Research On Advanced Treatment Of Pulping And Paper-making Wastewater From Zhongyeyinhe Company

The wastewater generated in the middle section of paper industry is very complex, which is the key to pollution control. Basically, the treatment of wastewater is treated at one or two levels, and other substances of lignin formation are difficult to be degraded and bleached, resulting in a lot of color darker wastewater. There is a large number of CODcr, does not comply with the "pulp and paper industry water pollutant discharge standards (3544-2008 GB)" provisions. Study of two grade effluent in the middle of the paper industry, make the content of CODcr reduce, decolorization, is the important problem of paper industry and environmental protection.The research based on the key elements to improve the water quality, the use of the Fenton oxidation and mixed coagulation precipitation method+sand filtration combined process for advanced treatment of secondary effluent of pulping and papermaking middle stage wastewater, the main research contents are:optimum conditions of Fenton oxidation; coagulation and precipitation the optimum process conditions; sand filter optimum conditions; combined process under the optimum process conditions combined with dynamic experiment; Fenton oxidation reagent cost optimization; coagulation and sedimentation process reagent cost optimization; combined process in process reagent cost optimization under the condition of combined dynamic experiment; combined process of engineering design; combination process engineering application processing analysis and cost effectiveness analysis.The results show that:(1) Using 98% sulfuric acid as the acid source of Fenton oxidation,the optimal running process conditions of Fenton oxidation:the pH value is 5.0,27.5%H2O2 throws the increment is 200mg/L,FeSO-7H2O throws the increment is 400mg/L,the reaction time is 40min, the water temperature is normal atmospheric temperature.The optimal running process conditions of the coagulation precipitation after Fenton oxidation:the water temperature is normal atmospheric temperature; the pH value is 8.0; dissolved concentration of CPAM is 0.15%; CPAM throws the increment is 4.0mg/L. s,When it runs under above condition that the continuous dynamic test of Fenton oxidation-coagulation precipitation, the CODcr removal rate is 77.9%,the SS renivak rate is 80.9%,color removal is 74.5%,the operation pharmacy cost is RMB 0.803 yuan/m3.(2)Using NaOH to callback pH value of the waste water before coagulation precipitation, the optimal running process conditions of coagulation precipitation:water temperature is normal atmospheric temperature; the pH value is 6.0; dissolved concentration of CPAM is 0.1%; CPAM throws the increment is 2.0mg/L. When it runs under above condition that the test of the coagulation precipitation after the Fenton oxidation,theCODcr removal rate is 23.2%,the SS renivak rate is 66.1%,color removal is 46.7%,the operation pharmacy cost is RMB 0.324 yuan/m3.(3)the optimal running process conditions of sand filtration:water temperature is normal atmospheric temperature; the pH value is 6.0;the filtration rate is 8m/h, the filter thickness is 1.2m, the rinse cycle is 24h, the backwash air intensity is 15-16L/m2·s,waterbackwish intensity is 4-5L/m·s.(4)Contrasting treatment effect and process pharmacy costs when Fenton oxidation respectively use titanium dioxide waste acid、iron sulphate picking waste liquid,98% H2SO4 as acid source, the process pharmacy costs is the lowest and the treatment effect is almost that Fenton oxidation uses titanium dioxide waste acid as the acid source.So titanium dioxide waste acid was chosen as the acid source of Fenton oxidation。The optimal running process conditions:the reaction time is 40min, the water temperature is normal atmospheric temperature, titanium dioxide waste acid throws the increment is 3.35ml/L,27.5%H2O2 throws the increment is 200mg/L, The optimal running process conditions of the coagulation precipitation after Fenton oxidation:the water temperature is normal atmospheric temperature; dissolved concentration of CPAM is 0.1%,the pH value is 6.0; CPAM throws the increment is 2.0mg/L. the value of PH is 6.0, Join 2.Omg/L.s CPAM,When it runs under above conditions that the continuous dynamic test of Fenton oxidation-coagulation precipitation, the CODcr removal rate is 77.1%,the SS renivak rate is 81.3%,color removal is 75.2%,the operation pharmacy cost is RMB 0.803 yuan/m3.(5)Contrasting treatment effect and process pharmacy costs respectively to use NaOH, white liquor, lime to callback pH value of the waste water before coagulation precipitation, the process pharmacy costs is the lowest and the treatment effect is almost that coagulation precipitation uses lime to callback pH value of the waste water.So lime was chosen to callback pH value of the waste water before coagulation precipitation。The optimal running process conditions is that water temperature is normal atmospheric temperature; the pH value is 6.0;dissolved concentration of CPAM is 0.1%,; CPAM throws the increment is l.Omg/L. s,Under the conditions, the CODcr removal rate is 25.4%,the color removal is 46.9%,the operation pharmacy cost is RMB 0.0587yuan/m3.(6)Engineering application results show:the CODcr removal rate is 83.9%,the SS renivak rate is 90.4%,the color removal is 84.9+%, the CODcr of the treated water is 43mg/L,the SS of the treated water is 16mg/L,the color of the treated water is 40 double,when the combined process of Fenton oxidation-coagulation precipitation-the operation-sand filtration uses titanium dioxide waste acid as the acid sourse and use lime to callback the pH value of the waste water after Fenton oxidation.The treated water fully meets the most stringent emission standards for pulp and paper effluent..The running cost to deal with tons of water is RMB 0.563 yuan, the cost is the half of the tradition pulp and paper wasrewater treatment costs,where the operation wastewater pharmacy cost is RMB 0.217yuan/m3.