(280e) Self-Regulating Behavior of a Pilot Scale Forward Osmosis-Reverse Osmosis Hybrid System

Although reverse osmosis (RO) is an industrially mature and widespread desalination technology, its susceptibility to fouling makes it challenging to operate using more difficult feedwaters. Pretreatment is one approach to reducing fouling in RO membranes and such systems often comprise a majority of a desalination plant’s total footprint. Hybridization of forward osmosis (FO) with RO has been considered as an alternative configuration to more conventional pretreatment schema, but the lack of understanding of how these systems might operate and the potential for complex control schema to balance fluxes between the FO and RO systems create uncertainty in system design. In this work, we demonstrate self-regulating behavior of FO-RO hybrid systems that can lead to reduced complexity of these systems at scale. We show this behavior using a module-scale test bed that can mimic the behavior of larger scale systems. The system shows permeate flow rate near-convergence between the FO and RO modules after startup or when perturbed by a change in RO module pressure. Such a result indicates that FO-RO hybrid system do not require complex control schemes to ensure even flows between the two processes.