A novel in situ membrane technology was developed to remove nitrate (NO3-) from groundwater. Membrane-fed hydrogen gas (H2) was used as an electron donor to stimulate denitrification. A flow-through reactor fit with six hollow-fiber membranes (surface area=93cm2) was designed to simulate groundwater flowing through an aquifer with a velocity of 0.3m/day. This membrane technology supported excellent NO3- and nitrite (NO2-) removal once H2 and carbon limitations were corrected. The membrane module achieved a maximum H2 flux of 1.79×10-2mg H2/m2s, which was sufficient to completely remove 16.4mg/L NO3--N from a synthetic groundwater with no NO2- accumulation. In addition, this model in situ treatment process produced a high quality water containing <0.5mg/L total organic carbon.
- Groundwater remediation
- Hollow-fiber membranes