Unlocking Biochar’s Potential in Wastewater & Agriculture
- Perspektiv
- Aug 28
- 4 min read
With the climate clock ticking and pressure mounting on utilities and agribusiness to deliver on climate commitments, biochar is emerging as a multi-dimensional solution: a carbon sink, a revenue opportunity, and a sustainable soil enhancer.
What Is Biochar?
Biochar is essentially charcoal engineered from organic waste, such as sewage sludge, agricultural residues, and municipal organic matter, through pyrolysis (heating without oxygen). Unlike compost or untreated sludge, biochar is highly stable, locking carbon in a form that can persist for centuries. Beyond its role as a soil amendment, it also acts as a powerful water and pollutant adsorbent.
Why It’s a Net-Zero Gamechanger
Carbon Sequestration & Emission Reduction
Our modelling shows that applying biochar to farmland can sequester enough carbon to not just offset WWTP emissions, but in some cases deliver a 126% reduction in net operational emissions. In other words, utilities can go beyond “net zero” into “carbon positive” territory.
Wastewater treatment plants (WWTPs) contribute ~4% of global GHG emissions. Studies show that integrating biochar into wastewater processes can reduce emissions by up to fivefold, equivalent to 300–660 million tonnes of CO₂ mitigation annually worldwide.1
In agriculture, biochar enhances soil organic carbon by up to 20% and reduces nitrous oxide (N₂O) emissions by around 15%.2
Beyond Carbon - The Strategic Co-Benefits
Nutrient Recovery & Fertiliser Role
It’s important to be clear: biochar is not a direct substitute for fertiliser, nor is it a direct substitute for fertiliser compared to sludge; it provides fewer immediately available nutrients for plants. Farmers seeking a quick nutrient boost will still see sludge as more effective in the short term.
Where biochar excels is in the long-term benefits:
It retains nutrients in the soil, reducing leaching in sandy or drought-prone regions.
It contributes to sustained fertility by improving soil structure and organic matter stability.
It avoids many of the contamination risks that come with spreading sludge, providing a cleaner, safer pathway for nutrient cycling
A landmark PNAS study found that biochar derived from human waste could supply up to 7% of global phosphorus needs, and when paired with urine-derived nutrients, that figure rises to 15% phosphorus, 17% nitrogen, and 25% potassium annual application. This offers a circular solution to global fertiliser shortages, while reducing reliance on fossil fuel–intensive production. 3
Pollution Adsorption & Soil Safety
Biochar helps strip heavy metals, nutrients, pathogens, and organic contaminants from wastewater, while reducing the mobility of PFAS and microplastics compared to applying sludge directly to land.4
Soil Health & Water Resilience
UK biochar start-up DarkBlack Carbon estimates soils treated with biochar can sequester 10+ tonnes of CO₂ per hectare per year. Even a 1% increase in soil organic carbon can hold an additional 87 kL of water, making farmland more resilient to drought.5
Market Momentum
Carbon Credits & Market Viability
Biochar removals are recognised under Puro.earth’s CORCs, the world’s first independent standard for durable carbon removals. Credits are currently trading at around US$179/tCO₂e. For a 36 ML/day facility, that equates to ~US$1,288/day in potential revenue.6
Australia is also developing an ACCU methodology for biochar, which could open the door to domestic crediting in the near future.7
Biochar is now the leading carbon dioxide removal (CDR) method in the voluntary market, with corporates like Swiss Re committing to 70,000 tonnes of biochar credits to meet their climate targets.8
Growing Fertiliser & Biochar Markets
The global biochar market, valued at USD 315 million in 2023, is projected to surge to USD 525 billion by 2032.9
The biochar fertiliser segment alone is expected to triple, from USD 2.2 billion in 2023 to USD 6.2 billion by 2033.10
Farmers are already paying AU$400–700 per tonne for biochar, recognising its role in boosting yields, improving soil moisture, and cutting fertiliser costs. For utilities, this transforms sludge disposal costs into a new revenue stream.11
Making It Happen: A Strategic Roadmap
Carbon Accounting & Verification Use ISO-aligned LCAs and the Puro Standard to ensure integrity and eligibility for CORCs.
Offtake Agreements Secure early revenue through pre-purchase contracts with corporates seeking durable removals.
Agricultural Partnerships Supply biochar directly to farming networks looking for regenerative solutions.
Highlight Co-Benefits Position biochar as more than carbon removal—an enabler of nutrient recycling, pollution control, and soil resilience.
Real-World Headlines
The Bottom Line
Biochar is no longer experimental; it is a proven, scalable pathway for utilities and agribusiness to move from waste management to climate leadership. It offers durable carbon removal, credible crediting pathways, new revenue streams, and critical co-benefits for soil and water systems.
The window for first-mover advantage is now. Utilities, agribusinesses, and policymakers that act today can unlock climate-positive operations, new income streams, and resilient agricultural systems for the future.
If you would like to explore how biochar can work in your operations, let’s talk. From carbon accounting to project certification, we can help turn waste into climate action.
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