Reclaimed water can be used in ecological landscape, industrial production, urban greening, road cleaning, vehicle washing, construction, urban miscellaneous use and other fields to reduce the intake of urban fresh water and the external discharge of sewage. Nowadays, from street car wash shops to urban industrial parks, the use of reclaimed water has entered people’s daily production and life. According to the data, the consumption of urban renewable water conservancy in China was 16.1 billion cubic meters in 2021, an increase of 18.9% over 2020.
In 2021, the national development and Reform Commission, the Ministry of housing and urban rural development and other 10 departments jointly issued the guiding opinions on promoting the utilization of sewage resources, which proposed that by 2025, the utilization rate of reclaimed water in water deficient cities at and above the prefecture level in China will reach more than 25%, and that in Beijing, Tianjin and Hebei will reach more than 35%.
How to achieve this goal? In recent years, Beijing, Yinchuan, Shanghai Chongming and other places have been actively exploring and accelerating the resource utilization of urban domestic sewage.
improve the treatment capacity and broaden the use scenario of reclaimed water
Since the 13th five year plan, Beijing has continuously promoted the construction of reclaimed water facilities with improving the quality of urban and rural water environment as the core. The city has newly (expanded) 28 urban reclaimed water plants and upgraded 12 urban sewage treatment plants. The sewage treatment capacity of reclaimed water plants above designated size has reached 6.879 million cubic meters / day. The consumption of reclaimed water in the city has increased from 1 billion cubic meters to 1.2 billion cubic meters, of which the allocation of reclaimed water has increased to 490 million cubic meters. The scope of reclaimed water use has been further expanded to become a stable and reliable “second water source”.
Under the supply of reclaimed water, the basins of Qinghe River, Bahe River, Liangshui River and Tonghui River in the central urban area have been basically paid off, and the black and smelly water bodies in the built-up area of Beijing have been basically eliminated. Four water systems, such as ribbons, linger around the capital, and flow into the two cultural belts of the Grand Canal and Yongding River, which flow into the sub center of Beijing, Tianjin and Hebei Province, significantly improving the water environment and natural ecology of Beijing, Tianjin and Hebei.
In addition, Beijing also takes the use of reclaimed water as an important way to promote water conservation and broaden the use scene of reclaimed water. “During the construction of reclaimed water plant, we will comprehensively consider the conservation and recycling of water resources, and gradually promote the use of reclaimed water in the main production process links of industrial enterprises, toilet flushing in office areas, river and lake water replenishment and other aspects.” The relevant person in charge of the Beijing Municipal Water Department said that, for example, as China’s largest and most technologically advanced integrated circuit chip manufacturing enterprise, Semiconductor Manufacturing International Corporation(688981) has a large water consumption in its production line. In order to save resources, the enterprise has developed a complete set of filtration and recovery equipment for industrial wastewater. The produced cleaning wastewater is removed by activated carbon adsorption particles, security filter, RO (reverse osmosis) membrane and other equipment. After passing the test, it is supplied to ultra pure water equipment again to replace tap water as production water. The plant has been built for nearly 20 years. Through the recycling system, more than 24 million tons of water resources have been saved.
do a good job in “water article” and inject “water power” into urban development
“Yinchuan is a serious water shortage city, and the per capita share of water resources is only 60% of the national average. The shortage of water resources has become the main bottleneck restricting the social development of our city.” The relevant person in charge of Yinchuan Municipal Administration said that according to the requirements of the national water saving action plan and the guiding opinions on promoting the resource utilization of sewage, Yinchuan will further accelerate the resource utilization of sewage.
In order to give full play to the utilization value of reclaimed water, Yinchuan has built the first and second reclaimed water plants. At present, the first and second reclaimed water plants in Yinchuan are in orderly operation, which can not only be used for ecological water replenishment, but also provide sufficient landscape water, municipal miscellaneous water and industrial water for the whole city, so as to realize the recycling of water resources.
It is reported that in March this year, Yinchuan reclaimed water development and utilization Co., Ltd. was officially inaugurated and established, and signed the reclaimed water supply agreement with various greening management and maintenance units, industrial enterprises and community property service enterprises of Yinchuan garden Administration Bureau. Since then, Yinchuan has realized the transformation from “asking for water from the government” to “looking for water from the market”.
“Soon, the reclaimed water in Yinchuan will become the new ‘second water source’ of the city, gradually solve the problem of reclaimed water use in industrial enterprises, landscape water system and scattered landscaping in the city, inject ‘water power’ into urban development, and achieve the goal of ‘the utilization rate of reclaimed water in Yinchuan will exceed 50% by 2025’ as soon as possible.”
focus on key areas and promote sewage resource utilization
In order to effectively improve the utilization rate of sewage resources, Chongming District of Shanghai has integrated the use of reclaimed water into the great protection strategy of the Yangtze River, carefully benchmarked the implementation plan of Shanghai for promoting the utilization of sewage resources, and vigorously promoted the utilization of sewage resources in key areas such as urban domestic sewage, rural domestic sewage and industrial wastewater.
In terms of promoting the utilization of urban domestic sewage, Chongming district has explored and built a complete set of reclaimed water utilization system with Chongming Chengqiao sewage treatment plant as the pilot base. The water intake point of the whole system is the regeneration pool behind the ultraviolet disinfection pool (with a capacity of 150 m3), which is transported to each water consumption point through pipeline pump and independent reclaimed water pipeline, and obvious signs are set at each water consumption point. This has successfully used reclaimed water for internal water needs such as drying and deodorization spray cooling of sewage treatment plant, greening irrigation and landscape pool replenishment, as well as municipal road cleaning and greening irrigation in Chengqiao town. The comprehensive utilization of reclaimed water inside and outside the plant has reached 2450 m3 / day.
