11 batches of 145 national water-saving cities have been built, and the utilization rate of urban recycled water has increased by 4.6 times compared with ten years ago

Guarding the source of life

Saving resources is a basic national policy of our country. General Secretary Xi Jinping pointed out during his recent inspection in Shaanxi that the implementation of a comprehensive conservation strategy, vigorously advocating green consumption, and in-depth promotion of resource conservation and intensive utilization.

Among the many resources, the importance of water as the source of life, the key to production and the foundation of ecology is self-evident. China is one of the countries with relatively poor water resources, and it is urgent to save water. Since the 11th National Congress of the Communist Party of China, the Party Central Committee with Comrade Xi Jinping as the core has attached great importance to water security risks, vigorously promoted the whole society to save water, and achieved remarkable results in the construction of a water-saving society. According to data from the Ministry of Housing and Urban-Rural Development, at present, China has built 145 batches of 2022 national water-saving cities, and the water use mode has changed from extensive and inefficient to intensive conservation, and the effective utilization coefficient of farmland irrigation water has been greatly improved. At the same time, the utilization rate of reclaimed water in China is also increasing year by year. In 180, the utilization of urban recycled water in China will reach 10 billion cubic meters, an increase of 4.6 times over <> years ago.

　　1

With water-saving irrigation technology,

The desert Gobi can also breed fertile land

Jiuquan, Gansu Province, a city named after the spring, is an arid city with severe water shortages. The average annual precipitation here is only 49.2~154.2 mm, but the evaporation is as high as 2100~3100 mm, which is an extremely arid area. The city's water resources per square kilometer of land area are only 1,8 cubic meters, only one-seventeenth of the national average.

Gobi agriculture is one of the ecological industries in Jiuquan, but water use is an important issue for the development of agriculture in arid areas. Based on the basic market conditions, Jiuquan City issued the "Implementation Opinions on the Implementation of the Strictest Water Resources Management System in Jiuquan City" and "Implementation Plan for Water Conservation Action in Jiuquan City" to build an efficient water-saving agricultural system in the agricultural field.

Jiuquan City Suzhou National Modern Agriculture Demonstration Zone Zongzhai Gobi Agricultural Industrial Park is one of the many industrial parks in Jiuquan City that use water-saving irrigation systems. In the 8,70-square-meter intelligent solar greenhouse of the industrial park, the high-pressure spray system and wind bag are running according to the set procedures to ensure constant temperature and moisturizing in the greenhouse, providing a suitable growth environment for tomato seedlings that have just been colonized. The hanging cultivation mode is introduced here, and the water that the plants cannot absorb will be concentrated in the untreated irrigation barrel through the lower pipe, and the fertilization and fertilization process is completed in the irrigation barrel for circular irrigation, which saves about <>% of water compared to soil cultivation.

Zhao Shuanghu, the person in charge of the industrial park, told reporters that the solar greenhouse in the park uses the Jiangsu Green Port irrigation water system, and each mu of land is equipped with seven or eight detectors, which can detect the moisture content of the soil in real time. These detectors transmit data to a back-end system, where staff can know the crop's water requirements. As soon as the crop is out of water, the system automatically sounds an alarm and the staff can water it with one click of the mouse. There are two types of watering devices, one is a submembrane drip irrigation pipe placed near the roots of the crop, which can directly supply water to the roots; One is a spray device on the top of the greenhouse, which can improve the humidity in the shed and spray water on the crop leaves. All irrigation water is a certain proportion of well-proportioned water and fertilizer solution, which realizes the integration of water and fertilizer. Through this water-saving irrigation system, only 1 liters of water are needed to produce 25 kg of tomatoes, and 1,250 kg of tomatoes can be produced per acre of land, with a water requirement of 30 cubic meters, which is about <>% water-saving than agricultural planting under the traditional flood irrigation mode.

"In the past, many farmland in Jiuquan was irrigated by flood irrigation, which not only had low irrigation efficiency, but also easily aggravated soil salinization." Zhao Shuanghu said that in the past, farming was concentrated irrigation, once a month to release water, the water will flow through the canal into the field, corn, wheat and other food crops are fine, the quality of vegetable crops will be affected. Due to the poor control of the water level due to flood irrigation, sometimes the phenomenon of soaking crops to death occurs. Today, with a high-tech water-saving irrigation system, not only less water is used, but the quality of vegetables is also greatly improved.

With water-saving irrigation technology, fertile fields can also be bred on the desert Gobi. Relevant data show that in 2022, Jiuquan City will demonstrate and promote 78,41 mu of high-efficiency water-saving technology in farmland, implement 7,15 mu of high-efficiency water-saving area, implement high-standard farmland construction of 9,30 mu, achieve fertilizer saving of 40% and water saving of more than 10% in the integrated demonstration area of water and fertilizer, achieve the task goal of saving more than 0% of water in the implementation area of ridge and furrow irrigation, and the effective utilization coefficient of farmland irrigation water will reach 605.<>.

　　2

Innovate a new mode of water-saving management, and the recycling device of the circulating cooling water film system turns sewage into ultrapure water

In China's total social water consumption, industrial production is one of the major water users. Last year, the Ministry of Industry and Information Technology and other six departments issued the "Industrial Water Efficiency Improvement Action Plan", which clarified the overall requirements, main objectives, important ways and safeguard measures for further improving China's industrial water efficiency during the "14th Five-Year Plan" period, which is not only conducive to changing China's industrial water use mode and improving industrial water efficiency, but also providing a guarantee for promoting industrial green transformation and upgrading and promoting industrial green and high-quality development.

In Pinghu City, Zhejiang Province, a national water-saving city, industrial water-saving management has become an important part of green development here, and Zhejiang Satellite Petrochemical Co., Ltd. (hereinafter referred to as Satellite Petrochemical) located in the local area is a typical case. At the site of the first phase of propane dehydrogenation project at the satellite petrochemical Pinghu base, 12 sets of automatic operation equipment are discharged sequentially, through which the sewage generated in production will not directly enter the sewage treatment plant, but into the circulating cooling water film system recovery device, after treatment, it becomes higher quality ultrapure water, which can be directly recycled as a production water source.

"This is a new model of contract water-saving management adopted by our company, which is a market-oriented long-term water-saving management mechanism, we do not need to make any cost investment, we only need to sign a contract with the relevant company to provide the site, power supply, etc., and the water-saving service operator will be responsible for providing the circulating cooling water film system recovery device, and responsible for the daily operation, maintenance and fault repair of the equipment." Su Yunwei, manager of the company's public works management department, said that the biggest win-win aspect of this model lies in the recycling of sewage and the multi-channel output of benefits. Through this project, 7 million cubic meters of water can be recycled, 1100.1290 million cubic meters of fresh water can be reduced, 1200 million cubic meters of sewage discharge can be reduced, and the cost of fresh water replenishment and sewage treatment fee of 2640 million yuan can be reduced for enterprises within 1800 years, achieving a win-win situation of economic, ecological and social benefits... All this is thanks to the new model of contract water-saving management innovatively used by the Pinghu base of Zhejiang Satellite Petrochemical Co., Ltd.

Satellite Petrochemical Pinghu Base is the main production area of domestic acrylic acid, which belongs to high-water-consuming industrial enterprises, and its main water use link is cooling water. "Due to its proximity to the sea, our industrial water has high chloride ions and conductivity, and in order to ensure normal production, our company uses more fresh water than other areas, and the equipment is more corrosive." As a result, Su Yunwei said, the cost of water use, sewage treatment and equipment purchase and maintenance has remained high.

How to solve this puzzle? Satellite Petrochemical also set up a technical research team to explore water treatment and water recycling processes, compared various options, and finally chose a new membrane treatment technology standard cooling water recovery device provided by a third-party company. Su Yunwei said that now the company has installed 24 sets of such equipment, according to this amount, the company can recover 360 tons of water in one hour, saving 288.25 million tons of water a year, and the water saving rate reaches <>%.

Not only satellite petrochemical, at present, water-saving management and water resource recycling have become an important part of the green transformation of many domestic enterprises. In the Yuncheng Washing Branch of Nanfeng Group Shanxi Daily Chemical Sales Co., Ltd., in recent years, the factory has replaced all water-saving appliances with high-efficiency water-saving appliances that meet national standards, and the water consumption has been reduced by 50% under the condition that daily water habits remain unchanged. At the same time, the factory has also formulated a water conservation system and a water metering management system, and installed a water distribution meter for each workshop. According to the water-saving index, the factory will issue the monthly water-saving plan to each workshop, compact the responsibility to the person, and strengthen the water-saving management with the system.

　　3

The transformation of water supply pipelines and the use of reclaimed water, water-rich cities must also strictly save and take precautions

Zhangzhou City, Fujian Province, one of the national water-saving cities, is located on the southeast coast and has abundant water resources, but it still faces water problems. As early as 2018, the Zhangzhou Housing and Urban-Rural Development Bureau and Zhangzhou Water Supply Enterprise found that the water supply of a number of old residential areas had problems such as running and dripping, frequent pipe bursts, and serious water pressure insufficient, which not only affected residents' lives, but also caused a huge waste of water resources.

"Most of these old communities were built around 2000, and the standard of the pipe network laid in the early days was low, such as the Jinbao Garden Community in Zhangzhou City before the renovation, and we later found through comparative data analysis that the amount of leakage water in the pipe network in the community reached 24 tons in just 312 hours a day, which is even more than the amount of water used by all residents in the community in a day." Shen Feng, head of the urban construction section of Zhangzhou Housing and Urban-Rural Development Bureau, introduced.

Taking the opportunity of creating a national water-saving city, Zhangzhou City has included the renovation of water supply facilities in old residential areas into the key projects of the municipal party committee and municipal government for private enterprises, and ensured that the "last mile" of residents' daily water supply enters the "water-saving" mode through high-standard transformation and professional operation and maintenance.

"Since 2018, a total of 197 old residential areas and 288 kilometers of old pipe networks have been renovated in the central urban area of Zhangzhou, benefiting 6,7 households." Shen Feng introduced.

The problem of water saving in old communities has been fundamentally solved, how can new communities avoid these problems to the greatest extent? Shen Feng said that in order to avoid the recurrence of these problems, under the promotion of relevant units of Zhangzhou Housing and Urban-Rural Development Bureau, the innovative mechanism of "construction and management integration" of water supply facilities has broken ground in Zhangzhou. "In layman's terms, it is to encourage and guide developers to entrust water supply enterprises to the unified construction and unified management of community water supply facilities, and to have high standards, strict requirements and strong management from the beginning."

"In 2016, the construction project of Zhangzhou Vanke City Jingyuan Community took the lead in implementing the 'construction and management integration' of water supply facilities. So far, this mechanism has been fully rolled out in Zhangzhou, and at present, 100 new community project water supply facilities in Zhangzhou urban area have implemented 'construction and management integration', of which 60 have been completed and put into use, and 40 are under construction. Zheng Jinhe of Zhangzhou Development Water Group believes that this is a win-win mechanism, developers can ensure the quality of water supply facilities, water supply enterprises can avoid later maintenance and repair difficulties, and residents can avoid increased public sharing costs due to serious water leakage.

"The report of the 20th National Congress of the Communist Party of China pointed out that 'carry forward the spirit of diligence and thrift in the whole society' and 'coordinate the governance of water resources, water environment and water ecology, and promote the ecological protection and governance of important rivers and lakes'. Although Zhangzhou is not an arid area, it is also necessary to practice economy and take precautions. Shen Feng said that focusing on the idea of "water conservation first, spatial balance, system governance, and two-handed efforts" for water control, Zhangzhou City is guided by the goal of creating a national water-saving city, and while continuing to do a good job in the transformation of water supply facilities in old communities, it is also constantly promoting the use of reclaimed water. At present, two sewage treatment plants have been built in the main urban area: the East Dun Sewage Treatment Plant and the West District Sewage Treatment Plant.

"Taking the Dongdun sewage treatment plant with a daily treatment scale of 26,24 tons, through the use of membrane treatment process and ultraviolet disinfection and other processes, the treatment of tailwater has reached the 'quasi-four category' reuse standard, and is currently implementing the construction of reuse pipelines, and plans to add reuse pipelines and water intake points to the main roads of cities around Jiangbin Road and Jianyuan East Road to realize the use of reclaimed water for green irrigation, road flushing, and fire fighting water." Shen Feng said, "The tailwater discharge of the Dongdun Sewage Treatment Plant is about 1,6 tons a day, and if these tailwaters are treated and recycled to replenish the inland water of Jiujiu Bay, the amount of water accounts for almost 1/3 of the flood period of Jiujiu Bay, and if it is a dry period, it can even reach <>/<>." ”

In fact, in 2020, the high temperature weather in Zhangzhou urban area lasted for more than a month, and the meteorological drought in many places was serious, and the daily average daily reclaimed water discharge of 28,<> tons of tailwater from the two sewage treatment plants has played a good role in the ecological replenishment of inland rivers. (China Discipline Inspection and Supervision Daily reporter Wang Yajing)