By Eric Meliton
While often discussed interchangeably, reducing greenhouse gas (GHG) emissions and removing carbon dioxide from the atmosphere (CDR) are distinct processes. Emissions reduction focuses on preventing GHGs from entering the atmosphere. CDR methods aim to extract and permanently sequester existing atmospheric carbon dioxide, often leveraging natural processes like photosynthesis.
Biochar production involves pyrolyzing organic waste in a low-oxygen environment, stabilizing carbon that would otherwise decompose and release methane, so it can contribute to both processes. It converts plant matter into a stable product, providing a sustainable pathway for carbon removal and sequestration, while at the same time helping to prevent the release of methane that would have otherwise been produced by the plant matter decomposing in a landfill.
Industries, such as agriculture, mining, and construction, are finding innovative ways to integrate biochar into their operations, lowering cost, improving performance and/or further driving down their carbon footprints. In agriculture, biochar enhances soil health and fertility while suppressing nitrous oxide emissions. In mining, biochar helps stabilize tailings, preventing the release of heavy metals and acidic runoff while mitigating emissions associated with traditional remediation processes. Even the construction sector is exploring biochar-infused concrete to lower the embodied carbon of building materials, offering a more sustainable alternative to conventional aggregates.
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Treatment applications
Recently, biochar has gained recognition for its potential in wastewater treatment and landfill leachate filtration. Its highly porous structure and chemical properties enable the removal of key contaminants, including ammonia, phosphorus, biological oxygen demand (BOD), chemical oxygen demand (COD), and persistent organic pollutants such as PFAS and pharmaceutical residues.
Composed of a complex mixture of organic and inorganic contaminants that threaten soil and water resources, landfill leachate represents a significant environmental hazard. Conventional treatment methods, including chemical precipitation, membrane filtration, and biological treatments, can be costly and energy intensive.
Biochar’s effectiveness as a filtration medium is directly linked to its distinct physical and chemical properties, which can be tailored to target specific contaminants found in landfill leachate and agricultural runoff. One of its major characteristics is its alkalinity. This makes it particularly effective for treating acidic effluents, as it promotes neutralization and facilitates the precipitation of heavy metals and other pollutants. The high pH also contributes to the removal of ammonia (NH₄⁺).
Biochar’s porous structure is also a significant factor in its filtration efficiency. Its porous variety (micropores, mesopores, and macropores) provides a large surface area for adsorption, to trap contaminants. As well its particle size can be optimized to control flow rates and maximize contaminant contact, making it a highly adaptable solution for wastewater treatment applications. Biochar also maintains a high cation exchange capacity, which enhances its ability to capture dissolved metals, nutrients, and organic pollutants.
Phosphorus and nutrient removal from wastewater
Biochar presents a viable cost-saving alternative to traditional filtration media, such as steam-activated charcoal and activated carbon for wastewater treatment. While activated carbon remains a widely used adsorbent, due to its high surface area and contaminant removal effectiveness, biochar can provide advantages that enhance both environmental and economic feasibility in large-scale treatment applications.
The most significant benefits of biochar lie in its lower production cost and reduced carbon footprint to generate. It is inherently carbon-negative, offering a dual benefit of wastewater treatment and carbon sequestration.
Excess phosphorus from agricultural runoff and municipal wastewater treatment plants contributes to harmful algal blooms and eutrophication in freshwater systems. Biochar, particularly when engineered with metal oxides, has demonstrated significant phosphorus adsorption capacity. Its alkaline nature facilitates phosphorus precipitation, preventing nutrient overloading in aquatic environments.
Once biochar reaches saturation in filtration systems, it retains value through secondary applications, which enhances overall circularity. Contaminant-laden biochar can be repurposed as an additive in construction materials such as concrete, asphalt, or bricks, effectively locking in heavy metals and other pollutants, while reducing the environmental impact of traditional building materials.
Phosphorus-laden biochar can also be repurposed as a soil amendment, as it becomes a medium for slow-release of nutrients. In some cases, biochar can also be regenerated and reused in filtration systems, further extending its overall utility.
PFAS and pharmaceutical contaminant filtration
Biochar presents a scalable alternative to activated carbon and ion exchange resins to address PFAS, particularly when optimized through hydrophobic interactions and electrostatic attraction.
Biochar also shows potential in filtering pharmaceutical residues and dyes, which are increasingly detected in wastewater effluents. Its adsorption capabilities, combined with the potential for microbial degradation in biochar-enhanced treatment systems, make it an attractive option for effective mitigation of emerging pharmaceutical contaminants.
Industry adoption, scalability, and commercial viability
As industries and governments intensify their focus on climate resilience and sustainable waste management, biochar is emerging as a commercially viable and scalable solution. Unlike other carbon-based adsorbents that require energy-intensive processing, biochar can be produced from a wide range of organic feedstocks, offering a low-cost and resource-efficient alternative with a built-in waste diversion benefit.
Biochar’s commercial potential extends to carbon credit markets. Companies committed to net-zero targets are actively seeking verifiable CDR solutions. The carbon-negative nature of biochar production aligns with the evolving standards of voluntary carbon markets and corporate sustainability programs. Organizations such as Frontier Climate, Shopify, and Microsoft are already investing in high-integrity CDR solutions, signaling a growing demand for biochar’s climate mitigation potential globally. Additionally, governmental shifts toward sustainable waste-to-value strategies may further incentivize biochar adoption through subsidies, tax credits, and policy-driven procurement programs.
Despite its overall promise, widespread biochar adoption faces scalability and commercialization challenges. Production consistency, feedstock availability, and process optimization remain key considerations. Ensuring that biochar meets industry-specific filtration requirements will be crucial for broader industry integration.
Additionally, while biochar is generally cost-competitive with activated carbon, initial infrastructure investments and regulatory approvals can create barriers to entry. Collaborative validation efforts among government agencies, research institutions, and industry stakeholders are essential to overcoming these hurdles to overall market viability.
To further incentivize industry participation in Canada, the Sustainable Finance Action Council has provided recommendations on removing barriers to increase private capital flow into net-zero and resilience solutions, including enhancing financial mechanisms that support investments in technologies like biochar production. This aligns with the growing demand for CDR solutions and offers industries the potential to access carbon credit markets, further enhancing biochar’s economic viability.
Policy support for biochar in Canada
Public policy is pivotal in advancing biochar’s role as a CDR solution for wastewater treatment. Federal and provincial governments could implement incentive structures (such as carbon credits and subsidies) to encourage investment in CDR solutions. Programs such as Canada’s Clean Growth Program and international carbon credit markets present opportunities for biochar producers to monetize carbon sequestration. Additionally, Canada’s Carbon Management Strategy outlines a vision for a robust carbon management sector that supports sustainable economic growth and high-value employment. This strategy emphasizes technology-enabled carbon management solutions, which would include biochar production to reduce, remove, and reuse CO₂ emissions.
These policies and initiatives at all government levels underscore Canada’s commitment to fostering a conducive environment for biochar and other CDR solutions, promoting overall scalability and commercial viability.
Canadian regulatory frameworks must also evolve to support biochar’s classification as a validated CDR technology. Establishing clear standards for biochar quality and application guidelines will provide industry confidence in its long-term viability. This will positively trickle down into provincial and municipal regulations, pushing for acceptance as markets evolve over time.
Eric Meliton is with Echion Group. Email: eric.meliton@echiongroup.net
This article appeared in the June 2025 edition of Environmental Science & Engineering Magazine.
