Beijing uses reclaimed water to replenish rivers and lakes

Amid the heat wave, clean rivers and lakes such as the Kunyu River and Forbidden City Moat have brought some cool to the city of Beijing. Residents perhaps do not realize that the clean water in those rivers mostly came from recycled water.

According to statistics issued by Beijing Water Bureau on July 21, a total of 110 million cubic meters of water was injected into Beijing's urban rivers and lakes in the first six months of this year, an increase of 28 million cubic meters year-on-year. Of this, 75 percent came from recycled water.

There are 52 major rivers within Beijing's Sixth Ring Road, with a total length of 520 kilometers. These rivers have all been treated and cleaned for years. To keep up the water volume in the river channels and to create a sound urban water environment, Beijing's water departments have annually increased the amount of water used for rivers and lakes through comprehensive management and scientific arrangements.

Beijing is a city that is seriously short of water, and its current per capita volume of water resources is less than 300 cubic meters, only one eighth of China's average. In order to save precious water resources, Beijing has strengthened efforts to improve the recycling of water resources. Currently, Beijing has a total of 13 water treatment plants that can supply 710,000 cubic meters of recycled water a day. The proportion of sewage water treated in urban districts has reached 93 percent and the ratio of recycled water used is 53 percent. In 2008, large amounts of recycled water had been used for Beijing's lakes and parks, as well as over 70 percent of urban water channels. A total of 180 million cubic meters of recycled water has been utilized annually.

Using recycled water to supplement rivers and lakes in the city can save a significant amount of ground water and surface water. However, some of Beijing's water treatment plants were established a long time ago and were designed in accordance with national water discharge standards compiled for urban water treatment plants. Thus, although all the recycled water discharged from these plants meets discharge standards, problems like eutrophication will occur if they are used for urban landscapes, resulting in environmental issues such as algae. In 2009, Beijing launched projects to upgrade nine water treatment plants. Deep membrane treatment and other technology will be used in the water purification process to improve the water quality of deeply purified sewage water, which indeed is better. Technicians said that upon the completion of the upgrade, key quality indicators of recycled water will reach the surface water Class-IV standard, so it will be allowed to enter lakes and rivers in the city for scenery. People will not notice any difference between recycled water and surface water or groundwater.

It is now the middle of summer when water-related environmental problems like algae tend to emerge. Urban river and lake administrative departments said that their personnel will step up efforts to randomly check water environments every day and clean rivers and lakes in the city three times a day to ensure no flotsam. In addition, administrative departments remind residents that the water in rivers and lakes are recycled water and they should not go swimming or fishing in them.

 

[source:china daily]