The sewage treatment industry embarks on the road of "green advancement"

A document issued recently has pointed out the direction for the "green advancement" of the sewage treatment industry in the new year. On December 29, 2023, the National Development and Reform Commission, the Ministry of Housing and Urban-Rural Development, and the Ministry of Ecology and Environment jointly issued the "Implementation Opinions on Promoting the Synergistic Efficiency of Pollution Reduction and Carbon Reduction in Sewage Treatment" (hereinafter referred to as the "Implementation Opinions").

The "Implementation Opinions" pointed out that my country's ecological civilization construction has entered a critical period with carbon reduction as the key strategic direction. Sewage treatment is not only an important starting point for deepening the battle against pollution prevention and control, but also an important field for promoting greenhouse gas emission reduction. By 2025, my country will build 100 green and low-carbon benchmark sewage treatment plants with efficient recycling of energy resources.

Experts analyzed that sewage treatment should achieve synergistic efficiency of pollution reduction and carbon reduction through its own energy conservation and consumption reduction, improving treatment efficiency and increasing carbon sinks. At the same time, policy support and scientific and technological support for the industry are also indispensable.

Filling the gaps, reducing pollution and carbon emissions have become key topics

"So far, my country has built nearly 5,000 urban and county sewage treatment plants, with a total treatment capacity of more than 250 million cubic meters per day, and an urban sewage treatment rate of more than 98%." The "Implementation Opinions" pointed out that in recent years, my country's sewage collection and treatment facilities have been continuously improved, but "shortcomings" such as low sewage collection efficiency, high greenhouse gas emissions during sewage treatment, and low energy resource recycling and utilization levels still exist.

Based on the actual situation of my country's sewage treatment industry, the "Implementation Opinions" deployed key tasks such as strengthening water conservation and efficiency at the source and improving sewage collection efficiency. In addition, strengthening energy conservation and carbon reduction in sewage treatment is also key.

Grille rooms, sedimentation tanks, and biochemical tanks are interlinked, and sewage flows in and out between various equipment. Industry insiders pointed out that as an enterprise dealing with various pollutants in domestic sewage, although sewage treatment plants are responsible for the green mission of improving effluent water quality standards and reducing water environmental problems such as black and odorous water bodies and eutrophication, the sewage treatment model of "exchanging energy consumption for water quality" will inevitably produce certain carbon emissions during the operation of the equipment, and there is also a risk of transferring water pollution to air pollution.

Relevant data show that carbon emissions from the sewage treatment industry account for about 1% of the total emissions of the whole society, mainly from the release of greenhouse gases such as carbon dioxide, methane and nitrous oxide after the degradation of organic pollutants in the water. In addition to the above direct emissions, the consumption of electricity and heat energy required for the operation of sewage treatment plants, and the production and transportation of chemicals used for sewage treatment, will also indirectly generate carbon emissions.

In recent years, with the increase in sewage treatment volume brought about by urbanization development, upgrading and transformation have become the unanimous action of many sewage treatment plants, and the resulting carbon emissions have also increased accordingly.

The reporter consulted public information and found that in June 2023, an "Administrative Penalty Decision" issued by the Beijing Municipal Ecological Environment Bureau showed that a local company whose main business was sewage treatment and reclaimed water reuse treatment was fined more than 2 million yuan for exceeding the quota of carbon dioxide emissions by more than 4,000 tons.

Carbon reduction has become a topic that the sewage treatment industry must face. This "Implementation Opinions" puts the synergy of pollution reduction and carbon reduction in a prominent position.

Energy saving, efficiency improvement, and carbon sink increase, multi-channel carbon reduction

How should the sewage treatment industry move towards green and low-carbon development?

The "Implementation Opinions" pointed out that sewage treatment plants can offset carbon reduction and carbon emissions by saving energy and reducing consumption, improving treatment efficiency or increasing carbon sinks.

Yuan Shuai, executive vice president of the China Academy of Urban Development and the Institute of Agricultural, Cultural and Tourism Industry Revitalization, told our reporter that the sewage treatment industry should first improve the efficiency of sewage treatment, reduce the emission of harmful substances in sewage, and reduce energy consumption and carbon emissions; second, promote the resource utilization of sewage, recycle the treated sewage as water resources, reduce the demand for fresh water resources, and reduce the carbon emissions of water treatment; third, strengthen energy conservation and carbon reduction and carbon footprint management, comprehensively monitor and manage energy consumption and carbon emissions in the sewage treatment process, and take targeted measures to reduce energy consumption and carbon emissions.

"The difficulty lies in how to balance the relationship between sewage treatment, carbon reduction and energy conservation, and achieve synergistic efficiency among the three. In addition, the layout of sewage treatment plants also needs to consider multiple factors such as terrain, climate, and population density, and reasonably plan the sewage collection and treatment system to improve the efficiency of sewage collection and treatment." Yuan Shuai said.

In terms of energy conservation and carbon reduction transformation, the "Implementation Opinions" proposed to promote the selection of general products and equipment such as high-efficiency and energy-saving motors, fans, water pumps, and lighting fixtures, and combine the upgrading and transformation of factory areas to accelerate the elimination of old and inefficient key energy-consuming equipment. Promote the construction of smart water management systems, carry out intelligent regulation and optimization of the entire process, and achieve precise aeration and reflux control, digital metering and precise dosing, etc.

The reporter previously noticed in an interview that more and more sewage treatment plants have increased their investment in smart equipment in daily operations, and sewage treatment plants in some areas have achieved full coverage of operation projects by the big data production and operation dispatching and command system.

It is worth mentioning that the "Implementation Opinions" proposed that cities with scarce land resources can build fully underground or semi-underground sewage treatment plants, and encourage the rational use of ground space through the construction of park greening activity venues, etc., to improve the regional environmental quality and urban ecosystem carbon sequestration capacity.

In Yinchuan, Ningxia Hui Autonomous Region, a "net-famous" recycled water plant has "landed" this idea on the ground. The recycled water plant adopts a semi-underground building form, and the top of the sewage treatment tank is designed as an open ecological landscape park, so that citizens' entertainment and water plant operation and production can not interfere with each other. Zhou Wenbin, director of the recycled water plant, once told reporters that more than 100,000 tons of domestic sewage are collected here every day. After treatment, the effluent reaches the surface quasi-IV class, which meets the reuse standard and can be used nearby for urban greening irrigation, river and lake water replenishment, municipal miscellaneous uses, etc.

Not only that, public reports show that in Wuhan, Chengdu, Ningbo, Dali... Such garden-style recycled water plants are spread across many provinces and cities in my country. The sewage treatment industry is actively seeking to solve the problem of synergistic efficiency of pollution reduction and carbon reduction to achieve a win-win situation of recycling water resources and enhancing urban ecological carbon sinks.

New opportunities at the policy and technical levels

my country's ecological civilization construction has entered a critical period with carbon reduction as the key strategic direction and promoting synergistic efficiency of pollution reduction and carbon reduction. This also points out the direction for my country's sewage treatment industry in the future period.

In June 2022, the Ministry of Ecology and Environment issued the "Implementation Plan for Coordinated Efficiency Improvement of Pollution Reduction and Carbon Reduction", which proposed requirements for optimizing governance targets, governance processes and technical routes in multiple fields such as water, atmosphere, soil, solid waste, and greenhouse gases. The "Implementation Opinions" mentioned that by 2025, 100 green and low-carbon benchmark sewage treatment plants with efficient recycling of energy resources will be built. This specific goal will bring new development opportunities to the sewage treatment industry.

"In terms of policy, the country will increase policy support and capital investment in the sewage treatment industry, encourage the sewage treatment industry to carry out technological innovation and research and development, and promote technological progress and industrial upgrading in the industry. In addition, there are market opportunities. With the acceleration of urbanization and the improvement of people's environmental protection awareness, the market demand for sewage treatment will also increase further." Yuan Shuai pointed out.

The "Implementation Opinions" pointed out that financial support for sewage treatment pollution reduction and carbon reduction upgrading and transformation projects should be increased, and eligible projects should be included in the scope of support for local government special bonds, issue real estate investment trusts, apply for green credit or finance through green bonds. At the same time, tax preferential policies in the fields of environmental protection, energy conservation and water conservation should be implemented.

The prosperity of policies and markets will further promote the innovation and improvement of sewage treatment technology and achieve high-efficiency and low-energy consumption treatment effects. Zhang Xinyuan, head of research at Co-Found, a domestic consulting agency, told reporters that the application of renewable energy in sewage treatment should be strengthened, such as solar energy and wind energy, to achieve energy self-sufficiency or significantly reduce energy consumption. Implement carbon emission control, such as using anaerobic digestion technology in sewage treatment to improve sludge treatment efficiency and reduce carbon emissions.

The "Implementation Opinions" also proposed to increase scientific and technological support. Carry out key green and low-carbon technology research for sewage treatment, focusing on breakthroughs in key common technologies such as high-concentration organic wastewater and high-salt wastewater treatment and recycling, high-performance membrane materials, environmentally friendly agents, greenhouse gas control, intelligent monitoring and optimization control, and promote the integration and development of digital technologies such as big data, artificial intelligence, and digital twins with sewage treatment processes.