Comparison of phenomenological membrane bioreactor activated sludge biological models with alternative versions based on time series input-output approaches

Data was taken from a full scale sidestream membrane bioreactor (MBR) plant that has been treating industrial wash water from a salad processing factory based in Worcestershire. Various online and offline measurements were taken during an intensive sampling period for the complete flow train. Offline tests included measuring extra-cellular polymeric substance (EPS) and soluble microbial product (SMP) levels in the sludge water which are the main foulants on the associated membrane [1]. Two modified phenomenological Activated Sludge models based upon the ASM1 and ASM3 that included EPS/SMP concentrations were calibrated and validated using these offline and online measurements [2–6]. In order to see whether a simpler model structure could be formulated for advanced control purposes that was based wholly upon measured historical data sets, further conceptual models were developed based on system identification procedures and input-output times series analysis methods [7]. These model forms utilised autoregr...