New concept of pump-less forward osmosis (FO) and low-pressure membrane (LPM) process

Abstract

We tested the possibility of energy-saving water treatment methods by using a pump-less forward osmosis (FO) and low-pressure membrane (LPM) hybrid process (FO-LPM). In this pump-less FO-LPM, permeate migrates from the feed solution (FS) to the draw solution (DS) through the FO membrane by use of osmotic pressure differences. At the same time, within the closed DS tank, inner pressure increases as the DS volume increases. By using the DS tank’s internal pressure, the LPM process works to re-concentrate the diluted DS, maintaining the DS concentration and producing clean water. In this study, a polymer - polystyrene sulfonate (PSS) was used as a draw solute. Based on the results of each individual portion of the process, the optimal range of the PSS DS was determined. The performance of the pump-less FO-LPM process was lower than that of a single process; however, we observed that the hybrid process can be operated without a pump for regeneration of a diluted DS. This research highlights the feasibility and applicability of pump-less FO-LPM processes using a polymeric DS for water treatment. Additionally, it is suggested that this novel process offers a breakthrough in FO technology that is often limited by operation and management cost.

Removal and Reuse of Collagen, Gelatine and Total Chromium from a Raw Leather Industry Wastewater using a Sequential Up flow Anaerobic Sludge Blanket Digestion (UASB) / Aerobic Forward Osmosis (FO) Reactor Configuration

“…These factors enhance the water permeability and mass transfer coefficient and reduce viscosity, resulting in increased water flux and RSF values. These results are in a good agreement with the results from the previous studies related to temperatures in membrane field(You et al, 2012;Im et al, 2017).…”

Continuous juice concentration by integrating forward osmosis with membrane distillation using potassium sorbate preservative as a draw solute

“…To achieve a stable water flux, it is critical to provide a constant draw solution concentration during the FO process. Nanofiltration (NF) and reverse osmosis (RO) have been explored to integrate with the FO process for the concentration of draw solutions [10][11][12][13], but, they could not be used to concentrate high osmotic draw solutions due to the limit of operation pressure.…”

Membrane distillation hybrids for water production and energy efficiency enhancement: A critical review

“…It is considered as a low energy desalting process [195], since it utilizes a high concentration stream namely a draw solution, DS and a low concentration feed solution, FS to create an osmotic pressure gradient to drive water flux. One of the main FO drawbacks is that it requires an additional recovery process, such as distillation [196], MD [197], NF [198] or RO [199] to regenerate the concentrated DS and produce fresh water (Fig.…”