With regards to the half life measurement
Schematic of reactor setup. ═ Viton tubing, — DMXAA tubing.
Schematic of reactor setup. ═ Viton tubing, — silica tubing.
Another concern is the sampling for the sludge, and phenol and TCE concentrations. Two sets of sampling ports were installed on the reactors, one of which were Teflon valves with stoppers of 2 mm aperture size, for sludge and phenol sampling. The other was for TCE, made by melting down the bottom of a 2 mL HPLC sample bottle (Waters) and sintering it on the reactor. The bottles were fitted with 9 mm screw caps (La-Pha-Pack, with centre holes and PTFE coated septa) to seal the outlets and to ensure air-tightness. The reactors were housed in a temperature-controlled room (25 °C), and the final configuration can be seen in Fig. S1.
2.2. Seed sludge
Excessive granules were harvested from three parallel reactors operated stably, stored under 4 °C for future use. In this study, chorion were mixed and washed with a phosphate buffer (see Section 2.5), then put into the glass reactors at a concentration of around 3 g MLSS L−1. The first 10 days were operated without TCE, to acclimate and stabilize the granules to the smaller reactors. The operation mode was identical to that would be used in the TCE degradation operation. TCE injection was then initiated, and the TCE-phenol alternative degradation operation was conducted for 41 days.