Study On Treatment Of Acrylic Ester Wastewater By Coagulation-Anaerobic Reverse Sulfide-EGSB Technology

The acrylic ester wastewater of one chemical company has the characteristics of high salt and high CODCr concentration, concentration of acrylic acid sodium is 63000~65000mg/L, the methyl benzene sulfonic acid sodium concentration is 27000~28000mg/L,CODCr concentration is 120000 mg/L. According to the "removal salt first, then organic matter",formed a " Triple effect evaporation remove salt, iron carbon micro electrolysis, A2/O removal organic material " technical route. Under the temperature of the evaporation, Sodium acrylate polycondensation in wastewater, the evaporation residue has high moisture content and viscosity, the moisture content is more than 80%,adhesion on the inner wall of the evaporator,evaporation circulating pump will not work, cannot achieve the complete separation of salt,and the residue disposal is difficult and need high cost.This topic research with coagulation and anaerobic technology to deal with acrylic ester wastewater,replace existing"Triple effect evaporation,iron carbon micro electrolysis ”pretreatment process. The acrylic ester wastewater by coagulation sedimentation after removing part of CODCr and SS, and treat by anaerobic biological.In anaerobic technology Set hydrolysis acidification reactor in front of the EGSB reactor, using hydrolysis acidification reaction conditions, reach the coordination devulcanization of sulfonate, dosing Fe2+,to form FeS and separate from water, reflux controlling hydrolysis acidification reactor sulfide below value, residual water continue to EGSB reactor process. Both prevent the accumulation of sulfide in the hydrolysis acidification reactor, and reduced the sulfide to the toxicity of anaerobic bacteria in the EGSB reactor, give full play to the efficiency of the anaerobic bacteria, implements the acrylate to the anaerobic biological treatment of wastewater. Determine the alternative "negative pressure evaporation, iron carbon micro electrolysis" the feasibility of pretreatment process. Research conclusions are as follows:(1) The coagulation stage: raw water pH value of 9,in acrylate wastewate,CODCr concentration is 120000 mg/L, concentration of SS is 353 mg/L, in adding the 2000 mg/L of PAC, 30 mg/L of APAM, certain hydraulic condition, effluent CODCr is 99100 mg/L, the removal rate is 17.4%; SS is 24 mg/L, removal rate is 93%;(2) Anaerobic reverse sulfide stage: Sludge after two times to start the microbes to adapt to the water quality and achieve the degradation of pollutants; Volume load up to 9kgCOD/(m3.d), sulfide concentration of 190 mg/L in the reactor, the processing volume load decline; To control the hydrolysis acidification reactor sulfide inhibits density, acrylic ester wastewater after coagulation pretreatment and after hydrolysis acidification dosing Fe2+sulphur removal water mixed reflux after the treatment, CODCr is 99100 mg/L, the water effluent CODCr is 32000 mg/L, the removal rate is 67.7%;(3) The EGSB reactor pilot stage: In the EGSB reactor after domestication finish of granular sludge, the water volume load increase to 12 kgCOD/(m3.d), CODCr is 32000 mg/L,the water effluent CODCr is about 5120 mg/L, the removal rate is 84%;(4) Using hydrolytic acidification reverse sulfide, FeCl2 processing can be completed in addition to sulfur, EGSB reactor acrylate anaerobic biological treatment of wastewater, and replace existing ‘Triple effect evaporation + iron carbon micro electrolysis’ pretreatment process.