Targeted Removal of Dissolved Organic Matter in Boiler-Blowdown Wastewater: Integrated Membrane Filtration for Produced Water Reuse

Abstract

The efficacy of coagulation and membrane filtration was studied for the treatment of boiler-blowdown (BBD) wastewater to enable reuse and minimize the overall water consumption in steam-assisted-gravity-drainage (SAGD), thermally enhanced, oil recovery operations. Direct nanofiltration of chemically unadjusted BBD at its original pH was the optimal treatment option with respect to the flux stability and the removal of dissolved organic material and salinity, which if not removed would result in the fouling and failure of downstream process equipment. The naturally high solute hydrophilicity allowed for prolonged operation with an elevated flux of 60 L m⁻² h⁻¹ (LMH) and recovery up to 85% while maintaining solute removal as high as 80% and 45% for dissolved organic carbon and total dissolved solids, respectively. Comparatively, neither precoagulation nor preacidification improved the rejection of dissolved organic material or salinity and consistently resulted in increased membrane surface fouling and flux decline. The proposed filtration treatment solution would result inasmuch as a 4-fold reduction in the volume of makeup water required and BBD wastewater disposed compared to a conventional SAGD facility