Study On Pretreatment Of Pesticide Wastewater By Ozone/Fe-C Microelectrolysis

Pesticide production wastewater is a kind of high-concentration refractory wastewater.It has high phosphorus content,high organic concentration(CODcr>10000 mg/L),high salinity,high toxicity,poor biodegradability,etc.,and its non-compliance discharge will cause severe environmental impacts.Pollution,along with national and local governments' strict discharge of water quality indicators for polluted wastewater,faces new challenges in wastewater depth compliance and emissions.For the pesticide production enterprises,not only should they consider whether the wastewater treatment of pesticides meets the standard,but they are more concerned with whether the energy consumption of wastewater treatment is within the economic capability of the enterprise.Therefore,whether the wastewater treatment process can be accepted by enterprises has become a major concern for water treatment workers.Based on the review of the research status of pesticide wastewater treatment technologies,the paper selected the wastewater from a large-scale pesticide production plant in Sichuan Province as the research object,and proposed ozone/iron-carbon micro-electrolysis combined with pretreatment of pesticide wastewater to improve the influent water quality of subsequent processes.In turn,pesticide wastewater is effectively treated.In this dissertation,ozone/iron-carbon microelectrolysis was used to pretreat pesticide wastewater.Firstly,several single-factor tests were conducted on iron-carbon microelectrolysis and ozone experiments.The COD removal rate and TOC removal rate were analyzed at parity indices to obtain various factors.The optimal reaction conditions,followed by the kinetic analysis of iron-carbon microelectrolysis and ozone experiments,respectively,followed by iron-carbon microelectrolysis + ozone,ozone + iron carbon in the optimal reaction conditions of iron-carbon micro-electrolysis,ozone experiments and single factors.The micro-electrolysis test was conducted by analyzing COD removal rate and TOC removal rate.Finally,under the optimal reaction conditions of each single factor,the pesticide wastewater was measured by iron-carbon microelectrolysis,ozone,iron-carbon microelectrolysis + ozone,ozone + iron.The biodegradability after carbon microelectrolysis treatment and comparative analysis.Through the research of this topic,we hope to provide a set of low-cost,high-efficiency pretreatment methods to provide certain basic data support for pesticide wastewater treatment.Experiments show that:(1)Compared with different initial pH conditions;the target wastewater was degraded by ferro-carbon micro-electrolysis.It was found that the smaller the pH,the higher the COD and TOC removal rate of the pesticide wastewater.In this paper,when the initial pH is 2,iron carbon micro Electrolysis works best.(2)The test was conducted under the conditions of 200 ml of raw water,initial pH=3.0,aeration volume of 2 L/min,temperature of 25?,and reaction time of 120 min.The removal rates of COD and TOC by the blow-off were 14.7%and 13.5%,respectively.(3)When the amount of aeration is less than 2L/min,the amount of aeration increases,and the removal of COD and TOC from waste water increases significantly with ferro-carbon microelectrolysis.However,when the amount of aeration is greater than 2L/min,the efficiency of waste water degradation is affected.The increase in gas volume is not obvious.(4)In the initial pH = 3.0,the original wastewater 200ml,iron-carbon filler 212g,temperature 25 ?,aeration 2L/min for iron carbon micro-electrolysis experiments,micro-electrolysis degradation of pesticide wastewater is divided into rapid response and slow reaction Stages:The rapid response phase meets zero-order kinetics,and the slow response phase follows second-order kinetics.(5)The optimal reaction conditions for iron-carbon microelectrolysis treatment of pesticide wastewater:initial reaction pH = 3?4,reaction time 120min,aeration volume 2L/min.Under the optimum reaction conditions,the influent COD was 7535 mg/L and the TOC=2943 was removed by micro-electrolysis for 2 hours.The removal rates were 31%and 27.7%,respectively.(6)The ozone degradation of target wastewater in alkaline conditions is more effective than that in acidic conditions,and the degradation is best when the pH is 9 or 11.When the pH is higher than 11,the degradation effect is reduced.(7)In a certain range,as the temperature increases,the removal rate of COD and TOC from the target wastewater increases with ozone.At 40?,the COD and TOC removal rates of the wastewater by the ozone method are 18%and 19%,respectively.(8)Increased ozone dosage will promote wastewater degradation.When the ozone dosage increases from 1.07g/L to 3,19g/L,the COD removal rate increases from 3%to 12%,and the TOC removal rate is 1%increase to 10%respectively.(9)Optimum reaction conditions for ozone treatment of pesticide wastewater:initial pH=9,temperature 20?,and ozone dosage 3.19 g/L.Under the optimal reaction conditions,the influent COD was 7780mg/L,and the removal rate of TOC=2945 after 120min ozone treatment was 24%and 16%,respectively,(10)In the target wastewater 200mL,initial pH = 9.0,ozone dosage 3.19g/L.temperature 20 ? experiment,ozone degradation COD reaction in wastewater to meet the first-order kinetic model,the reaction rate constant k = 0.0029.(11)Under the optimal conditions;the target wastewater was degraded by the combined process of iron-carbon microelectrolysis + ozone(IE+O3).The renmoval rates of micro-electrolysis COD and TOC were 43.8%and 36.5%,respectively.The removal rates of COD and TOC by ozone method were At 22.5%and 23%,the COD and TOC removal rates after combined treatment were 66.3%and 59.5%,respectively.After combined degradation,BOD5/COD increased from 0.23 to 0.37.(12)Under the selected conditions,ozone + ferric-carbon micro-electrolysis(O3+IE)combination process was used to degrade pesticide wastewater.After ozone process,the removal rates of COD and TOC in pesticide wastewater were 30%and 23.6%,respectively.The removal rates of COD and TOC for pesticide wastewater were 15.9%and 21.6%,respectively.The combined COD and TOC removal rates for wastewater were 54.6%and 45.2%,respectively.After the combined process,BOD5/COD increased from 0.25 to 0.32.(13)The two different sequential combination processes can effectively remove the COD and TOC from the pesticide wastewater,but the combination of iron-Carbon microelectrolysis+ozone(IE+O3)is more effective.