首页
登录
职称英语
Biogas: a Solution to Many Problems In almost all developing
Biogas: a Solution to Many Problems In almost all developing
游客
2023-10-13
42
管理
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 ma-nurial 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.
The production of biogas by fermentation of animal and vegetable wastes is a technology that has been largely developed and used in the【R1】______countries. Only very recently have scientists in the industrialized nations begun to show an interest—presumably because of the "energy【R2】______".
Family-sized-biogas【R3】______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【R4】______One Chinese study has shown that digestion of animal【R5】______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. [br] 【R2】
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://tihaiku.com/zcyy/3094749.html
相关试题推荐
Diamondshavelittle______valueandtheirpricedependsalmostentirelyontheir
ThomasMalthuspublishedhisEssayonthePrincipleofPopulationalmost200
ThomasMalthuspublishedhisEssayonthePrincipleofPopulationalmost200
ThomasMalthuspublishedhisEssayonthePrincipleofPopulationalmost200
ThomasMalthuspublishedhisEssayonthePrincipleofPopulationalmost200
ThomasMalthuspublishedhisEssayonthePrincipleofPopulationalmost200
Thesocialsciencesareflourishing.Asof2005,therewerealmosthalfamil
Thesocialsciencesareflourishing.Asof2005,therewerealmosthalfamil
Thesocialsciencesareflourishing.Asof2005,therewerealmosthalfamil
Diamondshavelittle_________valueandtheirpricedependsalmostentirelyonth
随机试题
TheAttorneyGeneralorderedafederalautopsyofBrown’sbody,seekingto______
Theword"option"inthesecondparagraphcanbereplacedby________.[br]When
[originaltext]TheEducationSelectCommitteehasbeenexaminingtheunderac
[originaltext]FromCaliforniatoConnecticut,babiessitonthelapsofthe
2017年5月,全球的十几万电脑受到勒索病毒WannaCry的攻击,电脑被感染后
商品的二因素是由生产商品的劳动二重性决定的。()
脑性瘫痪运动障碍的特征是A.进行性中枢性运动障碍 B.复发缓解性中枢性运动障碍
李某的月均收入为4500元,购买小汽车每月须偿还的贷款额为800元,住房抵押
颌面及颈部接受放射治疗的患者常发生A.慢性龋 B.继发龋 C.深龋 D.猖
《中华人民共和国增值税暂行条例》是由()制定的。A.全国人民代表大会
最新回复
(
0
)