Reverse osmosis desalting

Enormous advances in membrane technology have resulted in the maturation of brackish water and seawater reverse osmosis (BWRO and SWRO) to the point where it is considered the benchmark method for the industry. The Centre is pursuing the following improvement opportunities in RO desalting:

 

Applying a fibre-optic based surface plasmon resonance sensor prototype in desalination

Primary Investigator: Prof. Kamal Alameh, Edith Cowan University
Research Participants: Edith Cowan University
Funded by: National Centre of Excellence in Desalination
Total project value: $844,500

Further to the previously-funded project, this project will develop a prototype of nano-engineered fibre-optic based surface plasmon resonance (SPR) sensors. Based on doping various ligands onto gold nanolayers, the proposed optical fibre sensor will detect specific chemical contents and microbes in water. This will serve as a powerful tool for environmental and process monitoring in Desalination plants, featuring high sensitivity and excellent discrimination capability, high selectivity, low cost and corrosion free.

 

Assisted forward osmosis for energy savings in RO desalination

Primary Investigator: A/Prof. Pierre Le-Clech, The University of New South Wales
Research Participants: The University of New South Wales, University of Nevada, Nanyang Technological University (Singapore)
Funded by: National Centre of Excellence in Desalination
Total project value: $673,500

The concept of assisted forward osmosis (AFO) will be applied as a pretreatment step for reverse osmosis (RO) desalination, resulting in significant dilution of the sea/brackish waters and optimisation of the use of renewable energy. In AFO, a slight pressure is applied to the feed side, resulting in greater dilution of the RO feed, and thus significant reduction in the energy cost for RO operation. In this project, anti-fouling strategies will be investigated to decrease AFO operational costs, detailed modelling will be performed to optimise the process, and novel membranes will be studied for this specific osmotic application.

Publications:

 

Control of organic membrane fouling through limitation and control of extracellular microbial products

Primary Investigator: Prof. Goen Ho, Murdoch University
Research Participants: Murdoch University, Environmental Biotechnology CRC, Nanyang Technological University (Singapore), University of California Irvine, Water Corporation, Chemistry Centre
Funded by: National Centre of Excellence in Desalination, Environmental Biotechnology CRC
Total project value: $810,000

The behaviour of model polysaccharide foulants on flux decline has been investigated and key bacterial species identified by molecular profiling of membrane autopsies. Clearly, bacterial extracellular polysaccharides (EPS) and bacterial biofilms are involved, although the exact contribution between the two is not well understood. The project will identify the source of most problematic EPS in order to develop the best removal strategies, identify which conditions increase EPS fouling of membranes and EPS production using suitable model polysaccharides and biofilm-forming bacterial isolates, and use forward osmosis as a simple testing platform for EPS fouling behaviour and compare with reverse osmosis.

 

Publications:

Development of cleaning guidelines for desalination membrane users

Primary Investigator: Dr Marlene Cran, Victoria University
Research Participants: Victoria University, Integrated Elements, Nalco
Funded by: National Centre of Excellence in Desalination, Nalco
Total project value: $102,000

Scale and other foulants in feed water can build up on the surface of desalination membranes and significantly reduce their performance. While membrane suppliers provide generic guidelines for cleaning and sanitisation, they do not address specialised cleaning chemicals and regimes required for specific fouling issues. This project aims to develop a set of clean-in-place guidelines for desalination membrane users in the form of a comprehensive handbook, structured based on various scaling and fouling issues that affect Australian desalination membrane users.

Publications:

 

Development of universally applicable coatings and additives for state-of-the-art reverse osmosis and pre-treatment membranes

Primary Investigator: Prof. Amanda Ellis, Flinders University
Research Participants: Flinders University, Wind Prospect, SA Water, Siemens
Funded by: National Centre of Excellence in Desalination, SA Water
Total project value: $1,904,000

Two key problems with current membrane technology are biofouling and mechanical degradation of the membranes. The objectives of this three-year project are to develop a coating for commercially available membranes, which will inhibit biofouling and/or biofoulant growth or reproduction, and to design and synthesise a ‘universal’ additive, which will improve the mechanical properties of membranes. The fabrication of an anti-biofouling, antimicrobial coating on reverse osmosis and pre-treatment desalination membranes will result in a minimum of at least four times bio-fouling improvement over commercially available membranes, while still maintaining competitive permeation flux and rejection properties.

 

Fibre-optic sensor for water quality monitoring

Primary Investigator: Prof. Kamal Alameh, Edith Cowan University
Research Participants: Edith Cowan University
Funded by: National Centre of Excellence in Desalination
Total project value: $456,000

This project aims at developing a unique optical fibre sensor for gauging water salinity and dissolved oxygen levels. The sensors are based on optical fibre technology and compared with existing sensors demonstrate superior performance. The proposed sensor will have high sensitivity and excellent discrimination capability, be corrosion-free, selectively enabled, economically efficient and suitable for use in environmental and process monitoring in desalination.

Publications

 

Green chemicals for effective biofouling removal from and preservation of reverse osmosis membranes

Primary Investigator: Prof. Zhiguo Yuan, The University of Queensland
Research Participants: The University of Queensland, Veolia Water Australia, Seqwater
Funded by: National Centre of Excellence in Desalination
Total project value: $130,000

This project aims at investigating and demonstrating the effectiveness and benefits of a novel, low cost, non-oxidising cleaning agent, free nitrous acid (FNA), applied alone and in combination with hydrogen peroxide, for the prevention and removal of biofouling as well as for scale control in RO membranes. In order to deliver a complete assessment of the potential of these novel cleaning agents, their impact on the membrane integrity and life will also be investigated, which is expected to be very limited, to support a full quantification of the benefits both economically and environmentally. The project will be divided in 4 distinct phases: (1) Fouling control, (2) Membrane preservation, (3) Membrane integrity assessment, and (4) Integrated economical and environmental impact evaluation.

 

Highly productive and selective bio-organic hybrid membrane water filters – Phase 1

Primary Investigator: Prof. Michael J. Monteiro, The University of Queensland
Research Participants: The University of Queensland
Funded by: National Centre of Excellence in Desalination, The University of Queensland
Total project value: $995,000
Date completed: July 2013

This 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.

Publications

 

Highly productive and selective bio-organic hybrid membrane water filters – Phase 2

Primary Investigator: Prof. Michael J. Monteiro, The University of Queensland
Research Participants: The University of Queensland, Stanford University
Funded by: National Centre of Excellence in Desalination
Total project value: $953,500

The project follows on from the previous research project funded by NCEDA to develop novel bio-organic hybrid membranes with high selectivity, high water permeation rates and with low energy requirements. Protein membranes that already show excellent water purification will be utilised into a designer artificial polymer membrane that acts to capture, orientate and support the biomolecules in the correct position on the polymer surface. These membranes now have the potential to be made on industrial scales. This research aims to deliver the next generation in membrane technology by attempting to replicate nature’s own filtration process.

 

Mitigation of membrane biofouling using natural polysaccharide surface coating – Phase 1

Primary Investigator: Dr Thuy Tran, CSIRO
Research Participants: CSIRO
Funded by: National Centre of Excellence in Desalination
Total project value: $402,000
Date completed: September 2012

This project forms Phase 1 of a three-phase research program aiming to develop a novel, scaleable, non-toxic and cost-effective anti-biofouling technology using natural polysaccharide coatings. The key objectives of this project are to develop a platform technology to form durable covalent bonds between the polysaccharides and existing membrane surfaces and to demonstrate the anti-biofouling effects of the polysaccharide coatings. The anti-biofouling effect of these polysaccharide coatings is potentially more effective than traditional methods mainly because of their ability to formunique hydrophilic coatings with heavily hydrated and randomly oriented chains. The project is anticipated to bring significant improvements in membrane performance and benefits to the water treatment industry.

 

Mitigation of membrane biofouling using natural polysaccharide surface coating – Phase 2

Primary Investigator: Dr Thuy Tran, CSIRO
Research Participants: CSIRO
Funded by: National Centre of Excellence in Desalination
Total project value: $356,076

This project forms Phase 2 of a three-phase research program aiming to develop a novel, scaleable, non-toxic and cost-effective anti-biofouling technology for water treatment processes by coating a natural polysaccharide on existing membrane surfaces. In Phase 1, we have developed a method to immobilise this polysaccharide on reverse osmosis (RO) polyamide membrane via covalent linkages. The polysaccharide coating has been shown to be durable under realistic water treatment conditions and exhibited exceptional anti-biofouling effect. The key objectives of Phase 2 are to maximise the water flux and anti-biofouling effect of the coated membrane, as well as to optimise the time and temperature conditions of the coating process. The outputs of Phase 2 will form a basis for the scale-up
and pilot plant trial stages planned in Phase 3. The research program is anticipated to bring significant improvements in membrane performance and benefits to the water treatment industry.

 

Optimising SWRO concentrate discharge during “hot standby” operation

Primary Investigator: Dr Badin Gibbes, The University of Queensland
Research Participants: The University of Queensland, Seqwater, BMT WBM, Veolia Water Australia
Funded by: National Centre of Excellence in Desalination, Seqwater
Total project value: $798,000

This project aims to provide industry relevant information on the dynamics of seawater reverse osmosis (SWRO) concentrate following discharge through an offshore diffuser under a range of ‘hot standby’ operating scenarios. Using environmental monitoring systems and numerical models, we will characterise the SWRO concentrate dynamics in the vicinity of the discharge zone of the Gold Coast Desalination Plant. This will provide a valuable opportunity to validate hydrodynamic models within and outside the mixing zone by comparing predicted and observed diffuser performance and will guide the development of operating procedures and monitoring/modelling technology that can be applied to SWRO facilities globally.

 

Real time detection and management of biofouling conditioning films in seawater reverse osmosis

Primary Investigator: Prof. Greg Leslie, The University of New South Wales
Research Participants: The University of New South Wales, University of South Australia, SA Water, Sydney Water, InPhaze
Funded by: National Centre of Excellence in Desalination
Total project value: $540,000

Reducing the impact of biofilms on reverse osmosis (RO) membranes requires early detection and prevention of the development of organic conditioning films. This project seeks to adapt and evaluate impedance spectroscopy for on-line monitoring of the deposition of conditioning films and the development of biofouling. An important outcome of this project will be the provision of desalination plant operators with tools to combat the insidious problem of biofouling in RO plants.

 

Smart materials for corrosion management

Primary Investigator: Prof. Maria Forsyth, Deakin University
Research Participants: Deakin University, Monash University, Ohio State University, AECOM, ASIS Scientific, AusComposites
Funded by: National Centre of Excellence in Desalination
Total project value: $2,542,000

This study will address two key areas of interest in the management of corrosion problems associated with desalination: (1) Understanding the corrosion performance of existing materials components and structures within the complex environmental conditions of desalination plants exposed to major and minor threats including hypochlorite, water and soil problems; and (2) Development of dedicated, lower cost, maintenance materials, and life cycle extension to maximise output and efficiency in the desalination industry.

 

Validation of the assisted forward osmosis – nanofiltration (AFO-NF) concept

Primary Investigator: A/Prof. Pierre Le-Clech, The University of New South Wales
Research Participants: The University of New South Wales, Ghent University
Funded by: National Centre of Excellence in Desalination
Total project value: $381,500

This project aims to further validate the concept of AFO-NF, recently developed within a study funded by the NCEDA. Additional experimental work will be based on a range of commercially available NF membranes, so to define the relative benefits of the concept, and to allow the detailed scoping of a patent to be filed within the first 6 months of the project. A detailed energy model will also be developed in collaboration with Ghent University. Finally, technology transfer will be considered trough initial discussion with relevant membrane manufacturers to develop module prototype.

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