Sludge Digesters Filtration Aerobic Treatment Waste Water Activated Sludge Sludge ADI-Hybrid reactor: A high-rate system that combines elements of two anaerobic processes—the UASB (upflow anaerobic sludge blanket) on bottom and UFF (upflow fixed film) on top—and retains process advantages of each. In addition, minimum land space is required. Other advantages include: Granular sludge bed. Minimal space requirements. Two-stage separation of solids and collection of biogas. Uses gas-lift principle to induce internal circulation of treated effluent. Superior biomass retention under high organic loading conditions.