The Research And Application Of Wastewater Treatment For Peroxide Production

With the publish of more and more strict industrial discharging standard and the increasing output of organic peroxide in Tianjin site,the organic peroxide waste water treatment system has to be optimized,and which now becomes the first priority of the site.The waste water with peroxide production has some special properties,e.g higher COD,lower BOD and including more complicated component;the new treatment process of "Readjustment-coagulation floatation-hydrolysis acidification-secondary aerobic biochemical treatment" has been implemented,which is improvement on the previous technology.By using the new technology,the waste water handling capacity is increased and meanwhile all the checkpoint data of discharging water are stable within the tolerance of the standard.Mixing polymer flocculant PAM with inorganic coagulant PAC and Fe SO4·7H2O shows better performance than single inorganic coagulant.According to experiment,the optimum ratio of coagulant is: Fe SO4·7H2O with 150 mg/L,PAC with 250 mg/L,PAM with 10mg/L and the p H with 8.After coagulation,floc was separated by pressure dissolved air flotation at gas floating pressure 0.5 MPa with 35% reflux ratio,the number of tiny air bubbles dissolved in one cubic meter waste water can reach to2.38 x 1012.The removal rate of COD can reach to 30% in the stage of coagulation,which can change the turbidity waste water into clear and transparent water.The design and implementation of hydrolytic acidification process has obvious effectiveness on the removal of refractory pollutants.The effluent COD can be decreased by 80mg/L and the biochemical rate of wastewater can be increased from0.27 to 0.37.The aerobic activated sludge process(AB)which is used to treat organic peroxide wastewater got the good results.About 70% of the pollutants are removed at this stage.Through controlling the condition of aeration tank at dissolved oxygen(DO)3.5-4.5 mg/L,the sludge concentration(MLSS)at 5.5 g/L,and the optimum reflux ratio at 65%,and maintaining the sludge in a good condition,the COD of the wastewater dropped from 7000mg/L to below 200mg/L.COD removal efficiency can reach 98.64%,the effluent discharge index is in line with Tianjin local government sewage discharge standard(DB12/356-2008)completely.