18.3.1 The government and urban residents should play different roles in water saving

For a long time, affected by the traditional concept of "inexhaustible water resources", residents have a weak concept of cherishing and protecting water resources, and residents have no habit of reusing domestic wastewater. Before residents have reached the habit of self-discipline and water saving, it is necessary for the government to restrain residents' water use behavior (heteronomy) through its own functions. This can not only reduce the pressure of urban water use, but also help residents to form a water-saving concept. In this respect, the government can use administrative means such as stipulating the water quota for urban residents and increasing the price of water exceeding the quota progressively; Raise the water price and sewage treatment charging standard, so as to promote sewage emission reduction and water conservation, implement an incentive system for water conservation, reward the development of new water-saving technologies, and give economic support to improve old technologies and popularize new water-saving technologies [3]. But the most fundamental thing is to cultivate residents' awareness of self-discipline and water saving. In addition to using various media, advertisements and columns for publicity, the government can also hold exhibitions of various forms and sizes, or organize enterprises and institutions to hold some small-scale exhibitions in various units and communities, so as to achieve the goal of being known to everyone. At the same time, we should also increase the content of protecting and saving water resources in the textbooks of primary and secondary schools, so that teenagers can establish the consciousness of protecting and saving water resources from an early age [4].

it is necessary to further rationalize and gradually raise the price of urban water supply and raise the charging standard of sewage treatment, so as to promote the purpose of reducing sewage discharge and saving water. Especially when the current urban water supply price is generally low, it is necessary to adjust the water price timely and reasonably. In the process of adjusting and reforming water prices, all localities should, as soon as possible, formulate detailed rules for the implementation of the measures for the management of urban water supply prices according to the actual situation in their own regions, establish a water price formation mechanism that meets the requirements of the socialist market economy, and scientifically standardize the management of urban water prices. While adjusting and rationalizing the water price, we should speed up the reform of water supply and drainage industry and enterprise system, introduce market mechanism, reduce costs, strengthen management and improve water utilization efficiency.

18.3.2 Strengthen the control of urban water pollution

Maintaining the natural form of rivers and maintaining good water quality is related to providing a good living environment for urban residents and ensuring the sustainable development of cities. There are many ways to control urban water pollution, among which it is very important to take measures to avoid the "ditch" of urban rivers. First, when financial resources permit, gradually establish a self-contained urban sewage system and build a sewage treatment center to change the phenomenon that rivers are directly discharged into sewage as sewage ditches; Second, the landscape on both sides of the river should be rectified, illegal buildings should be demolished, and heavily polluting enterprises should be relocated. During the rectification, attention should be paid to preserving the original form of the river to avoid the loss of self-purification ability of the riverbed cement; Third, on this basis, publicize the benefits of maintaining the beautiful landscape of rivers to the residents, expand the scope of door-to-door garbage collection in urban areas, and take supporting punishment measures to gradually enhance the public's awareness of environmental protection [5].

in view of the serious problem of industrial wastewater discharge along the Meijiang River, Meizhou Municipal Government strengthened management and demolished a number of polluting enterprises, such as the original Meixian Dongfeng Cement Plant and Meixian Iron and Steel Plant. The paper industry was ordered to rectify, requiring it to take the road of clean production and stop self-pulping. In 2113, there were 11 industrial wastewater treatment projects in the city, with an investment of 1.28 million yuan and 7 completed wastewater treatment projects, with an additional wastewater treatment capacity of 3121t/d

. The data were provided by Meizhou Jiangnan Wastewater Treatment Plant. . In order to avoid the old road of pollution first and treatment later, the government has increased its efforts to clean Meijiang River. In March 2114, the Jiangnan Sewage Treatment Plant (Figure 18.3) with a total investment of 65 million yuan was put into operation. In that year, * * * treated 7.72 million tons of sewage, including 5.14 million tons of domestic sewage, with a treatment rate of 31.6%. The sewage treatment plants in Tai Po, Xingning and Fengshun have started construction, with a total investment of 22.73 million yuan; Meicheng continued to carry out the management of swill oil recovery. Since last year, more than 151 tons of waste oil from catering industry in urban areas has been recycled, which greatly reduced the pollution load of wastewater and protected the water quality of Meijiang River system. In terms of water resources protection, the city has designated 37 first-class water source protection zones, covering an area of 314.69km2, of which the drinking water source protection zone of Qingliangshan Reservoir covers an area of 119km2

Meizhou Daily (June 15, 2115). .

generally speaking, the urban sewage treatment in Meizhou is far from enough. First of all, we must improve the efficiency of Jiangnan sewage treatment plant and avoid repeating the mistake of "sunbathing" in some domestic sewage treatment plants; Secondly, speed up the site selection and construction of Jiangbei sewage treatment plant to improve the sewage treatment rate of the whole city; Thirdly, improve the sewage treatment system of counties (cities, districts) as soon as possible; Fourth, we should strictly implement the relevant provisions in the Notice on Remediation of Sewage and Oil Fume Pollution of Catering Industry in Meizhou City, and the competent administrative department of environmental protection should earnestly perform its duties and strengthen the supervision and management of pollution prevention and control; Fifth, the relevant functional departments of industry and commerce, health, planning and urban construction should, according to their respective responsibilities, cooperate with the administrative department of environmental protection to rectify the discharged sewage and lampblack pollution.

18.3.3 Strengthen the management of groundwater resources

The development, utilization and protection of groundwater is not only a resource management issue, but also a planning and construction issue, which is closely related to urban development. The layout and location of water source wells must meet the requirements of urban planning, and at the same time, the exploitation amount should be strictly controlled to prevent land subsidence, which has been precedent in Meizhou City. For example, on August 21th, 2114, a large-scale subsidence occurred in Shuangtou Town, Wuhua County due to the rapid change of groundwater level, which destroyed 725 houses and stores, among which nearly 211 houses were seriously damaged, destroying 2.1km of roads, 2 small bridges and 8 subsidence places, with 445 affected households and 2,611 people, and the direct economic loss reached 55 million yuan

Meizhou Daily .

Groundwater is a relatively high-quality water source, which should be mainly used for urban domestic water. In areas where urban public water supply can be reached, self-provided water sources should no longer be developed. The exploitation amount of self-provided water should be strictly controlled and gradually reduced, and self-provided wells should be gradually closed. Strict management should be carried out on groundwater extraction in car washing industry to prevent the loss of resources. For areas where surface water is available, on the basis of ensuring the balance between mining and compensation, groundwater is regarded as a strategic reserve or the second water source of the city (Figure 18.3).

Figure 18.3 Meizhou Jiangnan Sewage Treatment Plant

18.3.4 Explore the secondary recycling and utilization of sewage

Reuse of urban sewage is the focus of many experts and scholars to discuss how to solve the problem of urban water shortage in recent years. 81% of urban water supply is converted into sewage, and 71% of it can be recycled after collection and treatment. This means that through sewage reuse, the available water consumption in cities and towns can be increased by more than 51% without changing the existing water supply [6]. For Meicheng, increasing the available water resources by 51% means that it can reduce the expenditure of water supply projects and alleviate the possible shortage of water resources in the next few years, and it is also an important embodiment of adhering to the sustainable development of water resources.

the non-drinking water that can be reused in a certain range after the domestic sewage has been treated reaches the specified water quality standard is usually called reclaimed water [7]. Reclaimed water can be widely used in: first, as a low-quality water source. After treatment, industrial wastewater can replace fresh water as a low-quality water source, such as cooling water for thermal power plants. Second, it is used for irrigation. Agriculture does not require high water quality, and wastewater can be used for farmland irrigation and garden irrigation after regeneration. Third, it is used for daily water use in some cities. The treated sewage can also be used as a water source without direct contact with human body. Such as flushing toilets, watering flowers, flushing cars, urban water environment landscape, etc.

Urban sewage is also a kind of resource. With the construction and development of sewage treatment facilities, the amount of urban sewage treatment is increasing year by year, and the problem of sewage recycling should be put on the important agenda. First of all, it is necessary to make overall planning, adjust measures to local conditions, and adopt a combination of centralized and decentralized methods to economically and reasonably determine the construction scale and treatment technology of sewage reuse facilities. Secondly, for some industrial water and municipal, environmental sanitation and ecological landscape water, treated sewage can be used. It is necessary to comprehensively plan and solve the problem of insufficient water resources with a strategic vision. Thirdly, on the basis of overall planning of water resources, a comprehensive economic and technical comparison should be made between long-distance water transfer and reuse after sewage treatment, so as to make more economical and reasonable use of existing water resources. Fourth, we should scientifically determine the order of water supply sources, so that surface water comes first, then groundwater, local water first and then transit water.

although there are still technical and financial constraints in the promotion of sewage recycling in Meicheng, the development and utilization of reclaimed water resources is a powerful means to solve the pressure of water use in Meicheng in the future and alleviate the water resources problem in the urban area, which is of great guiding significance to the future water management of this city.