A newly developed bio-reactor design for municipal sewage treatment was evaluated on a pilot scale (150 m(3)/d). The reactor system included both anaerobic/anoxic and aerobic treatment stages with external/internal airlift circulation loops integrated with a central sedimentation chamber. The design was conceived to enhance the removal of organic compounds and nutrients (phosphorus and nitrogen) within a smaller footprint than existing treatment processes. The downcomer of the internal circulation loop is integrated with the sedimentation tank facilitating high efficiency solid-liquid separation in a compact configuration. The external/internal airlift circulation stages increase the potential for bio-reactivity, while reducing energy consumption for process flows. Overall, the integrated configuration reduces the footprint required compared to conventional systems with equivalent hydraulic loads, ie, hydraulic retention time of ~12.8 hours with a hydraulic loading area of 10.3 m(3)/d/m(2). The trial run data indicated removal efficiencies for COD, phosphorous, ammonia, and total nitrogen of 94.5%, 94.5%, 96.8%, and 78.6% respectively. Moreover, the treatment system also demonstrated a robust capacity to handle a wide range of COD influent concentrations (ie, ~ 120-860 mg/L).