The Rimrock Cattle Company Ltd. feedlot will continue to emit odours as part of feedlot operations whether the proposed biodigester is built or not. Biodigestion is a proven technology that is currently the most advanced and effective option to reduce feedlot odours.
How? The biodigester facility will capture odour-causing greenhouse gases from feedlot manure and, through a fully closed system, convert them to a usable energy resource called renewable natural gas (RNG). Today, those greenhouse gases are currently being released to the atmosphere. It will also help reduce feedlot operational odours by doubling the rate of livestock pen cleanouts and reducing the need for seasonal storage of raw manure at the feedlot (because feedlot manure will be used as feedstock instead).
Based on air quality modelling completed by a qualified third party in July 2023, the operation of the proposed biodigester facility is predicted to result in an approximate 47% net reduction in feedlot odour. This approximate net decrease of 47% considers:
- 49% reduction in feedlot odours due to pen cleanout frequencies and manure stockpiling reductions.
- 2% addition and inclusion of potential odour sources introduced by the biodigester facility (e.g., solid digestate staging, manure staging, and liquid digestate pond).
We agree that community members should not be subjected to additional odours as a result of the proposed biodigester facility, and we are committed to doing our part by designing the facility to mitigate potential odours and implementing best odour management practices at the facility.
From the beginning, the proposed biodigester facility design includes key odour abatement features, such as:
- Anaerobic digester tanks that operate as a fully closed system.
- Biogas upgrading where activated carbon filters and ammonia scrubbing vessels will trap volatile organic compounds (VOCs), ammonia (NH3) and hydrogen sulfide (H2S), to produce pipeline quality RNG which will be injected into the local ATCO Gas distribution system.
- Screw presses that will separate digestate into solid and liquid fractions for odour mitigation in both the staged solid and liquid digestate.
Recent design changes have also been made to further mitigate potential odours, including new odour abatement technologies such as:
- Enclosed feedstock receiving area, including building and tanks, organic food resource tanks, and digestate separation building and tanks are all connected to the odour abatement system, removing approximately 95% of odorous emissions from those sources.
- Mechanical aeration in the first cell of the liquid digestate pond will remove approximately 95% of odorous emissions from the entire pond through oxidation.
See the Odour Abatement Technologies section of the Facility Information page for more details.
Odour reduction strategies will also be implemented throughout the facility lifecycle through a continuously improving odour management control plan which will include:
- Administrative controls like operator training and awareness, and the establishment of rigorous maintenance, inspection, and cleaning schedules.
- Odour management procedures for manure and organic food resources transportation, receiving and processing.
- Odour prevention and control measures that will be implemented during both standard and non-standard operating conditions (start-up, shut-down, maintenance and/or upset operating conditions).
- Routine monitoring of the performance of the anaerobic digesters and facility odour containment and control equipment as part of the facility inspection and maintenance program. For example, gas detectors will be used as an operational tool to adjust the feedstock schedule if undesired gasses are being produced.
Any conditions stipulated in the EPEA approval, if granted, related to air emissions limits, monitoring and reporting, along with any odour management requirements for the facility will be strictly adhered to. The EPEA approval and conditions will be publicly available.
Regional Air Quality and Odour Monitoring
Regionally, in 2022, the Calgary Region Airshed Zone (CRAZ) and Town of High River announced a partnership in concert with Alberta Environment and Protected Areas to bring air quality monitoring to High River with one objective being the establishment of a baseline Air Quality Index for the area. The Natural Resources Conservation Board (NRCB) has also installed a CTair unit at the same location as the CRAZ sensor to measure additional air quality parameters specific to feedlots. The CTair unit will provide the NRCB with another tool to help monitor and address odours related to the Rimrock Cattle Company Ltd. feedlot west of High River.
Recognizing the proposed facility is in an area of high existing odour sources such as other feedlots, a meat processing facility, a wastewater treatment facility, and a landfill, Rimrock is open to cooperating and supporting a regional monitoring program through the Province, County, or other organization.