Application of a membrane bioreactor to denitrification of brine

This study describes a hybrid method of the removal of nitrates from brine, combining biological denitrification with a membrane process. A bioreactor containing the halophilic bacteria H. denitrificans was used to denitrify brine. Brine was enriched with magnesium and potassium ions, microelements, and methanol as a source of carbon. The aim of the study is to determine the efficiency of nitrate removal from brines for various initial inoculum concentration and for different dilution ratios (D). Fluorescence microscopy was used to detect changes in the counts of live and dead cells within the bioreactor and measure a progressive decrease in filtration efficiency caused by membrane fouling. The highest specific nitrate reduction rate was recorded for the dilution ratio D = 0.6, amounting to 1.30 g NO3− – N·g d.s.·day−1.