Novel desalting can exploit the unique properties of water and saline solutions. The Centre
is particularly interested in identifying and piloting novel technologies for Australia’s rural
and remote needs, against a benchmark of BWRO. The Centre’s novel desalting projects include:

• Silica removal from groundwater for reverse osmosis water recovery enhancement and waste brine volume reduction, led by Dr Peter Sanciolo and Prof. Stephen Gray, Victoria University
• Fertilisers as draw solutes for forward osmosis desalination: a novel approach for fertigation in the murray darling basin, led by Dr Ho Kyong Shon, University of Technology, Sydney
• Non-brittle ceramic hollow fiber membranes, led by Prof. Huanting Wang, Monash University
• Application of capacitive deionisation in inland brackish water desalination, led by Prof. Linda Zou, University of South Australia
• High water recovery inland desalination using membrane distillation with ceramic membranes, led by Prof. Joe da Costa, University of Queensland
• Developing highly conductive graphene electrodes for capacitive desalination, led by Prof. Linda Zou, University of South Australia
• Reverse osmosis brine management by membrane distillation crystallisation, led by Prof. Stephen Gray, Victoria University
• Highly productive and selective bio‐organic hybrid membrane water filters, led by Prof. Michael J. Monteiro, The University of Queensland
• Development of a novel low grade heat driven desalination technology, led by Prof. Hui Tong Chua, The University of Western Australia

Silica removal from groundwater for reverse osmosis water recovery enhancement and waste brine volume reduction

This project will investigate the opportunity to achieve high water recovery (above 95% of the feed flow) and low waste brine volumes (less than %5 of the feed flow) in the reverse osmosis desalination of bore water using an interstage treatment to remove silica – one of the major scale precursor species present in the bore water. The proposed process is based on literature studies that have shown that it is possible to generate RO brines with silica concentrations of approximately 1000 mg/L without silica scale formation. For groundwater containing 100 mg/L silica, this would equate to a 90% water recovery. It is proposed that the remaining brine concentrate be further treated by precipitation and coagulation, and/or adsorption onto activated alumina, and/or seeded precipitation to further allow RO treatment of the brine and thus achieve water recoveries above 95%.

Fertilisers as draw solutes for forward osmosis desalination: a novel approach for fertigation in the murray darling basin

Drought and water scarcity are common in Australia and desalination is increasingly sought to augment fresh water supplies to meet the growing water demand. Although, the cost of reverse osmosis base desalination has substantially reduced, it still remains energy intensive. Forward Osmosis (FO) is an emerging and novel desalination technology with significant lower energy but still lags large scale application due to a lack of suitable draw solution that can be easily recovered with minimal energy. However, FO technology is particularly suitable where the separation of the draw solute and desalinated water is not essential. Our recent investigation with some fertilisers indicates that most commercially available fertilisers can be used as osmotic draw solutes. This led to the idea of applying FO technology in agriculture where the diluted fertiliser draw solution containing desalinated water can be used directly for fertilised irrigation (fertigation) instead of further subjecting to a separation process. Such technology can be suitably applied in the Murray-Darling Basin to convert brackish groundwater into nutrient rich irrigation water with minimum energy. The FO desalination process can be integrated with the existing salt interception scheme in the basin where brackish groundwater is pumped out and simply lost through evaporation. Such desalination scheme can a significant impact on the agriculture in the drought prone areas of Australia, leading to sustainable use of brackish groundwater. However, this concept is still at an early stage and lacks literature on the fundamentals and its application. Therefore, this project aims at firstly evaluating the potential of various forms of fertilisers for use as FO draw solute and then optimising the process parameters for desalination of brackish groundwater ultimately leading to the design of a pilot scale FO desalination unit for fertigation application.

Non-brittle ceramic hollow fiber membranes

This project aims to develop non‐brittle ceramic hollow fiber membranes for pre‐treatment of seawater in seawater desalination processes. Existing ceramic hollow fiber membranes tend to be brittle, and thus limit their widespread industrial applications. In this proposed research, non‐brittle ceramic hollow fiber membranes will be developed via incorporation of ceramic nanofibers into porous ceramic structure. This project is expected to lead to a cost‐effective technique for fabrication of ceramic hollow fiber membranes with high toughness and tunable pore sizes for efficient pretreatment of seawater.

Application of capacitive deionisation in inland brackish water desalination

The overall objective is to transfer the capacitive deionisation technology into real applications for inland drinking water supply and direct agricultural use by desalting brackish groundwater. A coordinated approach is proposed to include a regional inland location in Northern Territory. The project will evaluate the available CDI units and select the most up to date and robust cell technology. Site trials will be conducted to investigate the full operational performance of the technologies. For inland communities in Australia, the only reliable waterresource is groundwater and limited surface river water but much of this contains salt that is higher than the acceptable drinking water guideline value. It is necessary to use a desalination process to remove the salt andproduce drinking water (<500 mg/L salinity). The key outcomes will establish the feasibility of this novel technology in real world situations, and provide answers to a series of technical challengesfaced when applying this new desalination technology for inland water supply and for direct agricultural uses. The CDI operation requires DC power, so it matches well with state of the art renewable energy sources, for example, solar photovoltaic panels associated with battery banks can directly supply the power for CDI units.

High water recovery inland desalination using membrane distillation with ceramic membranes

Inland desalination is a growing practice due to the increasing water needs of inland based communities and commercial operations. Conventional technologies such as reverse osmosis can be used for such purposes,although there are associated problems with fouling, power supply and brine disposal. Hence, there is a need to develop novel enabling desalination technologies that address these problems and also deliver value to inlandcommunities and companies. This project aims to trial a new thermally based robust ceramic desalination membrane to achieve higher water recoveries at lower capital and operating cost. These ceramic membranes will be field tested using a membrane distillation pilot plant that will be built as part of this project, with a targeted production capacity of 10 litres perday. The anticipated performance and cost data from this research will be critical for scaling‐up to larger trials and identifying the commercial potential for this new technology.

Developing highly conductive graphene electrodes for capacitive desalination

Capacitive deionisation (CDI) is a promising alternative technology in desalination. It targets the removal of salt ions which are only a small percentage of the feed solution, as compared to most other technologies that aim to shift water which accounts of 90% of the feed solution. As a result, CDI requires less energy to operate and the electrodes are easily regenerated. Porous carbon materials are the most important component in the CDI processes, as they are used as the electrodes that play a significant role in the efficiency of the desalting process. The ideal electrode materials for CDI should be both highly conductive and of high surface area and suitable pore structures. The currently available carbon electrodes limit the desalination efficiency of CDI due to their low conductivity and non-ideal pore structure and pattern. Previous research has demonstrated that the efficiency of CDI strongly depends upon the surface properties of the carbon electrodes, such as surface area and pore microstructure. Many kinds of carbon materials have been investigated as CDI electrodes such as carbon aerogel, carbon cloth, carbon nanotubes and mesoporous carbons. The aim of this project is to build on the existing research projects in my research group, to develop and evaluate the potential of using graphene nano platelets as novel electrode materials in capacitive desalination. The research challenge is to achieve ideal highly conductive properties as well as desirable nano platelet structure. Both are crucial for attaining high desalination performance.

Reverse osmosis brine management by membrane distillation crystallisation

Desalination is a widely used technology in the world to meet the increasing demand for fresh and clean water. The main operation used in the conventional desalination process is reverse osmosis (RO). However, a key challenge imposed by desalination by RO is the brine management and disposal issue because the current membranes reach a water recovery and produce liquid brine reject. For inland desalination, the standard approach to manage this reject is the use of evaporation ponds. While evaporation ponds are a simple technology, they come at a significant capital cost as lined evaporation ponds are required by state environmental protection agencies. Membrane distillation (MD) is potentially able to decrease the size of the evaporation ponds and increase water recovery. The current challenges in developing an MD process are: 1) the module design, 2) systems and protocols to clean the membranes and 3) process design for efficient energy use. This project would seek to address all these aspects, and to do so by demonstration on an industrial RO brine concentrate. Additionally, a brine crystalliser for zero liquid discharge will also be trialled.

Highly productive and selective bio‐organic hybrid membrane water filters

The project will develop novel bio‐organic hybrid membranes with high selectivity, high water permeation rates and with low energy requirements. This research aims to deliver the next generation in membrane technology by replicating nature’s own filtration process. We will use the excellent water purification ability of membrane proteins; to capture, orientate and support these proteins into designer artificial membranes.

Development of a novel low grade heat driven desalination technology

Low‐grade heat driven desalination plants provide solutions for water needs in remote and rural communities, remote mine sites (both for drinking and mineral refining) and the water intensive process industry. In many such instances reverse osmosis systems cannot supply the desired freshwater owing to various factors such as extremely high salinities, presence of toxins from mine wastes, natural geological resources and radioactive deposits and lack of available electrical power. These limitations do not apply to the Multi‐Effect‐Distillation (MED) process since it is an established low‐grade heat driven technology that can deal with any contaminants and salinity levels. The Western Australian Geothermal Centre of Excellence has developed a novel technology which boosts the efficiency of standard MED by 30% and more in terms of freshwater yield with a standard coolant temperature of 20°C. This is done by exploiting the unique nature of low-grade heat such as for instance supplied by a geothermal bore, or low-grade heat rejection from process industry. This proposal is the first step towards commercialisation of the novel MED technology which is proposed in three phases: (1) Demonstrate the technology with a containerised 1 m3/day first generation two‐effect prototype proposed to be built and evaluated at the NCED Rockingham site. (2) Build a containerised second generation 4 m3/day three‐effect MED prototype at the NCED site. (3) Demonstrate a four‐effect prototype under field conditions in an already identified commercial water intensive mineral processing plant, with a nominal capacity of 4000 m3/day of freshwater production.