節約工業用節水 | 環境資訊中心

節約工業用節水

2001年08月27日
ENS報導;陶俊 編譯;吳國玢、李瑞玉 審校

一般說來,工業是用水大戶。根據南非水務部的資料,工廠每生產一輛小型轎車得耗水45萬公升,每生產一輛自行車耗水130公升,製造一雙鞋子耗水53公升。莫三比克在進行開採煤礦和洗煤過程中,估計每秒鐘就得用掉1立方公尺的水。雖然非洲的工業部門用水量相對較低(例如,在南非的用水比例是8%不到),但是仍有很大的改善空間。在世界上某些地方,某些用水需求量大的工業已大幅減少了生產所需之水量,其中包括化學、鋼鐵和造紙工業。在某些國家,這些工業部門在目前的生產過程中既再利用用過的水,又回收用過的水,而且還重新設計出用水量較少的製程。例如,在1950年到1990年期間,美國工業用水量下降了三分之一還多,工業產值卻增為四倍。在前西德地區,今日工業用水總量與1975年的相同,工業產值卻增加45%。在瑞典,嚴格的污染控制措施已使紙漿和造紙工業的用水量減少一半,而在十年略多一點的時間內,其產量則增加了兩倍。

然而,發展中國家在這方面的進步仍舊緩慢。例如,在中國每生產一噸鋼需要23~56立方公尺的水,而在美國、日本和德國,平均只需要6立方公尺不到的水。同樣地,在中國製造一噸紙需要約450立方公尺水量,是歐洲國家造紙用水量的兩倍。現在中國很多大型流域都面臨嚴重的經常性缺水。黃河是中國最大的河流之一,但現在人們認為這條河由於被過度超量取用,河水很快就會乾涸。此外,中國還有100多座城市因過度抽取地下水而發生危險的地層下陷。

Industrial Water Conservation

Industry is, generally speaking, water-intensive. According to South Africa's Department of Water Affairs, a factory can use 450,000 litres of water to produce a small car, 130 litres to produce a bicycle, and 53 litres to make a pair of shoes. Coal mining in Mozambique has been estimated to use up to 1 cubic meter per second in the mining and washing process. Although water use for the industrial sector is relatively low in Africa (for example, it is under 8% in South Africa), there is still much room for improvement. In some parts of the world, certain water-intensive industries have greatly reduced the amount of water needed for production, including chemicals, iron and steel, and paper. In some countries these industries are both reusing and recycling water in current production processes and redesigning production to require less water. For example, in the US, industrial water use dropped by over one-third between 1950 and 1990, while industrial output nearly quadrupled. In the former West Germany the total amount of water used in industry today is the same as in 1975, while industrial output has risen by nearly 45 percent. In Sweden, strict pollution-control measures have cut water use in half in the pulp and paper industry, while production has doubled in little more than a decade.

Progress has been slow in developing countries, however. In China, for instance, the amount of water needed to produce a ton of steel ranges from 23 to 56 cubic metres, whereas in the US, Japan and Germany, the average is less than 6 cubic metres. Similarly, a ton of paper produced in China requires around 450 cubic metres of water, twice as much as used in European countries. China now faces severe, chronic water shortages in many of its largest watersheds. China's Yellow River, one of its largest rivers, is now considered to be ephemeral because it is so over-allocated. China also has more than 100 cities that are sinking dangerously due to excessive extraction of groundwater.