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 Current Status 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

Following the implementation of sewage control measures in the Taihu Lake Basin, all areas within the basin have actively undertaken rural domestic wastewater treatment. While new wastewater collection and treatment facilities have been constructed, many urban wastewater treatment plants have also undergone upgrades to meet the tightened effluent discharge standards. Selecting an appropriate treatment process for rural domestic wastewater can effectively mitigate future problems and risks. Distributed wastewater treatment systems are better suited to low-density communities and offer cost savings compared with centralized systems; thus, they are particularly suitable for sparsely populated rural areas. In the course of constructing new wastewater treatment facilities across different localities, both centralized and decentralized treatment approaches have been adopted, with varying treatment processes employed accordingly. For instance, the constructed wetland system featuring floating islands has been used to treat rural wastewater in the Taihu Lake Basin. After more than a year of operation, it has been found that the performance of this system is unaffected by climatic conditions: the COD removal rate ranges from 68% to 79%, the ammonia nitrogen removal rate from 48% to 74%, and the total phosphorus removal rate exceeds 80%. The effluent quality consistently meets the Level B discharge requirements stipulated in the “Integrated Wastewater Discharge Standard (GB 8978-1996).” In addition, the combined treatment system integrating composite filters with constructed wetlands, as well as the underground soil infiltration treatment system, have demonstrated excellent treatment performance. The effluent concentrations of COD, BOD, ammonia nitrogen, and total phosphorus all comply with the pollutant discharge standards for urban wastewater treatment plants specified in GB 18918-2002, specifically meeting the 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 the Jiangsu Region

1. There is a problem

(1) Piping network and process design

There are numerous uncertainties surrounding rural domestic water consumption, including variations in water-use periods and habits, within the Taihu Lake Basin. Observations indicate that in some rural areas, well water and river water account for a substantial share of water use. In older residential areas, some farmers habitually discharge used water directly onto the ground, while others connect domestic sewage from kitchens or balconies to rainwater drainage risers. Such practices have, to a certain extent, reduced both water-use efficiency and collection rates. If design calculations continue to be based on population counts or standard water quotas, the actual inflow volume or pollutant load will be underestimated, thereby compromising the effectiveness of rural wastewater treatment.

When the new rural sewage treatment project in Taicang, Suzhou was hastily launched in 2008, the lack of relevant design specifications and adequate implementation experience led to the selection of more than 20 different treatment processes at the local level. However, the treatment performance of most of these processes failed to meet the required standards, primarily because single-stage ecological treatment processes lacked thorough preliminary research, exhibited poor resistance to shock loads and temperature fluctuations, and operated with significant instability—factors that severely compromised overall treatment effectiveness. Furthermore, the absence of targeted, application-specific process selection not only undermined assurance of satisfactory treatment outcomes but also made it difficult for diverse, decentralized processes to achieve economies of scale. The slow pace of industrialization further posed challenges for subsequent maintenance and management.

(2) Sewage collection and treatment facilities

The sewage pipe networks and septic tanks in older residential areas were constructed many years ago, while the early sewage systems and septic tanks in the rural areas surrounding Taihu Lake in Wuxi have been in place for nearly two decades. Given that most of these rural dwellings are arranged in vertical rows, the narrow roads left in between are typically quite confined. The limited depth of excavation during initial construction restricts the thickness of the overlying soil, which in turn results in narrow access routes that have become the daily thoroughfares for numerous private vehicles. Consequently, the road surfaces are often cracked or pitted, making pipe disconnections and fractures all too predictable. In the early stages, brick-built septic tanks were predominantly used, but their seepage-proofing performance was unreliable. These factors not only lowered the sewage collection rate but also led to significant leakage and associated environmental pollution.

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 multiple departments, including water affairs, water conservancy, housing construction, environmental protection, and agriculture. This fragmented, multi-agency management model, coupled with unclear delineation of responsibilities and authorities, leads to difficulties in comprehensive planning during the design phase and hinders effective coordination of work interfaces. Moreover, the relevant management institutions are often incomplete; for instance, the operation and maintenance of sewage treatment facilities are typically overseen by ad hoc agencies (such as town-level environmental protection offices), while dedicated, specialized management bodies are lacking.

(4) Operation and supervision

Based on the specific circumstances and management systems of each region, the operation and management models for processing facilities are broadly categorized into two types: self-operation and custodial management. Owing to funding shortages, dispersed locations, and inadequate management at most facilities, the government assigns responsibility for their operation and maintenance to town (village) or community authorities, which then manage these facilities independently, typically through part-time staff.

(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 technologies that require minimal space, can be installed at shallow depths, and are easy to maintain, thereby reducing overall costs. Reference may be made to advanced foreign process equipment; currently, Norway has approved more than ten types of micro-scale equipment for use. In addition, draw on recommended processes while taking into account the actual operational results in different regions, and select standardized, batch-produced process systems to facilitate unified and effective management. Effectively advance the implementation of technical specifications for rural domestic wastewater treatment projects within the basin. Choose design and construction firms with extensive experience, high qualifications, and a strong reputation, and rigorously oversee design review, construction supervision, and project handover.

2. Improve the administrative responsibility mechanism

Rural sewage treatment efforts can establish a dedicated supervisory agency. Multi-agency management often leads to mutual buck-passing, thereby reducing operational efficiency. Centralized management under a specialized water affairs agency can enhance administrative effectiveness and strengthen monitoring in the later stages of implementation. It is essential to put in place a clear oversight system that ensures the effective fulfillment of supervisory responsibilities, increases transparency in rural sewage treatment information, leverages public opinion as a powerful tool for oversight, promptly addresses public complaints, and publicly discloses the outcomes of treatment initiatives.

3. Strengthening the rural operation system

Strengthen the rural sewage operation system in various places and explore a reasonable operational model. Technical guidance from the Water Affairs Bureau can be delegated to the village’s specialized property management organization for effective maintenance and management; alternatively, the extensive expertise of environmental protection companies can be fully leveraged to shift from the traditional “one-to-one” model to a “one-to-many” model, ensuring that operations meet established standards. Subsequently, the village’s dedicated management team will provide guidance and take over responsibilities, thereby driving and enhancing local maintenance and management efforts. In addition to reinforcing external training for non-professional operators, operational effectiveness is also contingent upon internal performance evaluations of the administrative responsible person, so as to ensure that sewage treatment facilities are integrated into a routine operational framework characterized by staffing, timely repairs, and ongoing maintenance.

4. Broaden financing channels

Jiangsu Province is promoting support for rural sewage treatment through reward and subsidy mechanisms. However, significant gaps remain in rural sewage treatment, which currently relies heavily on government funding. The province encourages economically stronger local entities to establish dedicated special funds for rural sewage treatment, earmarked for the construction of sewer networks and sewage treatment facilities. Additionally, it is gradually exploring the feasibility of converting environmental sewage charges into taxes in developed areas with high wastewater discharge volumes, with a view to fully transitioning such charges into tax revenue. This approach involves broad-based and intensive expropriation, leveraging economic incentives to ensure that “special funds for specific purposes” are effectively utilized, thereby providing a reliable source of funding for pollution control and environmental governance.

5. Increase public participation

To achieve long-term success in rural sewage treatment, it is essential to raise environmental awareness and enhance public participation. This requires robust, comprehensive, and diversified efforts to promote and implement environmental protection education; the establishment of incentive mechanisms for areas that demonstrate superior treatment outcomes; the leveraging of model zones as exemplars; and the full mobilization and harnessing of public oversight awareness and capacity.

Source: Environmental Protection Network