Application Of MBR Process For The Treatment Of Fuel Ethanol Wastewater

Membrane bioreactor(MBR)is one of the effective means to realize the resourcezation of waste water.It has the characteristics of little occupied area,high degree of automation,easy installation and maintenance.Membrane bioreactor for wastewater treatment not only save water resources,but also decrease the operation cost,which is one of the important development of water resourcezation treatments in China.In this paper,MBR process was used to treat wastewater of corn ethanol and cassava ethanol.The cleaning solution of membrane was optimized,and economics of MBR process was also evaluated ultimately.The main contents and results are listed as follows:(1)MBR was used to treat corn ethanol wastewater,and the results showed that MBR process for corn ethanol wastewater treatment presented good performance,the average removal rate of COD can reach 94%,and the average removal rate of chromaticity was 70%,the membrane flux can reach 16.5 L/(m2·h),and it can keep long-term stable operation.(2)MBR was also showed better treatment effect for cassava ethanol wastewater,the average removal rate of COD and chromaticity was 84.5%,75.9%,respectively.Although the water didn't reach the emission standards,the treatment effect was far better than conventional treatment processes.The cassava ethanol wastewater treated by MBR and double membrane processes,finally the water quality reach the "fermentation ethanol and liquor industry pollutant emission standards"(GB 27631-2011)and the standard of urban sewage recycling and utilization industry(GB/T19923-2005).So the water can recycle druing the process of ethanol fermentation.(3)In this work,three steps of tap water-sodium hypochlorite-acid was used to clean the polluted membrane,water flux recovery was 35%when the membrane was cleaned by water,and that can reach 68%when cleaned by sodium hypochlorite.After the cleaning of sodium hypochlorite and hydrochloric acid,the membrane flux recovery can reach 98%,the experimental results showed that the membrane flux can recover by adopting the appropriate cleaning method.(4)Compared with conventional aerobic processes,MBR showed significant economic advantages.Except the cost of land,although the investment cost of MBR process increased by 1.6 million than that of the traditional process,the running cost of the MBR was 0.9 yuan/ton lower than that of traditional process,3 million 800 thousand was saved in five years,if the water recycling was considered,then the economic advantages of MBR was more obvious.Therefore,it is significant to use MBR technology to treat the fuel ethanol wastewater to obtain better water quality and reduce the operation cost of the enterprise.