SRB exposed to ERY exhibited a more obvious inhibition of activity than encountered with MPA as shown in Fig. 2c. At
400 mg L1, the relative SSA in the intact sludge decreased to 44.34%, and to 25.5% with the disrupted sludge. The inhibition caused by ST is shown in Fig. 2d. At 50 mg L1, the relative SSA of intact and disrupted sludge was 68.7% and 51.0% respectively. When ST concentration increased to 400 mg L1, the relative SSA decreased by 11.1% and 8.63%. This indicates that ST has a low Kinh as shown in Table 1 and that SRB is only slightly sensitive to higher concentrations.