Abstract

Denitrification was studied in anoxic batch cultures of a simulated fish processing wastewater at 37°C and pH 7.5, using a denitrifying enrichment culture from fishery wastewater. Different initial nitrate to biomass ratios (So/Xo) were used: nitrate and biomass varied from 7.5 to 94.7 mg NO3-Nl-1, and from 20 to 4300 mg volatile suspended solids l-1, respectively. The specific maximum denitrification rate (rm) and the cell yield (YX/S) depended on the So/Xo ratio under anoxic conditions: rm increased from 1.2 to 1584 mg NO3-N g-1 VSS h-1 and YX/S decreased from 42 to 0.03 mg VSS mg-1 NO3-N when So/Xo varied from 5.5 · 10-3 to 9.3 mg NO3-N/mg VSS.