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Process overview

​Overview of the anaerobic digestion process to produce RNG and digestate.


Process steps:

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Step 1: Collecting feedstock

​​Livestock manure will be collected from Cattleland’s pens and transported to the immediately adjacent facility by truck. External feedstock in the form of other organics such as paunch manure, and fats, oils, and greases will also be accepted at the facility (up to 50% of total feedstock). The manure and external feedstock will be temporarily stored at the facility in separate holding tanks or on receiving pads until it is fed into the system.​​​​​​

Step 2: Pasteurization to remove pathogens

​​Some external feedstock will undergo pasteurization where the feedstock will be heated to 70 degrees Celsius, similar to pasteurizing milk, removing potential pathogens from the material before it goes into the anaerobic digestion tanks. To reduce overall energy use, heat from the pasteurizer will be recycled.​​

Step 3: Feedstock processing
Manure and solid external feedstock will be fed into the system and blended with liquid external feedstock and process water to create a slurry. Some o​f the process water required for this step will be recycled from liquid digestate (one of the outputs of the process). The remainder of the required process water is anticipated to be sourced from a water license off the Bow River and delivered to the Project through the Western Irrigation District infrastructure.​
Step 4: Anaerobic digestion

​​​The slurry will be sent to fully enclosed tanks where it will be maintained at 40 degrees Celsius in an oxygen-free environment for up to 65 days. During this step, natural microbiological processes will break down the organic material to produce two products: biogas and nutrient-rich digestate. These fully enclosed tanks are designed to contain the biogas and any odours resulting from the anaerobic digestion process.​​

Step 5: Upgrading the biogas

​Activated carbon filtration systems and membranes will remove carbon dioxide (CO2) and other impurities from the biogas to produce RNG that will meet the specifications for injection into the existing natural gas pipeline system, where it will be used just like conventional natural gas.​​​​​

Step 6: Preparing the digestate

The digestate will be pumped from the anaerobic digestion system into machines that dewater the material to form both solid and liquid digestate. The solid digestate will be spread on to agricultural land by Cattleland, as is currently being done with livestock manure. Excess liquid digestate that is not recycled will be land applied. The volume of solid digestate will be 40% lower than the manure that was used as feedstock, reducing the amount of material that will need to be spread.

The liquid digestate will be collected in an on-site double-lined lagoon and a portion of this liquid will be recycled for use as process water to create the slurry (Step 3). Liquid digestate that cannot be recycled will be used by Cattleland to irrigate its agricultural land through the existing irrigation system.

Renewable Natural Gas (RNG)

RNG is a pipeline-quality gas that is fully interchangeable with conventional natural gas.

  • RNG is a biogas that has been cleaned to yield purified methane (biomethane) that can be readily incorporated into natural gas pipelines, making it a promising renewable energy source.
  • RNG can be produced through anaerobic digestion of organic materials (or ‘feedstocks’) including livestock manure, agricultural by-products, commercial organics, and commercial by-products like fats, oils and greases.​

Anaerobic digestion

  • Anaerobic digestion (AD) is a natural process where microorganisms degrade organic matter in the absence of oxygen to produce biogas and digestate. 
  • AD has the dual advantage of presenting a sustainable process for waste management and production of both renewable energy and nutrient rich digestate, while reducing GHG emissions.
  • AD facilities are widely used across the world in municipal, agricultural and agri-food sectors.
  • In many parts of Europe, Agricultural AD facilities have been in place for many years; for example, in Germany AD facilities are producing biogas at over 8,000 agricultural sites.
  • In Canada there are currently 45 agricultural AD facilities and 126 municipal facilities that produce biogas.
  • In the United States there are more than 200 anaerobic digesters safely operating on farms.​

EPCOR’S experience with anaerobic digesters, biogas and natural gas

  • EPCOR operates 11 anaerobic digesters at two​ sites: Edmonton and Regina.
  • EPCOR through its two operated facilities, produces approximately 315,000 GJ of biogas per year.
  • EPCOR operates natural gas utilities in Ontario and Texas.​

​Project pa​ges to review

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Project benefits

Discover how the​​ proj​ect is expected to​​​ benefit the community and the environment once it is ope​rationa​l.
Project benefits​​​

 

What to expect from EPCOR and the facility

Learn more about EPCOR, what ty​pe of n​eighbour EPCOR and the facility will be​ and predicted odour conditions.
What to expect​​​​​​​​​​

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Next steps 

View our next steps, project timelines and regulatory approvals needed along the way. 
Next steps and timelines​​​​​​​​

 

Abou​t the​ facility

Get to know​​​ what the facility will do, and view renderings ​of site plans and what it will look like. 
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