Three fluidized biofilters (height 3.9 m,
diameter 0.31 m; operational volume 0.206 m3) were filled with sulfur particles (0.30 mm effective particle
size; static bed depth approximately 0.9 m) and operated in triplicate mode (Phase I: 37–39%
expansion; 3.2–3.3 min hydraulic retention time; 860–888 L/(m2 min) hydraulic loading rate) and independently
to achieve a range of hydraulic retention times (Phase II: 42–13% expansion; 3.2–4.8 min
hydraulic retention time).