Performance evaluation of a correlation-based spectroscopic method for ammonia equivalents in sewers and WWTP influents

Ammonia monitoring in wastewater is essential for environmental protection and process optimization, yet traditional methods are costly and maintenance-intensive. This study evaluates the potential of in-situ UV/Vis spectrometers for monitoring ammonia equivalents in sewers and WWTP influents, which has been overlooked in literature. We assess three calibration approaches—multiple linear regression, partial least squares, and random forest—across two catchments in Switzerland. Initial results show promising predictive performance (R² of best performing models between 0.6 and 0.8). Wavelength importance analysis shows a clear reliance on UV wavelengths for ammonia predictions.