Statistical Monitoring of Wastewater Treatment Plants Using Variational Bayesian PCA

Multivariate statistical projection methods such as principal component analysis (PCA) are the most common strategy for process monitoring in wastewater treatment plants (WWTPs). Such monitoring strategies can indeed recognize faults and achieve better control performance for fully observed data sets but can be more difficult in the case of having missing data. This study presents a variational Bayesian PCA (VBPCA) based methodology for fault detection in the WWTPs. This methodology not only is robust against missing data but also reconstructs missing data. Furthermore, a novel historical data preprocess method is proposed to deal with diurnal behaviors in the WWTPs with fast sample rate. These methodologies have been validated by process data collected from two WWTPs with different process characteristics and different sample rates. The results showed that the proposed methodology is capable of detecting sensor faults and process faults with good accuracy under different scenarios (highly and lowly instrumented WWTP).