Dewatering Reverse Osmosis Concentrate from Water Reuse Applications Using Direct Osmosis

Reverse osmosis (RO) is an effective barrier in water production systems when removal of dissolved contaminants or salts is needed to achieve high finished water quality. RO concentrate usually comprises 10–30% of the influent for surface water and 50–75% of the influent for seawater. While coastal communities can utilize the ocean to discharge the RO concentrate, inland facilities must rely upon more problematic conventional alternatives, such as surface water or sanitary sewer discharge, evaporation ponds, deep well injection, and land applications. These options are costly, not environmentally sustainable, and increasingly difficult to permit. Thus, proper handling and disposal of the RO concentrate have become a critical environmental issue, particularly for an inland community. The project investigates the viability of utilizing FO for dewatering RO concentrate, alternative membrane configurations for FO applications, innovative draw solutions and compare them with baseline draw solutions, and the economic feasibility of dewatering RO concentrate by using FO.

Originally funded as WERF project Reuse-05-09.