From Waste To Worth: How Biochar Is Transforming Waste Water Treatment

A recent trial at Scottish Water’s Development Centre has shown how biochar can turn a challenging waste water stream into a valuable circular resource.

Screening Waste: A Hidden Problem
Waste water treatment plants produce screening waste – fibrous material filtered from incoming water – that is typically sent to landfill at significant cost and environmental impact.

With no recycling option, this material remains both a practical challenge and an untapped resource.

The Solution: Turning Waste into Opportunity

Carbogenics, an Edinburgh-based cleantech company, is dedicated to transforming challenging waste streams into high-value carbon products.

As part of Scotland’s biotechnology innovation community, the company develops circular solutions that reduce waste, cut emissions and support sustainable industries.

Carbogenics flagship product, FilaChar, is a patent-pending biochar designed to improve the efficiency of waste water treatment while delivering a carbon-negative footprint.

The Trial in Action
With support from Innovate UK, Carbogenics partnered with Scottish Water’s Research & Innovation team and its subsidiary Scottish Water Horizons, to explore whether screening waste could be upcycled into FilaChar biochar.

Waste collected from nine waste water treatment sites across rural and industrial regions, was dried and pyrolyzed to create FilaChar.

Trials were conducted using a pilot Sequencing Batch Reactor (SBR) at Scottish Water’s Waste Water Development Centre. This facility replicates real treatment conditions, using “live” feeds from the adjoining waste water treatment works.

Carbogenics evaluated the performance of FilaChar in reducing key contaminants, including chemical oxygen demand (COD), nitrogen, phosphorus, and volatile organic compounds (VOCs). The results demonstrated significant pollutant removal – including up to a 22% reduction in phosphorus and increased nitrification rates – while maintaining stable operating parameters such as pH and conductivity. Additionally, the treatment achieved a consistent reduction in odour.

These results provided Carbogenics with valuable insights into FilaChar performance and process integration and will now guide further development to establish a strong foundation for future research and potential scale-up.

The Power of Collaboration
The trial was a team effort, bringing together the expertise and experience of Carbogenics, Scottish Water, and Scottish Water Horizons. By working hand-in-hand, the teams were able to test FilaChar under real-world conditions and gain practical insights into how it could perform in waste water treatment.

Dr. Loïc de Carvalho, Head of Research, Development and Consulting at Carbogenics, said “This collaboration has shown the potential to unlock value from one of the most challenging waste streams in waste water treatment.

“The trial not only highlights environmental benefits but also points to potential cost savings, improved efficiency, and stronger operational resilience. We’re excited to continue developing FilaChar alongside Scottish Water as we build a more sustainable future for the sector.”