Anaerobic Digestion
and Biogas

What is Anaerobic Digestion?

Anaerobic Digestion (AD) is an ideal circular organic waste management solution, creating valuable biogas from organic waste streams. Using a Combined Heat and Power (CHP) unit, the biogas can be converted into renewable heat and power.

By using a biogas upgrading system, the biogas can also be turned into biomethane capable of fuelling vehicles or injecting into the natural gas grid to render Renewable Natural Gas (RNG).

Anaerobic Digestion Solutions by Convertus

As Canada’s largest and most advanced organic waste processor, we design and build AD systems based on our customers’ requirements. We analyze the waste streams to provide the optimal solution using wet Anaerobic Digestion, dry Anaerobic Digestion or a combination of both.

Our dry Anaerobic Digestion (dry AD) batch system processes waste in-vessel without oxygen to produce biogas.

Our decades of experience in the organic waste sector enables us to create the ideal process for your organic waste management issue, to capture the most benefit from municipal, commercial and domestic organic waste.

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Organic waste is received at the facility.

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Upon arrival a shredder tears open the bags to access organics and reduce the size so it can be processed more efficiently.

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The waste is then spread across AD tunnels. Air is removed from the tunnel to create Anaerobic conditions, and a nutrient-rich liquid is sprayed to convert organic matter into biogas

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Next, the biogas is moved into an upgrader where it’s washed, compressed and converted into natural gas.

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The finished byproduct (renewable natural gas) is then injected to a natural gas grid where it can be used to power the city’s waste collection fleet.

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The remaining material (digestate) is mixed with ‘starter compost’ and spread across composting tunnels so that it can be converted into compost.

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Next, the compost mix is processed through a screening line to remove plastics, glass and heavy solids.

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The compost is tested by a third-party lab before it’s sold as fertilizer for nearby agricultural crops.

Our wet Anaerobic Digestion (wet AD) systems use digester tanks full of bacteria to break down the organic waste and produce methane.

Our decades of experience in the organic waste sector enables us to create the ideal process for your organic waste management issue, to capture the most benefit from municipal, commercial and domestic organic waste.

Wet ad infographic

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Dry ad - organic waste

Organic waste is trucked into the facility.

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Dry ad - upon arrival

Upon arrival a shredder tears open the bags to access organics and reduce the size so it can be processed more efficiently.

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Dry ad - biogas

Next, the organics are made into a slurry and contaminants removed.

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The organic slurry is pumped to an AD tank for digestion.

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The gas collected from the digestion is upgraded to strip out undesirable gases.

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The finished byproduct (renewable natural gas) is then injected to a natural gas grid where it can be used to power the city’s waste collection fleet – like our Surrey location.

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The CO2 collected from the biogas upgrader can be liquified for use in many industries like greenhouses.

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After digestion the liquid is pasteurized to become fertilizer for land application.

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The finished liquid fertilizer is sold to local farmers for land application.

Why Choose
Anaerobic
Digestion

In addition to landfill diversion and the production of valuable soil amendments, Anaerobic Digestion has the potential to provide a sustainable, renewable and environmentally friendly green energy source.

With our Anaerobic Digestion technology you can add power and heat, or renewable natural gas to your product portfolio, for a ‘closed loop’ waste management system that literally powers itself!

Keep It Simple

Organic household waste is full of energy and ready to be re-used as a sustainable resource. The aim is simple: organic waste in, quality compost out and biogas out.

Household waste has a miscellaneous and undefined composition by nature. Our Anaerobic Digestion systems are designed to handle exactly that, without complicating the process.

Benefits of Dry Anaerobic
Digestion Technology

  • No liquifying, mixing or pumping of the feedstock
  • Foolproof and low maintenance
  • Resilient to input fluctuations and feedstock contamination
  • Modular design, scale up in phases
  • Low operational cost
  • No dewatering of digestate
  • Seamless integration with in-vessel composting
  • Batch tracking and batch reporting to prove permit compliance
  • Seamless integration with liquid waste digestion

Benefits of Wet Anaerobic
Digestion Technology

  • Wide range of feedstock/materials with high moisture content can be treated.
  • More consistent feeding to the AD tanks.
  • Higher biogas production
  • Linear biogas production process
  • Low initial investment required
  • Low operating costs
  • Natural biological desulpurization
  • Less manpower required
  • Digestate slurry can be pumped rather than loaded

Key Features

Tunnel System

The tunnel system is modular and perfectly compatible with in-vessel composting systems.

Each tunnel is equipped with a dedicated pre-fab skid that controls the tunnel process. This is connected to the central process computer. A central fermentation tank serves as the heart of the system and enables perfect integration with liquid waste streams.

Gas Engine

By means of a gas engine, the biogas can be turned into renewable heat and power. The biogas can also be upgraded to renewable natural gas serving the grid or fueling your own fleet of waste collection vehicles and other municipal transport. We guarantee a level of gas production based on the gas potential in the feedstock.

Digestate Composting

Dry Anaerobic Digestion has the advantage that the digestate does not need any dewatering and can be composted without any further pre-treatment. This leads to less handling costs and a better water balance than competing technologies.

Biogas

Turning organic waste into energy.

When you partner with Convertus, you can tap into the renewable energy potential of everyday organic waste materials in just a matter of weeks. Using compost starter, our anaerobic digester tunnels convert organic waste into Renewable Natural Gas (RNG). This gas is then used to fuel waste collection fleets and heat buildings – closing the loop for a sustainable future.

What is Biogas?

Biogas is a natural by-product of the breakdown of organic materials by microorganisms in the absence of oxygen, a process known as anaerobic digestion. Most biogas consists mainly of methane and carbon dioxide, but the exact composition depends on what organic materials feedstock is used.

Biogas can be upgraded to natural gas standards, and/or used as renewable energy source to power homes or fuel vehicles.

Benefits of Biogas

Biogas is the by-product of waste treatment solutions for everyday organic waste.

Biogas is a by-product of effective management of organic / green waste from municipalities, businesses and homes.

Anaerobic digestion is a natural process that requires only the absence of oxygen. There are no added chemicals and the process actually breaks down most pathogens and chemicals present in the green waste.

Organic waste accounts for up to 30% of landfill, both a waste of resources and a potential source of methane gas. Methane is a greenhouse gas that is highly efficient at trapping heat in the earth’s atmosphere . According to the EESI, methane will absorb 86 times more heat in 20 years than an equal volume of carbon dioxide.

Composting and the production of biogas significantly reduces soil and water pollution associated with unmanaged organic waste runoff or leaching of pathogens, chemicals, antibiotics, and nutrients from landfill.

The removal of organic materials from landfill removes the danger of large methane build-ups on landfill sites that are dangerous for landfill staff and harmful to the environment.

The compost and fertilizer created by anaerobic digestion (known as digestate) is a commercially valuable product that can be used by agriculture and homeowners alike to revitalize soils and promote healthy plant growth.

Bottom-Line Savings and
ROI Using Biogas

Biogas production creates a true closed loop solution. Biogas produced can be immediately used onsite for Combined Heat and Power (CHP) for the digestion plant itself. Biogas can also be used to power an engine, fuel cells, or gas turbines, producing electricity to be used on-site or fed into the national grid system.

Municipalities can save money on fuel costs to transport organic waste to landfills, and in turn power their vehicles using the biogas produced from the treated organic waste. Use of biogas as vehicle fuels reduce dependence on fossil fuels, and reduces greenhouse gas emissions compared to conventional gasoline or diesel.

Want to learn more about our organic
waste management processes?