Waste Co-processing: A Green Path for Vietnam’s Cement Industry

Vietnam’s cement industry is facing a strategic choice: shifting from primarily consuming coal and using traditional fossil fuels to utilizing the massive waste stream of society as alternative raw materials and fuels. This is the “co-processing” model in the clinker kiln. This model does not only hold environmental significance by reducing CO2 emissions and reliance on fossil fuels. It also opens up new economic possibilities: utilizing waste as a resource, saving fuel costs, and moving toward a circular economy.

However, despite the clear benefits, expanding the co-processing model still faces numerous policy, technical, and economic barriers. Even with pioneering enterprises like INSEE Ecocycle (part of Siam City Cement Vietnam) or Hoa Binh High-Tech Environment Joint Stock Company (HBHTE) demonstrating its feasibility, there remains a long way to go before it becomes a common solution across the industry.

Potential and Multi-faceted Benefits of Co-processing

Co-processing waste in clinker production is not merely a simple waste treatment method but a comprehensive strategy that brings dual benefits for the environment and the economy.

1.1. Environmental Benefits and CO2 Emission Reduction

The most apparent benefit of co-processing is the reduction of greenhouse gas emissions. Replacing coal with high-calorific waste like Refuse Derived Fuel (RDF) or Specified Refuse Derived Fuel (SRF) helps directly reduce coal consumption. In the cement industry, CO2 emissions come from two main sources: fuel combustion (about 40%) and limestone decarbonation (about 60%). Reducing direct coal consumption will directly cut this 40% of CO2 volume.

Furthermore, diverting tens of millions of tons of Municipal Solid Waste (MSW) and industrial waste from landfills to cement kilns helps mitigate Methane (CH4) emissions, a greenhouse gas with a global warming potential 25 times higher than CO2. By thoroughly utilizing waste materials, co-processing also contributes to the goal of natural resource conservation, reducing the mining of limestone, clay, and other additives.

1.2. Massive Potential Energy Source from Waste

According to statistics, the total amount of Municipal Solid Waste in Vietnam reaches about 23.3 million tons/year, equivalent to over 64,000 tons/day. Although the average calorific value of Vietnamese waste (1,500–2,000 kcal/kg) is still low compared to developed countries due to high moisture and organic content, if pre-treated and converted into fuel with a higher calorific value, this energy source could be equivalent to 5.8 to 7.8 million tons of coal.

With the cement industry’s annual coal demand being 9–11 million tons, the potential for replacing fossil fuels with solid waste is enormous. National goals are clearly outlined in Decision 1266/QD-TTg (2020), setting milestones:

• By 2025, a minimum of 20% of raw materials in clinker production must be reusable materials.
• By 2030, the alternative fuel ratio should reach 15%, aiming for 30% in the 2031–2050 period.

Achieving these goals will position the cement industry as a vital part of the national waste treatment value chain.

1.3. Superior Technical Advantages of Cement Kilns

The clinker kiln is considered the safest and most effective waste treatment solution due to its optimal operating conditions:

• Ultra-High Temperatures: Temperatures in the burning zone reach 1,450 C, and the flame temperature can be up to 2,000 C. This temperature ensures the complete destruction of toxic organic substances, including Dioxins and Furans, converting them into simple, harmless compounds.
• Long Residence Time: Solid waste has a residence time of about 30 minutes in the kiln, and the gas phase has a burning residence time of about 8 seconds, ensuring thorough thermal destruction.
• Alkaline Environment: The nature of the clinker production process creates an alkaline environment (due to the presence of CaO). This environment neutralizes potential acidic gases from the waste (HCl and SO2), turning them into stable salts integrated into the clinker structure.
• No Secondary Waste Generation: Unlike waste-to-energy incineration methods that often create toxic fly ash requiring landfilling, the ash from co-processed waste is completely integrated into the clinker product, eliminating secondary waste.

Current Benefits and Scale of the Cement Industry

Vietnam’s cement industry currently has about 61 factories with 87 synchronous technological lines, with a total designed capacity of over 108 million tons of clinker/year, equivalent to about 121 million tons of cement (data announced by the industry).

Production output in the 2019–2024 period has been maintained at a high level, averaging over 80 million tons/year, with about 20 million tons designated for export. To achieve this output, the industry consumes over 9–11 million tons of coal/year, making it one of the sectors with significant carbon emissions.

The extensive use of coal in clinker production places considerable pressure on the cement industry regarding environmental concerns and emission policies. Therefore, utilizing waste as an alternative raw material and fuel has become an inevitable direction: reducing dependence on fossil fuels while simultaneously reducing CO2 emissions.

Furthermore, according to a study, Vietnam currently generates about 23.3 million tons of Municipal Solid Waste per year (over 64,000 tons/day) with an average calorific value of 1,500–2,000 kcal/kg. This is equivalent to 5.8 to 7.8 million tons of coal if utilized, representing a very large potential energy and material source for cement kilns.

From an environmental-economic perspective, co-processing brings a dual benefit:

• Reducing traditional fuel costs (coal, oil, etc.).
• Reducing waste treatment and landfill costs, lessening reliance on landfill space.
• Reducing greenhouse gas emissions, contributing to the Net Zero commitment.
• Supporting the development of the circular economy: turning “waste” into resources instead of simply disposing of it.

Implementation Reality and Barriers to Expansion

Despite its huge potential, the actual implementation in Vietnam remains quite limited. Surveys indicate that only about 15 out of 61 cement factories use waste as alternative fuel; most of this is industrial waste with a calorific value above approximately 3,500 kcal/kg. The total substitution rate across the industry is only about 3–4%. Some pioneers have reached 35–45%, but these are few, and many models are still at the pilot or intermittent operation stage.

Evidently, a “large potential – small implementation” situation is occurring. The main reasons stem from three core groups of barriers:

Unstable Supply Chain and Waste Source

Collecting, sorting, pre-processing, and supplying compatible high-calorific waste (e.g., RDF, SRF) to the cement industry face difficulties: the waste source is unstable, quality fluctuates significantly, and there is a lack of a complete supply chain covering collection, pre-processing, transportation, and supply. For example, one study points out that most Municipal Solid Waste in Vietnam is not sorted at the source, making its conversion into alternative fuel challenging.

Technical and Technological Standards

To use waste as fuel in clinker kilns, specific conditions must be met: high and stable temperature, sufficient burning residence time, alkaline environment, and negative pressure, all according to international standards to ensure no toxic gas is emitted and clinker quality is unaffected. Co-processing technology requires significant investment, continuous emission monitoring systems, and very strict fuel quality control.

Unclear Policy and Economic Framework

Although there are guiding documents like Decision 1266/QD-TTg of 2020 setting targets: a minimum of 20% of raw materials in clinker production must be reused materials by 2025; the alternative fuel ratio should reach 15% by 2030 and aim for 30% in the 2031–2050 period. However, specific support mechanisms are very limited: there are no clear preferential prices for alternative fuels, carbon credits are non-existent or unclear, investment and waste pre-treatment costs are high, and legal procedures are complicated (environmental permits, collection and transport permits, etc.), making businesses hesitant.

Economics for Businesses Are Not Yet Attractive

Investing in co-processing systems and waste management, pre-treatment, sorting, and transportation all incur higher costs than using traditional coal. Without subsidies, businesses must weigh the risks and benefits. Some studies show fuel savings have occurred, but without accounting for investment and operational costs at high volumes.

Alternative Raw Materials are Competed Against by Cheaper Sources

The use of ash, slag, sludge, and steel slag as alternative raw materials in clinker production is also limited. In part, because natural raw materials are still abundant and cheaper, businesses are not enthusiastic about major changes.

Therefore, despite the readily available technology in Vietnam’s cement industry and the massive potential waste source, for the co-processing model to become a widespread solution instead of just remaining with pioneering models, a clear policy framework, technical standards, and appropriate incentive mechanisms are needed.

Notable Pioneer Models

Below are two typical examples illustrating the application of co-processing in Vietnam:

INSEE Ecocycle (under Siam City Cement Vietnam)

• INSEE Ecocycle has been a pioneer in deploying waste co-processing in clinker kilns since 2003.
• The system has a network of 7 storage warehouses, 2 transfer stations, and over 330 partners across 34 provinces/cities nationwide, having treated over 1.8 million tons of waste and reduced approximately 1.7 million tons of CO2 emissions over the past 18 years.
• INSEE’s co-processing technology operates at temperatures up to 2,000 C, with a long residence time (8 seconds for gas and 30 minutes for solids), in an alkaline and closed environment, generating no secondary waste. A 24/7 emission monitoring system ensures that indicators like NOx, SO2, HCl, or CO2 do not exceed limits.
• The Thermal Substitution Rate (TSR) at the Hon Chong plant has gradually increased and is expected to reach nearly 50% by 2025—the highest in Vietnam’s cement industry.
• The biggest challenge, according to an INSEE representative: not receiving treatment fees or subsidies like waste-to-energy incineration or landfilling options, while investment and quality control costs are much higher; poor source separation of waste increases pre-treatment costs and affects RDF fuel quality.

Hoa Binh High-Tech Environment Joint Stock Company (HBHTE)

• This enterprise connects the waste treatment sector with the cement industry through Refuse Derived Fuel (RDF). With an investment capital of about 600 billion VND and a modern production line capacity of 1.4 million tons/year, the company produces RDF pellets from difficult-to-recycle plastic waste, achieving a calorific value of 5,570–7,168 kcal/kg, with moisture 10%, fully meeting the technical standards for cement kilns.
• According to Dr. Pham Van Dien – Director of the Hoa Binh High-Tech Environmental Research Institute, Hoa Binh’s RDF technology helps reduce CO2 emissions by 25–30% compared to coal, while saving 15–25% of fuel costs for cement plants. RDF has been practically applied at Vicem But Son Cement plant, replacing part of the coal and FO oil without affecting clinker quality.
• The company also emphasizes barriers: the absence of national standards for RDF/RPF, a lack of a transparent pricing mechanism, and limitations in logistics infrastructure for waste collection-transportation. Hoa Binh recommends issuing national standards for RDF, providing “green” credit support and tax exemptions for renewable energy projects, and developing a carbon credit market to encourage businesses to invest in circular waste treatment.

Strategic Perspective: Success, But More is Needed for Popularization

From the overall industry perspective to specific models, it is clear that waste co-processing is not just an environmental solution but also a sustainable energy strategy for Vietnam’s cement industry. However, for this model to spread and become the industry standard, several strategic points need attention:

• Clear Policy and Legal Framework: Issuing and enforcing national standards related to co-processing (such as standards for RDF/RPF, monitoring systems, technical requirements) is crucial. For example, Vietnam’s environmental sector recently introduced a new technical regulation on waste co-processing in cement kilns, effective from February 9, 2026.
• Economic and Financial Incentive Mechanisms: Businesses need support through preferential policies (tax, green credit, lower waste treatment fees, etc.), carbon credit trading mechanisms, and accurate accounting of waste collection-pre-treatment costs. Otherwise, the model is difficult to scale up as the economic benefits are not clearly attractive enough.
• Building a Synchronous Waste Supply Chain: From source collection and sorting, pre-processing, transportation, to supply to cement plants—a complete system is needed to ensure a stable waste source, consistent quality, and reasonable cost.
• Public-Private Partnership and Logistics Infrastructure Development: Waste collection, transportation, and treatment require large infrastructure and the linkage of many parties (local authorities, waste treatment companies, cement plants). PPP cooperation, and planning specialized areas for waste collection and RDF supply, could be viable solutions.
• Technology Investment and Strict Quality Control: Cement plants and waste treatment units need to invest in suitable technology, emission monitoring systems, and control of alternative fuels to ensure no adverse impact on the environment or clinker quality.
• Communication – Awareness among People and Businesses: Source separation of waste and raising awareness of the benefits of turning waste into resources are critical to ensuring an appropriate waste stream.
• Clear Monitoring and Evaluation of Results: Measuring TSR, CO2 reduction, cost savings, and sharing data for all parties to learn from and replicate successful models.

The implementation of waste co-processing in Vietnam’s cement industry is a strategic direction—both protecting the environment and increasing industry competitiveness by reducing fuel costs and embracing the green production trend. Companies like INSEE Ecocycle and HBHTE have proven the model feasible, and its widespread adoption would have a huge impact: millions of tons of waste treated, millions of tons of coal replaced, and millions of tons of CO2 reduced.

However, to transition from “pioneer model” to “industry standard,” Vietnam needs decisive action on three pillars: policy, technology, and supply chain. If delayed, the model will remain a localized solution and fail to realize its enormous inherent potential.

With national targets such as achieving an alternative fuel ratio of 15% by 2030 and aiming for 30% in the 2031–2050 period, Vietnam’s cement industry and related stakeholders have a great opportunity to lead the green transition but must act resolutely to avoid missing out.