Desalination & Reuse Handbook - Flipbook - Page 22
IDA
WATER SECURITY
HANDBOOK
The Year in Technology
Desalination and reuse
Microbial genomics platform promises biofouling revolution
CosmosID’s microbial genomics platform picked up the 2018 Global Water Summit Technology Idol in Paris, which highlights
promising new technologies in desalination and water reuse. The technology is used in clinical applications to identify pathogens and
antibiotic-resistant genes, and could transform biofouling prevention in desalination by allowing for targeted dosing of antifoulants.
With desalination clients at King Abdullah University of Science and Technology and the Singapore Public Utilities Board, CosmosID is
in the early stages of commercialisation and is working to provide an 8-hour turnaround for biofilm samples. CosmosID founder Rita
Colwell, whose discovery is used by the company, also received the Lee Kwan Yew prize at the 2018 Singapore International Water Week.
Electrodialysis gains ground on RO
Electrodialysis (ED) is attracting more interest as it becomes
more cost competitive with reverse osmosis (RO). Usually used
in brackish water applications, its resistance to silica scaling is a
key advantage compared to RO. The technology’s small pool of
suppliers has limited uptake, as clients are unwilling to be tied
to single technology providers, but some market entrants such
as Fujifilm are looking to provide modular ED units. Evoqua
has also entered the ED/EDR market with its NEXED system,
which has been piloted extensively in Singapore and the USA.
In the medium-term, the technology is anticipated to find
applications in altering water chemistry prior to RO treatment
in order to reduce membrane fouling. Meanwhile, demand for
electrodeionisation (EDI) systems is likely to increase, driven by
growth in the microelectronics sector where EDI has traditionally
been used for polishing in ultrapure water, and by increased
uptake from the power industry as end-users move away from
ion exchange systems for boiler feedwater.
Electrodialysis
The electrodialysis process dates back to the 1950s and is still
widely used to remove salts from water, but numerous processes based on ED principles have evolved according to market
needs.
Feed solution
C
Anode
Evcon brings membrane distillation a step closer to the mainstream
A
C
A
Cathode
Concentrate
Diluate
Following the liquidation of memsys in 2016, membrane distillation (MD) technology made a surprise recovery in mid-2018. EvCon
is currently working on a 20,000 m³/d MD unit for seawater applications, with financial backing from Algeria-based Cevital. The
technology evaporates warm water through a series of Gore-Tex-type membranes at progressively lower pressure, with the use of
plastic materials making it cheaper than traditional distillers at the cost of a larger system footprint. It has small-scale references in the
Seychelles, whilst the larger unit is being trialled by US and German pharmaceutical customers. Operation and commercialisation of
MD remains a significant area of research, but there are precious few serious commercial players marketing the technology.
Chemical-free ZLD technology licensed
New Zealand-based Aquafortus Technologies signed its first exclusive licensing agreement for its AquaFortus NTR membrane-free
zero liquid discharge (ZLD) technology in May 2018, with PetroH2O installing a 1.6 m³/d demonstration unit in Texas in conjunction
with RODI Systems. The system uses a proprietary hydrophilic absorbent to crystallise salts out from brine, before transferring the
resulting solution to a proprietary regenerant. The regenerant causes the absorbent to change state from hydrophilic to hydrophobic,
which separates the two chemicals. Nanofiltration is then used to recover the regenerant. Aquafortus was an audience-selected winner
at Singapore International Water Week’s TechXChange event in July 2018. Meanwhile Advanced Water Recovery, which had also offered
a chemical brine concentration technology, ceased operations in March 2018 following difficulties with cost-effective recovery of its own
proprietary solvent.
Micro-and nano-scale aeration
Moleaer’s XTB NanoBubble Generator continued to pick up commercial sales in 2018, while akvola Technologies launched its MicroGas
bubble generator, both with applications in dissolved air flotation (DAF), membrane bioreactor (MBR) and ozonation/oxidation
processes. The MicroGas system injects compressed gas into diffuser disks to produce a cloud of 50–70 micrometre bubbles, which
reduces the moving parts needed to operate the system. The Moleaer system produces bubbles that are 100 times smaller at 100
nanometres, resulting in slower flotation and more efficient oxygen transfer. Although nanobubble technology remains a new addition
to the water sector, its physical properties present numerous opportunities for retrofits in existing water and wastewater applications.
3D printing boosts membrane flux rates
3D printing in membrane production is gathering speed, with Aqua Membranes and NanoSun scaling up production in 2018. New
Mexico-based Aqua Membranes prints a 0.011 inch thick feed spacer directly onto its RO membrane sheet, increasing membrane
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