Tag: Reverse Osmosis
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Low-Biofouling Polypropylene Feedspacers for Reverse Osmosis Applications
Polypropylene (PP) is a commercial polymer that is ubiquitous in membrane filtration as feedspacer due to its high chemical stability, low cost and versatile properties. The goal of this project was to develop low-biofouling polypropylene reverse-osmosis (RO) feed spacers, which can be used for desalination, through the functionalization of PP with copper ions since copper…
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Doing away with RO energy-recovery devices
Energy-recovery devices have been a crucial element in the reduction of the cost of desalination during the past decade, bringing the technology within reach of conventional water resources costs in certain circumstances. Typical energy consumption for seawater reverse osmosis (SWRO) is now around 2.5 kWh/m . Desalitech’s Closed Circuit Desalination, which does away with an…
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Desalination Concentrate Disposal: Salt Production For Zero-Discharge System
Since large-scale desalination started, the question of how to dispose of the reject material produced by the process has occupied the minds of engineers and economists. The quantity of brine discharged from desalination plants is increasing, and this trend will be maintained for the near future. The minerals extracted must have a value, but how…
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Possibilities for energy optimisation in design and operation of SWRO plants
Seawater desalination with reverse osmosis (SWRO) has taken a noteworthy upturn during recent years. One of the reasons for the success of the membrane process is its lower energy consumption in comparison with thermal desalination processes. The high-pressure RO desalination stage is undoubtedly the dominating energy consumer of an SWRO plant. Energy consumption of SWRO,…
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Carlsbad project plan for green SWRO
The largest and most advanced seawater desalination project under development in the USA today is the 189,000 m³/d plant in Carlsbad in southern California. This project is collocated with the Encina coastal power generation station, which currently uses seawater for once-through cooling. The Carlsbad seawater desalination project is developed as a public-private partnership between Poseidon…
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Desalination using forward osmosis with nanofiltration membranes
Forward osmosis (FO) is an emerging membrane technology, often used for desalination. Like reverse osmosis (RO), FO uses a semi-permeable membrane to separate water from dissolved solutes. The semi-permeable membrane acts as a barrier that allows water to pass through while blocking salts. Generally, any dense, non-porous, selectively permeable material can be used as a…
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Advantages of Polyethersulfone (PESU) membranes for pretreatment for SWRO applications
Membrane pretreatment for large-scale seawater desalination has grown rapidly in the last few years. Existing examples seem to show that the additional cost can be more than recouped in reduced chemical costs alone, but there are also environmental advantages. This article is the first of two discussing the advantages of polyethersulfone (PESU) membranes for filtration…
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Gold Coast’s twin intake/outfall tunnels save space and environment
A key part of the anti-drought strategy in Queensland, Australia, has been the construction of a 125,000 m³/d seawater reverse-osmosis desalination plant, located at Tugun on the Gold Coast, due to start producing water in November 2008. This plant will supply up to 20% of the average demand for the Brisbane/Gold Coast Region. The Gold…
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Large Diameter RO Desalination Elements
In recent years, increasing the diameter of spiral elements has been studied as a method of lowering the cost of membrane treatment. It has been shown that the installed cost of a reverse osmosis (RO) plant can be reduced by up to 27% using larger diameter elements.Large diameter elements provide savings in footprint and building…
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Antiscalant removes need for acid in wastewater RO
Field trials of a new scale-inhibiting chemical for use with reverse-osmosis membranes in wastewater reuse plants show that, at a low dose rate, it can increase the solubility of calcium phosphate by over one hundred times, obviating the need for using dangerous and costly acid. Current design practices for large effluent reuse projects are focused…