China Has New Way to Relieve Water Hyacinth Plague

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Last updated at: (Beijing Time) Friday, February 08, 2002

China Has New Way to Relieve Water Hyacinth Plague

A new drink with water hyacinth, a nutritious aquatic plant, as raw material, has been selling well in Hubei Province, central China.

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A new drink with water hyacinth, a nutritious aquatic plant, as raw material, has been selling well in Hubei Province, central China.

The developer, a local company, has also developed a new technology for extracting nutrient from the aquatic plant. The company is planning to produce additives to foodstuffs, health care products, medicine and feed with the technology.

This plan is hailed by environmentalists. Weng Lida, head of the Yangtze River water resources protection bureau said, "When people are striving to get water hyacinth to make profits, a series of ecological problems caused by the aquatic plant will be solves easily."

Water hyacinth, rich in protein, amino acid, carotene and microelements, was imported from Venezuela into southern China in the 1950s and was used to feed pigs.

The water plant, which one can harvest more than 300 tons in a hectare of water area, helped pig raisers overcome the difficulty of grain shortage.

However, with the growth in grain production in the last two decades, few farmers nowadays bother to gather the plant in water.As a result, water hyacinth grows "at an amazing speed" in eutrophic streams in the process of rural industrialization in southern towns, said Liu Shixin, an expert from Hubei Academy of Agricultural Science.

Under such circumstances, the fast reproducing aquatic plant, which has slender rootstocks, feathery roots, and rosettes of spongy and inflated stalked leaves, often clogs slow-flowing streams in inland rivers and lakes.

Yunnan Province, in southwest China, has earmarked more than four billion yuan (482 million U.S. dollars) in the past few years,trying to control water hyacinth in Dianchi Lake.

Last autumn, a large stretch of water hyacinth was seen floating on the lower reaches of the Hanjiang River near Wuhan City in central China for 20 days; Yaojiang, Fenghua and Yongjiangrivers that cut through Ningbo City in east China were almost clogged up by the aquatic plant.

In part of the preparations for the Asian Pacific Economic Cooperation leader's meeting in Shanghai last October, more than 30 workers spent nearly 10 days to clear 455 tons of water hyacinth floating on the Suzhou River.

Some scholars enlist the plant as one of the world's top ten vermin plants since it may become obstacles in waterways and irrigation channels or even aggravate dangers by affecting the effort to drain waterlogged fields in time of flood.

Growing in big density, water hyacinth also affects the growth of underwater plants and reduces the output of aquatic products, said 62-year-old Liu, a specialist in the study of the water plant.

"As a matter of fact," he said, "water hyacinth contributes a lot in purifying polluted water." Under proper conditions, a hectare of water hyacinth can absorb the elements of nitrogen and phosphor exhaled by 800 persons in a single day.

It is a low-cost, energy-saving and efficient to purify polluted water by growing water hyacinth, Liu said. But the problem is it costs a lot to dredge up the water plant and what isgathered has to be handled as refuse, thus causing new pollution.

To solve the problem, Liu and his colleagues spent ten years and finally found solutions to the re-utilization of water hyacinth.

According to their research results, the water plant can be turned into high-protein forage when properly fermented; organic and inorganic fertilizers can be produced based on the rich nitrogen, phosphor and kalium in the plant; and food, medicine andfeed additives can be made with nutrition elements extracted from it.

If water hyacinth can be first used to purify water and then processed on a large scale in the above three ways, the ecologicaltroubles caused by it can be eradicated, Liu said.

China has an annual discharge of 41.5 billion tons waste water,with more than 47 percent of its waterways polluted.

According to Weng, director of the Yangtze River water resources protection bureau, they are considering using water hyacinth to deal with polluted water in a bid to turn them into useful resources, with the help the solutions found by Liu and hiscolleagues.

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