Organics and nitrogen recovery from sewage via membrane-based pre-concentration combined with ion exchange process

This study proposes the recovery of organics and nitrogen from sewage through membrane-based pre concentration (MPC) combined with ion exchange (IE) process. Unlike conventional activated sludge process, MPC-IE redesigned organic carbon flow to increase chemical oxygen demand (COD) conversion for energy recovery via anaerobic digestion (AD). This process also achieved nitrogen recovery instead of destruction. Membrane-based pre-concentration of COD was conducted using actual sewage for one month. As high as 65% COD was recovered. Batch IE adsorption and regeneration experiments were conducted. However, these experiments recovered only 37.5% NH4-N because of the selectivity of IE for hard ions over ammonium. Despite the low rate of recovery, the process could achieve a total of 0.38 kWh/m(3) energy recovery by combining energy production with anaerobic digestion of pre-concentrated organics (0.26 kWh/m(3)) and energy saving via nitrogen reuse (0.12 kWh/m(3)). Highly efficient energy and nitrogen recovery from sewage via MPC-IE process was expected after optimization. (C) 2016 Elsevier B.V. All rights reserved.