B BioTherm™ By using BioTherm™ the amount of sludge is reduced as a considerable part of the organic matter contained within the sludge is converted into biogas, and the digested sludge is dewatered to achieve a high dry solids content. Sludge treatment H Hydrex™ Comprehensive range of water treatment chemicals to suit all water treatment needs. Sludge treatment Hydrotech™ Drum Filters Patented mechanical self-cleaning drum filter for municipal and industrial recovery water applications. Filtration