The Biopebble requires less energy to be agitated in solution than standard biocarriers and is available in recycled or virgin plastic.

An all-round improvement for RAS wastewater treatment


Luton-based Warden Biomedia has developed a new sustainable filter media after a three-year research partnership with Cranfield University. Biopebble is described as the next generation of filter media, designed for efficient biological wastewater treatment for recirculating aquaculture systems (RAS).

At Cranfield, Warden Biomedia demonstrated that spherical-shaped media design can reduce the energy input required in the effluent treatment system by 35-40%.

The spherical design requires less energy to be agitated in solution than standard industrial standard tubular-shaped biocarriers, improving wastewater treatment efficiency, and is available in 100% recycled plastic. The new Biopebble media also showed high ammonia removal and phosphorus removal rates in tests against other media.

Large surface area

The structure and surface textures are designed specifically to provide a large, protected surface area (500m²/m³) and high voidage (81%) for optimum biofilm attachment and biological treatment performance.

Warden Biomedia said the new design offers significant benefits for RAS including reduced aeration energy requirements, improved biological commissioning times and process security, higher biomass retention, increased wastewater treatment capacity, reductions in required tank volume, promotion of generation of healthy and thin biofilms, and generation of biofilms with resistance to shock loads.

The research project was part of a Knowledge Transfer Partnership (KTP) programme, partially funded by Innovate UK. Following successful pilot and full-scale trials, Biopebble is now available to the aquaculture market. The media is manufactured in the UK, available in both high-quality recycled or virgin polypropylene, guaranteed free from halogens, and fully recyclable at the end of its process life.