Water quality problems and potential for wetlands as treatment systems in the Yangtze River Delta, China

This paper summarizes water pollution problems in the Yangtze River Delta, China, caused by rapid economic growth and lack of wastewater treatment. Although precipitation and river runoff are abundant, surface waters in and around the delta are seriously polluted because of the dense population that contributes domestic sewage, and non-point source drainage from intensive agriculture, aquaculture, animal husbandry, and numerous small enterprises. On the other hand, the delta itself is a huge wetland with many artificial and natural wetlands, such as paddy fields, reed marsh, lakes, and rivers. How to make full use of these wetlands to improve the water quality in the Yangtze River Delta is an important challenge for wetland scientists. Potential solutions include establishment of constructed wetlands near outlets of sewage discharge tunnels, and developing floating mats on open water surfaces. Pilot experiments in the Yangtze Delta have shown improvements to water quality. In the meantime, clean industrial production lines, recycling water usage, and large scale application of water purification techniques should be implemented to mitigate the sources of water pollution.