−99%
is how much dioxin emissions from these plants fell in the US between 1990 and 2005, thanks to modern filters.5
Air & health
Does it pollute? The straight answer.
Every industry emits something, and we won’t tell you otherwise. Here’s the whole truth: what comes out, how much, compared to what, and how you can check it yourself.
Compared to what
Trash already pollutes. Nobody measures it.
The question isn’t “plant or nothing.” It’s “plant or what we have today.”
What happens today
- Uncontrolled methane. Waste is almost 15% of the country’s greenhouse gases.1
- Leachate. Polluting liquid that must be contained for decades.
- Backyard and lot burning. Ground-level smoke with no filter at all.
- Smells, flies and vultures. For communities next to landfills.
- Zero public data. Nobody publishes live what comes out of a landfill.
With Orchidean One
- No landfill methane. What isn’t buried doesn’t rot.
- No leachate. Trash is transformed in days, it doesn’t stay forever.
- Treated gases. Several cleaning stages before the stack.*
- Sealed building. Odors are drawn in and burned.
- Public data. Continuous readings on this site and on public screens.
How the air is cleaned
Several barriers before the stack.
What leaves a modern plant’s stack is mostly water vapor, nitrogen and CO₂. The rest is caught along the way.
- 1
Controlled combustion
Between 850 and 1,100 °C, with gases held at least 2 seconds above 850 °C. At that temperature, hazardous organic compounds are destroyed.
- 2
Nitrogen oxide reduction
A reagent (urea or ammonia) is injected to turn nitrogen oxides into nitrogen and water vapor.
- 3
Acid neutralization
Lime captures acid gases: sulfur dioxide, hydrochloric acid and hydrofluoric acid.
- 4
Activated carbon
Traps dioxins, furans and mercury — like an aquarium filter, at industrial scale.
- 5
Bag filters
Thousands of fabric bags hold back the finest dust before the gas reaches the stack.
-
And at the end: continuous, public measurement
Analyzers in the stack measure emissions all the time. Results are published on this site and on public screens outside the plant and at the municipalities. See monitoring
* Typical modern-plant configuration; final setup is defined in detailed engineering.
The rule
Europe’s limits, here.
The European Union has some of the world’s strictest rules for these plants. Orchidean One is designed to meet them.3
It also complies with Costa Rica’s emissions regulation for thermal waste treatment, and aims for the “best available techniques” the EU updated in 2019.94
| Substance | Limit |
|---|---|
| Particulate matter (dust) | 10 mg/Nm³ |
| Nitrogen oxides (NOx) | 200 mg/Nm³ |
| Sulfur dioxide (SO₂) | 50 mg/Nm³ |
| Hydrogen chloride (HCl) | 10 mg/Nm³ |
| Hydrogen fluoride (HF) | 1 mg/Nm³ |
| Carbon monoxide (CO) | 50 mg/Nm³ |
| Total organic carbon | 10 mg/Nm³ |
| Mercury (Hg) | 0.05 mg/Nm³ |
| Dioxins and furans | 0.1 ng TEQ/Nm³ |
What the data says
Modern plants aren’t what they used to be.
20×
more dioxin is emitted by household fireplaces and wood stoves in Germany than by all its waste plants combined.6
No fine print
What we won’t hide from you.
When someone says “but what about…”, here are the answers.
Yes, it emits CO₂.
Like any combustion, mainly from plastics. But it avoids landfill methane, which over 20 years warms the planet about 80 times more than CO₂. Studies involving US EPA researchers found that generating electricity from waste emits fewer greenhouse gases than a landfill — even one that captures its gas. 27
Yes, there’s ash.
About a tenth of the original volume. Bottom ash can be reused in construction — Denmark reuses nearly all of its own. Fine ash from the filters is a small share and is handled under Ministry of Health oversight. 8
Yes, trucks arrive.
The same ones that go to the landfill today, but with shorter trips. Planned routes, closed trucks and unloading inside the building.
Don’t trust us. Check.
When Orchidean One operates, you’ll see what leaves the stack, compared to the limit: on this site and on screens outside the plant and at the municipalities.
Questions about air & health
Does the plant pollute?
Every industry has emissions, and we won’t pretend otherwise. What matters is how much, compared to what, and who controls it.
Today, trash already pollutes: landfills release methane and leachate, and in many backyards trash is burned with no control at all. Orchidean One treats its gases in several stages before release, is designed to meet European Union limits — among the strictest in the world — and publishes its readings. See the full answer.
Will it smell?
No. Trash arrives in closed trucks and is unloaded inside a sealed building. The air inside is drawn into the furnace: odors don’t escape, they get burned. That’s why plants like these operate in the middle of Vienna, Copenhagen and Tokyo.
Is it dangerous for neighbors’ health?
Modern plants changed radically. In the United States, dioxin emissions from these plants fell more than 99% between 1990 and 2005 thanks to modern filters. In Germany, household fireplaces and wood stoves emit about 20 times more dioxin than all its plants combined.
Orchidean One is designed with that cleaning technology, with continuous measurement and the data in plain sight. If a value goes over the limit, people will know.
Costa Rican trash is very wet. Does it work?
Good question. Our trash has a lot of organic matter and moisture. That’s why a study of the country’s actual waste — moisture and heating value — is under way to fine-tune the design. Trash rests in a sealed pit to drain, and a moving multi-stage grate keeps it moving and mixing so it burns completely, between 850 and 1,100 °C.
What happens to the ash?
Trash shrinks to about a tenth of its volume. Metals are recovered for recycling. Bottom ash can be reused in construction (Denmark reuses nearly all of its own). The fine ash from the filters — a small share — is handled under Ministry of Health oversight.
Was this useful? Pass it on.
One informed person is worth a thousand rumors. Send this link to your family, your neighborhood group or your local council.
Sources
- PNUD Costa Rica. Inventario Nacional de Gases de Efecto Invernadero (2017, publicado 2022): residuos = 14,8% de las emisiones.
- IPCC AR6, GT I, cuadro 7.15: potencial de calentamiento del metano.
- Directiva 2010/75/UE sobre emisiones industriales, Anexo VI, parte 3 (límites para incineración de residuos).
- Decisión de Ejecución (UE) 2019/2010: conclusiones sobre mejores técnicas disponibles (MTD) para incineración de residuos.
- US EPA. Emisiones al aire de combustores de residuos municipales (dioxinas: −99% entre 1990 y 2005).
- Ministerio Federal de Ambiente de Alemania (BMU, 2005). “Abschied von der Dioxinschleuder”.
- Kaplan, Decarolis y Thorneloe (2009). “Is it better to burn or bury waste for clean electricity generation?” Environmental Science & Technology.
- CEWEP. Hoja informativa sobre reutilización de cenizas de fondo.
- Decreto 39136-S-MINAE (2015). Reglamento sobre condiciones de operación y control de emisiones para coincineración de residuos sólidos ordinarios.