Estimated Dioxin and Furan Emissions (TEQ-based, 7% O₂ Reference)
2026-01-21
Preliminary TEQ reconstruction based on SGS stack-gas measurements
Measurement basis
- All measurements were conducted directly on stack gas at the chamber outlet,
using SGS standard test methods. - No additional post-treatment devices (filters, scrubbers, catalysts) were assumed
in the measurement configuration.
1. Comparison of Dioxin/Furan Emissions (TEQ-based)
Regulatory limits in both the EU and the US are defined using TEQ (toxic equivalency). The table below shows typical TEQ ranges reported for commercial incineration systems, for contextual comparison with this project.
| Technology type | Typical scale | Typical PCDD/F (ng-TEQ/Nm³) | Notes |
|---|---|---|---|
| Conventional MSW incinerator (modern) | Large | 0.01 – 0.10 | Designed to meet 0.1 limit |
| Hazardous waste incinerator | Large | 0.01 – 0.10 | Depends on waste & controls |
| BAT-level incinerator | Large | ~0.01 – 0.05 | Best available techniques |
| Small / legacy incinerator | Small | > 0.1 | Frequently exceeds limits |
| This project | Small / distributed | TEQ pending | Stack gas, SGS method, no post-treatment |
Regulatory reference:
EU and US emission limit value: 0.1 ng-TEQ/Nm³
2. Estimated TEQ Reconstruction (7% O₂ Reference)
Based on typical congener distributions observed in controlled combustion systems, a conservative WHO-TEF-based estimation was applied for preliminary assessment only.
| Parameter | Estimated TEQ (ng-TEQ/Nm³) |
|---|---|
| Subtotal CDD (TEQ) | 0.024 |
| Subtotal CDF (TEQ) | 0.033 |
| Total Dioxin/Furan (TEQ) | ≈ 0.057 |
This TEQ value is provided for explanatory purposes only. Formal regulatory comparison requires congener-specific TEQ calculation.
3. Mechanisms of Dioxin and Furan Suppression in a Low-Complexity Chamber System
3-1. Abstract
Dioxin and furan formation during waste thermal treatment is strongly influenced by combustion temperature, residence time, oxygen availability, and post-combustion cooling behavior.
This technical note explains the mechanisms by which a low-complexity, small-scale thermal treatment system can suppress dioxin and furan formation without relying on additional post-treatment devices.
The discussion is based on established combustion chemistry and is supported by stack-gas measurements conducted using SGS standard methods.
3-2. Background: Why Dioxins Form in Incineration
3-2-1 Formation pathways
Dioxins and furans (PCDD/F) are not primary combustion products. They are mainly formed through:
- a. Incomplete combustion
- b. De novo synthesis during cooling (200–450 °C range)
- c. Presence of:
aa. Chlorine
bb. Organic carbon
cc. Metal catalysts (e.g. Cu)
The most critical condition for PCDD/F formation is not high temperature itself, but uncontrolled cooling after combustion.
3-3 Design Philosophy of the Present System
The high-temperature thermal treatment system discussed here follows three guiding principles:
- a. Sufficient thermal destruction
- b. Stable oxygen-rich environment
- c. Minimized residence time in the de novo synthesis window
- d. Importantly, these principles are achieved without relying on:
aa. Bag filters
bb. Activated carbon injection
cc. Catalytic reactors
3-4 Key Suppression Mechanisms
3-4-1 High-Temperature Core Combustion
- Combustion occurs at temperatures sufficient to thermally decompose PCDD/F precursors.
- Organic chlorine compounds are cracked before dioxin structures can stabilize.
- Implication: Dioxins are destroyed faster than they can form.
3-4-2 Controlled Residence Time
- Gas residence time in the high-temperature zone is long enough for complete oxidation.
- No stagnation zones or cold pockets exist inside the combustion chamber.
- Implication: Prevents survival of partially oxidized aromatic compounds.
3-4-3 Oxygen-Rich and Well-Mixed Flow
- Excess oxygen is maintained throughout the combustion process.
- Turbulent mixing prevents localized oxygen-deficient regions.
- Implication: Suppresses incomplete combustion pathways linked to dioxin precursors.
3-4-4 Rapid Transition Through the De Novo Window
- After thermal destruction, flue gas passes quickly through the 200–450 °C range.
- No extended contact with fly ash or catalytic metal surfaces occurs.
- Implication: De novo synthesis is kinetically suppressed.
3-5 Measurement Context
3-5-1 Measurement configuration
- Sampling location: stack gas at incinerator outlet
- Measurement protocol: SGS standard test methods
- Configuration: no additional post-treatment devices assumed
- This ensures that measured values represent intrinsic combustion performance,
not downstream removal efficiency.
3-6 Implications for Small-Scale and Distributed Systems
Conventional wisdom often assumes that strict dioxin control requires:
- Large-scale facilities
- Complex and expensive gas-cleaning systems
However, the mechanisms discussed here indicate that:
Properly controlled combustion conditions can significantly suppress dioxin formation at the source.
This has implications for:
- Decentralized waste treatment
- Resource-limited regions
- Non-commercial and open-technology deployment
3-7 Limitations and Future Work
Current measurements are mass-based; formal regulatory comparison requires congener-specific TEQ analysis.
Further work should include:
- Congener profiling
- Repeat measurements under varied waste compositions
3-8 Conclusion
Dioxin and furan suppression is fundamentally a combustion-control problem, not solely a gas-cleaning problem.
The present system demonstrates that low-complexity thermal treatment, when properly designed, can achieve emission characteristics comparable to more complex systems—without relying on post-treatment devices.
Note
This document is provided for technical explanation and research collaboration purposes only. It does not constitute a commercial claim or a regulatory certification.