Desalination Explained

By Paddy Padmanathan
(Edited by Alison M.  Jones, NWNL Director)
Pictures and graphics provided by Paddy Padmanathan

Mr. Padmanathan, a professional civil engineer for over 35 years, is President and CEO of ACWA Power, a company that delivers desalinated water in 11 countries. His goal today is to promote localization of technology and industrialization of emerging economies.

NWNL:  While we can’t squeeze water out of thin air, we can squeeze potable water out of salt water. The high cost of desalination and ecosystem degradation by its brine waste are now being studied and corrected.  Thus, as our planet seeks more freshwater, NWNL asked this author, whom we recently met, to share his assessment of desalination and to describe recent adjustments to former desalination processes in this blog.

Picture5.pngShuqaiq 2 IWPP, RO desalination plant

Desalination’s Recent Global Development

Desalination is the process by which unpotable water such as seawater, brackish water and wastewater is purified into freshwater for human consumption and use. Desalination is no longer some far-fetched technology we will eventually need in a distant future to secure global water supply.

Desalination technology has been used for centuries, if not longer, largely as a means to convert seawater to drinking water aboard ships and carriers. Advances in the technology’s development in the last 40 years has allowed desalination to provide potable fresh water at large scale.

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Desalination Capacity (Source: Pacific Institute, The World’s Water, 2009)

In the Arabian Gulf, desalination plays a particularly crucial role in sustaining life and economy. Some countries in the Gulf rely on desalination to produce 90%, or more, of their drinking water.  The overall capacity in this region amounts to about 40% of the world’s desalinated water capacity. Much of this is in Kuwait, the United Arab Emirates, Saudi Arabia, Qatar and Bahrain. The remaining global capacity is mainly in North America, Europe, Asia and North Africa. Australia‘s capacity is also increasing substantially.

Global desalination capacity has increased dramatically since 1990 to a 2018 value of producing 105 million cubic meters of water daily (m3/day). Of this cumulative capacity, approximately 95 million m3/day is in use.

Picture2.pngQuadrupling of worldwide desalination capacity (1998-2018) continues.

Proponents and Critics of Desalination

Estimates indicate that by 2025, 1.8 billion people will live in regions with absolute water scarcity; and two-thirds of the world population could be under stress conditions. Desalinated water is possibly one of the only water resources not dependant on climate patterns. Desalination appears especially promising and suitable for dry coastal regions.

Proponents of desalination claim it creates jobs; stops dependence on long-distance water sources; and prevents local traditional water sources from being over-exploited.  It even supports development of energy industries, such as the oil and gas industries in the Middle East. As well, research and development are making desalination plants increasingly energy efficient and cost-effective.

It is valid that the environmental impacts of desalination plants include emission of large amounts of greenhouse gas emissions, because even with all the advances in technology to reduce energy intensity, desalination is still an energy-intensive process. While the industry continues to work on reducing energy intensity, the solution to reducing greenhouse gas emissions is to link desalination with renewable energy.

Energy is also the most expensive component of cost of produced water, contributing up to one-third to more than half of the cost. Renewable energy costs are now becoming competitive with fossil-fuel-generated energy in many locations where desalination is the only option available for providing potable water. As a result, more attention is turning towards de-carbonization of desalination.

Desalination also degrades marine environments through both its intake and discharge processes. After separating impurities from the water, the plant discharges the waste, known as brine, back into the sea. Because brine contains much higher concentrations of salt, it causes harm to surrounding marine habitats. Considerable attention and investment are going towards minimizing the damage with more appropriate design of intake and discharge facilities. In the case of discharge, temperature and salt concentrations are reduced though blending prior to discharge. Ensuring this discharge only at sufficient depths of sea water and spreading discharge across a very wide mixing zone will ensure sufficient and quick dilution.

Desalination Technologies

Main water sources for desalination are seawater and brackish water. Key elements of a desalination system are largely the same for both sources:

  1. Intake — getting water from its source to the processing facility;
  2. Pretreatment — removing suspended solids to prepare the water for further processing;
  3. Desalination — removing dissolved solids, primarily salts and other inorganic matter from a water source;
  4. Post-treatment — adding chemicals to desalinated water to prevent corrosion of downstream infrastructure pipes; and
  5. Concentrate management and freshwater storage — handling and disposing or reusing the waste from the desalination; and storing this new freshwater before it’s provided to consumers.

The majority of advancements in technology has happened at Stage 3, the desalination process itself.

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The 5 Stages of Desalination (with Stage 3 details in the blue circle) .

There are two main categories of desalination methods: thermal (or distillation) and membrane. Until 1998, most desalination plants used the thermal process. Thereafter, the reverse osmosis (RO) desalination process via a membrane-based filtration method took hold.  As more and more technological advancements were developed, the number of plants using membrane technology surpassed that of thermal. As of 2008, membrane processes accounted for 55% of desalination capacity worldwide, while thermal processes accounted for only 45%.

Thermal Methods

There are three thermal processes; multistage flash (MSF), multiple effect distillation (MED), and mechanical vapor compression (MVC), which all use the same basic principle of applying heat to create water vapor. The vapor then condenses into pure water, while separating it from most of the salts and impurities.  All three thermal processes use and reuse the energy required to evaporate water.

Thermal distillation was the earliest method used in the Middle East to commercially desalinate seawater for several reasons:

  1. The very saline and hot Arabian Gulf and Red Sea periodically have high concentrations of organics. Until recent advances in pre-treatment technologies, these organics presented challenging conditions for RO desalination technology.
  2. Only in recent times, with advances in membrane science, have RO plants been reliably utilized for the large production capacities required in this region.
  3. Dual-purpose, co-generation facilities in the Middle East combine water production with electric power to take advantage of shared intake and discharge structures.This usually improves energy efficiencies by 10% to 15% as thermal desalination processes utilize low-temperature waste steam from power-generation turbines.

In the past, these three reasons, combined with highly-subsidized costs of energy available in the Middle East, made thermal processes the dominant desalination technology in this region.  Amongst the three thermal processes, MSF is the most robust and is capable of very large production capacities. The number of stages used in the MSF process directly relate to how efficiently the system will use and reuse the heat that it is provided.

Picture4.pngShuaibah 3 IWPP:  An MSF [thermal] desalination plant.

Membrane Methods

Commercially-available membrane processes include Reverse Osmosis (RO), nanofiltration (NF), electrodialysis (ED) and electrodialysis reversal (EDR). Typically, 35-45% of seawater fed into a membrane process is recovered as product water. For brackish water desalination, water recovery can range from 50% to 90%.

Reverse Osmosis (RO), as the name implies, is the opposite of what happens in osmosis. A pressure greater than osmotic pressure is applied to saline water.  This causes freshwater to flow through the membrane while holding back the solutes, or salts. The water that comes out of this process is so pure that they add back salts and minerals to make it taste like drinking water.

Today, the Reverse Osmosis (RO) process uses significantly less energy than thermal distillation processes due to advances in membranes and energy-recovery devices. Thus, RO is the more environmentally-sustainable solution; and it has reduced overall desalination costs over the past decade.

Picture6.pngShuaibah Expansion IWP, RO membrane racks & energy recovery, RO desalination plant

Desalination Technology Today: Comparisons and Areas for Improvements

While all the desalination technologies in use today are generally more efficient and reliable than before, the cost and energy requirements are still high. Ongoing research efforts are aimed at reducing cost (by powering plants with less-expensive energy sources, such as low-grade heat) and overcoming operational limits of a process (by increasing energy efficiency).

Since the current technologies are relatively mature, improvements will be incremental. Emerging technologies such as Forward Osmosis or Membrane Distillation will further reduce electric power consumption and will use solar heat. To approach the maximum benefit of desalination, it will take disruptive technologies such Graphene membranes. They are in very early stage of development.  Ultimately, no desalination process can overcome its thermodynamic limits. However, desalination is a valuable contribution to today’s increasing needs for fresh water supplies.

The Evolution of NWNL

by Alison M. Jones, Director of NWNL

My photographic career began in 1985 on my first visit to Africa. After years of photographing landscapes, wildlife and cultures for magazines, exhibits and stock photography, I had the honor of helping start Kenya’s Mara Conservancy.  From then on I focused on conservation photography, with NWNL as my signature project.

2-K-ELE-2009.jpgLone elephant before establishment of Mara Conservancy, Mara River Basin

Flying low in a Cessna over sub-Sahara Africa in 2005, I saw from my copilot’s right-hand window, what looked like green ribbons strewn on the ground. They were the lakeshores and river corridors dotted with homes and animals. The rest was empty, grey miombo woodland. I kept repeating, “In Africa, it’s obvious. Where there’s no water, there’s no life.” I had a title, but not yet a topic.

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Aerial view of riverine forest in sub-Sahara Tanzania

I considered a “Waters of Ethiopia” photography project, because when most think of Ethiopia they imagine a dusty desert. Few know Ethiopia holds the largest water tower in the Horn of Africa. Monsoonal torrents supply 75% of the Nile River via Ethiopia’s Blue Nile and 90% of Kenya’s Lake Turkana via its Omo River. An environmental resource manager suggested I include watersheds on other continents as well, for more interest and issues. Thanks to this soon-to-be Founding Advisor, focus then centered on African, N. American and S. American watersheds, as I already had photographed these regions.

4-Jones_070630_WA_5501.jpgMount Adams behind Trout Lake, Columbia River Basin

A second Founding Advisor, now Director of African People and Wildlife, suggested NWNL cover only two continents. South America was dropped, and so were incoming queries asking, “Why not India or China?” Now we could zero in on differences and similarities of water issues in developed v. developing nations. While every watershed presents compelling scenarios of threats and solutions, we chose 3 case-study watersheds on each continent. Those 6 river basins would allow us to raise awareness of almost all of the world’s watershed values and vulnerabilities.

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Women washing clothes, Omo River Basin

We established our expedition-based Methodology, outlining a process we’ve followed step by step for 65 expeditions. Each expedition begins in the office as we study our in-house research outlines (many created by summer college interns) to determine our expedition’s focus. We conclude with a finalized itinerary of expedition contacts to interview and sites to visit.

1-MO-JOH-107.jpgRecreational swimmers and sunbathers, Mississippi River Basin

Having set our case-study watersheds, procedures and website, it seemed NWNL was set to launch. But that first Advisor said that I needed to go back to school before the launch.  Even though I was the photographer in our mission to combine photography and science – not the scientist – she worried I’d embarrass myself (and NWNL) in front of Ph.D. scientists. So, I took Columbia University courses in Watershed Management and Forest Ecology. On completion, the forestry professor asked to be a NWNL Advisor; and I thanked that young advisor with 2 Master’s degrees who sent me back to school for being so astute and such a wise daughter!

8-Jones_100331_UG_4184.jpgMunyaga Falls in Bwindi Impenetrable Forest National Park, Nile River Basin

Credentials of today’s NWNL Team include expertise in still and video photography and training in environment, history and biology, forest and restoration ecology, and natural resource management. Our Advisors and Researchers set the focus and itinerary for our expeditions. Our Staff develops outputs from those expeditions. This structure has allowed me to lead 65 watershed expeditions, often joined by professional or passionate amateur photographers and conservationists.

6-Jones_080503_NJ_0198.jpg“Kids at Play” sign along tributary of Upper Raritan River

Since NWNL began, awareness of the degradation of our water resources has grown – from a bare mention in the news in 2007 to front-page coverage almost daily today. Working in tandem with that growing awareness, we’ve documented the drainage of water from 11 African countries into the Mara, Omo and Nile River Basins (about 10% of Africa’s land mass. With our focus on N. America’s Columbia, Mississippi and Raritan Basins, we’ve gone from coast to coast and covered 50% of the US. Our scope has included the US’s most rural and most densely-populated states (Mississippi and New Jersey).

9-IMG_9861.jpg2015 NWNL exhibition, “Following Rivers,” at Beacon Institute for Rivers and Estuaries

The NWNL Team is proud of the process and products it has created. We hope that – as a result of the efforts of NWNL, the 900+ scientists and stewards we’ve met and many others- nature and all its species will have enough clean water.

 

All photos © Alison M. Jones.

Wild and Scenic River: Merced River

Sections of California’s Merced River were added to the Wild and Scenic River System at two separate times, November 2, 1987 and October 23, 1992. The designated sections include  the Red Peak Fork, Merced Peak Fork, Triple Peak Fork, and Lyle Fork, from their sources in Yosemite National Park to Lake McClure; and the South Fork from its source in Yosemite National Park to the confluence with the main stem. A total of 122.5 miles of the Merced River are designated under the Wild and Scenic River System. 71 miles are designated as Wild, 16 miles are Scenic, and 35.5 miles are Recreational. No Water No Life visited the Merced River in Yosemite National Park during the fifth California Drought Spotlight Expedition in 2016. For more information about NWNL’s California Drought Spotlight please visit our Spotlights page.  For more information about the Wild and Scenic Rivers Act read the first part of this blog series. Here are a few pictures of the Merced River from the 2016 expedition taken by NWNL Director Alison Jones.

Jones_160927_CA_5991Sign marking the Jan 2, 1997 flood level of Merced River in Yosemite National Park
Jones_160927_CA_5996View of the Merced River in Yosemite Valley from Sentinel Bridge
Jones_160927_CA_6088Sign explaining Merced River’s early name “River of Mercy” in Yosemite Valley
Jones_160927_CA_6002View of Merced River in Yosemite National Park with Half-Dome in the background

 

Source:

https://www.rivers.gov/rivers/merced.php

All photos © Alison M. Jones.

NWNL “Pool of Books” 2017

NWNL has compiled a list of new and old favorite books about water issues and our case-study watersheds for your reference for gifts and for the New Year. Many of the authors and publishers are personal friends of NWNL. All of them are worth reading. The links provided below go to Amazon Smile, where a portion of all purchases go to an organization of the buyers choice. Please help support NWNL by selecting the International League of Conservation Photographers to donate to.

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Global:

Rainforest by Lewis Blackwell (2014)

Replenish: The Virtuous Cycle of Water and Prosperity by Sandra Postel (2017)

Water from teNeues Publishing (2008)

North America:

The Salish Sea: Jewel of the Pacific Northwest by Audrey Della Benedict & Joseph K. Gaydos (2015)

Rancher, Farmer, Fisherman: Conservation Heroes of the American Heartland by Miriam Horn (2016)

The Last Prairie: A Sandhills Journal by Stephen R. Jones (2006)

Yellowstone Migration by Joe Riis (2017)

Sage Spirit: The American West at a Crossroads by Dave Showalter (2015)

Heartbeats in the Muck: The History, Sea Life, and Environment of New York Harbor by John Waldman (2013)

East Africa:

Serengeti Shall Not Die by Bernhard & Michael Grzimek (1973)

Turkana: Lenya’s Nomads of the Jade Sea by Nigel Pavitt (1997)

To the Heart of the Nile: Lady Florence Baker and the Exploration of Central Africa by Pat Shipman (2004)

India:

A River Runs Again: India’s Natural World in Crisis, from the Barren Cliffs of Rajasthan to the Farmlands of Karnataka by Meera Subramanian (2015)

Hippos, Crocodiles and Snakes – Oh My!

By Joannah Otis for No Water No Life 

This is the fourth in our blog series on The Nile River in Egypt by NWNL Researcher Joannah Otis, sophomore at Georgetown University. This essay addresses the significance of the most prevalent species of fauna living along the Nile River Basin in Ancient Egypt. [NWNL has completed documentary expeditions to the White and Blue Nile Rivers, but due to current challenges for photojournalists visiting Egypt and Sudan, NWNL is using literary and online resources to investigate the availability, quality and usage of the main stem of the Nile.]

Animals played a significant role in Ancient Egyptian life as pets, hunting partners and religious embodiments of various gods. Wildlife in the Lower Nile River Basin served as physical manifestations of deities, allowing early Egyptians to foster a closer connection to their gods.1 Their importance is evident from the hundreds of animal mummies found in tombs of the pharaohs and officials.  Hippos and crocodiles, due to their size and potential for harm to boats and laborers on the Nile River banks, were worshipped in the hopes that they would not bother humans.

william Hippopotamus (“William”), ca. 1961-1878 B.C.

 

Ancient Egyptians attempted to placate hippos by giving offerings to the goddess Taurent, depicted as a pregnant hippo since she was believed to be the goddess of fertility.2 The most famous Egyptian hippopotamus today is found at the Metropolitan Museum of Art and nicknamed “William.”  Residing in the museum since 1917, William has become an endearing mascot of the institution. He was molded in faience, a ceramic material of ground quartz, during the Middle Kingdom circa 1961-1878 BCE in Middle Egypt. His blue-glazed body is decorated with river plants indigenous to Egypt.  

Since hippos were thought to reside in the waterways along the journey to the afterlife, they were considered as an animal to be respected both in life and in death. This is evidenced by William’s three broken legs, which were purposely maimed to prevent him from harming the deceased.3 

As well as wild animals, domesticated animals, such as sheep, cattle, horses, cats and dogs doubled as objects of religious worship. Sheep were employed to trample newly-sown seed into flooded plots of land, in addition to providing their owners with wool, skins, meat and milk. Thus rams, associated with Amun the god of Thebes and Khnum the creator god, were interpreted as signs of fertility.  Cattle were similarly prized and imported as war spoils. Horses, introduced to Egypt around 1500 BCE, became symbols of wealth and prestige due to their rarity before breeding programs developed. Chariots pulled by a pair of horses were used for ceremonies, hunting, and battle.4

ramRam amulet c. 664-630 BCE

Cats became perhaps the most popular pets and sacrificial objects for the Ancient Egyptians after their domestication between 4000 and 3500 BCE. They were closely associated with the fertility and child-rearing goddess Bastet. Many families would sacrifice female cats in the hopes of becoming pregnant. It is believed that some temples kept cats on their premises strictly for the purpose of providing worshippers with an easy offering.  As well, cats were kept as pets to prevent mice, snakes and rats from ruining precious Nile River crops and food sources.4 Similarly, dogs were kept as pets, for hunting and for guard duty.5

cat amuletCat figurine, ca. 1981–1802 B.C.

Less friendly felines and other ferocious wildlife on the floodplains were given reverence for their ability to cause harm.  Offerings were made and prayers were uttered in the hopes that dangerous wild animals would not cause trouble for their human neighbors sharing the same riverbanks. Cheetahs, as well as other large cats such as lions, were hunted for their prized furs, but also captured and kept as house pets. Such highly-regarded animals were aligned with the pharaoh, who was described as fearless and brave as a lion. Nile River crocodiles were given a divine status and associated with the god Sobek so as to give them an incentive to avoid humans. Given that these crocodiles could grow up to six meters long, it was important for the Egyptian people to feel that they had some sort of defense against them.

crocodileCrocodile Statue, Late 1st century B.C. – early 1st century A.D.

Snakes also were cause for caution as the poisonous Egyptian cobra and the black-necked spitting cobra had fatal venom. These snakes became protectors of the pharaoh and were often depicted poised on his brow.7 Although some animals were worshipped because they were feared, others were simply associated with important matters of life like fertility or bravery. All of these creatures, however, were vital to the religious livelihoods of the Ancient Egyptians, as well as to the Nile River Basin’s ecosystem.

Sources

1Partridge, Robert. “Sacred Animals of Ancient Egypt.” BBC. 17 February 2011. Web.
2Partridge, Robert. “Sacred Animals of Ancient Egypt.” BBC. 17 February 2011. Web.
3“Hippopotamus (‘William’).” The Metropolitan Museum of Art. Web.
4Partridge, Robert. “Sacred Animals of Ancient Egypt.” BBC. 17 February 2011. Web.
5Douglas, Ollie. “Animals and Belief.” Pitt Rivers Museum. Web.
6Partridge, Robert. “Sacred Animals of Ancient Egypt.” BBC. 17 February 2011. Web.
7Partridge, Robert. “Sacred Animals of Ancient Egypt.” BBC. 17 February 2011. Web.

All photos used based on Public Domain, courtesy of The Metropolitan Museum of Art

World Conservation Day 2017

In honor of World Conservation Day, NWNL wants to share some of it’s favorite photographs from over the years of each of our case-study watersheds.

Trout Lake in the Columbia River Basin
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Aerial view of the largest tributary of the Lower Omo River
Ethiopia: aerial of Mago River, largest tributary of Lower Omo River

 

Canoeing on the Mississippi River
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Fisherman with his canoe on the shore of Lake Tana, source of the Nile River
Ethiopia: Lake Tana, source of the blue Nile, fisherman and canoe on the shore.

 

Wildebeests migrating toward water in the Mara Conservancy
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Raritan River at sunset
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All photos © Alison M. Jones.

The Raritan River We Know and Love

By Judy Shaw, Ph.D., Urban Environmental Planner,
Watershed Policy Coordinator, Author

The Raritan River, a long unsung treasure of New Jersey, was high on the list of special places for No Water No Life Founder and Director, Alison Jones. She lived in this NWNL case-study watershed all through her childhood and much of her adulthood. Thanks to documentary efforts by Alison and other Raritan stewards, the Raritan has risen in the esteem of many.

I had the pleasure of working with her and the many organizations that dedicate themselves to restoring and protecting this river. My recently-published book, The Raritan River: Our Landscape, Our Legacy, contains her images and those of many others who clearly love this river and this region.

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The book presents the story of key organizations and their leaders by region, so everyone can appreciate their hard work and dedication to the protection of the watershed. The beautiful banks of over 2000 miles of tributaries moved many area photographers and artists to capture its magical nature.

The book offers New Jersey people across the country to say, “Hey. This is the New Jersey we know and love. It’s more than a turnpike and heavy industry. It’s beautiful and it’s really special.”

USA: New Jersey, Mountainville, Upper Raritan River Basin, Tewksbury Township, spring blooms on hard wood tree, Saw Mill Rd.

Since I retired from Rutgers University in December as the Founding Director of the Edward J. Bloustein School’s Sustainable Raritan Initiative, I’ve had the pleasure of seeing the stewardship torch pass brightly on to the many who care as much as I did. So, get out and enjoy your natural treasures and capture the wonder in photos or paintings. You’ll be glad you did!

–Blog Post Written By Judy Shaw, NWNL Advisor

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