is regarded as another future means of water provision. According to Bashitialshaaer et al (2009), in 2009 there were 33 wastewater treatment plants with a capacity of 748 billion cubic metres per year.
3. Requirements要求
Cost should be the principal consideration of water provision because an expensive cost might limit the scale of application of methods. This also includes the cost of energy consumption.
Social acceptance plays a significant role in the development of water supply technologies. If the water cannot be accepted by society, it will lead to very little consumption.
Environment has a profound influence on human beings. In order to prevent water supply technology undermining the environment, its impacts on the environment should be considered.
4. Presentation of options选项介绍
4.1 Desalination
Desalination is “a specific treatment process to take minerals from saline water to purify for drinking water and irrigation” (Al-Sahlawi, 1999). Sometimes this process is used to take salinity and other pollutants from wastewater. The general method of desalination is reverse osmosis or multi-stage flash distillation (Lone Star Chapter of the Sierra Club, 2008).
4.2 Water Reuse
Water reuse means treating wastewater to a specific quality, and then using treated or reclaimed water from one application for another application (McKenzie, 2005; Asano, 2006). The resources for wastewater reuse are various; according to Asano (2006), they could be domestic wastewater, industrial sewage, municipal sewage or agricultural wastewater.
5. Comparison of Options期权比较
5.1 Cost
Although the cost of desalination has decreased dramatically in the past three decades, it is still expensive to use in large scale. Alghariani (2003) points out that the expenditure of desalination consists of initial investment for equipment, running costs (including staff and maintenance), as well as chemicals or specialised parts. At present, according to the Third World Water
Assessment Report (UNESCO, 2009: 155), the average cost of desalination is between $0.60/m3 and $0.80/m3. Moreover, Owens and Brunsdale (2000, cited in Alghariani, 2003: 5) claim that the cost of desalination in Florida can even be less than $0.55/m3, which is one-tenth of the cost price in 1979. However, as Wright (2009) points out, this cost is still higher than other water supply technologies. Apart from expenditure, desalination is generally considered a high-cost process due to the enormous energy consumption (Abu-Arabi, 2007). Nevertheless, this does not seem to be a problem for Saudi Arabia. According to the CIA (2010), the proven oil and gas reserves in Saudi Arabia are respectively the first and fifth in the world. As Abu-Arabi (2007) points out, in Saudi Arabia the annual solar energy received by each square kilometre of land is equivalent to 1.5 million barrels of crude oil. Abundant energy may lead to a low price.
Nevertheless, oil is non-renewable and oil reserves are estimated to last less than one century (World Energy Council, 2010), so the consumption of energy should be taken into account as a considerable cost. Moreover, the treatment of the waste gas ge
本论文由英语论文网提供整理,提供论文代写,英语论文代写,代写论文,代写英语论文,代写留学生论文,代写英文论文,留学生论文代写相关核心关键词搜索。