Bench-scale experiments were inoculated with biomass and process flows taken directly from the full-scale system immediately before initiation of the batch experiments. The bench-scale PBR experiments were conducted using effluent from the full-scale mix tank (20 L). To ensure the biomass in the mix tank batch experiments had adequate stored carbon (at the start of the experiment) to observe organic carbon mobilization, the mix tank experiments were conducted using secondary effluent combined with the biomass from the bench-scale PBR that was not sampled (2.2 L and 5.8 L, respectively, to match the mixing ratio in the full-scale mix tank).