| With the development of industry,electroplating process has been widely used in various fields,and at the same time,this also lead to the rapid increase of electroplating wastewater.Electroplating waste water contains not only carcinogenic teratogenic and mutagenic toxic substances such as copper,cadmium,chromium and other heavy metal ions,but also contains many refractory organic compounds.These toxic and harmful substances,if not properly treated,are likely to cause great harm.In this paper,we constructed IEEB reactor(ion-exchange enhanced electrochemical bioreactor)based on ion exchange particle electrode,the metal ions in wastewater were used as catalyst to decompose the refractory organic matter under the action of electric field,and then removed by microorganism.Use ion exchange material as carrier,ferric chloride and manganese chloride as active material,after the pretreatment and preload two processes,preparation of one component and two-component ion-exchange type particle electrode with different proportions was finished.Study on the catalytic effect of different ion exchange electrode,it was found that the highest removal rate of CODcr for simulated wastewater was the particle electrode preload with Fe:Mn=1:1.The CODcr adsorption capacity of the ion exchange electrode was 6.08mg/g,CODcr removal rate was 13.39% when the adsorption equilibrium was reached;when the particle electrode was used for second times,the removal rate of CODcr was reduced by about 5%,then no change.With the increase of electrolyte concentration,catalytic efficiency of particle electrode also increased,which is suitable for electroplating wastewater with high conductivity.Bulit IEEB reactor using selected particle electrodes,and the membrane was hung by the method of inoculating the membrane,at the same time,the reactor was compared with the non electric reactor.After 10 days of continuous inlet,CODcr removal rate of IEEB reactor was 81.59%,ammonia nitrogen removal rate was up to 85.7%;The CODcr removal rate was 70.7%,the removal rate of ammonia nitrogen was 82.4% for comparative reactor.All two reactor reached a high level of CODcr and ammonia nitrogen removal rate and the running steady.It was considered that the artificial inoculation with activated sludge of the two reactor was successful.The effects of different current intensity,hydraulic retention time and pollutant load on the removal of CODcr,TOC and metal ion in the two reactors were investigated in the stable operation stage of the reactor.Current intensity selection 20 mA,40mA,60 mA.The experimental results show that the optimum current of the IEEB reactor is 40 mA,At this current intensity,the removal rates of CODcr,TOC,Cu and Cr in the IEEB reactor were 84.02%?80.13%?94.63%?79.02%,CODcr,TOC and copper removal rate were 27.75%,39.91% and 31.18% higher than that of the comparative reactor,the difference of chromium removal rate between two reactor was 0.82%.Hydraulic retention time is selected for 2.3 hours and 3.5 hours,in the case of a residence time of 3.5 hours,the wastewater is in greater contact with the ion exchange type particle electrode and the removal rate is better,the removal rates of CODcr,TOC,Cu and Cr in IEEB reactor were 84.02%,80.13%,94.63% and 79.02%,the corresponding removal rates of IEEB reactor with 2.3 hours were 73.34%,63.49%,95.92%,74.92%.Water intake of pollutant load selected 150mg/L,300mg/L and 450mg/L,when the influent CODcr load was 150 mg / L,the removal rates of CODcr,TOC,Cu and Cr in IEEB reactor were 86.21%,80.33%,82.11% and 32.42% respectively.when the influent CODcr load was 300 mg / L,the removal rates of IEEB reactors were 84.02%,80.13%,94.63% and 79.02%,When the influent CODcr load was 450 mg / L,the removal rate of IEEB was 73.61%,65.70%,96.58% and 75.55%.The experimental results show that the amount of contaminant that can be removed per unit volume of IEEB reactor is much higher than that of the comparative reactor.To analysis of the principle of IEEB reactor,use GC-MS to analysis the inlet and outlet water of IEEB reactor,result shows that the long chain substance in the wastewater was reduced from 70.72% to 52.51%,and the short chain was increased from 15.04% to 34.44%.Combined with the analysis of the biodegradability of wastewater by measure B/C,it was considered that the IEEB reactor could decompose the refractory materials into small molecules which could be biodegraded.EDS analysis showed that the ion exchange type particle electrode can effectively load metal ions in the water during operation,and there was no appear to reduce the pollutant removal rate during the operation process under the same conditions,It is indicated that the particle electrode replaces the lost pre loaded catalyst by the metal ions in the wastewater,and can maintain the catalytic effect. |
PDF Full Text Request