Full Description

Ion exchange (IX) resins can reduce nitrate concentrations in groundwater to very lowlevels; however, regeneration brines containing high nitrate concentrations pose adisposal problem. This research investigated hydrogenotrophic (hydrogen utilizing)biological reduction of nitrate in regenerant brines. Salt tolerant denitrifying batchcultures were enriched from the denitrification stage of a wastewater treatment plant andmarine sediments from Cape Cod, Massachusetts and the Dead Sea. The cultures wereinoculated into nitrate nutrient media, with and without added NaCl, with hydrogen as thesole electron donor. The salt tolerant cultures were able to denitrify 800 mg/L NOsub3/sub-N inthe presence of 12.6 g/L NaCl to 200 mg/L NOsub3/sub-N. The cultures were inoculated into twodifferent hollow fiber membrane bioreactors (HFMBs), one fed 50 mg/L NOsub3/sub-N with noadded NaCl (non-brine) and the other fed 600 mg/L NOsub3/sub-N with 12.5 g/L NaCl (brine).The non-brine HFMB was able to consistently reduce nitrate to less than 8 mg/L at ahydraulic residence time (HRT) of 5 hours when pH and biofouling were controlled. Thebrine HFMB only achieved partial denitrification at an HRT of 53 hours. Currentresearch is focused on treatment of the brine in a batch HFMB. Includes 11 references, figures.

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Edition: Vol. - No. Published: 06/01/2006 Number of Pages: 10File Size: 1 file , 280 KB