Fig. 1. Summaries of the operating conditions and physicochemical conditions of the digester across the time series.

A Wire diagram of the four process configurations across the two-year time series. SOI Standard Operation I, CEPT Chemically Enhanced Primary Treatment Operation, SOII Standard Operation II, SER Serial Operation, MS mixed sludge waste from primary and secondary treatment), CH₄ (biogas), BS biosolids, Labels “1” and “2” indicate the two anaerobic digesters (all samples for this study were taken from AD1). B Temporal physicochemical sparklines of AD performance. Methane % volumetric percent of biogas as methane, HRT hydraulic retention time, OLR organic loading rate, Biogas (total volumetric biogas generated), VFAs volatile fatty acids. Box plots of configuration groups represent 75^th, 50^th (median), and 25^th percentiles, with whiskers representing 90^th percentiles and outlier position as filled points above whiskers (n = 16 for SOI, 10 for CEPT, 11 for SO II, and 6 for SER).