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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 Gold Bar

With continued investment in odour reduction, see the results from our investments and future odour projects.

Learn more

What causes odours at Gold Bar 

Odours at Gold Bar are a natural part of the wastewater treatment process; we continue to meet air quality objectives. 

About odours

Gold Bar air quality monitoring reports

View our monthly air quality fenceline monitoring reports and see how annual odour levels have decreased over time.

View our reports

​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 several projects that will further reduce odour impacts from Gold Bar WWTP, while also meeting current and future odour level standards:

  • Enhanced Primary Treatment (EPT) Scrubber Upgrades: redesign of the current EPT Scrubber and adding an additional scrubber for revised capacity and better performance
  • Grit and Screen Buildings Ventilation Upgrades: includes upgrading ventilation and adding odour control in the headworks building
  • Seal Fermenter Roofs: sealing fermenter roofs to prevent escaping odour emissions

​Give us feedback: new air monitoring station

In coordination with Alberta Environment and Parks, we're planning to install a new continuous monitoring station between the Gold Bar WWTP and the nearest receptors (homes along 109A Avenue).

Let's Talk

We believe in listening to and engaging stakeholders. Community input and involvement is an important part of our decision-making and we want to hear what you think about our initiatives.

Phone: (780) 412-3599


Learn more about the other commitments
we've built into our long term plan.

Our commitments to you

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.

Different H2S levels

Reference H2S level (parts per billion)​
​Threshold for human detection 6-10 (average 8)*
​AEP 1-hour air quality objective (average) ​10
​OH&S short term exposure limit (15 minutes) ​15,000
​OH&S 8-hour exposure limit ​10,000
​Immediately dangerous to life or health (IDLH) ​100,000

 *Source: Hydrogen Sulfide: Human Health Aspects published by World Health Organization

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 our 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.


Learn more about the other commitments
we've built into our long term plan.

Our commitments to you

Gold Bar air quality monitoring reports

SIA ambient air monitoring network

As mentioned, EPCOR is a member of the Strathcona Industrial Association (SIA) Ambient Air Monitoring Network. The SIA conducts environmental monitoring across the East Edmonton and Strathcona County region. Their monitoring assesses ambient air quality. There are two monitoring stations near the Gold Bar Wastewater Treatment Plant.

Fence line monitoring

EPCOR consistently monitors 8 locations around the Gold Bar plant fenceline for H2S levels (numbered). The readings at these stations are spot readings which may only exist for a moment in time, so these results are not compared to standards that are quantified in 1-hour, 8-hour or 24-hour averages.

Monthly reporting

Data from the previous month is posted by the 15th of the following month.

Previous annual reporting

The chart below shows the average H2S levels from spot readings recorded annually at each station.


 Regulatory requirements for air monitoring

The Environmental Protection and Enhancement Act (EPEA) is the primary Act in Alberta through which regulatory requirements for air, water, land, and biodiversity are managed.

The Act supports and promotes the protection, enhancement and wise use of the environment by designating proposed activities for which an approval or registration is required.

EPCOR Water Services Inc. has an EPEA approval for operating and maintaining the Gold Bar Wastewater Treatment Plant (GBWWTP). EPEA approval holders are responsible for monitoring and reporting air quality as per the Air Monitoring Directive (AMD).  

The Air Monitoring Directive (AMD)

The AMD sets out the Provincial requirements for monitoring and reporting air quality.  The AMD requires that:

  • If an approval holder's monitoring duties are fulfilled by an airshed or monitoring network, the airshed or network would monitor and report on behalf of the facility and must adhere to AMD requirements.
  • Airsheds and networks must submit their air data and reporting (on a monthly and annual basis).
  • Monthly and annual reporting meets the minimum data, information and content standards.

EPCOR fulfills these requirements through monitoring and reporting completed by the Strathcona Industrial Association (SIA) on our behalf.

Strathcona Industrial Association (SIA) air monitoring network

The Strathcona Industrial Association (SIA) is a multi-stakeholder environmental monitoring network. The SIA conducts air, water, and land monitoring in the Strathcona Industrial area. EPCOR is a member of the SIA since 1999. The Gold Bar Air Monitoring Station is managed by the SIA. It monitors air quality at the Gold Bar Water Treatment Plant, measuring Hydrogen Sulphide, Sulphur Dioxide, Oxides of Nitrogen, along with wind speed, direction, and temperature.  SIA stations are regularly audited by Alberta Environment and Parks. Find out more about the SIA

Air monitoring station locations



Since 2011, EPCOR has been tracking average hourly and average daily H2S levels captured by the SIA Beverly Station (1 km NE of the GBWWTP) and the Gold Bar Station (1 km S of the GBWWTP). These levels are compared to the AAAQO of 10 ppb over a one hour period and an average of 3 ppb over a twenty-four hour period.

As shown in the graph below, the number of one hour exceedances over the AAAQO average of 10 ppb had been trending down since 2011 until 2015 when the odour scrubbing equipment at the GBWWTP failed. The odour scrubbers were returned to full working order in January 2016. Since the operational improvements and emissions reduction plan began to be implemented in early 2016, there has been continuous improvement in ambient air quality, with just four confirmed exceedances in 2016, one in 2017 and two in 2018.  There was one exceedance in 2020 at the Gold Bar Station. While our air dispersion/odour model determined the GBWWTP was unlikely to be the source of the exceedance, it was attributed to our site as a result of the current reporting methods used by the SIA.