Three fluidized sulfur biofilters (285 L, height 3.9 m, diameter 0.31 m; Fig. 1)
were operated at The Conservation Fund’s Freshwater
Institute (Shepherdstown, West Virginia, USA) for 253 days
to quantify nitrate removal from aquaculture wastewater (Phase
I: 225 days, 13 March 2014 to 23 October 2014; Phase II: 28
days, 24 October 2014 to 20 November 2014). During Phase I,
the three biofilters were operated in triplicate fashion, each fluidized
at 37–39% expansion with a hydraulic retention time (HRT)
of 3.2–3.3 min and a hydraulic loading rate of 860–888 L/(m2 min)
based on the mean flow rate of 63–65 L/min