首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Biogas: a Solution to Many Problems In almost all developing countries, the lack of adequate supplies of cheap, convenient a
Biogas: a Solution to Many Problems In almost all developing countries, the lack of adequate supplies of cheap, convenient a
admin
2012-05-29
70
问题
Biogas: a Solution to Many Problems
In almost all developing countries, the lack of adequate supplies of cheap, convenient and reliable fuel is a major problem. Rural communities depend largely on kerosene, wood and dung for their cooking and lighting needs. But kerosene is now priced out of reach of many people and wood, except in heavily forested areas, is in short supply. The search for firewood occupies a large part of the working day and has resulted in widespread deforestation.
Dung is in constant supply wherever there are farm animals and, when dried, it is convenient to store and use. But burning dung destroys its value as fertilizer, thus depriving the soil of a much needed source of humus and nitrogen.
Rural areas of developing countries are also plagued by a lack of adequate sanitation. Improper waste disposal spreads disease, contaminates water sources and provides breeding grounds for disease-carrying insect.
The problems of improving environmental hygiene, conserving resources and finding alternative sources of fuel may be unrelated. Their solutions, however, are not, as many countries experimenting with biogas technology are discovering. Biogas, a mixture of methane and carbon dioxide, is produced by the fermentation of organic matter. The process of anaerobic fermentation is a natural one occurring whenever living matter decomposes. By containing the matter—and the process—in a digester or biogas plant, the combustible gas can be trapped and used as fuel for household lighting and cooking. The digested slurry that remains can be used on the land as a soil conditioner and fertilizer.
Biogas plants have attracted much interest in recent years and they are in use in several Asian countries: 36,000 are reported in rural areas of India, 27,000 in Korea and more than 80,000 in China. In most countries the value of the gas has been the prime factor leading to their adoption; 70 per cent of India’s plants, for instance, were built during the energy and fertilizer crisis of 1975-1976—although their use in that country dates back to 1951. Similarly in Thailand and Korea, biogas is being investigated as an alternative to costly charcoal and to save compost materials from being burned.
In Japan and China, reducing pollution from animal wastes has been an important factor. Privies, hen houses and pigpens are bud! in proximity to the fermentation chamber in China. Examinations of the digested slurry have shown that the total number of parasite eggs was reduced by 93. 6 per cent, hookworms by 99 per cent and no schist some flukes were found.
The greatest benefits from biogas systems, however, are probably to be derived from the manurial value of the slurry, although it is not widely used outside of India and China. Vegetable farmers near Calcutta found that the digested slurry produced bigger and better tasting peas than did other fertilizers and the weight of root vegetables increased by nearly 300 per cent.
Summary
The production of biogas by fermentation of animal and vegetable wastes is a technology that has been largely developed and used in the【71】countries. Only very recently have scientists in the industrialized nations begun to show an interest—presumably because of the "energy【72】,". Family-sized-biogas【73】first came into widespread use in India in the 1950s in an effort to make a cleaner and more efficient use of cattle dung. The programme really expanded in the 1970s, and today there are as many as 100,000 plants throughout the world. Most are in domestic use to provide fuel for plants, but some larger units are operated in order to recycle wastes, supply fertilizer, control pollution and improve【74】. One Chinese study has shown that digestion of animal【75】in the airtight digesters greatly reduces health hazards from parasitic diseases. One Indian study has estimated that the value of the fertilizer obtained is in itself greater than the cost of producing the biogas. Thus, the system is economically sound, in addition to other benefits such as a cleaner, healthier environment.
选项
答案
cooking and lighting
解析
第四段,…the combustible gas can be trapped and used as fuel for household lighting and cooking,由于字数的限制,可以去掉修饰词。combustible易燃的。
转载请注明原文地址:https://kaotiyun.com/show/iQyK777K
本试题收录于:
A类竞赛(研究生)题库大学生英语竞赛(NECCS)分类
0
A类竞赛(研究生)
大学生英语竞赛(NECCS)
相关试题推荐
Likepeople,eachcountryhasuniquecharacteristics.Manycountriesareknownbytheproductstheyproduce.Theseproductsare
Forecastingwhatlifeisgoingtobelikeyearsdownthelineisariskybusiness.Eventheexpertsdon’talwaysgetitright.T
Whenyouopenthebusinesssectionofanynewspaperattheendoftheyear,allthereportsseemtobeaboutresultsforthefis
Whenyouopenthebusinesssectionofanynewspaperattheendoftheyear,allthereportsseemtobeaboutresultsforthefis
Althoughhehasnoeducation,heisoneofthe______businessmeninthecompany,whichwasestablishedbyMr.Smiththreeyearsa
Diamondshavelittle______valueandtheirpricedependsalmostentirelyontheirscarcity.
Mymotherhasalwayshadatendencyto__________theimportanceofminorproblems.
TheMid-AutumnFestivalisanimportantfestivalinsomeAsiancountries.Becausethedateofthisfestivalissetaccordingto
TheMid-AutumnFestivalisanimportantfestivalinsomeAsiancountries.Becausethedateofthisfestivalissetaccordingto
Onceyourbusinessbecomesinternational,_________constantlywillbepartofyourlife.
随机试题
下列选项中,必须接受义务教育的是()
有机磷杀虫药中毒时引起体内大量蓄积的物质是
新中国成立后,我国第一部《工会法》颁布于_________。
关于芒硝现代应用叙述错误的是
关于抗疟药,下列哪一项叙述是正确的
患者,女性,45岁。下班后感到心慌而就诊。护士为其数脉搏时,发现每隔两个正常的搏动后出现一次过早的搏动。该护士判断此脉搏是
关于《建设工程工程量清单计价规范》运用的说法,正确的是()。
同时履行抗辩权的适用条件是( )。
WhoisEugeneLang?
Manycountriesneedtodomoretooffereducationandtrainingforpeopleofallages.SosaysanewreportfromtheOrganizatio
最新回复
(
0
)