Nitrous oxide (N₂O) is increasingly recognised as a material Scope 1 greenhouse gas emission from wastewater treatment, with evolving IPCC guidance and measurement-based approaches likely to increase the visibility and reported significance of emissions across the UK water sector. There is therefore a growing need for operationally grounded case studies that link process emissions with energy efficiency, compliance resilience and asset-specific design intent. This presentation describes how South West Water, in collaboration with BI-Zen and Jacobs, is delivering a 12-month N₂O monitoring, optimisation and control programme as part of a wider five-year strategy to scale process-emissions understanding. The core case study compares two identically designed carbonaceous activated sludge works serving coastal catchments exposed to infiltration, wet-weather loading, temperature variation and highly variable load profiles driven by tourism. One site operates using South West Water’s in-house aeration control strategy, while the other provides a direct baseline reference. Fixed and mobile N₂O monitoring is integrated with high-granularity (15-minute) datasets including dissolved oxygen, redox, ammonia, nitrate, nitrite, airflow, energy, flow and temperature. The study examines how load variability and unintended nitrification influence N₂O emissions risk, providing evidence to inform scalable operational strategy across the wider asset base.