“…Research into the design and operation of activated sludge systems are supported traditionally by two communities: (a) on the one hand, the environmental biotechnology 10 community with the advances in gene sequencing technology and molecular probes (such as qPCR, FISH, phylogenetic trees, operational taxonomic units (OTUs), meta-transcriptomics, proteomics, metabolomics, etc.) studies underpinning microbiological community (who are they and what they do) responsible for nutrient removal in the plant, and (b) process design, modeling and control community [12][13][14][15][16] that works with process models and uses traditional process data (such as influent COD their fractions (SS, XS, SI, and XI), nitrogen (NH 4 , NO 3 , NO 2 -N, TKN), PO 4 , TP, MLSS, VSS, BOD, etc.) to develop and validate new models and techniques to support design and operation of the plants.…”