Wastewater treatment is a notable contributor to greenhouse gas emissions, with nitrous oxide (N₂O) released during biological nitrogen removal representing a key concern. The Catalysing a Net Zero Future (CNZF) project explores an alternative, intensified biological ammonia removal pathway designed to significantly reduce or eliminate N₂O formation. This paper describes the design, operation, and early performance of a pilot-scale wastewater treatment system that uses encapsulated microbial biocatalysts within combined anoxic and aerobic processes. The pilot plant comprises a 2.5 m³ anoxic reactor, a 5 m³ aerobic reactor, and a clarifier, with return activated sludge and aerobic effluent recycled to the anoxic tank based on influent flow. The system is installed at Severn Trent’s Resource Recovery and Innovation Centre (R2IC) at Spernal STW (UK). The study evaluates a staged implementation of an Integrated Microvi Activated Sludge (IMAS) process. The IMAS system is composed of an anoxic–aerobic configuration employing nitrifying (AEROVITM) and denitrifying (Pseudomonas stutzeri) biocatalysts. Performance is assessed through detailed monitoring of nitrogen species, dissolved N₂O, organic carbon, and operational parameters. Initial results will demonstrate ammonia and total nitrogen removal efficiency, N₂O emissions, and system resilience, highlighting the potential of biocatalyst-based solutions to support low carbon, energy efficient wastewater treatment.