China passes new regulations focused on the efficiency of domestic sewage collection and treatment, industrial wastewater, and domestic sewage mixed treatment.

Last month, the General Office of the Jiangsu Provincial Government issued the "Implementation Opinions on Accelerating the Construction of Urban Sewage Treatment Capacity and Centralized Sewage Collection and Treatment Improvement", focusing on the low efficiency of domestic sewage collection and treatment, industrial wastewater and domestic sewage mixed treatment, and other problems.

So what do "implementation opinions" require?

Newly-built metallurgy, electroplating, chemical, printing, dyeing, and API manufacturing (except API manufacturing enterprises that have industrial wastewater treatment qualifications and whose effluent reaches national standards) and other industrial enterprises that discharge wastewater containing heavy metals, refractory wastewater, and high-salt wastewater shouldn’t discharge into centralized sewage collection and treatment facilities.

Wuxi City, Changzhou City, and Suzhou City should accelerate the process of the classified collection and quality treatment of industrial wastewater and domestic sewage by 2024.

Nanjing City, Nantong City, Yangzhou City, Zhenjiang City, and Taizhou City should gradually start the process of the classified collection and quality treatment of industrial wastewater and domestic sewage by 2025.

Xuzhou, Lianyungang, Huai'an, Yancheng, and Suqian focus on building the capacity of collection pipelines. By 2025, industrial parks above the provincial level and other qualified parks will have to finish the process of the classified collection and quality treatment of industrial wastewater and domestic sewage.

For a long time, industrial wastewater has been discharged into the urban sewage pipe network after pretreatment and then discharged after being combined with urban domestic sewage. In the last couple of years, the excessive inflow of water leads to excessive outflow, which has been the case in most sewage treatment plants.

Even after the industrial wastewater had been pretreated and had reached the acceptable standard, due to the complex composition of industrial wastewater pollutants and the unstable water volume, an imbalance of carbon, nitrogen, phosphorus, and other substances in the biochemical system of the urban sewage treatment plant is still possible.

There are also a few enterprises that illegally discharge untreated wastewater directly into the urban pipe network. The high concentration of pollutants in the influent water further increases the pressure on the sewage treatment plant.

Furthermore, some industrial wastewater may contain toxic substances, persistent pollutants, and pathogenic microorganisms, to name a few, which may be discharged into surface water through urban sewage treatment plants.

In the last couple of years, as industrial enterprises have moved away from the city to the industrial parks, industrial wastewater has been pretreated and added to the park's sewage treatment plant for centralized treatment, which has alleviated some of the pressure on the municipal sewage plants. However, due to changes in the conditions for attracting investment in some industrial parks, the actual resident enterprises are quite different from those in the design and planning stage of the sewage treatment plant. As a result, the treatment process of the built sewage treatment plants often doesn't meet the actual water quality requirements. The investment and operating costs of upgrading and renovation are also high, which is difficult for local governments and enterprises to accept, resulting in the inability of some projects to meet the standards.

Industrial wastewater is connected to the municipal sewage pipe network. Excessive water inflow leads to excessive effluent, and wastewater treatment plants bear legal responsibility.

In 2020, the Ministry of Ecology and Environment issued the "Notice on Further Regulating the Environmental Management of Urban (Park) Sewage Treatment", clarifying the responsibilities of all parties by the law, and reasonably determining the responsibility for the excessive treatment. If it is corrected and no harmful consequences are caused, administrative punishment may not be imposed.”

At the same time, the Notice provides a solution for sewage treatment enterprises, "reasonably organize accident regulation and storage facilities and environmental emergency measures that match the anti-risk capability and find that the water intake is abnormal, which may lead to damage to the sewage treatment system and excessive water output. The plants are advised to immediately start the emergency plan, implement the traceability of pollutants, retain water and mud samples, save monitoring records and on-site video and other evidence, and report to the ecological environment department and relevant competent authorities as soon as possible."

During the two sessions last year, the Environmental Chamber of Commerce of the All-China Federation of Industry and Commerce submitted the "Proposal on Improving the Water Inflow and Sludge Disposal of Environmental Protection Industry" to the national "two sessions" through the proposal of the All-China Federation of Industry and Commerce. It is advised that the data such as water quality and water quantity discharged by industrial enterprises should be shared with sewage treatment enterprises to provide a guarantee for the regulation and operation of sewage treatment plants and upstream supervision.

Enterprises that discharge industrial wastewater shall take effective measures to collect and treat all the produced wastewater to prevent pollution of the water environment. Those who have not obtained the permit for the discharge of sewage into the drainage pipe network shall not directly discharge industrial wastewater into the domestic sewage pipe network and treatment system. Industrial wastewater containing toxic and harmful water pollutants shall be collected and treated by classification, and shall not be diluted and discharged.

The "Implementation Opinions" issued by the General Office of the Jiangsu Provincial Government further require the classified collection and quality treatment of industrial wastewater and domestic sewage, and specifies the type and scope of industrial wastewater that cannot be connected to the urban sewage pipe network.