Op-Ed: Cementing a greener future – Turning Vietnam’s plastic waste into a resource

Vietnam’s twin challenge

Vietnam faces a dual crisis of surging plastic waste and rising carbon emissions. Per capita plastic use has risen from 4 kg in 1990 to 40 kg today. The country generates more than 3.5 million tonnes (Mt) of plastic waste annually, with 60–70% dumped across 1,180 mostly unsanitary sites. Recycling covers only 20%, mainly PET and HDPE, while flexible plastics lack markets. By 2030, 373,000 tonnes could leak into waterways - double 2018 levels.

Vietnam is investing in WtE plants (1,400 MW planned), but co-processing in cement kilns offers a faster, cheaper option to cut coal use, curb leakage, and support circular economy goals.

What is co-processing and why it matters

More than 5 billion tonnes of plastic already pollute the environment, much of it degrading into microplastics. This ‘fragmentation gap’ reveals a blind spot: global policies target new plastic flows but overlook vast legacy stockpiles leaking from dumpsites and rivers.

Co-processing helps close this gap while serving as a key lever for cement decarbonization. It replaces coal and virgin raw materials with non-recyclable plastic waste (NRPW) and other suitable wastes. Cement kilns operate at 2,000°C gas and 1,450°C material temperatures, ensuring complete destruction of plastic additives such as Phthalates, Bisphenol A (BPA), and flame retardants. Unlike incineration, no ash remains; minerals are locked into clinker.

The benefits are significant: expanded waste treatment capacity, landfill diversion, avoided methane emissions, reduced coal consumption, and direct CO₂ cuts. The IEA estimated that raising alternative fuels to 30% of cement kiln energy globally by 2050 could save 0.9 Gt CO₂, equal to 12% of the sector’s reduction potential in a 2 °C scenario.

Vietnam’s cement industry, with 57 plants with 83 kilns, emits 60 Mt CO₂ annually, over 15% of national emissions. Yet only 10 plants co-process waste, with a national Thermal Substitution Rate (TSR) of 4%, far below >50% in the EU and >75% in Norway.

Scaling up is urgent. With the Global Plastics Treaty stalled in Geneva in August 2025 (INC 5.2) over production cuts, trade controls, and a financial mechanism, co-processing offers a practical, scalable pathway to manage legacy plastics and accelerate progress toward ending plastic pollution.

Success stories: Co-processing in action

The OPTOCE project, funded by Norad and led by SINTEF, has demonstrated the power of co-processing at scale. It piloted 20 large-scale demonstrations across 8 Asian countries, including Vietnam. These pilots diverted over 1 Mt of NRPW from rivers and dumpsites, substituted 0.5 Mt of coal, and achieved substantial CO₂ reductions. Scientific assessments confirmed that co-processing is environmentally safe, with no elevated emissions of dioxins or other pollutants.

In Vietnam, OPTOCE partnered with leading cement producers to prove the concept locally. At the INSEE (formerly Holcim) Hon Chong plant in the south, pilots utilized plastic waste from the country’s largest paper manufacturer and residues from the footwear industry. In the north, the Lam Thach Green Cement Company (QNC) successfully co-processed low-value, non-recyclable rejects from the craft villages of Minh Khai (Hung Yen) and Trang Minh (Hai Phong).

 Today, both INSEE and Lam Thach achieves 35–40% TSR. These achievements bust long-standing myths about technical feasibility and environmental safety, showing that with supportive policies and partnerships, Vietnam can rapidly scale co-processing to cut coal use and curb plastic leakage.

Synergy for Vietnam’s Waste Strategy

Vietnam is investing heavily in Waste-to-Energy (WtE) incineration, with the Soc Son plant in Hanoi processing 4,500 tonnes of waste daily and 15 more facilities planned. Yet WtE faces structural challenges: high capital and operating costs, low efficiency, and residues such as hazardous fly ash and bottom ash that require treatment or landfill. Incineration of wastes (MSW, plastics, etc.) is not a complete treatment solution; around 25–30% end up as residue that must be landfilled, with possible long-term impacts. 

By contrast, co-processing in cement kilns is cheaper, cleaner, and leaves no residues. A SINTEF–RTI study in India showed that treating municipal Refuse-Derived Fuel (RDF) costs about USD 25 per tonne, less than half the USD 62 per tonne required for incineration.

But this is not a competition. Co-processing and WtE are complementary. Dry, high-calorific fractions such as low-value plastics, textiles, and multi-layer packaging are best suited for cement kilns, while mixed wastes in urban areas can be directed to WtE plants. Regional planning can allocate feedstock efficiently, prevent competition, and maximize treatment capacity.

Vietnam should establish a national coordination committee to harmonize co-processing and WtE development, backed by life-cycle analysis to guide investment. Together, the two approaches can drastically reduce landfilling and cut fossil fuel use.

Scaling up co-processing: What’s needed next

Vietnam can unlock co-processing at scale with three decisive actions:

- Enforce landfill diversion: Mandate that all waste with calorific value above 1,500 kcal/kg is directed to cement kilns or WtE facilities, supported by phased and realistic diversion targets (Vietnam’s current goal of reducing landfill disposal to below 10% by 2030 is ambitious). Strengthen local segregation systems to improve RDF quality and ensure accountability.

- Implement QCVN 41:2025 with global benchmarks: Finalize the regulation with Best Available Techniques/Best Environmental Practices (BAT/BEP)-aligned emission limits, continuous emission monitoring systems (CEMS), independent third-party audits, and public disclosure to ensure integrity and certainty.

- Incentivize RDF infrastructure: Support pre-processing hubs through Public-Private Partnerships (PPPs), tipping fee alignment, tax breaks, and carbon credits linked to TSR performance. Standardize RDF quality to ensure reliable, high-quality feedstock for kilns.

A call to action

With over three decades of experience in waste management, I see Vietnam at a pivotal crossroads. The convergence of a mounting plastic crisis and the global push for decarbonization offers a unique chance to lead. Co-processing is a proven, cost-effective solution - ready to scale. By using cement kilns to consume hundreds of thousands of tonnes of waste, Vietnam can cut coal use, prevent plastic leakage, and slash CO₂ emissions.

To unlock this potential, the country must finalize clear regulations, incentivize investment, and build robust waste systems, transforming cement kilns into eco-friendly powerhouses tackling plastic pollution and industrial emissions together.