Sulfur-based autotrophic denitrification of drinking water using a membrane bioreactor

Abstract

Sulfur-oxidizing autotrophic denitrification process has drawn significant attention due to its high efficiency, elimination of carbon requirement and the effluent contamination by organic compounds. In the process, nitrate and sulfur are used as electron acceptor, and electron donor, respectively. In the present study, a novel sulfur based autotrophic denitriflcation process utilizing membrane bioreactor (MBR) was tested for nitrate removal from drinking water. A bench-scale MBR equipped with hydrophilic flat sheet polyethersulfone (PES) membranes (0.45 mu m) was used. Sulfur was externally added to the MBR considering the theoretical requirement. Almost complete denitrification efficiency was achieved when the influent nitrate concentrations were 25-50 mg NO3--N/L at HRT as low as 5 h corresponding to nitrate loading rates up to 0.24 g NO3--N/(L d), The generated sulfate concentrations were close to the theoretical values. Membrane fouling was not significant at fluxes <= 20 L/(m(2) h). (C) 2015 Elsevier B.V. All rights reserved.