Along with the speedy expansion of economy and the constant increase of urbanization, water pollution worsens day by day in China. Statistics show that in 1999, the total amount of sewage in the cities and towns throughout China was 60.6 billion tons. Of them, 67% is industrial wastewater, twice of that in 1980. Monitoring result shows that 21% of the rivers suffered from the pollution in 1980 and 38% suffered from it in 1999. The rivers with the heaviest pollution are: 80% in Huihe, 64% in Hailuan, 60% in Songliao and 50% in Yellow Rivers...