The Beijing municipal government promotes the use of treated wastewater, rather than potable water, at scenic locations, in order to make the most efficient and effective use of water resources.

      Additional treatment of Grade II treated water - the most common product of a wastewater treatment plant - brings the quality level to Grade III. At this grade, recycled water can be used for a greater variety of purposes than at lower grades. It is mostly used for irrigation, washing restrooms and roadways, and supplementing rivers.

      It can also be used in integrative environment management - for purposes such as dust-alleviation - or for washing vehicles or industrial cooling.

      Currently, these four plants can produce 190,000 cubic meters of Grade III treated water daily.

      Qinghe Wastewater Treatment Plant, the country's largest Grade-III, recycled-water-production plant, can produce 80,000 cubic meters of recycled water daily. Of this, 60,000 cubic meters are used for sightseeing purposes in the Olympic Park, while the restsupplements the Qinghe River.

      The Qinghe Wastewater Treatment Plant was China's first domestic wastewater treatment plant and uses advanced ultrafilter-membrane technology, in which its filters are equipped with six units of 0.02-micrometer ultrafilter membrane. Once filtered through these membranes, the water can be further treated with activated carbon and ozone sterilization to reach international standards.

      Today, Beijing's five thermal plants all use recycled water for circulated cooling. Five-million square meters of grassland in the municipality are irrigated with treated water. And more than 18 million cubic meters of reused water will supplement the capital's rivers this year.