Yunnan Province is experimenting with digitized means to restore part of the eutrophic water in Dianchi Lake, the largest freshwater lake on the Yunnan-Guizhou Plateau in southwest China.

With a total area of nearly 300 square kilometers, Dianchi Lake has been suffering from eutrophication since the 1980s. A direct result was an over-reproduction of blue green alga. And the lake lost its beauty, as it has been covered by a layer of the greenish, greasy neuston. To restore the eutrophic lake has been included in major ecological restoration projects under the state plan.

How to contain proliferation of the blue green alga has been a thorny problem in the eco-restoration project. At a recent seminar on water pollution control in Dianchi, held in Kunming, capital of Yunnan, a digital eutrophication control system ushered in by Shanghai Sun Ai Environmental Protection Technology Engineering Co., Ltd. was highly evaluated.

In April 1999, the company started to adopt the computerized system to help put the alga inhibitor made from biological enzyme and bacteria compound into a 1-square kilometer eutrophic water in Dianchi. The experiment took 10 days and achieved encouraging results as the water quality reached set standards, said a company official at the seminar.

Some specialists in water pollution control suggested that the digital technology be applied to a larger area of the eutrophic Dianchi Lake.

Eutrophication refers the degradation of water function and the deterioration of water quality, caused by discharge of nutrients and organic pollutants to water body.

(Xinhua News Agency February 7, 2005)