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The Development of Sustainable Water Resources in Northern China

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This page was developed from a paper written by a delegate to the 2008 APEC Youth Camp held in Puno, Peru. The purpose of the Youth Camp was to learn about sustainable development especially as it pertains to water-based economies as well as to investigate the culture and economy of the Lake Titicaca region in Peru.


Contents



Abstract

Available useable water resources are a constant problem in northern China. According to the 2003 census, northern China is home to about 42% of the nation’s population with access to only 14% of the nation’s water resources. China as a whole has an annual water availability of 2206 m³ per person, but Northern China only has a water availability of 757 m³ per person. The optimum solution will is a combination of technology and planning that addresses the environmental, economic and social perspectives of the problem.


In keeping with these issues I suggest three things: water reclamation, Virtual Water, and Reverse Osmosis techniques. Since only 5% of the available water resources are used for human consumption and the other 95% need only be fit for industrial and agricultural uses, water reclamation increases the available water resources for both consumption and industry. Reverse osmosis techniques have a greater than 90% water recovery rate and purify the reclaimed water from rivers, rain collection and sewage into sterile water fit for human consumption. Finally, the concept of Virtual Water, or the amount of water going into food and other production goods, allows China to relocate water intensive industries to the south where water is more available.

Full Text of Paper

Introduction

The availability of useable water resources is a constant problem in northern China. According to the 2003 census, northern China is home to about 42% of the nation’s population but only has access to 14% of the nation’s water resources . The World Bank defines “water stress” on a per capita basis as an annual availability of 2,000 m³ per person or less. China as a whole has an annual water availability of 2206 m³ per person, but northern China only has a water availability of 757 m³ per person. . Obviously northern China is a severe case of water stress. The Chinese government is currently implementing the South-to-North Water Diversion Project to help allay some of the water scarcity issues. The government plans to construct a pipeline that will divert 44.8 billion m³ of water annually to the population centers in the north. This project will cost $62 billion dollars—twice as much as the Three Gorges Dam Project. The South-to-North Water Diversion Project is a temporary solution to a growing problem and one that will be expensive to build and maintain. The optimum solution to the water shortages is a combination of technology and planning that addresses the environmental, economic and social perspectives of the problem without incurring a large financial debt. In keeping with these issues, I suggest a combination of three methods/approaches; water reclamation to collect water and re-hydrate the aquifers, membrane technology to purify, and virtual water to allocate the distribution.


Rainwater Collection

Water reclamation increases the available water resources for both consumption and industry . Reclaimed water is defined by Singapore’s National Water Agency as water that has been treated to remove solids and certain impurities, and then allowed to recharge the aquifer rather than being discharged to surface water . Since only 5% of available water resources are used for human consumption, the other 95% need only be fit for industrial and agricultural purposes. Reclaimed water can be collected from the run-off from fields as well as through rainwater harvesting. The latter is especially useful since 85% percent of rainfall in northern China falls between July and September. Furthermore, 40-70% of that rainfall often occurs within a three-day period, making the region prone to drought and flooding. Rainwater harvesting would prevent some of the flooding during the intense rains and would store it away for the periods of drought. Rainwater harvesting is inexpensive and easily accessible to economically disadvantaged areas since collection can be performed on an individual basis in more rural areas or on a larger scale in the urban areas. Rainwater is typically collected from roofs and other large flat surfaces, but before the rain can be collected for filtration and use, it must run through a “first-flush diverter”. Since roofs are a natural collection point for dust, leaves, sticks, bird droppings, insects and other airborne particulate, the first few gallons of reclaimed water from the roof must be dumped–about ten gallons for every 1000 square ft of collection surface . After the initial roof washing, all rainwater goes through a removable screen to filter out any remaining objects and then run to a storage tank; finally, the water is sent through a sand filtration system to remove any particulate. At this stage, the water is not clean enough for human consumption, but it can be used for irrigation, industrial purposes, power generation and fire protection. Reclaimed water has a significant advantage for industrial and agricultural uses: it costs less to produce than drinking water; it reduces the amount of needed fertilizer because the water retains some of the base nutrients such as phosphorus and nitrogen; it reduces the stress on the available drinkable water source; it reduces the water disposal into waterways, which can help reduce nutrient loads in bays and rivers ; and because this water is used to recharge the aquifers it reduces the amount of water lost due to ground water evaporation.


Reverse Osmosis

In order to prepare the reclaimed water for human consumption, a more rigorous sanitation process is required. Reverse osmosis techniques have a greater than 90% water recovery rate; also, they purify the reclaimed water from rivers, rain collection and sewage into consumable water. The water is first pretreated by microfiltration—where the water is forced through a micro-porous membrane with a pore size 0.1 to 10 micrometers (µm) —removing all bacterial contamination. The water is then treated by reverse osmosis. Reverse osmosis is a separation process that uses pressure to work against the natural osmosis gradient by forcing the pure solvent through the membrane while leaving the solutes on the other side of the membrane. The filtered water is now completely free of biological and viral contaminates. This system is also used for the desalinization of salt water, making sea water a viable water resource. One concern with reverse osmosis is the level of membrane fouling or the clogging of the membrane pores by biological and inorganic contaminates. Even though pre-treatment via micro filtration will limit the amount of membrane fouling, the membranes will eventually have to be replaced. Alternatives to reverse osmosis are the use of chemicals such as chlorine or ozone to sterilize the water or activated carbon as a secondary filtration system.


Virtual Water

Finally, the concept of Virtual Water, or the amount of water that is embedded in food or other products needed for its production, helps find a solution to water stress caused by industry. For example, the production of one ton of rice requires two-thousand tons of water, so this is the virtual water value of rice. The quantification of the water value illustrates the advantages of trade with other nations, rather than attempting to produce water intensive goods locally. This also demonstrates the need for China to relocate water intensive industries to the south where water is more available. An infrastructure designed with the concept of Virtual Water in mind can help ease the pressure on northern China’s meager internal freshwater resources and provide the structure for an economic solution to the water scarcity issue. Since water is now viewed as a tradable commodity with an associated value that the economy can use to regulate the distribution and use of water as consumable material.

Conclusion

Overall, the scarcity of available water resources in northern China will not be solved by a singular solution. While, the Chinese South-to-North Water Diversion Project will help provide northern China with a supplement to the current ground water supply it will not be a permanent solution unless other measures are taken to reduce consumption and to increase availability of a useable water supply. Educating people as to how to reduce current water usage, growing more water efficient crops, limiting the amount of water that industrial processes utilize, and developing an improved sewage treatment system will be the basis for solving the bulk of the water consumption issues. An increase in the available water supply will be reached only through the implementation of water purification and reclamation infrastructures and economic plans to limit and control the distribution of water.

References

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