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★ ★ ★ mrzhengyao(金币+150, 翻译EPI+1):兵贵神速,牛啊,凌晨4点多翻译的!全部给你了! 2010-06-01 06:35:15 wypward(金币+3):欢迎新虫,精神可嘉 2010-06-01 10:02:03
With the development of industrialized production and increase of population in cities, the amount of industrial waste water, domestic sewage and sewage sludge is raising dramatically. There are many poisonous and harmful substances in the sludge, such as pathogens, viruses, parasitic ova and heavy metals, which would cause seriously secondary pollution to environment if no proper management is applied to them. Currently, there are two problems existing in the management of sludge: one is no effective method that can be widely used and friendly to environment; second is the huge cost of the management of sludge, for example, the cost for sludge's management is as high as the 60% to 70% of the total capital expenditure of a wastewater treatment plant. The accumulation of sludge not only occupies much space but also influences the urban sanitation due to the severely impaired factors that include parasites, heavy metals, pathogens, organic contaminants and stinks. At present the common methods to handle sludge are sludge burial, sludge incineration and ocean disposal, however, there are many short-comings for these methods. (1) the prevailing burial mainly is sanitary landfills. The advantages of it are smaller-investment, larger-capacity, faster-effect, but using this method should pay attention to choose the place, consider the hydrological and geographic conditions so that to avoid polluting ground water, leaking exudates, and releasing degradation gas etc. Due to the growth of population and shortage of land resource place for burial is very limited. And the very severe problem is the inflows of landfill liquid to groundwater, which leads to the pollution of groundwater. (2)incineration's superiority is thoroughness, the reduction ratio could reach as high as 95%. But there are still many problems: high-expenditure of investment and manipulation, difficulty of operation, and fly ash, slag and smoke from the burning procedure. There are many heavy metals like Cd, Pb in the fly ash, which is hazardous waste. Lethal substances, like dioxin and furan, exist in the discharged gas and smoke, which would cause seriously secondary pollution to environment if without a proper management. In addition to high-requirement and difficult-determination of the measurement of dioxin, the substances in slag also cannot be used effectively. (3) ocean disposal doesn't solve the environmental problem basically since it causes ocean pollution and threat for marine ecosystems and human food chain, which is drastically opposited by many people. Therefore, the fundamental outlet to sludge disposal is resource utilization, which leads to many researches currently, such as, hydrogen production and compost etc.
MFC is anew-fashioned bioreactor that is developed on the basis of electrochemical techniques and uses microorganism as catalysis to convert chemical energy of organic compounds to electric energy. Besides the advantages of the high-efficiency and pollution-free like other common fuel battery, MFC instrument also obtains many other advantages, such as wide-ranging flue resource and mild reaction conditions. MFC uses different substances to generate electric energy. Through MFC, Oh and Min independently used food waste water and swine-raising waste water to generate electricity and organic compounds acetate, lactate and butyrate salts that also can be used as fuel. There are many organic substances in sludge, according to investigation, the percentage of organic substance in sludge is up to 50% to 70%, which is mainly carbohydrate that belongs to high-carbohydrate low fat type. Sludge also contains abundant N, P, K nutrient elements and Ca, Mg, Cu, Zn, Fe microelements. As the development of modern cities and industries, the amount of sludge increases drastically. Facing the issue how to handle the problems of high-investment and difficult-operation, many experts is zealously looking for various new techniques and solutions for resource utilization of sludge. Therefore, under this background this experiment proposes using the new technique----MFC, which provides a novelty thought for development of resource utilization of sludge, and hopes generating electric energy while decreasing the cost by using this technique. So making waste profitable will definitely achieve excellent economic and social benefits. If MFC can output long-term and stable electric energy and make it on the level of value-in-use, MFC will be more practical.
翻译的很累啊!希望LZ不要惜金啊![](//muchongimg.xmcimg.com/data/emuch_bbs_images/smilies/cool.gif) |
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