This project transforms sewage-sludge, a by-product of wastewater treatment, into sustainable, carbon-negative building materials such as bricks, brick-slips, and tiles. UK construction accounts for roughly 25% of national emissions, and traditional clay bricks contribute significantly to embodied carbon due to energy-intensive production. Our approach uses pyrolysis to convert sewage-sludge into stable biochar, destroying harmful contaminants like PFAS and locking carbon permanently away from the atmosphere. The resulting biochar is incorporated into construction materials that sequester more carbon than they emit, helping homes and buildings become carbon sinks rather than carbon sources. For example, a standard brick produced from our biochar stores -2.1 kg of CO₂, while traditional bricks release carbon. The project will assess material performance, safety, and regulatory compliance, ensuring these waste-derived products meet UK standards for construction. We are collaborating with water companies, pyrolysis partners, and testing labs to validate the technology and supply chain feasibility. Beyond environmental benefits, this project creates economic and social value: * Circular economy: Diverts sewage sludge from disposal or land application into high-value construction materials. * Green jobs and regional impact: Supports low-carbon manufacturing and installation in the UK. * Carbon reduction: Reduces embodied carbon in buildings by over 50% and stores carbon in the built environment. * Innovation leadership: Provides a replicable model linking the water and construction sectors, demonstrating how waste can become a sustainable asset. If successful, our project could transform a significant waste stream into a scalable, low-carbon material, helping the UK meet net-zero targets while creating new revenue streams for utilities and supporting sustainable construction practices.

Decarbonising is a big challenge for the construction industry due to the very large amount of resources required in the erection of buildings and the absence of carbon neutral construction materials. Composite Designers Ltd will demonstrate feasibility of manufacturing net-zero construction materials in this project. We will achieve this by substituting traditional kiln fired clay bricks with bricks bonded using no-bake binders. This will eliminate the need for firing and reduce carbon process emissions. In addition, we will substitute silica (sand) aggregates which is becoming a rare commodity with other fillers. We have identified fillers which can have carbon storage potential. We will benchmark existing types of bricks for binder -- filler ratios and prepare test mixtures to identify most promising solutions. We will also benchmark other solutions trialled in the literature when preparing novel cements or asphalts. We will qualitatively and quantitatively evaluate our test samples and produce prototype bricks with the most promising test mixtures. Aside from their carbon credentials, we will also evaluate the processability of our mixtures to ensure that our products can be produced using existing production plants to promote quick adoption of our products. We are confident that our outside-the-box development approach to this civil engineering challenge will help the industry to become resource efficient and the UK industry more resilient to outside factors.