1 Hydrogen-Based Membrane Biofilm Reactor for Wastewater Treatment

Abstract. The H2-based membrane biofilm reactor (MBfR) delivers H2 gas to a biofilm that naturally accumulates on the outer surface of bubbleless membranes. Although the MBfR is proven for the reduction of nitrate and perchlorate in drinking-water and groundwater settings, its most extensive application may be for advanced nitrogen removal in wastewater treatment, where existing approaches either fail to achieve the goals of advanced-N removal or have severe problems of cost, reliability, and safety. By utilizing H2 gas as the electron donor to drive denitrification, the MBfR completely eliminates an added organic electron donor, which overcomes major problems: a large increase in excess biomass generation, over- or under-dosing of donor, safety concerns, and relying on specialized methanotrophs. In addition, the MBfR is simple to operate and can be used for tertiary denitrification or placed within a pre-denitrification process. Preliminary results reported here show that a biofilm of autotrophic denitrifiers accumulates rapidly in the wastewater setting, the MBfR can drive NO3- concentrations below 1 mgN/L, and the H2 pressure controls the NO3- flux