Fact sheet: Incineration

From: Public Services and Procurement Canada

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Description

Incineration consists of burning and volatilizing the contaminants to be treated in the presence of oxygen at sufficiently high temperatures ranging from 870 °C to 1,200 °C (1,600 °F to 2,200 °F) to destroy contaminants. Several types of matrices can be treated by incineration, including soils, sludge, liquids and gases. A secondary combustion chamber collects and processes gaseous emissions and other by-products resulting from combustion.

There exist different types of incinerators. Incineration by circulating beds uses high velocity air to contain contaminated materials to be treated and creates a highly turbulent combustion zone that destroys toxic hydrocarbons at temperatures ranging from 780 °C to 870 °C (1,450 °F to 1,600 °F), which is lower than conventional incinerator temperatures. The turbulence produces a uniform temperature in the combustion chamber and a hot cyclone. The system also completely mixes the contaminated material to be treated during combustion. Effective mixing and low combustion temperatures reduce operating costs and potential vapours such as nitrogen oxides and carbon monoxide.

Incineration by infrared combustion uses electrical resistance heating elements or indirect fired radiant U-tubes to heat contaminated material to be treated passing through an incinerator chamber on a conveyor belt. The operational temperatures are up to 870 °C (1,600 °F). A blower delivers air to selected locations along the belt to control the oxidation rate of the contaminated material. Any remaining combustible are incinerated in an afterburner at the end of the conveyor.

Rotary kiln incinerators are used to treat solids, liquids, sludge and debris. The rotation of the combustion chamber, consisting of a slightly inclined cylinder, allows the complete mixing of its contents during the treatment. A secondary combustion chamber allows high temperature gas treatment (1,700 °F to 2,000 °F).

Sources:

Implementation of the technology

An incinerator, including the primary and secondary burning units as well as the effluent gas treatment system, may be constructed temporarily directly on-site, or the contaminated materials may be transported to the fixed incinerator.

The implementation of an incineration treatment may include:

  • Preparation of the site for the installation of the incinerator and other equipment (such as the preparation of the work site, the installation of a fence, the construction of a platform, etc.).
  • Recovery of materials to be treated (for example excavation of soils, sediments, sludge or waste, in the case of solid materials).
  • In the case of groundwater or surface water, facilities (wells, trenches, drains) and/or pumping equipment will be required for their removal.
  • Transport of the materials to be treated is required if the incinerator is not installed on the site.
  • Installation of all necessary equipment for the incinerator.
  • Recovery and management of treated materials.
  • The dismantling of the facilities and the restoration of the site.

The installation of a temporary incinerator is subject to compliance with certain laws and regulations that may require obtaining permits or authorization.

Materials and Storage

  • The operation of an incinerator requires oxygen or sufficient air, fuels adapted to the type of combustion apparatus and to the incinerator’s capacity.
  • A secondary treatment system for the cooling and treatment of gaseous effluents must also be put in place.

Residues and Discharges

  • Incineration generates residual material, such as treated soils, sediments and sludge, as well as ashes resulting from combustion.
  • Incineration also produces combustion gases that must be cooled and treated before being released to the atmosphere, to reduce air contamination.
  • Residues from the gaseous effluent treatment system could also be generated.

Recommended analyses for detailed characterization

Physical analysis

  • Soil water content
  • Soil granulometry
  • Contaminant physical characteristics including:
    • viscosity
    • density
    • solubility
    • vapour pressure
    • etc.
  • Matrix fusion temperature
  • Calorific value (soils, sediments, sludge)

Recommended trials for detailed characterization

Chemical trials

  • When new materials are to be processed, feasibility studies are recommended to determine the composition of gaseous emissions and ash formed during incineration at the site. No testing is required when materials are processed off-site.

Other information recommended for detailed characterization

Phase III

  • Volume of contaminated material to treat

Notes:

These data are required for each batch of material to be treated that must be sent to the incinerator.

Applications

  • Incineration can be used to remediate soils contaminated with explosives and chlorinated organic compounds such as polychlorinated biphenyls and dioxins and furans.
  • Efficient with semi-volatile organic compounds and pesticides.
  • Less effective for some volatile organic compounds and certain petroleum hydrocarbons.
  • Applicable to a wide variety of media such as soil, sludge, sediments, as well as liquids and gases.

Applications to sites in northern regions

Given the amount of energy required for incineration and maintenance of high temperatures, incineration in northern environments can be a costly treatment method. Similarly, this type of installation requires rigorous monitoring that could be limited in this type of environment that is often isolated.

Treatment type

Treatment typeApplies or Does not apply
In situ
Does not apply
Ex situ
Applies
Biological
Does not exist
Chemical
Does not exist
Control
Does not exist
Dissolved contamination
Does not exist
Free Phase
Applies
Physical
Applies
Residual contamination
Applies
Resorption
Applies
Thermal
Applies

State of technology

State of technologyExist or Does not exist
Testing
Does not exist
Commercialization
Exist

Target contaminants

Target contaminantsApplies, Does not apply or With restrictions
Aliphatic chlorinated hydrocarbons
With restrictions
Chlorobenzenes
Applies
Explosives
Applies
Metals
Does not apply
Monocyclic aromatic hydrocarbons
With restrictions
Non metalic inorganic compounds
Does not apply
Pesticides
Applies
Petroleum hydrocarbons
With restrictions
Phenolic compounds
With restrictions
Policyclic aromatic hydrocarbons
Applies
Polychlorinated biphenyls
Applies

Treatment time

Treatment timeApplies or Does not apply
Less than 1 year
Applies
1 to 3 years
Applies
3 to 5 years
Does not apply
More than 5 years
Does not apply

Long-term considerations (following remediation work)

The materials to be treated must first be recovered (excavated or pumped). For example, a site where incineration is planned should normally meet the applicable criteria and not require long-term monitoring.

If an incinerator is to be built on the site, it will be dismantled when all the materials have been treated.

Secondary by-products and/or metabolites

  • Incinerators may release carcinogenic and toxic chemicals, including heavy metals, partially burned organic material such as polyvinyl chloride, herbicide residues, and other organic chemicals.
  • When chlorinated hydrocarbons are incinerated, there is a risk of forming partially oxidized compounds including polycyclic aromatic hydrocarbons, dioxins and furans. Several of these sub-products are known or suspected human carcinogens.
  • Material contaminated with heavy metals can produce a bottom ash with high concentrations of hazardous compounds. These ashes may require treatment before being disposed of.
  • Some heavy metals, including lead, cadmium, mercury and arsenic, may partially vaporize and leave the combustion chamber with the gas emissions.
  • Metals can react with other elements in the feed stream or combustion chamber, such as chlorine or sulfur, forming compounds that are more volatile and toxic than the original compounds. Most of these compounds are short-lived reaction intermediates that can be destroyed.

Limitations and Undesirable Effects of the Technology

  • Emissions of toxic gas that must be controlled and treated.
  • Sodium and potassium form low melting point ashes that can attack the lining of the furnace, and form a sticky particulate that may obstruct the gas treatment system.
  • Off-site fixed facilities are associated with contaminated material manipulation and transportation risks.
  • Because the energy requirements for incinerators are high, and gas emission requirements are strict, incineration tends to be the most expensive type of remediation technologies.
  • Public acceptance of incineration is low.

Complementary technologies that improve treatment effectiveness

  • Sieving of the contaminated matrix to concentrate the contaminants in a smaller volume can reduce the cost of incineration treatment.
  • Incineration treatment is often the end line treatment of serial ex situ soil remediation technologies.

Required secondary treatments

  • Gas emission collection and treatment systems are required to remove particulates and neutralize and remove acidic gases (hydrogen chloride, nitrogen oxide and sulfur oxide).
  • A gas emissions cooling chamber (quench) may be required after the treatment of gas emissions, and before its discharge.
  • Regular monitoring of emissions into the atmosphere.
  • Proper disposal of the ash and other compounds formed during incineration must be achieved while considering the composition of these materials.

Application examples

The following sites provide application examples:

Performance

Incineration, primarily off-site, has been selected or used as the treatment method at more than 150 Superfund sites in the United States. In Canada, incineration is subject to a series of technology-specific regulations.

The destruction and removal efficiency of properly operated incinerators exceed the 99.9% requirement for hazardous waste, which corresponds to the treatment objectives for polychlorinated biphenyls and dioxins and furans.

Measures to improve sustainability or promote ecological remediation

  • Optimization of the heating system installation to reduce energy requirements
  • Optimization of gaseous effluent treatment processes

Potential impacts of the application of the technology on human health

Main Exposure Mechanisms

Applies or Does Not Apply

Monitoring and Mitigation

Dust

Applies

Monitoring conditions favourable to dispersion during the excavation of the materials to be treated.

Atmospheric/Steam Emissions—Point Sources or Chimneys

Applies

Emissions monitoring (choice of parameters, types of samples and type of intervention [source, risk or local requirements])

Atmospheric/Steam Emissions—Non-point Sources

Does not apply

N/A

Air/steam—by products

Applies

Emissions monitoring (choice of parameters, types of samples and type of intervention [source, risk or local requirements])

Runoff

Does not apply

N/A

Groundwater—displacement

Applies

Modelling the effects of required pumping and monitoring using pressure sensors

Groundwater—chemical/ geochemical mobilization chimique/géochimique

Applies

Modelling the effects of required pumping and monitoring using pressure sensors

Groundwater—by-product

Does not apply

N/A

Accident/Failure—damage to public services

Applies

File checks and licensing prior to excavation, development of excavation and emergency procedures

Accident/Failure—leak or spill

Applies

Risk review, development of accident and emergency response plans, monitoring and inspection of unsafe conditions

Accident/Failure—fire/explosion

Applies

Risk review, development of accident and emergency response plans, monitoring and inspection of unsafe conditions

Other—Handling contaminated soils or other Solids

Applies

Risk review, development of accident and emergency response plans, monitoring and inspection of unsafe conditions

Other

Does not apply

N/A

References

Author and update

Composed by : Josée Thibodeau, M.Sc, National Research Council

Updated by : Martin Désilets, B.Sc., National Research Council

Updated Date : June 8, 2016

Latest update provided by : Nathalie Arel, P.Eng., M.Sc., Christian Gosselin, P.Eng., M.Eng. and Sylvain Hains, P.Eng., M.Sc., Golder Associés Ltée

Updated Date : March 22, 2019

Date Modified: