Experimental Study On Advanced Treatment Of Tannery Wastewater And Village Mixed Sewage By Electro-Fenton Reagent

Tannery industrial wastewater seriously pollutes the water environment and it is very difficult to treat. But the practice shows that treatment of tannery wastewater by the mentioned method can not remove those non-biodegradable organic contaminates in the wastewater. Effluent COD is generally200mg/L or more, only to achieve 《Integrated Wastewater Discharge Standard》(GB8978-1996) secondary standard. Thus, manage the tannery wastewater by the advanced treatment technology in order to achieve tanning wastewater discharge standards can effectively reduce water contamination, to reduce contaminates discharge into the environment, and eventually in line with the strategic requirements of sustainable development.This mixed sewage of villages is a mixture of rural sewage and tannery wastewater. Tannery wastewater Separate processing need a higher technical requirements, the process is more complicated, the cost of processing is large. When the tannery wastewater mixed with domestic sewage in rural areas, water quality can be mitigated and reduce wastewater pollution load, at the same time, can add nutrients, it will be a certain amount of tannery wastewater mixed with an appropriate amount of sewage in rural areas, to improve the processing efficiency, reduced processing costs. Water shortages and water pollution has seriously hampered the sustainable development of China’s economy, harmful to the environment and people’s lives, wastewater reuse has a good economic, social and ecological benefits, through wastewater reuse can be a considerable extent to ease the water shortage problem.This paper studies the electrolyte-treatment of tannery wastewater and villages mixed wastewater with Electro-Fenton technology, by single factor experiments and orthogonal test. The main factors and optimum conditions of Electro-Fenton method for experiment. The influence on apparent generation rate of·OH in this system was also studied to provide a useful parameter to improve the efficiency for advanced treatment of tannery wastewater and villages mixed wastewater by Electro-Fenton reagent. Results showed that when using Electro-Fenton to treat tannery wastewater and villages mixed wastewater, various factors contributed to influence the treatment efficiency differently in the following order:pH value> hydrogen peroxide dosage> electrolysis voltage> electrolysis time> electrolyte concentration. The optimal p arameter combinations were:pH of3, hydrogen peroxide dosage of4ml, electrolysis voltage of5V, electrolysis time of80min and the electrolyte concentration of10g/L;pH of3, hydrogen peroxide dosage of2.5ml, electrolysis voltage of5V, electrolysis time of80min, the electrolyte concentration of11g/L. Validation experiment results showed:when using Electro-Fenton to treat secondary settling tank effluent of tannery wastewater, the effluent COD removal and color removal rate reached60.0%and92%respectively, with the effluent COD<100mg/L, color down to below10degrees, which met well with the relevant National Discharge Standards;Experiments on the A/O process secondary sedimentation tank effluent Electro-Fenton effluent COD removal rate reached81%,90%color removal, the effluent COD in19-25mg/L, chroma to5degrees, achieve the reuse water quality standards.By examining the tannery wastewater’s system on the influence of pH, peroxide of hydrogen dosage and the electrolysis voltage on the apparent formation rate of·OH, results showed that when the pH value was3, hydrogen peroxide dosage was4mL and the electrolysis voltage was5V, OH apparent formation rate reached its maximum.