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
2013-02-03
114
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 built 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 schistosome 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【61】countries. Only very recently have scientists in the industrialized nations begun to show an interest--presumably because of the "energy【62】". Family-sized-biogas【63】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【64】. One Chinese study has shown that digestion of animal【65】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
crisis
解析
(从题干中的presumably(推测起来,大概)可知,该题属常识推理题。第四段,沼气事实上可以帮助conserving resources and finding alternative sources of fuel,可以猜想工业化国家对沼气感兴趣可能是由于能源危机,即energy crisis。)
转载请注明原文地址:https://kaotiyun.com/show/4UyK777K
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
WhilebaseballisoftendescribedasthenationalsportoftheUnitedStatesofAmerica,itprobablydevelopedfromaneighteent
TensofmillionsoftelevisionviewersaroundtheworldhavebecomefamiliarwiththemusicaltalentshowTheXFactor,whichor
Seedcataloguesfeaturehundredsofdifferentfloweringspecies.Forthepersonjustbeginningagardenthiscanbebewildering,
Inordertogetinformationaboutdistantplanets,scientistsinventedspacecrafttotravelintothesolarsystemtoseethepla
TherearetworeasonswhyIwantedtocometosouthernGermanytostudy.IwantedtobeatthecentreofEurope,withineasyrea
ThestudentislookingfortheEconomichistoryoffice.
Muchofthediscussionofenvironmentalproblemsinthepopularpressleavesthereaderwiththeimpressionthatmattershavebe
Peopletendtoamasspossessions,sometimeswithoutbeingawareofdoingso.Indeedtheycanhaveadelightfulsurprisewhenthey
Spaceandoceansarethenewworldwhichscientistsaretryingtoexplore.
Whenearlyexplorerssailedroundtheworld,theyusethestarstoshow【M1】________themtheirposition.Nowdriverscanusesate
随机试题
稳压二极管的反向特性曲线越陡,稳压效果________。
申请经济适用住房的家庭必须同时符合下列条件()
患者,男,35岁。因严重腹泻、呕吐2天就诊。经医生检查,发现患者出现低血压和代谢性酸中毒的症状。便常规检查为水样便,镜检无RBC,患者自述发病前曾食用未煮熟的虾类。患者粪便进行湿片镜检发现有穿梭样运动的细菌,则该患者感染的致病菌是何种细菌
A.葡萄球菌B.沙门菌C.变形杆菌D.孢霉菌E.镰刀菌进食乳制品引起食物中毒的常见病原体是
患者,男,30岁。十二指肠溃疡病史5年。今日突然呕血伴休克。应首选采取的抢救措施是()
一幢位于7度设防烈度区140m高的办公楼,可以采用下列哪种结构类型?
F热电厂2×300MW扩建工程的燃煤输送系统包括:煤仓,运煤系统,破碎系统和给煤系统。煤仓内堆煤最大高度为14m。燃煤由汽车运人电厂,采用带式输送机将煤送到磨煤机中磨成煤粉,煤粉送至锅炉喷燃器,由喷燃器喷到炉膛内燃烧。扩建工程使用该厂原有的2个容积500
宣宣是某幼儿园大班的孩子,在该幼儿园里,他是出了名的“身强体壮”的顽皮鬼,与其他小朋友矛盾不断,今天上午又挨了老师的一顿狠批。事情是这样的:前几天,宣宣所在的班刚转来了一个小朋友李明,李明个子也比较高,这样,宣宣和李明成为该班仅有的两个“高个”。宣宣主动找
某公司在初秋以每公斤0.5元的价格收购鲜玉米,采取保鲜技术处理,于冬春季出库上市,每公斤6元还供不应求。造成这种价格差异的原凶是()。
【米利都学派】(MilesianSch001)
最新回复
(
0
)