Energy-efficient hybrid FCDI-NF desalination process with tunable salt rejection and high water recovery

Assessment of salt-free electrodialysis metathesis: A novel process for brine management in brackish water desalination using monovalent selective ion exchange membranes

Performance evaluation of reverse osmosis (RO) pre-treatment technologies for in-land brackish water treatment

High recovery rate NF–FO–RO hybrid system for inland brackish water treatment

Optimizing energy efficiency in brackish water reverse osmosis (BWRO): A comprehensive study on prioritizing critical operating parameters for specific energy consumption minimization

Naturally occurring brackish water, normally containing 500–10,000 mg/L of total dissolved solids, is not safe for direct consumption due to its salinity. The salinity level needs to be reduced to a level below 500 mg/L to make it drinkable as per recommendations of the World Health Organization (WHO). Reverse osmosis (RO) process for water desalination purposes is currently considered to be the most effective, economical, efficient, and optimized method dominating the water purification market. An extensive research has been carried out in the field of membrane-based brackish water reverse osmosis (BWRO) process to improve its desalting performance. Various aspects of a BWRO process system such as nature and type of membrane material, module design parameters, process configuration, energy recovery devices, operating parameters, economical aspects are reviewed in this chapter. Theoretical background of a BWRO process, transport mechanism through BWRO membranes, and desalination performance of BWRO membranes are considered here. An updated review of different commercially available BWRO membranes, membrane modules, and process configurations is also provided. In addition, major components of a typical BWRO plant such as pretreatment unit, pumping system, membrane module section, and post-treatment unit are also described in this review. General process considerations, economic aspects, energy recovery options, and process optimization of a BWRO system are discussed here. High-performance BWRO membranes prepared from polymeric and thin-film composite materials are inserted in commercial spiral wound modules to make the desalting process economically efficient. Concentrated brine rejected from a BWRO plant can be economically treated by installing solar stills at sunlit places. A double-stage membrane process can enhance water recovery of BWRO plants from the usual range of 85–90% to about 95–98%. Brackish water can be purified by BWRO process at reduced cost by using high rejection membranes, installing larger pressure vessels, and adopting hybrid membrane design.

Performance optimization of integrated electrochemical capacitive deionization and reverse electrodialysis model through a series pass desorption process

Pretreatment of brackish water reverse osmosis (BWRO) concentrate to enhance water recovery in inland desalination plants by direct contact membrane distillation (DCMD)

Saline groundwater (SGW) is an alternative water resource. However, the concentration of sodium, chloride, sulphate, and nitrate in SGW usually exceeds the recommended guideline values for drinking water and irrigation. In this study, the partial desalination performance of three different concentrated SGWs were examined by pressure-driven membrane desalination technologies: nanofiltration (NF), brackish water reverse osmosis (BWRO), and seawater reverse osmosis (SWRO); in addition to one electrochemical-driven desalination technology: membrane capacitive deionisation (MCDI). The desalination performance was evaluated using the specific energy consumption (SEC) and water recovery, determined by experiments and simulations. The experimental results of this study show that the SEC for the desalination of SGW with a total dissolved solid (TDS) concentration of 1 g/L by MCDI and NF is similar and ranges between 0.2–0.4 kWh/m3 achieving a water recovery value of 35–70%. The lowest SECs for the desalination of SGW with a TDS concentration ≥2 g/L were determined by the use of BWRO and SWRO with 0.4–2.9 kWh/m3 for a water recovery of 40–66%. Even though the MCDI technique cannot compete with pressure-driven membrane desalination technologies at higher raw water salinities, this technology shows a high selectivity for nitrate and a high potential for flexible desalination applications.

The present study aims at evaluating a small-scale brackish water reverse osmosis (RO) process using parameter optimization. Experiments were carried out using formulated artificial groundwater, and a predictive model was developed by using response surface methodology (RSM) for the optimization of input process parameters of brackish water RO process to simultaneously maximize water recovery and salt rejection while minimizing energy demand. The result of multiple response optimization along with analysis of variance for RSM predictions showed that the optimal water recovery (19.18%), total dissolved solids rejection (89.21%) and specific energy consumption (17.60 kWh/m3) occurred at 31.94 °C feed water temperature, 0.78 MPa feed pressure, 1500 mg/L feed salt concentration and 6.53 pH. Furthermore, confirmation of RSM predictions was carried out by an artificial neural network (ANN) model trained by RSM experimental data. Predicted values by both RSM and ANN modelling methodologies were compared and found within the acceptable range. Finally, a membrane validation experiment was carried out successfully at proposed optimal conditions, which proves the accuracy of employed RSM and ANN models. Present methodology can be used as a generalized way for the optimization of different RO membranes available in the market in terms of increased water recovery and salt rejection with least energy consumption to make it commercially competent.

Pioneering demineralized and desalinated water cost reduction with innovative brackish water RO membrane technology

The resource efficiency of a conventional domestic reverse osmosis system is low because it operates at a low water recovery and energy efficiency. Besides, the quality of permeate cannot be controlled, leading to unusual taste, which may result in adverse health effects. In this article, a new system design and operational method of a domestic reverse osmosis system have been studied analytically and experimentally. The study shows that it is possible to tune the permeate quality, and a high water recovery can be achieved with this design and operational method. In addition, specific energy consumption can be reduced. This system is particularly useful in the case of low salinity feed with a trace amount of heavy metals. A synthetic feed solution of As+5 in pure water was used as a feed to verify the same. It was observed that a high water recovery (>85%) could be achieved while removing As+5 from the water. With global rise in decentralized desalination systems, the proposed system design and operational method can be used not only to tune the product recovery and quality but also to reduce the specific energy consumption as well. Hence, this work is in line with United Nations Sustainable Development goals (SDGs).

Photovoltaic-powered membrane was taken to filter brackish water. Effect of ammonia concentration, pressure and salinity on ammonia and total dissolved solids (TDS) removal, water recovery and energy consumption had been investigated. Results show that ammonia concentration did not influence ammonia and TDS removal, water recovery, and energy consumption obviously. Results of ammonia concentration of 10, 20 and 35 mg/l were similar to that of 5 mg/l. For salinity, the better filtration was achieved when the concentration of salinity was lower. With increment of pressure, ammonia and TDS removal increased simultaneously. The ammonia and TDS removal of more than 98% attained with the water recovery of 40.6% at the energy consumption of 2.0 kWh/m3. It illustrates that salinity and pressure were definitely crucial to brackish water filtration with photovoltaic-powered membrane.

Energy consumption in membrane capacitive deionization and comparison with reverse osmosis

Particle entrainment model for industrial flotation cells

Pre-desalination with electro-membranes for SWRO