Advanced Treatment Of Waste Water Based On Intensified Micro-Electrolysis Technology

Micro-electrolysis is one of the most important waste water treatment technologies. Based on thestatus quo that the effluent standards of waste waters are becoming stricter day by day and the problems ofconventional micro-electrolysis technology existing in the practical operation, this study mainly focused onthe improvement of the traditional micro-electrolysis technology and the optimization of the operatingconditions. The aim of this research is to develop intensified micro-electrolysis technologies （IME） andapply them to the advanced treatment of real waste waters.In order to solve the problems of passivation, lumping and canal of flow in the running of theconventional Fe-C micro-eletrolysis system, we tried adding aluminum, magnesium and copper into themicro-eletrolysis systems and investigated the results. Decoloration efficiency was studied with fullconsideration of the influence of the major controlling factors such as initial solution pH value, reactiontime and so on. The results showed that almost all the systems could remove Orange G effectively. Eachsystem has its suitable pH range and the optimum reaction time accordingly. Suitable IME systems shouldbe chosen in accordance with the specific types of waste water in practice. For instance, Fe-C, Mg-C andFe-Cu-C systems can be chosen for treating acidic waste water, whereas Al-C and Fe-Al-C systems aremore effective in the treatment of alkaline wastewater; All the IME systems studied have better effects asreaction time extends. Therefore, it is feasible to combine IME technology with oxidation pond, wetlandand some other long-time processes. This would be a promising developing tendency for micro-electrolysisin actual application; the application of aluminum in micro-electrolysis system lays a solid foundation forthe micro-electrolysis treatment of alkaline wastewater and cuts down the costs.Another IME technology in which DC and H₂O₂were injected as strengthening measures wasdeveloped to investigate the decolorization of OG in aqueous solution, and the effect of pH values,current intensity, the injecting modes of current, the dosage of H₂O₂and temperatures werealso studied. The optimum conditions were selected as: I=0.4A, pH=7.8（pH of raw OG aqueoussolution）,[H₂O₂]=0.3ml/L, T=25C and the current was intermittently injected （10s/30s）. Under the given conditions,98.5%of decolorization efficiency was achieved within60min. The kinetic studyimplied that under the motivation of DC, the strong oxidizing property of H₂O₂was displayed evenat high pH values in the present experimental system and a synergistic effect was speculatedto exist between DC and H₂O₂in the IME system. Besides, the decolorization of OG in IMEprocesses followed the first-order kinetics well. And the apparent activation energy Ea (27.96kJ mol^-1) wasmuch lower than ordinary thermal reactions, indicating that the decolorization of OG by IME technology isa easy process. In addition, the intermittent injecting mode of electric current not only saved the energy butalso improved the decolorization rate prominently, which has significance for practical application.Furthermore, the integrated technology of microbial method and IME in advanced treatment ofpetrochemical waste water and landfill leachate were investigated, and good treatment efficiency wasobtained. It was demontrated that the application of IME technology in further treatment of real wastewater was effective.