Owing to the population boom, urbanization and industrialization, the water demand all over the world has been increasing rapidly. Nevertheless, as a result of climate change and water pollution, the water supply becomes less. Many countries are faced with the problem of water shortage. Although Hong Kong does not encounter this problem now, the water condition is in great danger (Liu, 2012a).

According to the Water Supplies Department (WSD), 70%-80% of Hong Kong’s water supply comes from Dongjiang, a main branch of the Pearl River in Guangdong province, and the remaining 20%-30% comes from rainfall (WSD, 2012). The WSD has forecasted that fresh water demand in Hong Kong in 2030 will reach to 1.31 billion cubic meters, which is 360 million more than today (WSD, 2012). The increasing water demand and vulnerable water supply (which will be discussed later) causes severe water shortage risk for Hong Kong. In order to minimize the risk, the government has considered three major possible solutions, namely buying water from Dongjiang, developing desalination, and water reclamation. In my opinion, water reclamation is the most feasible way to minimize the potential water shortage risk for Hong Kong now.

The current solution to address the water issue that is buying water from Dongjiang is definitely not reliable. In fact, Dongjiang has become very vulnerable. First of all, the total water resources of the Dongjiang Basin have declined in recent years (Liu, 2012a). The quantity of average annual water resources over the last ten years was 23.1 billion m3, 30% less than the historical average of 33.1 billion cubic meters (Liu, 2012a). Therefore, the water supply for Hong Kong may not be guaranteed. Secondly, the Dongjiang River Basin directly supplies the industrial, domestic, and ecological water used by nearly 40 million people living in six cities in Guangdong province (Liu, 2012a). Some of the cities are experiencing rapid urbanization and industrialization, such as Dongguan and Heyang. As a result, the future water demand will increase rapidly. Meanwhile, the population growth rate in the region will continue growing, straining already highly stressed water resources (Liu, 2012a). The fierce water resources conflict in Guangdong province may also threaten the water supply for Hong Kong. More importantly, because of the water pollution along the Dongjiang Basin, the water quality of Dongjiang has been degraded. The rate of reaching the standard water quality of Dongjiang has dramatically dropped from 61.9% in 2008 to 21.7% in 2011, which causes higher costs for Hong Kong to purify the polluted water (Liu, 2012b). At the same time, more domestic and industrial pollution sources are moving up-stream in the Dongjiang Basin (Liu, 2012b). Hence, more water will be polluted. In one word, a vulnerable Dongjiang is a vulnerable Hong Kong (Liu, 2012a).

Another alternative is desalination. It may help address the potential water shortage problem in Hong Kong in the far future. Nevertheless, it is not a feasible way for current Hong Kong. Desalination provides a large amount of water for people in terms of both potable water and non-potable water. 1/50 of people in the world rely on desalination to get potable water (Baidu, 2013). In addition, since the water sources are not impacted by the outside climate condition, it is relatively stable. Additionally, the water quality is high as well. Although desalination has so many advantages, as to Hong Kong, desalination is not the most feasible way to tackle the potential water issue. The cost of desalination is extremely high, when compared with buying water from Dongjiang and reclaimed water. The government estimates that the production cost of desalination is HK$12 per cubic meter excluding transportation costs, while buying water from Dongjiang only costs HK$8 per cubic meter in total (Luo, 2013). Therefore, it is quite difficult for the public to accept much higher water price right now. That is to say, vigorously developing desalination is not a wise choice.

However, compared with buying water from Dongjiang and desalination, water reclamation is actually the most feasible solution for current Hong Kong. Reclaimed water is defined as “the end product of wastewater reclamation that meets water quality requirements for biodegradable materials, suspended matter, and pathogens” (Levine & Asano, 2004). For Hong Kong, reclaimed water should be used for non-potable purposes now, especially for toilet flushing, high-tech industry, fire fighting, road cleaning, car wash, irrigation of green areas (e.g. golf course), as well as fishponds and fountains. The reasons are as follows. On the one hand, the current technology in Hong Kong is not mature enough. On the other hand, the water quality requirement of non-potable usages is not very high, which reclaimed water can achieve. From its definition and usages, we can know that reclaimed water contributes a lot to saving water in a stable, environmentally friendly and economical way.

First of all, water reclamation is indeed beneficial in saving water resources. Water consumption of non-potable purposes takes up 10% to 20% of the total water consumption in Hong Kong. Therefore, implementing water reclamation is estimated to reduce water consumption by 10% to 20% correspondingly (Luo, 2006).

Secondly, reclaimed water is a stable water source. On the one hand, the quantity of wastewater is huge and stable. Now, about 2.6 million m3 of domestic and industrial sewage is generated in Hong Kong every day (WSD, 2012). On the other hand, reclaimed water is rarely impacted by the external interference, such as the weather. Thus, reclaimed water sources are not vulnerable.

What is more important is that reclaimed water is environmentally friendly, and it is quite beneficial to achieve sustainable water consumption, which is the vital advantage that either buying water from Dongjiang or desalination does not have. Compared with the current wastewater treatment that pouring the wastewater that has been simply treated into the Victoria Harbor, water reclamation recycles wastewater for meaningful uses and stops 800 tonnes of pollutants from entering the Victoria Harbor every day (WSD, 2012). Therefore, the marine water quality will be improved. In this way, the marine ecosystem will become better, and the marine life will grow better as well, which actually indirectly protects human health.

What is more, water reclamation is relatively economical. According to the WSD (2012), the total cost of reclaimed water is approximately HK$10 per cubic meter, which is 25% less than the production cost of desalination. Although its total cost is still higher than that of buying water from Dongjiang, reclaimed water is more reliable and environmentally friendly. Moreover, compared with the other two solutions, water reclamation also saves lots of abatement costs. The Hong Kong government has spent quite a large amount of expenditures to abate the water pollution in the Victoria Harbour. However, the water reclamation does not demand these costs at all. Besides, since total water consumption is reduced by water reclamation, less Dongjiang water is needed. Therefore, the cost used to buy Dongjiang water will be reduced to some extent. Although water reclamation still needs social costs, such as the technology input and the construction of pipeline, the costs are proved to be smaller than the profits and social benefits in other countries, such as Singapore (Tortajada, 2007).

In conclusion, for the sake of minimizing the potential water shortage risk, water reclamation is the most feasible way for current Hong Kong. The current solution that buying water from Dongjiang is not reliable in the long run. As for desalination, its potential capacity to tackle the issue is remarkable. Nevertheless, it is still extremely costly for Hong Kong now. In contrast, water reclamation is the most feasible one based on the following four aspects: it will indeed reduce water consumption; reclaimed water provides stable water sources; it is the most environmentally friendly way to tackle the problem; it is a relatively economical way to deal with the potential water shortage issue. However, the technology of reclaimed water in Hong Kong is still not mature enough. There is still a long way to go.





Reference:

Baidu. (2013). Reclaimed water. Retrieved from
http://baike.baidu.com/view/345439.htm

Levine, A., & Asano, T. (2004). Recovering sustainable water from wastewater. Environmental Sience and Techonology, 201A, Retrieved from
http://pubs.acs.org/doi/pdf/10.1021/es040504n

Liu, S. (2012). A vulnerable dongjiang is a vulnerable HK. Retrieved from http://chinawaterrisk.org/opinions/a-vulnerable-dongjiang-is-a-vulnerable-hong-kong/

Liu, S. (2012, December 27). The water quality of Dongjiang has been degraded. HKET. Retrieved from
http://www.hket.com/eti/article/57ccc163-b15b-4313-a5ea-af90683149ca-749911

Luo, J. S. (2013, February 28). Desalination plant is built up in Tseung Kwan O. Wenweipo, p. A10.

Luo, L. R. (2006, April 18). Using reclaimed water for non-potable purposes can save 20% water resources. Wenweipo. Retrieved from
http://paper.wenweipo.com/2006/04/18/HK0604180011.htm

Tortagada C. (2007). Water management in Singapre. Retrieved from
http://www.cscollege.gov.sg/Knowledge/ethos/Issue%202%20Apr%202007/Pages/W ater-Management-in-Singapore.aspx

Water Supplies Department. (2012). Water resources in Hong Kong. Retrieved from http://www.wsd.gov.hk/en/water_resources/raw_water_sources/water_sources_in_hong_kong/index.html



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