A Study on Co-Disposal of Concentrates from Nanofiltration and Reverse Osmosis Processes with Wastewater Treatment Plant Effluent for Direct Potable Reuse Applications

For direct potable reuse (DPR) applications, a multi-barrier based treatment scheme involving reverse osmosis (RO) has been ubiquitously regarded as the benchmark, however, the disposal of RO concentrate has always been a great challenge in inland areas. As a possible alternative to RO, the nanofiltration (NF) process will result in more molecules in the product water but will produce a less concentrated refuse stream, therefore opening the door for more concentrate disposal options. This study evaluates the performance of RO vs. NF for a DPR application, and investigates how different membrane types would impact the feasibility of co-disposal of the DPR treatment concentrate with the effluent of the wastewater treatment plant (s) by surface discharge, which could potentially be one of the most cost effective solutions for concentrate disposal in inland areas.