level increased from 0.19 to 0.45. Under the optimal process conditions, the total COD_Cr removal rate of polyester resin wastewater was 81%. The biodegradability of polyester resin wastewater was improved remarkably, its BOD₅/COD_Cr level increased from 0.19 to 0.45. The economic and technical analyze prove that the medicament cost is the largest proportion of the running cost in the process, which is about 3.5.In the paper, the laboratory wastewater was treated by coagulation and MBBR method. Some factors influencing the treatment process of coagulation and MBBR were studied. The result showed that the removal rates of SS and COD_Cr of the effluent can reach up to 92% and 94.4%. The pulp middle-stage wastewater was treated by MBBR method. The result showed that the removal rates of SS and COD_Cr of the effluent can reach up to 95% and 69.2%, and the cost of the method only reach to 0.3. The landfill leachate was treated by physical chemistry methods. The result showed that the removal rates of NH₃-N and COD_Cr of the effluent can reach up to 56.3% and 49.3%.On the base of general analysis of the technology and the cost through it, the treatment method which included coagulation, advanced oxidation technology and high speed biofilm reactor is practical in application. So it was feasible that heavily contaminated wastewater was treated by the method of coagulation, advanced oxidation technology and high speed biofilm reactor.