Study On The Treatment Technology Of Chloroacetic Acid Production Wastewater

With the rapid development of China’s economy,the process of industrialization in China is also accelerating,in which chemical plants have played a huge role.However,in the process,people found that chemical plants bring huge profits,but also bring a huge pollution load.There are many kinds of chemical wastewater with complex composition,unstable water quality and quantity.Most of them contain toxic and harmful pollutants such as refractory organic matter and heavy metal.How to treat such wastewater efficiently and cost effectively has been the focus of the industry.Chloroacetic acid as an important chemical product,with the continuous expansion of its application field,its demand is increasing year by year.However,at present,there are few researches on chloroacetic acid production wastewater,and the pollutants in wastewater have not been effectively degraded,which has caused a certain degree of impact on China’s water environment.Therefore,in this experiment,chloroacetic acid production wastewater produced in the production process of a chloroacetic acid production factory in Zhenjiang City was taken as the research object,and the process of "Fenton oxidation+coagulation precipitation+UAF+SBR" was proposed to treat the chloroacetic acid production wastewater.Various processes were tested and studied,and the following conclusions were drawn:(1)Fenton oxidation test was carried out on chloroacetic acid production wastewater.According to the single factor test results and the actual operation cost,the optimal conditions for Fenton oxidation test are determined as follows:pH 4,m(H2O2):m(CODCr)1,n(H2O2)/n(Fe2+)10,and reaction time 2h.At this time,the removal efficiency of CODCr in wastewater is the best,the removal rate reaches 60.56%,and the effluent concentration is 5916.7mg/L.(2)Experiments were carried out on wastewater after Fenton oxidation by coagulation sedimentation method.The removal of CODCr in sewage was improved by adjusting the pH of sewage to a predetermined value and adding coagulant PAC and coagulant aid PAM.According to the test and actual production costs,the content of CODCr in the effluent was the lowest at pH 7,PAC 0.1g/L,PAM 2mg/L,stirring for 15min,and precipitation for 30 min.The removal efficiency of CODCr was increased to 18.31%.(3)Gradually increase the concentration of CODCr in the influent,so that the anaerobic bacteria in the anaerobic biological pool can adapt.Under the condition of temperature 35℃,pH 7 and hydraulic retention for 48 hours,the CODCr concentration in the system increased from 1000mg/L to 5000mg/L,the removal rate of CODCr gradually decreased from 53%to 49%,and the remaining concentration reached 2547.62mg/L.(4)The UAF process was used to treat the wastewater.The results showed that:under the condition of 35℃,HRT 48h and pH 7,the UAF process was used to effectively treat the chloroacetic acid production wastewater.The content of CODCr in water is 4800-5000mg/L,and the CODCr in effluent is 2400-2500mg/L,and the removal rate is about 49%.(5)In the SBR reactor,the sludge activity was improved by gradually increasing the influent concentration,and a certain amount of ammonium salt and phosphate were added at the same time to keep the C:N:P in the device at 100:5:1.Under the condition of temperature 25℃,pH 7 and cycle of operation for 12 hours,the concentrations of CODCr,NH4+-N,TN and TP were increased from 600mg/L,27mg/L,30mg/L and 6mg/L to 1500mg/L,70mg/L,75mg/L and 15mg/L,the removal rates of CODCr,NH4+-N,TN and TP were stable at about 73.47%,62.27%,58.59%and 52.92%,respectively,and the pH value of the device was always maintained at about 7.After 10 days of culture and domestication,the SBR reactor was successfully started.(6)Through the study of the factors affecting the operation of SBR reactor,the treatment effect of SBR reactor is better under the conditions of influent temperature 25 ℃,pH value 7,aeration rate 0.64L/min,cycle of operation 12h,precipitation 2h,C:N:P 200:5:1.At this time,the concentrations of CODCr,NH4+-N,TN and TP in the effluent were 468.33mg/L,15.75mg/L,20.03mg/L and 3.75mg/L,respectively,and the removal rates were 70%,68.91%,65.68%and 50.95%,respectively.The removal kinetics of CODCr from chloroacetic acid production wastewater by SBR unit is close to the second-order reaction kinetics equation.