Draft approval released for proposed Bennett soil treatment facilityOn February 18, New Brunswick Environment and Local Government Minister Brenda Fowlie released for public comment a draft operating approval for Bennett Environmental's proposed high-temperature thermal oxidizer treatment facility in Belledune. Accompanying this document is an interim summary of issues and responses regarding the approval. The 120-day public comment period runs to April 19, 2004.
Bennett Environmental's planned facility will treat about 100,000 tonnes per year of soils and solid materials contaminated by non-chlorinated hydrocarbons and creosote; most of this material would come from site remediation projects within North America.
Categorized as a Class 1 source of emissions, the proposed facility is subject to the public participation regulation under New Brunswick's Clean Air Act, which requires a public participation process to be conducted before an operating approval is issued. The regulation provides for approvals to be issued by the Minister of the Environment and Local Government for a specified term of up to five years.
The draft air quality approval for the Bennett facility specifies requirements to prevent unfavourable air quality conditions. The conditions are generally wide-ranging, addressing matters such as:
limits on operational parameters;
requirements for testing and monitoring emissions from specific unit operations;
requirements for testing and monitoring the ambient air quality surrounding the facility;
requirements to operate air pollution control equipment;
limits on emissions that are approved to be released to the atmosphere;
provisions for equipment upgrade and/or maintenance;
requirements for environmental emergency and/or compliance reporting; and
other conditions aimed at minimizing the environmental impacts of the facility.
Between late November 2003, when the public participation process began, and mid-January 2004, the department received four submissions from individuals indicating support for the project, several inquiries about the public participation process and several submissions expressing concerns about the proposed facility.
One of the concerns relates to potential or likely levels of dioxin and furan emissions from the Bennett facility. The draft approval provides four levels of safety to address dioxins and furans, starting with the fact that the permit does not allow treatment of soils containing chlorinated compounds. Terms and conditions relating to operating and cooling temperatures are designed to destroy any dioxins and furans that may form and to prevent the reformation of these compounds. Bennett will also be required to keep air pollution control equipment (activated carbon injection system with a fabric filter baghouse) fully functional at all times while the facility is in operation to capture any dioxins and furans that may have been reformed.
Continuous emissions monitoring (CEM) will be required for emissions from the thermal process treatment stack; compounds to be monitored include sulfur dioxide, nitrogen oxides, carbon monoxide, total hydrocarbons, oxygen, moisture, as well as temperature and gas flow rate. Bennett will be required to have an annual CEM audit performed to ensure the accuracy of the monitoring equipment.
CEM for dioxins and furans will not be required because there is no proven technology available for accurate, continuous monitoring of these compounds, although this is under development.
The department has set a stack emission limit of 0.08 nanograms of dioxins and furans per cubic metre of stack gas. This limit conforms with the Canada-wide Standard (CWS) for dioxins and furans developed by the Canadian Council of Ministers of the Environment (CCME). Bennett will be required to test stack emissions from the facility annually, to verify that emissions are within the limits stipulated.
The approval will also require ambient monitoring of air quality surrounding the Bennett facility. The company will be required to install, maintain and operate two monitoring stations to measure ambient concentrations of fine particulate matter in the area.
Environment and Local Government staff will conduct periodic inspections and audits of the Bennett facility to verify compliance with the conditions of the approval to operate. These inspections and audits will be both scheduled and unscheduled and will include collection of soil samples to determine concentrations of various contaminants, including dioxins and furans. Conditions of the draft approval require Bennett to conduct regular soil and groundwater monitoring as well.
Concern was also expressed about air emissions from the facility's thermal relief vent (TRV) in the event of an upset in operating conditions at the Bennett facility. The department notes that the facility will have a back-up power supply to provide power to the critical components of the process during an event where the TRV has to be opened.
A condition in the draft approval would require the processing of contaminated soil in the primary combustion chamber to cease immediately if the TRV is opened, in order to avoid generating additional contaminants in the gas stream. This condition would requires the secondary combustion chamber burners to continued operating when when the TRV is opened in order to maintain temperatures high enough to destroy the organic compounds in the gas stream, including any dioxins and furans that may have formed.
Bennett will be required to report to the Department of the Environment and Local Government all incidents where the TRV has been utilized. Based on the company's operating experience at its thermal treatment facility in Quebec, a TRV opening would last from a few seconds to 30 minutes.
The draft operating approval and interim summary of issues and responses may be viewed on-line at www.gnb.ca/0009/0355/0005/I-0001_E.html. More information is available from the Department of Environment and Local Government offices in Bathurst (506/547-2092) or Fredericton, (506/444-4599).