Strengthening pollutant control and resource recovery can enhance sustainable waste incineration in China – Nature

Executive Summary

This report provides a systematic evaluation of the environmental and economic performance of China’s municipal solid waste incineration (MSWI) industry, based on operational data from 876 plants. The analysis, framed within the context of the United Nations Sustainable Development Goals (SDGs), reveals that while MSWI is pivotal for urban waste management, significant challenges in pollutant control and by-product utilization hinder its full potential. Key findings indicate that advanced flue gas treatment, while reducing harmful emissions (SDG 3, SDG 11), slightly compromises carbon benefits. Conversely, optimized leachate management and fly ash resource utilization substantially improve both environmental outcomes and economic viability, directly contributing to SDG 6 (Clean Water and Sanitation), SDG 12 (Responsible Consumption and Production), and SDG 13 (Climate Action). Scenario simulations project that the strategic implementation of stricter emission standards, expanded waste classification, and targeted co-incineration can yield significant carbon-negative and financial benefits by 2035. These findings underscore the synergistic potential of integrated pollution control and resource recovery in advancing the sustainable transition of China’s waste-to-energy sector, aligning its growth with key global development objectives.

Introduction: Aligning China’s Waste Management with Sustainable Development Goals

As the world’s largest producer of municipal solid waste (MSW), China is increasingly reliant on incineration to manage urban waste, processing 310 million tonnes in 2022. This approach supports SDG 11 (Sustainable Cities and Communities) by addressing waste management in rapidly growing urban areas and contributes to SDG 7 (Affordable and Clean Energy) through energy recovery. However, the industry’s expansion presents challenges to other SDGs. The management of by-products—leachate, flue gas, and fly ash—poses risks to SDG 3 (Good Health and Well-being) and SDG 6 (Clean Water and Sanitation). Furthermore, the high proportion of food waste in China’s MSW stream complicates incineration efficiency and increases leachate production, undermining progress toward SDG 12 (Responsible Consumption and Production). This report conducts a comprehensive life cycle assessment to evaluate the industry’s performance and identify pathways for a sustainable transition that balances economic growth (SDG 8), technological innovation (SDG 9), and climate action (SDG 13).

Current State of Municipal Solid Waste Incineration (MSWI) in China

Infrastructure and Operational Landscape

An analysis of 876 MSWI plants reveals a nationwide infrastructure with a combined design capacity of 329 million tonnes per year. However, the actual incineration volume is only 73% of this capacity, indicating widespread underutilization that impacts both economic efficiency and the potential to contribute to SDG 7 and SDG 8.

• Geographic Distribution: Plants are located across 30 provinces, with the highest capacities in Guangdong, Zhejiang, and Henan.
• Incinerator Technology: Mechanical grate incinerators are dominant (89.4% of plants), valued for operational stability. Circulating fluidized bed incinerators are mainly used in northern China.
• Operational Scale: The majority of incinerators (79.8%) operate in the 300–700 tonnes/day range. Integrating smaller-scale operations could enhance energy efficiency and GHG mitigation, aligning with SDG 9 (Industry, Innovation, and Infrastructure).

Technological Adoption for By-Product Management

The management of by-products is critical for mitigating environmental impacts and achieving related SDGs.

1. Leachate Treatment (SDG 6): Membrane-based technologies are the dominant approach, with UASB + MBR + NF + RO configurations used in 82% of plants. However, the resulting concentrate remains a management challenge.
2. Flue Gas Purification (SDG 3, SDG 11): The most common technology (66.7% of plants) is SNCR combined with semi-dry/dry processes and bag filters. Stricter emission standards are driving the adoption of more advanced, integrated systems.
3. Fly Ash Management (SDG 12): Landfill-based stabilization is the primary method (94.5%), largely due to cost. Resource utilization strategies like cement kiln co-processing and ceramsite production are limited by economic and market constraints, representing a missed opportunity for advancing a circular economy.

Environmental Performance and Climate Action (SDG 13)

Regional Carbon Emission Analysis

In 2022, the MSWI sector processed 240 million tonnes of waste, generating significant volumes of by-products. The life-cycle carbon emissions analysis reveals that flue gas treatment is the largest source of positive emissions (63.7%), followed by electricity consumption (17.3%). This highlights the need for technological innovations (SDG 9) to reduce the carbon footprint of pollution control measures. Provinces with underdeveloped waste classification systems, such as Hubei and Heilongjiang, exhibit higher leachate generation, increasing their environmental burden and hindering progress on SDG 6 and SDG 12.

Contribution to Net-Negative Emissions

From a life-cycle perspective, China’s MSWI industry has achieved a net carbon-negative status, providing an environmental benefit equivalent to avoiding 18.5 million tonnes of CO₂ eq/year. This directly supports SDG 13 (Climate Action) by offsetting emissions from fossil fuel-based power generation.

• Top Contributors: Guangdong province accounts for nearly 21% of the national carbon-negative benefit.
• Efficiency Leaders: Beijing leads in unit-level benefits (0.14 tonnes CO₂ eq avoided per tonne of MSW), primarily due to advanced fly ash resource recovery technologies that align with SDG 12.

These findings demonstrate that optimizing technological efficiency, particularly in resource recovery, is as crucial as expanding capacity to maximize the industry’s contribution to climate goals.

Economic Viability and Sustainable Growth (SDG 8 & SDG 9)

Provincial Economic Performance

In 2022, the MSWI industry generated a total annual revenue of RMB 7.05 billion, contributing to SDG 8 (Decent Work and Economic Growth). The leading provinces in terms of revenue are Guangdong, Shandong, and Jiangsu. However, analysis shows that high incineration volume does not always correlate with high unit-level economic benefits. For instance, Sichuan and Shanghai have high total revenues but lower unit-level profitability, indicating a need to improve operational efficiency and cost management to ensure the long-term financial sustainability of this critical infrastructure (SDG 9).

Cost-Revenue Structure and Challenges

• Expenditures: Capital investment is the largest cost (46%), followed by management, maintenance, and by-product treatment. High costs for fly ash and flue gas treatment in certain regions underscore the need for more cost-effective and sustainable technologies.
• Revenues: Revenue is primarily derived from electricity production (40%), MSW disposal fees (37%), and slag resource recovery (23%).

The phasing out of national subsidies for waste-to-energy poses a financial risk, particularly for smaller plants. To ensure operational stability and support its public service function, policy mechanisms such as dual-track tariff systems are recommended. Furthermore, enhancing the value derived from by-product resource recovery is essential for improving economic performance and advancing SDG 12.

Strategic Pathways for Enhanced Sustainability

Optimizing Operations for Climate and Environmental Gains (SDG 7, 11, 13)

Several strategies can significantly enhance the MSWI industry’s contribution to sustainable development.

1. Full-Load Operation: This strategy offers the highest potential for environmental benefits (8.8 million tonnes CO₂ eq avoided), particularly in provinces with low utilization rates. It maximizes energy output (SDG 7) and waste treatment capacity (SDG 11).
2. Waste Classification: Nationwide implementation could generate 1.3 million tonnes of CO₂ eq in environmental benefits by increasing the calorific value of waste and reducing leachate, supporting SDG 12 and SDG 13.
3. Sludge Co-incineration: This approach can improve furnace utilization and provide a sustainable solution for sludge management, contributing to both SDG 6 and SDG 11.

Advancing Resource Recovery and Air/Water Quality (SDG 3, 6, 12)

• Fly Ash Treatment Technology Transfer: Shifting from landfilling to resource utilization (e.g., producing ceramsite or cement) offers substantial emission reduction potential (7.8 million tonnes CO₂ eq) and promotes a circular economy in line with SDG 12.
• Leachate Treatment Upgrades: Optimizing leachate management can yield 6.4 million tonnes CO₂ eq in benefits and is critical for protecting water resources (SDG 6).
• Flue Gas Purification Upgrades: While advanced flue gas systems may slightly reduce carbon benefits, they are essential for reducing harmful air pollutants, protecting public health (SDG 3), and creating healthier communities (SDG 11).

Future Projections: A 2035 Outlook for Sustainable Waste-to-Energy

Projected Carbon-Negative and Economic Benefits

Scenario analysis projects a significant increase in the MSWI sector’s positive contributions by 2035.

• Business-as-Usual Scenario: The sector is projected to deliver 32.83 million tonnes of CO₂ eq in negative emissions, an 89% increase from 2022.
• Waste Classification Scenario: With the implementation of waste classification policies, the carbon-negative benefit could reach 92.5 million tonnes of CO₂ eq, a 407% increase from 2022.
• Optimal Scenario: Full implementation of technology transfers and co-incineration strategies could further increase carbon-negative benefits to 118.9 million tonnes CO₂ eq and generate RMB 364.3 billion in economic benefits.

The Role of Policy and Technology in Achieving SDGs

The projections demonstrate that a combination of policy enforcement (e.g., waste classification mandates) and technological advancement is crucial for maximizing the MSWI industry’s alignment with the SDGs. By 2035, under an optimal scenario, the average share of electricity revenue could rise from 40% to 49%, while leachate treatment costs could fall from 10% to 1%. This transition reinforces the dual environmental and financial value of sustainable MSW management, positioning the sector as a key contributor to China’s goals for climate action (SDG 13), sustainable cities (SDG 11), and responsible production (SDG 12).

1. Which SDGs are addressed or connected to the issues highlighted in the article?

The article on China’s municipal solid waste incineration (MSWI) industry addresses several Sustainable Development Goals (SDGs) by focusing on waste management, pollution control, energy generation, climate impact, and economic sustainability.

• SDG 3: Good Health and Well-being: The article discusses the control of harmful pollutants from incineration, such as “particulates, acid gases, toxic dioxins, and heavy metals,” which directly relates to reducing health risks from air and water pollution.
• SDG 6: Clean Water and Sanitation: The management of “leachate,” a significant by-product of waste incineration that can cause severe water pollution, is a central theme. The article evaluates various leachate treatment technologies to mitigate water contamination.
• SDG 7: Affordable and Clean Energy: The article frames the MSWI industry as a “waste-to-energy” sector. It highlights its role in “energy recovery,” mentioning that incinerators achieve “thermal efficiencies exceeding 80%” and generate revenue from “electricity production.”
• SDG 8: Decent Work and Economic Growth: The analysis of the “economic performance,” “financial benefits,” and “operational profitability” of the 876 incineration plants connects to sustainable economic growth. It explores how to improve the economic viability of the industry while decoupling it from environmental degradation.
• SDG 9: Industry, Innovation, and Infrastructure: The article focuses on upgrading industrial infrastructure by assessing “advanced flue gas treatment,” “optimized leachate management,” and other technological innovations to make the waste management industry more sustainable and efficient.
• SDG 11: Sustainable Cities and Communities: The core subject is the management of “municipal solid waste (MSW)” in the context of rapid “urban growth” in China. The article directly addresses the challenge of making cities more sustainable by improving waste treatment infrastructure and reducing their environmental footprint.
• SDG 12: Responsible Consumption and Production: The article emphasizes sustainable production patterns through “waste classification,” “by-product utilization,” and “resource utilization strategies” for fly ash and bottom slag. This promotes a circular economy approach by reducing landfill dependency and recovering value from waste.
• SDG 13: Climate Action: A significant portion of the article is dedicated to evaluating the climate impact of MSWI using “life cycle assessment models.” It quantifies “carbon emissions,” “carbon benefits,” and the potential for the industry to be “net carbon-negative,” directly contributing to climate change mitigation efforts.

2. What specific targets under those SDGs can be identified based on the article’s content?

Based on the issues and solutions discussed, several specific SDG targets can be identified:

1. Target 3.9: By 2030, substantially reduce the number of deaths and illnesses from hazardous chemicals and air, water and soil pollution and contamination.
   • Explanation: The article’s focus on “advanced flue gas treatment” to control emissions of “particulates, acid gases, toxic dioxins, and heavy metals” and on “optimized leachate management” to prevent water pollution directly contributes to this target by minimizing the release of hazardous substances into the environment.
2. Target 6.3: By 2030, improve water quality by reducing pollution, eliminating dumping and minimizing release of hazardous chemicals and materials, halving the proportion of untreated wastewater and substantially increasing recycling and safe reuse globally.
   • Explanation: The detailed analysis of different leachate treatment technologies, such as membrane-based systems (L1, L2, L3), aims to prevent the contamination of water bodies, directly aligning with the goal of reducing water pollution from industrial sources.
3. Target 7.2: By 2030, increase substantially the share of renewable energy in the global energy mix.
   • Explanation: The article evaluates the MSWI sector as a “waste-to-energy industry” that contributes to the energy supply through “energy recovery” and “electricity production.” Waste-to-energy is often considered a source of renewable or alternative energy, thus contributing to this target.
4. Target 8.4: Improve progressively, through 2030, global resource efficiency in consumption and production and endeavour to decouple economic growth from environmental degradation.
   • Explanation: The article assesses both the “environmental and economic performance” of MSWI plants. Strategies like “fly ash resource utilization” and “waste classification” are proposed to improve resource efficiency and achieve “financial benefits” while reducing pollution, embodying the principle of decoupling.
5. Target 9.4: By 2030, upgrade infrastructure and retrofit industries to make them sustainable, with increased resource-use efficiency and greater adoption of clean and environmentally sound technologies and industrial processes.
   • Explanation: The study’s evaluation of various incinerator types, pollution control systems, and by-product treatment technologies is aimed at identifying the most sustainable options. The recommendation to adopt “stricter emission standards” and upgrade technologies aligns perfectly with this target.
6. Target 11.6: By 2030, reduce the adverse per capita environmental impact of cities, including by paying special attention to air quality and municipal and other waste management.
   • Explanation: The entire article is centered on improving the management of “municipal solid waste” in China’s cities. By analyzing and proposing ways to enhance incineration practices, control pollution, and reduce the overall environmental burden of waste, it directly addresses this core urban sustainability target.
7. Target 12.4: By 2020, achieve the environmentally sound management of chemicals and all wastes throughout their life cycle… and significantly reduce their release to air, water and soil in order to minimize their adverse impacts on human health and the environment.
   • Explanation: The use of “life cycle assessment models” to evaluate the entire MSWI process, from waste input to the final treatment of by-products like “leachate, flue gas, fly ash, and bottom slag,” is a direct application of this target’s principle of environmentally sound management of waste.
8. Target 12.5: By 2030, substantially reduce waste generation through prevention, reduction, recycling and reuse.
   • Explanation: The article highlights the importance of “front-end waste sorting, especially food waste separation” and “waste classification” to improve incineration efficiency. Furthermore, it promotes “resource utilization strategies” for by-products like fly ash (e.g., “cement kiln co-processing, molten rock wool production, and ceramsite sintering”), which are forms of recycling and reuse.
9. Target 13.2: Integrate climate change measures into national policies, strategies and planning.
   • Explanation: The study’s analysis of “carbon emissions,” “GHG mitigation,” and the potential for “carbon-negative” outcomes provides a scientific basis for integrating sustainable waste management into China’s climate strategies. The scenario simulations projecting carbon benefits up to 2035 support long-term climate planning.

3. Are there any indicators mentioned or implied in the article that can be used to measure progress towards the identified targets?

Yes, the article mentions and implies numerous quantitative and qualitative indicators that can be used to measure progress.

• Indicator for Target 11.6 & 12.5:
  • Proportion of municipal solid waste incinerated: The article states that incineration accounted for “75% of the total treatment” in 2022. Tracking this percentage measures the shift away from landfilling.
  • Waste generation and treatment volumes: Data such as “310 million tonnes of MSW” processed in 2022 serves as a baseline for measuring waste management capacity.
  • Waste classification rates: The article implies this indicator by discussing the benefits of separating food waste and the shift from a “mixed waste treatment model to a refined waste separation system.”
• Indicator for Target 3.9 & 6.3:
  • Volume of pollutants and by-products generated: The article quantifies the generation of “65.4 million tonnes of leachate, 7.9 million tonnes of fly ash, and 35.2 million tonnes of slag,” which can be tracked to measure pollution loads.
  • Proportion of hazardous waste (fly ash) safely treated or utilized: The article states that “94.5% of the plants selected solidification/stabilization to landfill,” while only a small percentage used resource utilization. An increase in the utilization rate would be a key progress indicator.
• Indicator for Target 7.2 & 9.4:
  • Energy recovery efficiency: The mention of “thermal efficiencies exceeding 80%” is a direct indicator of the technological performance of waste-to-energy plants.
  • Amount of electricity generated from waste: While not given as a total national figure, the article identifies “electricity production” as a primary revenue source (40% of total), implying that the amount of energy produced is a key metric.
  • Adoption rate of advanced technologies: The article provides percentages for the adoption of specific flue gas (e.g., F8 at 66.7%) and leachate (e.g., L3 at 82%) treatment technologies, which can be monitored over time.
• Indicator for Target 13.2:
  • Net greenhouse gas (GHG) emissions from the waste sector: The finding that MSWI is a “net carbon-negative activity, generating environmental benefits equivalent to 18.5 million tonnes CO2 eq/year” is a critical indicator.
  • Carbon intensity of waste treatment: The article calculates unit-level benefits, such as “0.14 tonnes CO₂ eq avoided per tonne of MSW incinerated” in Beijing, which can be used to compare efficiency across regions and track improvements.
  • Projected GHG emission reductions: The scenario analysis projecting carbon-negative benefits to reach “118.9 million tonnes CO₂ eq” by 2035 under optimal strategies serves as a forward-looking indicator.
• Indicator for Target 8.4:
  • Economic revenue and profitability of the MSWI industry: The article quantifies “total annual economic revenue” at “RMB 7.05 billion” and analyzes the cost and revenue structure, providing a clear economic performance indicator.
  • Value generated from resource recovery: The revenue from “resource recovery from bottom slag” (23% of total revenue) is an indicator of the economic viability of circular economy practices.

4. Create a table with three columns titled ‘SDGs, Targets and Indicators” to present the findings from analyzing the article.

Source: nature.com