How to treat sewage?
According to local conditions, the construction mode and treatment process of combining pollution control and resource utilization, engineering measures and ecological measures, and centralization and decentralization are adopted
Deep in the mountains, the fields dyed green and gurgled out. Wang Xingmo, a villager in Wuling Village, Damu Township, Fuling District, Chongqing, used to water the corn field and need to rely on people to carry water up the mountain. Now he has a water pipe in the field and can open the valve to irrigate.
"It's all recycled water." "Waste water becomes fertilizer, saving money and fertilizing the land," Wang said.
Originally, in October 2021, the Wuling Village domestic sewage resource utilization facility project with a total investment of 2,643,900 yuan was completed, and the domestic sewage after resource treatment became recycled water, which can be poured by villagers. More than 30 mu of corn planted by Wang Xingmo's family relies on reclaimed water for irrigation. He said: "Listening to experts, recycled water is rich in nitrogen and phosphorus, can effectively improve soil fertility, and can save about half of the fertilizer application per mu." Together with the free irrigation of recycled water, my family's total income from planting last year increased by about 30,000 yuan compared with before the project was completed."
The mountains are high and the forests are wild. Wuling Village is located in the deep Wuling Mountains, more than 1700 meters above sea level, an area of 16.5 square kilometers, the population of only 350 people, scattered living in two village groups. If the centralized sewage treatment plant is built in the urban model, the pipe network has a large coverage, the sewage collection is low, and the construction cost is high, which is difficult for the village to afford.
How to find a low-cost, extendable path of rural domestic sewage treatment? In July 2020, Fuling District launched the construction pilot project of rural domestic sewage resource utilization facilities in Wuling Village.
Carrying a backpack, wearing a straw hat and sneakers, Ding Ying, head of the natural ecological protection section of the Fuling District Ecological Environment Bureau, plunged into the mountains and conducted field research in Wuling Village. The notebook is densely written - Wuling village is high in altitude, more than 2,000 summer tourists per day, the resident population is only a few hundred people in the tourism off-season, and the seasonal difference in domestic sewage treatment capacity is large, and there are peaks and troughs.
How to meet dynamic demand? According to the investigation, Fuling District Ecological Environment Bureau planned and designed two kinds of sewage treatment facilities. One is an integrated treatment facility with a capacity of 100 tons per day. After anaerobic treatment, aeration, cement separation and other technical links, the sewage is formed into standard discharge water. The other is the resource treatment facility, the construction cost is low, the daily treatment capacity is 10 tons, the sewage can not be discharged after treatment, but can be used to irrigate the dry land. The four sewage treatment facilities in the village are all started in the tourist peak season, and only the resource treatment facilities are used in the tourist off-season, and the operation and maintenance costs are greatly reduced.
In order to further reduce the operating costs of the facility, Ding Ying and his colleagues selected several sites and finally built the facility at a relatively low elevation in the village, so that the difference in height and height can be used to naturally collect sewage and reduce the electricity consumption of pumping water.
"The key is to treat rural domestic sewage according to local conditions." Ding Ying said that Fuling District has set up a rural domestic sewage resource treatment model of "septic tank effluent - ecological regulation tank water volume - pipeline network extension to crops - intelligent irrigation" by building facilities such as the new rural domestic sewage intelligent ecological control tank. "Villagers no longer have to pick and choose to bring water to the field." Wang Xingmo said.
In July 2019, the Central Agriculture Office, the Ministry of Agriculture and Rural Affairs, the Ministry of Ecology and Environment and other nine departments jointly issued the "Guiding Opinions on Promoting Rural Domestic Sewage treatment" (hereinafter referred to as the "Guiding Opinions"). "According to local conditions, the construction mode and treatment process combining pollution control and resource utilization, engineering measures and ecological measures, centralized and decentralized" and "actively promote low-cost, low energy consumption, easy maintenance and high efficiency sewage treatment technology".
In 2021, Fuling District raised more than 80 million yuan to implement domestic sewage resource utilization facility projects in 78 rural residential areas, serving about 38,000 surrounding population. In 2022, Fuling District will invest 20 million yuan to continue the construction of domestic sewage resource utilization facilities in the remaining 21 rural residential areas, and achieve full coverage of sewage treatment facilities in more than 100 rural residential areas in the district, saving 230,000 cubic meters of irrigation water and more than 70 tons of nitrogen and phosphate fertilizer use annually.
"Cleaning up pollution and controlling water takes a long time." Yu Guodong, director of Chongqing Ecological Environment Bureau, said that by the end of 2022, Chongqing has built more than 2,100 rural domestic sewage treatment facilities, with a daily treatment scale of more than 180,000 tons, and the city's rural domestic sewage treatment rate has reached nearly 40%.
Similar to Wuling Village, the scattered discharge of rural domestic sewage and the fluctuation of water quality and quantity are common problems plaguing many places. In Langzhong City, Sichuan Province, there are many low mountains and hills in the jurisdiction, both populated areas and single families living on the hills, how to carry out targeted treatment?
Langzhong City according to the principle of "appropriate collection, collection, appropriate division" classification policy
For single households with complex landforms, far away from cities and towns, and less sewage, the treatment of domestic sewage is closely combined with the "transformation of kitchen and toilet", and the process of "biogas digester + liquid storage pool + farmland utilization" is adopted to complete the sewage treatment of 36,000 households. In densely populated areas, 90 centralized treatment facilities were built, benefiting 21,300 rural households. For the farmers around the farm town, the nearest access to the township sewage treatment station for centralized treatment, to complete the sewage treatment of 1600 households. By the end of 2022, Langzhong has built more than 1,500 rural domestic sewage treatment terminal facilities, with the coverage rate of administrative villages reaching 90 percent and the benefit rate of farmers over 70 percent.
With no neighbors within 300 meters, Wang Suqing, a villager in Wulong Village, Tiangong Town, Langzhong City, lives alone on the slope. In the past, Wang could only throw domestic sewage outdoors. Now, the biogas digester and liquid storage tank have been built next to the vegetable field in front of the house, and the sewage is fed into the tank through the pipeline. After anaerobic fermentation and precipitation separation, the land can be poured to realize resource utilization.
In the second villager group of Wulong Village, 168 villagers live here, and there is a Wulong canteen nearby that is mainly used to receive tourists. Wulong Village sewage treatment station, which has 6.8 kilometers of pipeline and a daily capacity of 50 tons, was built here. Into the sewage treatment station, I saw a coarse grating at the water inlet, used to screen out large debris in the water; Then, the sewage goes into the septic tank and passes through a grate, where the small debris is sifted out. "After that, the sewage enters the anaerobic tank, anoxic tank and aerobic tank successively, thereby reducing the content of water pollutants such as chemical oxygen demand, total phosphorus and ammonia nitrogen. Finally, the sewage is deposited by the sedimentation tank and absorbed by the constructed wetland, so as to achieve the discharge and recycling of sewage standards." Yan Xingrong, a villager in Wulong Village, said, "The sewage treatment station is built using solar micro-power technology, which not only effectively treats sewage, but also reduces operating costs."
Where will the money come from?
Establish a fund raising mechanism with local governments giving priority, central subsidies and social participation, and adopt a variety of ways, such as replacing subsidies with awards, building first and then providing subsidies, and substituting work for relief
Shower break, Yan Xingrong came to Wulong village sewage treatment station routine inspection. "Since the treatment station, the smell of sewage has disappeared, and there are fewer flies and mosquitoes." As a part-time supervisor of the sewage treatment station, Yan Xingrong comes to check the operation of the facility every day.
"The government contributed a little, the collective contributed a little, the people contributed a little, and the villagers did not pay much money to build the sewage treatment facility." Yan Xingrong said that at the beginning of the construction of sewage treatment facilities in Wulong Village in early 2018, everyone also had doubts, "The construction of sewage treatment stations is a big investment, where does the money come from?"
The "Guiding Opinions" put forward that "establish a funding mechanism based on local governments, central subsidies and social participation" and "give full play to the role of government investment, adopt a variety of ways such as replacing subsidies with awards, building first and then subsidizing, and providing work instead of relief, and attract people from all parties to support the construction, operation and maintenance of rural domestic sewage treatment projects through investment, donation, approval and other forms."
"We raised construction funds through a variety of ways, such as state-owned company financing, upward bidding for projects, and fiscal budgets at the same level." Niu Changjun, deputy director of Langzhong Ecological Environment Bureau in Nanchong City, introduced that since May 2018, Sichuan Province has set up the provincial rural domestic sewage treatment "Thousand Villages Demonstration Project" to supplement funds with awards, and a total of 2.5 billion yuan has been arranged to support about 8,000 administrative villages to carry out rural domestic sewage treatment, of which 83 villages in Langzhong City have received financial support of 29.54 million yuan.
The construction of sewage treatment facilities in Wulong Village has a total of more than 1.1 million yuan of funds, covering all investment in the construction of main facilities such as sewage treatment stations and sewage pipe networks. However, some villagers are not motivated because they have to pay for the construction of household treatment facilities.
How to mobilize the enthusiasm of the villagers? Langzhong City to "change the toilet and kitchen" and domestic sewage treatment facilities together to build farmers, each family to give a financial award of 3000 yuan.
Learned that the sewage treatment facilities have awards to supplement funds, Yan Xingrong came to interest, do it yourself, dig septic pit, cement floor, connecting toilet and kitchen pipes. In less than a week, access facilities were built. Yan Xingrong won the award of 3000 yuan, enough for the construction.
Lush flowers in the courtyard, followed the path to the wall, Yan Xingrong pointed to the corner of the small septic tank, "the design capacity of two cubic meters, the family daily enough."
The construction needs initial capital, and the later operation also needs long-term investment, which is difficult to solve by financial allocation alone. How to establish diversified financing construction and operation mechanism?
Among the 90 centralized sewage treatment facilities constructed in Langzhong City, 78 sewage treatment stations with a daily treatment capacity of 50 tons or more are constructed and operated by Langzhong Village Water Supply and Drainage Co., LTD., and the rest are responsible for townships or streets. "We have secured a loan of RMB177 million from the bank for the construction, maintenance and operation of the sewage treatment station using our own operational projects as collateral." Langzhong town water supply and drainage Co., LTD. General manager Zhao Jiang said. In order to make up for the lack of funds for the construction and operation of enterprises, Langzhong City has also explored various modes such as financing loans and collecting sewage discharge fees, raising funds of 447 million yuan in the past three years.
Taking advantage of the policy of the National Development Bank to promote the "ecological protection and Urban-Rural integration development project of the Yangtze River Economic Belt" in Fuling District, Fuling District successfully applied for a loan of 270 million yuan for the construction and operation of rural domestic sewage facilities in December 2019. In order to spend every money to the edge of the knife, Fuling District ecological environment Bureau, the development and Reform Commission, the Finance bureau and other departments held many meetings, and each sewage treatment facility of 351 agricultural administrative villages (communities) in the district was marked on the map, and the planning scheme was formulated according to the specific situation of each village.
"The construction investment amount is large, and the operation and maintenance investment period is long." Li Lulu, deputy chief of the Economic Construction section of the Fuling District Finance Bureau, introduced that after detailed calculation, the operation costs of sewage resource utilization facilities include equipment and power costs, maintenance costs, labor costs, information transmission costs, etc., and each annual contracted subsidy of 10,000 yuan to the township of the facility; The integrated sewage treatment facility is settled at 3.12 yuan per ton or 60% of the design capacity, and is operated and maintained by a third-party professional organization.
For third-party operating companies, the profits of rural domestic sewage treatment are not high. "At present, it is mainly relying on the 'big factory with small factory' approach." Qin Tingwei, deputy general manager of Chongqing Fuling District Tuoyuan Sewage Treatment Co., LTD., introduced that the company supplemented the profits from the operation of large sewage treatment plants and government subsidies, and carried out operation and maintenance of small rural sewage treatment facilities in the form of "fat and thin matching and rich and poor".
In 2022, Chongqing Municipal and district financial authorities will invest 86.77 million yuan to support the operation and maintenance of rural domestic sewage treatment facilities.
How to manage built?
We should place equal emphasis on application, construction and management, and promote the establishment of an operational management and protection mechanism with systems, standards, teams, funds, and supervision
The walls are covered with stone and the roof is covered with grass. The exquisite residential houses along the Yellow Sea are sheltered among the trees and flowers. Stepping into the home of Yu Haiyang, a villager in Yandun Jiao Village, Lidian Town, Rongcheng City, Weihai, Shandong Province, there is a reminder sheet on the white column at the door, detailing the precautions for the use of harmless sanitary toilets in rural areas, and attaching the QR code for facility management and protection. The reporter took out a mobile phone scan and found that after simply filling in the information, you can make a maintenance application, and the staff will make on-site maintenance within 24 hours.
Born in the sea, grew up in the sea, in the sea is a native fisherman's son. "In the past, after the villagers washed their clothes, water poured on the door, and sewage flowed everywhere." Yu Haiyang recalled.
In 2016, Yandunjiao Village, as the first batch of pilot villages in Rongcheng City, completed the renovation of toilets and sewage treatment of 507 households, supporting sewage pipes for 21 kilometers, and built 28 household sewage processors, with a daily sewage treatment capacity of 126 tons. At present, 572 administrative villages in Rongcheng City have completed a total of more than 159,000 households, built more than 600 household sewage treatment units, and the treatment rate of rural domestic sewage has reached 73.5%.
The sewage has been treated, the environment has improved, the water into the sea has become clearer, and the wintering swans living in the bay have become more and more attractive, attracting a large number of tourists and photographers to stay in the fishing home, and the business of home accommodation in the ocean has become more and more prosperous. However, tourists come and go, the frequency of use of facilities is high, and the sanitary ware sometimes fails but I do not know who to find. At that time, each town and street is responsible for the management and protection of sewage treatment facilities, the lack of professional maintenance personnel, equipment maintenance is not timely, management and care technology is not high, and the problem of exceeding the water standard occurs from time to time.
Building well is only a starting point, and managing well can lead to a long run. The "Opinions on the implementation of Integrated Management of Urban and Rural sewage Treatment" issued by Rongcheng City proposed that the government should purchase services and entrust Rongcheng Water Group Co., Ltd. with unified management to build one, hand over one and run one. Rongcheng Water Group Co., Ltd. has set up a township sewage treatment branch, which has created a professional and efficient intelligent dispatching platform while adding supporting equipment and improving management and care capabilities.
Into the data service center of Rongcheng Water Group Co., LTD., a screen came into view, and the repair information of sewage treatment facilities in various towns and villages was updated in real time. Between the figures, the city's sewage treatment situation is clear. Zhang Ningning, deputy manager of the township sewage treatment branch of Rongcheng Water Group Co., LTD., pointed to the screen and said: "The platform has collected detailed information on sewage treatment and toilet improvement of all towns and villages in the city, and each farmer has a unique nine-digit code for real-time supervision and management."
Not long ago, Yu Haijia homesay's toilet water leakage problem, he scanned the code to report for repair, the information was quickly conveyed to the rural toilet management. According to Zhang Ningning, Rongcheng Water Group Co., Ltd. is equipped with part-time toilet managers in every village. Villagers can summarize the repair information to the toilet manager by scanning the QR code and making phone calls, and then uniformly report it to the platform.
Villagers report their needs, and the platform responds quickly. After receiving the repair information, the staff of the data service center should reasonably arrange the route of the management and care vehicle according to the system management and care map, combined with the problem location and fault degree. At the same time, the maintenance personnel also received the task, and quickly went to the village of Yandun. After the maintenance is completed, the maintenance personnel take out their mobile phones, take photos and upload the maintenance photo certificate to ensure that the task is completed within 24 hours.
How to guarantee the service quality? "We use the vehicle-mounted monitoring system to supervise the whole process, the toilet manager is present to supervise, and the satisfaction evaluation is conducted according to the feedback of farmers and the on-site operation." Zhang said that based on feedback from Yu Haiyang, toilet managers gave "good reviews" on the satisfaction option.
"Professional people do professional things, which effectively improves the efficiency of management and care." Zhang Ningning said that Rongcheng City Water Group Co., Ltd. township sewage treatment branch regularly organized maintenance management personnel to carry out inspections. At the same time, Rongcheng Municipal Housing and Construction Bureau randomly selects 40 villages every month to investigate the satisfaction of the masses, assigns points according to the proportion of satisfaction, and takes the assessment and spot check results as an important basis for the allocation of funds.
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