Desalination & Reuse Handbook - Flipbook - Page 23
THE YEAR IN TECHNOLOGY
surface area by 25%. Singapore-based NanoSun uses 3D printing to produce microfiltration and ultrafiltration (MF/UF) membranes,
aiming to eliminate chemical use in production and claiming a flux rate of five times that of its competitors. Aqua Membranes is in early
stages of commercialisation and NanoSun’s membranes are used in over 10 installations with capacities ranging up to 20,000 m³/d.
High recovery RO takes centre stage
2018 saw the launch of several high recovery RO systems. IDE Technologies launched its MAX H2O Desalter, claiming recovery rates
in excess of 90% in brackish water applications. The system’s batch RO process recirculates brine through a fluid bed reactor to remove
sparingly soluble salts, and alternates between two feed tanks in order to avoid interruption once brine concentration in one tank
reaches the osmotic limit. Meanwhile, FEDCO announced seawater reverse osmosis (SWRO) recovery rates of 60% using multiple
turbochargers for interstage boosting in a multi-stage RO configuration. The system was piloted on an 8,640 m3/d SWRO system in
Monterrey, Mexico in August 2018, but has yet to undergo formal evaluation of its permeate quality.
Membrane-based brine concentration is also seeing new activity, with a growing number of systems claiming to reach concentrations of
greater than 100,000 ppm – previously considered a major barrier for membrane technologies. Counter-current RO systems from Hyrec
and Gradiant use staged membrane configurations that mix brine with feedwater entering previous stages, which improves membrane
performance at higher concentrations by lowering the concentration gradient across the membrane. In contrast, the more established
Osmoflo BrineSqueezer takes a brute-force approach with specially coated membranes operating at extreme pressures to concentrate RO
reject. This results in a simpler operating procedure, but modules must be taken offline for cleaning and re-application of membrane
coatings every few days.
High recovery SWRO: Turbocharged desalination
FEDCO’s pitch for its multi-stage multi-turbo concept is that energy-related opex savings pale in comparison to capex savings
made by increasing recovery rates, which reduces a plant’s footprint, intake size and equipment requirements. The company
suggests that the design can be applied to any multi-stage RO configuration.
40-50 bar
50-60 bar
HPP
HPB1
1st stage
2-4 bar
FEED
VFD
PERMEATE
65-80 bar
M
2nd stage
48-58 bar
REJECT
0.5-2 bar
63-78 bar
20-40 bar
HPB2
*Patent applied for in the U.S. and abroad
Plant automation gathers speed
Desalination plant automation and optimisation made significant gains in 2017–2018. Whilst automation in wastewater treatment
plants remains their priority, key players such as Suez and Veolia are beginning to make moves towards desalination plant automation.
Acciona in particular is making significant progress on this front, while China’s KingTrol Data is also showing a close interest in
desalination plant automation. In the shorter term, Pani Energy offers software that optimises plant utilisation against the price of
energy, with several references at mid-sized industrial desalination installations in India. Meanwhile, ACWA Power applied data from
its desalination plants at Rabigh and Shuqaiq in Saudi Arabia to optimise different membrane and plant configurations against annual
variations in seawater conditions, which it hopes will vastly enhance its ability to integrate power and water production. Intelliflux
Controls also launched an upgraded version of its SmartMode automation and process control software for membrane systems. The
software acts as an ‘autopilot’, responding to new conditions in a plant with greater speed and accuracy than an human operator, and
uses artificial intelligence to accelerate the programme’s learning and system optimisation capabilities.
The desalination plant of the future will be able to self-manage in some aspects, and to
make autonomous decisions on how to operate or how to respond to situations that occur on
a day-today basis, such as flow adjustments, membrane replacement, and adjustments in the
dosages of chemicals.”
Frank Zamora, IT Director at Acciona Agua
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