Desalination, Water Re-use, and Halophyte Cultivation in Salinized Regions: A Highly Productive Groundwater Treatment System

Abstract

Groundwater salinization is a problem affecting access to water in many world regions. Though desalination by conventional reverse osmosis (RO) can upgrade groundwater quality for drinking, its disadvantages include unmanaged brine discharge and accelerated groundwater depletion. Here, we propose a new approach combining RO, forward osmosis (FO), and halophyte cultivation, in which FO optimally adjusts the concentration of the RO reject brine for irrigation of Salicornia or Sarcocornia. The FO also reuses wastewater, thus, reducing groundwater extraction and the wastewater effluent volume. To suit different groundwater salinities in the range 1−8 g/L, three practical designs are proposed and analyzed. Results include specific groundwater consumption (SGC), specific energy consumption (SEC), wastewater volume reduction, peak RO pressure, permeate water quality, efficiency of water resource utilization, and halophyte yield. Compared to conventional brackish water RO, the results show superior performance in almost all aspects. For example, SGC is reduced from 1.25 to 0.9 m 3 per m 3 of drinking water output and SEC is reduced from 0.79 to 0.70 kW h/m 3 by a FO−RO−FO system treating groundwater of salinity 8 g/L. This system can produce 1.1 m 3 of high-quality drinking water and up to 4.9 kg of edible halophyte per m 3 of groundwater withdrawn.

High Breakthrough Pressure in Hydrogels Enabled Ultrastable Treatment of Hypersaline Wastewaters

“…Desalination of seawater and inland brackish water emerges as a promising solution to combat freshwater scarcity . However, limited by the low recovery ratio of the current desalination technologies, desalination plants produce substantial quantities of concentrated brine, the disposal of which poses significant environmental challenges, particularly concerning land vegetation and the aquatic ecosystem. , Thus, there has been a growing imperative toward maximizing reuse of liquid waste to achieve zero liquid discharge. , Zero liquid discharge necessitates the continuous concentration of water to a hypersaline state, which heightens demands on both materials and systems to effectively resist wetting and fouling issues …”