摘要
A long-term pilot-scale H_(2)-based membrane biofilm reactor(MBfR)was tested for removal of nitrate from actual groundwater.A key feature of this secondgeneration pilot MBfR is that it employed lower cost polyester hollow fibers and still achieved high loading rate.The steady-state maximum nitrate surface loading at which the effluent nitrate and nitrite concentrations were below the Maximum Contaminant Level(MCL)was at least 5.9 g·N·(m^(2)·d)^(–1),which corresponds to a maximum volumetric loading of at least 7.7 kg·N·(m^(3)·d)^(–1).The steady-state maximum nitrate surface area loading was higher than the highest nitrate surface loading reported in the firstgeneration MBfRs using composite fibers(2.6 g·N·(m^(2)·d)^(–1)).This work also evaluated the H_(2)-utilization efficiency in MBfR.The measured H_(2)supply rate was only slightly higher than the stoichiometric H_(2)-utilization rate.Thus,H_(2)utilization was controlled by diffusion and was close to 100%efficiency,as long as biofilm accumulated on the polyester-fiber surface and the fibers had no leaks.
