Experimental Study On The Pretreatment Of High-concentration Refractory Organic Sewage

Highly concentrated refractory organic wastewater has a complex composition,color depth,highly toxic,difficult biological characteristics and so on.Discharged straightly without being treated or treated not processing,these wastewaters would pollute environment.We need to improve the biodegradability of wastewater by pretreatment,so that making the biochemical treatment more effective.The key points of pretreatment which directly affect the effect of biological treatment are how to reduce the concentration of organics,remove or reduce toxicity,and change the water qualities.In order to improve the biodegradability of the wastewater,change the property of pollutants in wastewater,so as to make the following treatment much easier,flocculating settling and iron-carbon micro-electrolysis followed by Fenton oxidation method was used in the pretreatment research in this paper.The first experiments using PAC and PAM as rflocculation treatment to pretreat the organic wastewater.Through single-factor experiment analysis,confirmed the best operation conditions of flocculating settling.The COD removal rate of the wastewater can reach above 25%.In this study,iron scrap and granular activated carbon were used as materials of micro-electrolysis to pretreat the organic wastewater by flocculating settling.Through single-factor experiment and orthogonal experiment analysis,confirmed the best operation conditions of iron carbon micro electrolysis technology.The COD removal rate of the wastewater can reach above 30%.30%hydrogen peroxide and ferrous sulfate reagent were used as materials of Fenton reagent oxidation to pretreat the organic wastewater by flocculating settling.Through single-factor experiment and orthogonal experiment analysis,confirmed the best operation conditions of iron carbon micro electrolysis technology.The COD removal rate of the wastewater can reach above 30%.In order to further reduce COD concentration of the organic wastewater,reduce the load of equipment in subsequent biological treatment,flocculating settling and iron-carbon micro-electrolysis treatment followed by Fenton oxidation treatment was used to enhance the treatment result of the wastewater in this study.Experimental results show that after the combined treatment,the COD removal rate reached above 75%,TOC from 3980 ppm to 1500 ppm,The effluent is clear and transparent,reached the requirements of biochemical treatment.Finally,according to the actual process of sewage treatment plant,this paper designed the process flow diagram.Provide the basis for further industrialization.