With the development of economy, pollution in the Taihu Lake Basin is serious. As one of the main areas in Jiangsu, the treatment of rural domestic sewage has become the main concern. Based on the analysis of the current situation of rural domestic sewage treatment in this area, this paper found that the design and construction of domestic sewage treatment facilities in Jiangsu Province did not meet the requirements of the design and construction of domestic sewage treatment facilities, lack of operation and maintenance funds, and improper operation modes, and proposed based on these existing problems. The corresponding reasonable countermeasures and suggestions are provided.

1. The status quo of rural domestic sewage treatment in Jiangsu

1. The model adopted in rural domestic sewage treatment

The uneven distribution of rural areas in Jiangsu, the different urban planning and development ideas and the different degree of pipe network coverage, determine that a reasonable rural domestic sewage treatment mode should be selected according to local conditions. The survey found that the rural domestic sewage treatment mode in this area mainly adopts two forms of collection treatment and decentralized treatment according to the distribution of households and the distance to the sewage treatment plant.

2. Current status of rural domestic sewage treatment

After the Taihu Lake Basin sewage control work was carried out, all parts of the basin actively carried out rural domestic sewage treatment work. While new sewage collection and treatment facilities were built, many urban sewage treatment plants were upgraded and upgraded due to the improvement of tail water discharge standards. Choosing an appropriate treatment process for rural domestic sewage can effectively reduce problems and risks in the future. Distributed sewage treatment systems are more suitable for low-density communities and save costs than centralized systems. Distributed treatment methods can be selected in scattered rural areas. When constructing new sewage treatment facilities in various places, centralized and decentralized treatment modes have been selected, and the processes adopted are also different. For example, the plant floating island wetland is used to treat rural sewage in the Taihu Lake Basin. After more than one year of operation, it is found that the plant floating island wetland treatment effect is not affected by the climate. The removal rate of COD is 68%-79%, and the removal rate of ammonia nitrogen is 48%-74. %, the removal rate of total phosphorus is more than 80%, and the effluent index can meet the level B discharge requirements of "Integrated Wastewater Discharge Standard (GB 8978-1996)". In addition, the composite filter-constructed wetland combined treatment system and the underground soil infiltration treatment system have good treatment effects. The COD, BOD, ammonia nitrogen, and total phosphorus indicators in the effluent meet the pollutant discharge standards for urban sewage treatment plants (GB 18918-2002) 》Level B standard.

At present, the effects of rural domestic sewage treatment in the Taihu Lake Basin are not all significant. In the study of hundreds of rural domestic sewage treatment demonstration projects established in the Taihu Lake Basin, it was found that the water quality of many completed treatment projects is difficult to achieve stable standards. The investigation found that the domestic sewage treatment rate of some highly developed rural areas in the Taihu Lake Basin reached 30%-50%, but in many areas it was less than 10%. In the survey and research on rural sewage treatment facilities in Changshu City, it is concluded that the removal effects of rural domestic sewage treatment facilities on TN and TP are not ideal, which are 78% and 54%, respectively.

2. Problems and countermeasures in rural domestic sewage treatment in Jiangsu area

1. There is a problem

(1) Pipe network and process design

There are many uncertain factors in the rural domestic water consumption, water usage period and water usage habits in the Taihu Lake Basin. According to observations, some rural areas use well water and river water for a large proportion. Some farmers in old residential areas are used to spilling used water on the ground, and some users connect domestic sewage from kitchens or balconies to rainwater risers. These practices have reduced the water use rate and collection rate to a certain extent, and if the calculation is still based on the number of residents or the water quota during the design, the actual water inflow or load will be low, which will affect the effect of rural sewage treatment.

When the new rural sewage treatment in Taicang, Suzhou was launched in a hurry in 2008, due to lack of relevant design specifications and corresponding experience, more than 20 different processes were selected locally, and the treatment effects of most of the processes could not meet the standard requirements, mainly due to single-stage The ecological treatment process lacks preliminary research, has poor ability to withstand impact load, temperature changes, etc., and its operation is unstable, which has a great impact on the treatment effect; in addition, the lack of targeted and applicable treatment process selections not only fails to obtain the treatment effect Assurance, many different types of distributed processes are difficult to form scale effects, and the slow industrialization development brings certain difficulties to later maintenance and management.

(2) Sewage collection and treatment facilities

The sewage pipe network and sewage septic tanks in old residential areas have been built for many years, and the early sewage pipe network and septic tanks in the rural areas around Taihu Lake in Wuxi have been built for nearly two decades. Since these rural houses are mostly in vertical rows, the roads left in the middle are generally narrow. The height of the excavated soil during the early construction is limited, so the thickness of the soil is limited, and these narrow roads have become the daily access channels for many private cars. , The surface is often cracked or dented, and the resulting pipe disconnection and fracture can also be imagined. In the early days, brick-built septic tanks were mainly used, and the anti-seepage performance could not be guaranteed. The above not only reduced the sewage collection rate, but also caused a certain amount of pollution leakage.

Many areas lack accurate topographical maps when constructing and renovating pipeline networks. Some pipeline networks and facilities are subject to topographical restrictions and farmers’ resistance. Routes and site selections are often changed, and construction schedules are delayed. In order to catch up with the construction period, the pipeline network and facilities are damaged. The quality has shrunk greatly. Some construction units lack strict quality control and inadequate supervision, which also leads to hidden dangers in the quality of the facilities.

(3) The main body of administrative management

The construction of sewage pipe networks and treatment facilities in many cities and towns involves departments such as water affairs, water conservancy, housing construction, environmental protection, and agriculture. This kind of multi-head management and the ambiguity of responsibilities and powers result in the inability to make overall planning during design and the work interface cannot be well connected. The corresponding management agencies are not perfect. The management of sewage treatment facilities is usually managed by related agencies (such as the town environmental protection office), and there is a lack of specialized management agencies.

(4) Operation and supervision

According to the actual situation and management system of each region, the operation and management modes of processing facilities are roughly divided into two types: self-operation and custody mode. Due to lack of funds and scattered distribution and insufficient management of most facilities, the government assigns the management and protection work to the town (village) or the community to operate and manage on its own, usually with part-time staff responsible for it.

(5) Funding issues

Based on statistics collected from multiple sewage treatment facilities, it is concluded that the preliminary investment and later operating costs of sewage treatment facilities are related. It is estimated that the rural sewage treatment rate will reach 90% in 2025. The cost of rural sewage treatment in Jiangsu area in the Taihu Lake Basin is predicted, and the rural sewage treatment will cost about 20.59 billion yuan. The national and provincial compensations are limited, and the financial resources of cities (counties) and towns are limited, and the funding gap is still large. Even if the pipeline network and facilities can be built, there is a lack of sufficient funds for operation and maintenance. On the other hand, this has caused "emphasis on construction and neglect of maintenance".

(6) Mass environmental awareness

The survey found that many villages (communities) have announced the supervision responsibility cards of the treatment facilities. It is difficult for this kind of single force to achieve better supervision and implementation effects. According to the survey results of public concern about rural sewage treatment facilities, nearly 70% of the people are not concerned about rural sewage treatment facilities, and some people even think that they occupy the available space and oppose the construction of treatment facilities near houses and garages. . The poor environmental awareness of the masses has to some extent allowed the disorderly discharge of sewage and the unmanned maintenance of treatment facilities.

3. Countermeasures and suggestions

1. Focus on facility selection and construction

Develop and promote the selection of energy-saving technology that occupies a small area, is shallow buried, and is easy to maintain to reduce various costs. Reference can be made to foreign advanced process equipment. At present, Norway has more than ten types of micro-equipment approved for use. And refer to the recommended process combined with the actual operating results of various regions, and select the same batch type process, which is convenient for unified and effective management. Effectively promote the promotion of technical specifications for rural domestic sewage treatment projects in the basin. Choose design and construction units with rich experience, high qualifications, and good reputation, and firmly grasp design review, construction supervision and project transfer.

2. Improve the administrative responsibility mechanism

The rural sewage treatment work can build a special supervision agency. Multi-head management is prone to mutual inducement, which reduces the efficiency of work. The unified management of the special water affairs agency can improve the management efficiency and strengthen the monitoring work in the later stage. Establish a clear supervision system, ensure the implementation of supervision responsibilities, increase the openness of rural sewage treatment information, give full play to the power of public opinion supervision, promptly handle complaints from the masses, and publicize the results of the treatment.

3. Strengthening the rural operation system

Strengthen the rural sewage operation system in various places, and explore a reasonable operation mode. The technical guidance of the Water Affairs Bureau can be handed over to the special property organization of the village for effective maintenance and management; or the professional experience of environmental protection companies can be fully utilized to change from the original "one-to-one" model to the "one-to-many" model, and the operation meets the standard Later, the special management team of the village will be given guidance and handover to drive and improve the local maintenance and management work. In addition to strengthening the external training of non-professional operators, the operation effect is related to the internal performance evaluation of the administrative responsible person, so that the sewage treatment facility is included in the normal operation track of manned, broken and repaired.

4. Broaden financing channels

Jiangsu Province promotes support for rural sewage treatment in the form of rewards and subsidies. There is still a big gap in rural sewage treatment, only relying on government support. Encourage economically better local forces to establish a special fund for rural sewage treatment, dedicated to the construction of pipe networks and sewage treatment facilities; and gradually explore the feasibility of changing environmental sewage charges to taxes in developed areas with large drainage, and implement sewage charges to taxes. Expropriation has a wide range and strong expropriation intensity. Through this economic means, the implementation of "special funds for special purposes" can provide an effective source of funds for pollution control and environmental governance.

5. Increase public participation

In order to achieve long-term results in rural sewage treatment, it is necessary to raise awareness of environmental protection and increase public participation. Effectively strengthen the comprehensive, multi-form publicity and implementation of environmental protection awareness, implement reward mechanisms for areas with better treatment effects, give play to the role of demonstration areas, and fully mobilize and bring into play the supervision awareness and strength of the masses.

Source: Environmental Protection Network