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Unorthodox desalination method could transform global water management by Staff Writers Water security is becoming an urgent global challenge. Hundreds of millions of people already live in water-scarce regions, and the UN projects that by 2030 about half the world's population will be living in highly water-stressed areas. This will be a crisis even for developed countries like the U.S., where water managers in 40 states expect freshwater shortages within the next 10 years. As the global population and GDP grow, so will the demand for freshwater. And, with the continuing rise of global temperatures, water shortages will only get worse. Desalination processes are increasingly being relied upon to
augment water supplies. In fact, global desalination capacity is projected to
double between 2016 and 2030. But these processes are expensive and can be
harmful to the environment. The ultrahigh salinity brines that are
the byproduct of desalination can be several times that of
seawater salinity and its management options are especially
challenging for inland desalination facilities such as those in Arizona,
California, Florida, and Texas. Over the past year, Columbia Engineering researchers have been
refining their unconventional desalination approach for hypersaline brines -
temperature swing solvent extraction (TSSE) - that shows great promise for
widespread use. TSSE is radically different from conventional methods because
it is a solvent-extraction-based technique that does not use membranes and is
not based on evaporative phase-change: it is effective, efficient, scalable,
and sustainably powered. In a new paper, published online June 23 in
Environmental Science and Technology, the team reports that their method has
enabled them to attain energy-efficient zero-liquid discharge (ZLD) of
ultrahigh salinity brines - the first demonstration of TSSE for ZLD
desalination of hypersaline brines. "Zero-liquid discharge is the last frontier of desalination,"
says Ngai Yin Yip, an assistant professor of earth and environmental
engineering who led the study. "Evaporating and condensing the water is
the current practice for ZLD but it's very energy intensive and prohibitively
costly. We were able to achieve ZLD without boiling the water off - this is a
major advance for desalinating the ultrahigh salinity brines that
demonstrates how our TSSE technique can be a transformative technology for
the global water industry." Yip's TSSE process begins with mixing a low-polarity solvent
with the high salinity brine. At low temperatures (the team used 5 C), the
TSSE solvent extracts water from the brine but not salts (which are present
in the brine as ions). By controlling the ratio of solvent to brine, the team
can extract all the water from the brine into the solvent to induce the
precipitation of salts - after all the water is "sucked" into the
solvent, the salts form solid crystals and fall to the bottom, which can then
be easily sieved out. After the researchers separate out the precipitated salts, they
warm up the water-laden solvent to a moderate temperature of around 70 C. At
this higher temperature, the solvent's solubility for water decreases and
water is squeezed out from the solvent, like a sponge. The separated water
forms a layer below the solvent and has much less salt than the initial
brine. It can be readily siphoned off and the regenerated solvent can then be
reused for the next TSSE cycle. "We were not expecting TSSE to work as well as it
did," Yip says. "In fact, when we were discussing its potential for
ZLD, we thought just the opposite, that the process would likely give out at
some point when there is just too much salt for it to keep working. So it was
a happy surprise when I convinced lead researcher Chanhee Boo to give it a
try, for the heck of it, on a Friday afternoon and we got such great
results." With a simulated (lab-prepared) brine feed of 292,500
part-per-million total dissolved solids, Yip's group was able to precipitate
more than 90% of the salt in the original solution. In addition, the
researchers estimated that the process used only about a quarter of the
energy required for evaporation of water - a 75% energy savings compared to
thermally evaporating the brine. They reused the solvent for several cycles
with no noticeable loss in performance, demonstrating that the solvent was
conserved and not expended during the process. Then, to demonstrate the practical applicability of the
technology, the team took a field sample of high-salinity brine, the
concentrate of irrigation drainage water in California's Central Valley,
where irrigation drainage water is difficult and costly to treat, and
achieved ZLD with TSSE. Conventional distillation methods require high-grade steam and
are frequently supplemented with electricity to power vacuum pumps. Because
TSSE requires only moderate temperature inputs, the low-grade thermal energy
necessary can come from more sustainable sources, such as industrial waste
heat, shallow-well geothermal, and low-concentration solar collectors. "With the right solvent and right temperature conditions,
we can provide cost-effective and environmentally sustainable concentrate
management options for inland desalination facilities, utilizing brackish
groundwater to alleviate the current and pending water stresses," Yip
notes. In addition to managing inland desalination concentrates, TSSE
can also be used for other high salinity brines including flowback and
produced water from oil and gas extraction, waste streams from steam-driven
electric power stations, discharges from coal-to-chemical facilities, and
landfill leachate. Yip's group is continuing to investigate the fundamental
working mechanisms of TSSE, to engineer further improvements in its
performance. This work includes further testing with real samples from the
field, as well as optimization of the overall process. Research Report: "Zero
Liquid Discharge of Ultrahigh Salinity Brines with Temperature Swing Solvent
Extraction" |
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Dear partners and
friends, We are pleased to invite you to participate in the upcoming webinar on “Cities experience and good practices on reopening and adjusting public health measures in response to COVID-19” to be held on Tuesday, October 6 from 7:30-9:00 am (NY time)/8:30-10:00 pm (Incheon time). Duration: 90 minutes The session will be in English and Spanish, with simultaneous interpretation available in six United Nations languages: Arabic, Chinese, English, French, Russian and Spanish. You may sign up for the
event through this
link  This webinar is co-organized by United Nations Office for Disaster Risk Reduction Global Education and Training Institute (UNDRR GETI), United Nations Office for South-South Cooperation (UNOSSC), and Pan American Health Organization (PAHO/WHO), as a part of the 5-week joint training series on “Making Cities Resilient: Developing and implementing local disaster risk reduction strategy to respond to COVID-19 and to better prepare for the future”. For more information, please visit https://www.undrr.org/event/undrr-unossc-paho-joint-webinar-cities-experience-and-good-practices-reopening-and-adjusting We look forward to your participation. Kind regards, UNDRR GETI, UNOSSC and PAHO/WHO |
We are nonpolitical, but involved in policy, and our communities as a major factor of our nonprofit corporate social responsibility.
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"
The right to vote is precious, almost sacred. It is the most powerful
nonviolent tool or instrument in a democratic society. Use it.”
– John Lewis
The
African Coalition will present the voting rights
awareness workshop on Friday, October 9th at 11.00 am
PT
(12 Noon MT, 1 pm CT, 2 pm ET) .
The
workshop will focus on important information on voter registration,
key dates, and more.
Please
find the attached flyer and join us.
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Black Emergency Managers Association International 1231-B Good Hope Road. S.E. Washington, D.C. 20020 Office: 202-618-9097 bEMA International
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Community\Civil Society Imperative. The impacts of climate change are increasing the frequency and intensity of disasters. Individuals, families, and communities must take a proactive approach and behaviors to save lives, their communities, their culture and heritage. Cooperation, Collaboration, Communication, Coordination, Community engagement, and Partnering (C5&P) A 501 (c) 3 organization. . |
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