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We continue to prioritize and​ invest in odour reduction​ at Gold Bar

We're working to continue to reduce odour emissions from the plant, improve monitoring and report data in a preferred format for the Gold Bar community.​​​


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Investing in odour reduction at G​old Bar

With continued investment in odour reduct​ion, see the results from our investments and future odour projects.
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What causes odours at Gold Bar 

Odours at Gold Bar are a natural part of the wastewater treatme​nt process; we continue to meet air quality objectives. ​
About odours

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​Odour reduction at Gold Bar

Previous odour mitigation projects has been completed to date at the Gold Bar Wastewater Treatment Plant (WWTP) and have significantly helped reduce odour emissions. Some projects include:

  • Sealed enhanced primary treatment clarifiers
  • Upgraded ventilation and odour collection
  • Scrubber upgrades

Over the next several years we have around $6 million planned to reduce odours at the front end of the plant.

Results from investments​

Our investments in odour management are showing results, and there has been a significant reduction in odours from 2017 to 2020.

​Future odour reduction

At the Gold Bar WWTP, we're taking steps to ensure odour levels consistently meet current and future standards and are safe for health and recreation. When it comes to monitoring and reporting odours, we are making changes at the facility to achieve the following:

  • Additional, continuous air quality monitoring in a place closer to the fenceline;

  • Real time results that are available in a format that is useful for stakeholders; and

  • New regulatory monitoring and reporting for stakeholders to reference so they can confirm the air quality remains safe for health and recreation. 

Additional odour management projects

We'll be carrying out sever​al projects that will further reduce odour impacts from Gold Bar WWTP, while also meeting current and future odour level standards:

  • Diversion Structure: At the headworks, where wasterwater enters the facility, we are designing a system that will capture and treat foul air from this wastewater by diverting it through a treatment system. We anticipate this project will be complete by 2026.​

  • Primary Clarifiers: Primary clarifiers are the large tanks where solids from wastewater settle out. Clarifiers can be covered to trap foul air, which can then be extracted and sent to treatment scrubbers. At the facility, we have already covered Clarifiers 9, 10, 11, and 12 and planning is underway to cover Clarifiers 5, 6, 7, and 8.​

  • Odour Scrubbers: Wet and dry scrubbers reduce odour by collecting and treating foul air using either a chemical solution or carbon filter. Four wet scrubbers and three dry scrubbers treat foul air from many areas of the facility.​

  • Air Quality Monitoring: We continuously monitor air quality at the Gold Bar facility and use this information to improve our processes. We have a facility-wide odo​ur monitoring system, including H2S monitors, an electronic nose (e-nose), a weather station and wind sensors. We also continuously measure air quality near the facility through our Gold Bar Park ambient air quality monitoring station.​

What causes odours at Gold Bar

Odours sometimes occur at Gold Bar and are a normal part of the treatment process due to the raw wastewater that flows through the plant. Most of these odours are related to hydrogen sulphide gas (H2S). H2S levels around Gold Bar can vary based on plant activities like maintenance work or from changes in water flow due to melting snow or rain. Most odours at Gold Bar come from the preliminary and primary treatment buildings, with some odour coming from the solid treatment buildings.

The safety of the public and our employees is always our number one priority. We are constantly monitoring air quality levels at Gold Bar to confirm our odour-control systems are working properly. 

EPCOR actively measures H2S levels at the plant. We're also members of the Strathcona Industrial Association (SIA), which does environmental monitoring across the region, including ambient air quality. While there are occasional times that H2S levels at the plant exceed Alberta Ambient Air Quality Objectives (such as during equipment maintenance), our H2S levels are much lower than those that can bring health concerns outlined in OH&S legislation.

​Understa​​nding H2S

​​​​1 PPB

​The air monitoring station equipment is more sensitive than the human nose. Humans start detecting hydrogen sulfide at 6-10 PPB. Our equipment will measure it at 1 PPB.​

Manag​​ement actions

​3 PPB​​​​

​AAQ​​O 24-Hour

​Ambient Air Quality Objectives (AAQOs) are set by Alberta Environment and Parks to assess general ambient air quality. Objectives are based ​​on an eval​uation of scientific, social, technical, and economic factors. An exceedence of the AAQOs might initiate a monitoring, reporting, or management action.​

​10 PPB

​AAQO 1-Hour

*6-10 PPB odour threshhold ​is when r​​​​otten egg smell may first become noticable.

Health & safety level

​​10,000 PPB​​

​OEL 8-Hour

​The Alberta Occupational Exposure Limit (OEL) for H2S states that hu​man health begins to be affected if exposed to concentrations higher than 10,000 PPB for eight hours. The likelihood that this concentration would ever be reached in the parkland and communities surrounding the Gold Bar plant is highly unlikely.

If the H2S levels ever exceed the OH&S legislation limits, EPCOR will let you know of any concerns and any precautions you should take. One of the ways we will notify you is our through o​​ur water outages and alerts page. Any alarms you hear at the Gold Bar plant are specific to onsite workers and don't apply to nearby communities.

Gold Bar air quality monitoring

​Learn how we collect and measure air quality data at Gold Bar.
Air quality monitoring​​​​​​


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