Experimental Study On Physicochemical Pretreatment Of Organosilicon Wastewater And Application Of Anaerobic Engineering

As an important part of the material industry of the national strategic emerging industry,organic silicon series materials are also indispensable supporting materials for other strategic emerging industries.The production of organic silicon in China is increasing day by day,and the problem of the treatment of organic silicon production wastewater needs to be solved urgently.Taking organic silicon wastewater produced by a material company in Jiangxi as an example,it has the characteristics of poor biodegradability,high concentration,complex composition and low acidity.The overall treatment process adopts the combination process of"two-stage air flotation+four-effect evaporation+Fenton oxidation+coagulation+UASB anaerobic reactor+A/O+biological filter".Focus on the anaerobic pretreatment（Fenton oxidation+coagulation）test analysis and field commissioning of anaerobic treatment equipment,so that the effluent can meet the required standards.Aiming at the single-factor test and orthogonal test designed by Fenton oxidation,the influences of reaction p H,reaction time,reaction temperature,n（H₂O₂）:n(Fe²⁺)on COD removal in wastewater are analyzed,and the conclusion is drawn that the degree of influence of Fenton test on COD removal is p H>n（H₂O₂）:n(Fe²⁺)>reaction temperature>inverse,and p H 4,reaction time 2h,reaction temperature 40degrees Celsius,n（H₂O₂）:n(Fe²⁺)6:1 conditions,the highest COD removal rate is35%.Based on the single factor test and orthogonal test of coagulation and precipitation design,the influences of reaction p H,PAC dosage,PAM dosage and reaction time on COD removal in wastewater were analyzed,and the conclusion was drawn:The influence degree of COD removal rate is as follows:reaction p H>5 coagulant PAC dosage>reaction time>PAM dosage,the best reaction condition is p H 8,reaction time 30 minutes,coagulant PAC dosage of 250 mg/L,PAM dosage of coagulant aid of4 mg/L under this condition,the COD removal rate is about 25%.The UASB anaerobic reactor was selected as the treatment equipment of the anaerobic process section of this project.After 105 days of debugging,the removal rate of COD and NH₃-N in wastewater by this equipment reached 85%and-8%.During the commissioning period,organic load gradually increased,which was divided into four stages:0.5 kg COD/（m3·d）,0.5～2.0 kg COD/（m3·d）,2.0～4.0 kg COD/（m3·d）,4.0～5.0kg COD/（m3·d）.During normal operation,the COD of raw water is about 59000 mg/L,and the NH₃-N is about 500-600 mg/L.After Fenton oxidation+coagulation pretreatment,the COD of wastewater entering UASB reactor is about 8800 mg/L;The concentration of NH₃-N is about 95 mg/L after mixing with the waste water in the intermediate tank.And the effluent COD is about 1300 mg/L.NH₃-N is about 100 mg/L.After subsequent wastewater treatment,the final effluent COD is about 110 mg/L and NH₃-N is about 10 mg/L,which meets the discharge standard.The above results provide a reference for the anaerobic treatment of wastewater from the production of organic silicon series products,and provide a reference for the treatment of similar water quality wastewater.