The ToOLTuBES project (Toxicity & Organic Load Tracking using BioElectrochemical Systems) will advance the development of a water quality biosensor towards technology readiness level TRL 7 (demonstration in an operating environment at pre-commercial scale). BES technology, which incorporates an electrode-supported microbial biofilm that generates electricity from oxidation of organics, and has great potential for low-cost, real-time sensing applications. The magnitude of the electrical current generated correlates with the organic loading and conversely when toxic compounds are present the signal is inhibited. The sensor will be used to monitor organic load and toxicity levels in real-time on wastewater influent samples from a real-world, wastewater treatment plant (WWTP). Long-term monitoring data will be collected over two years and used to inform design and cohesion of a combined sensor package, which will propel the technology towards commercial realisation.