Combined ion exchange/biological denitrification for nitrate removal from ground water under different process conditions

Biological treatment of ion-exchange brine regenerant for re-use: A review

“…Nitrate-to-sulphate selective resins are now capable of withstanding high sulphate concentrations; limited impact has been observed for the range 5-16 g SO 4 2− L −1 [11,13]. However, the reduction of sulphate can potentially lead to the formation of sulphide which is particularly toxic in its hydrogenated form H 2 S. Bicarbonate is concentrated during IEX and is also generated during denitrification [7].…”

“…van der Hoek et al [11,13] pioneered anionic IEX-bioprocessing, using an upflow sludge blanket reactor (USBR) followed by sand filtration for bacterial removal. Following successful bench-scale demonstration, the authors built a 3.3 m 3 USBR pilot plant at a site with an average nitrate concentration 13.8 mg NO 3 − -N L −1 [41,48].…”

“…Cang et al [2] suggested that spent IEX regenerant from treating raw water with 50-100 g ClO 4 − L −1 and 3-20 mg NO 3 − -N L −1 would contain 2.5-10 mg ClO 4 − L −1 and 150-500 mg NO 3 − -N L −1 . It has been recognised that certain regenerant constituents impede biological performance [11]. On this basis Lahav and Green [17] considered that the optimal NaCl concentration in the bio-process had to be much lower than the IEX regenerant concentration.…”

“…The use of brine evaporation ponds has been found to cause contamination of groundwater over a period of decades [9]. Ion exchange brine disposal now often entails tankering, representing a considerable process cost and carbon footprint as brine waste can constitute up to 0.8-2.4% of treated product flow [11].…”

Bioregeneration of single use nitrate selective ion-exchange resin enclosed in a membrane: Kinetics of desorption

“…To the best of my knowledge there are just couple of studies discussing the regeneration performance of nitrate selective resin [12][13][14]. Cyplik et al [12] have investigated the capacity and regeneration of selective resin IONAC SR-7.…”