Kinetic analysis and degradation pathway for m-dichlorobenzene removal by Brevibacillus agri DH-1 and its performance in a biotrickling filter

- Growth and degradation kinetics for m-dichlorobenzene degradation by a strain DH-1 were studied.
- A putative pathway for m-dichlorobenzene degradation was presented.
- m-Dichlorobenzene removal and pressure drop in a biotrickling filter inoculated with strain DH-1 was analyzed.

A strain, Brevibacillus agri DH-1, isolated from dry lands was used to remove m-dichlorobenzene. After 48 h culturing, the concentrations of m-dichlorobenzene decreased from 26-130 to 7.87-28.87 mg/L and dry cell weight for bacterial growth reached 52.43-75.05 mg/L. The growth and degradation kinetics were analyzed by the fitting of Haldane-Andrews model and pseudo first-order model. A degradation pathway was proposed according to major intermediates (phenol), chloride ion variation, ring-opening enzyme activity, and high mineralization (0.47 gCl-/gm-dichlorobenzene, 0.65 gco2/gm-dichlorobenzene, 0.15 gDCW/gm-dichlorobenzene). In addition, the performance in a biotrickling filter (BTF) was evaluated through removal efficiency and pressure drop values with increasing inlet loading rate from 4.10 to 122.57 g/m3/h at three empty bed residence time points (30 s, 60 s, and 90 s). The results demonstrated that strain DH-1 possessed high removal efficiency and stable operation in a BTF.

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