Atmospheric Water Harvester Takes out $1.5m XPrize

By Nick Lavars | October 20th, 2018

Skysource/Skywater Alliance develops deployable machines that can harvest freshwater from the air
(Credit: Skysource/Skywater Alliance)

Two years ago, XPrize extended its list of pioneering technology competitions with a new contest aimed at the problem of global water security. After revealing the five finalists earlier in the year, the foundation has today announced the grand prize winner, which outshone almost 100 competitors with its superior ability to harvest fresh water from thin air.

The Water Abundance XPrize drew 98 competing teams from 25 countries, who were asked to develop and demonstrate technologies capable of harvesting 2,000 L (528 gal) of water from the atmosphere each day. They needed to be powered entirely by renewable energy, and produce water at a cost of no more than two cents per liter (0.26 gal).

Over the month of September, two finalists were made to fully demonstrate their devices satisfying these requirements, with LA-based Skysource/Skywater Alliance coming up trumps. Its range of deployable machines pull moisture from the air, condense it and then filter it into fresh water, with outputs ranging from 30 gal (113 L) to 300 gal (1,135 L) per day.

Skysource/Skywater Alliance claims its device harvests atmospheric water more efficiently than any other method
(Credit: Skysource/Skywater Alliance)

The company's website states that it harvests atmospheric water more efficiently than any other method, and we guess it now has the accolades to back up its claims, along with US$1.5 million in prize money.

Coming in second place was Hawaii's JMCC WING, whose solution combines a high torque wind energy system with an atmospheric water harvester as a way of keeping energy requirements, and thereby costs per liter, to a minimum. JMCC WING has received $150,000 for its efforts.

JMCC WING's solution combines a high torque wind energy system with an atmospheric water harvester
(Credit: JMCC WING)

Story Source: https://newatlas.com/xprize-water-abundance-winner/56860/

Newly Discovered Bacterium Rids Problematic Pair of Toxic Groundwater Contaminants

Date: October 9, 2018
Source: New Jersey Institute of Technology
Summary: Researchers have detailed the discovery of the first bacterium known capable of simultaneously degrading the pair of chemical contaminants -- 1,4-Dioxane and 1,1-DCE.

Image of DD4 cells.
Credit: NJIT, Mengyan Li

Known as a chemical manufacturing by-product of many cosmetics and home cleaning products, the industrial solvent 1,4-Dioxane is now considered by the Environmental Protection Agency to be an "emerging contaminant" and "likely human carcinogen" that can be found at thousands of groundwater sites nationally -- potentially representing a multi-billion dollar environmental remediation challenge.

However, it is the contaminant's frequent co-existence with another toxic chemical -- 1,1-Dichloroethylene (1,1-DCE) -- that has been found to aid in 1,4-dioxane's resistance to certain remediation strategies, including degradation by naturally-occurring microbes.

Now, New Jersey Institute of Technology (NJIT) researchers have detailed the discovery of the first bacterium known capable of simultaneously degrading the pair of chemical contaminants -- 1,4-Dioxane and 1,1-DCE. The study, published in Environmental Science & Technology Letters, also showcases the efficiency of the microbe, called Azoarcus sp. DD4 (DD4), in reducing 1,4-dioxane and 1,1-DCE levels in co-contaminated groundwater samples.

"Nationwide, researchers have found that more than 80% of the groundwater sites contaminated with 1,4-dioxane also contain 1,1-DCE," said Mengyan Li, assistant professor of chemistry and environmental science at NJIT. "This pair of chemicals are toxic and costly to remove from the environment because the pair have very different properties that typically require separate treatment solutions. Biodegradation by DD4 is the first biological method we have found for treating both compounds concurrently, and it is also environmentally-friendly and cost-efficient."

Li's research team initially discovered the DD4 microbe from activated sludge samples collected from a municipal wastewater treatment facility. In the lab, Li's team was able to isolate and analyze DD4's ability to degrade 1,4-dioxane and 1,1-DCE simultaneously in contaminated groundwater samples over a two-week period.

Applying the microbe to the field samples, Li's team observed that concentration of 1,4-dioxane was degraded from 10 parts-per-million (10 ppm) -- or 3,000 times the limit of the EPA's guidance level of 0.35 parts-per-billion (0.35 ppb) -- to under 0.38 ppb. The lab also found 1,1-DCE concentration levels reduced from over 3 ppm to below 0.02 ppm.

Notably, DD4 displayed resistance to cellular toxicity produced by the metabolites of 1,1-DCE, which typically inhibit the ability of other bacteria capable of degrading 1,4-dioxane. Li's team observed that although DD4 was partially inhibited in its ability to degrade 1,4-dioxane when excessive amounts of 1,1-DCE were artificially spiked in the water samples, 1,4-dioxane degradation capability immediately recovered once the microbe had depleted 1,1-DCE.

"Overall, we were impressed by the performance of DD4," said Li. "We did not add nutrients like ammonia for the microbe to feed on, or other facilitators that might enhance the bacterium's activity. This demonstrated to us the potential of this bacterium for future use in the field."

In an analysis of the genetic makeup of DD4, Li's lab identified a potentially key gene related to the microbe's chemical degradation activity. Li says that the gene encodes for an enzyme, called soluble di-iron monooxygenase (SDIMO), with versatile capabilities of breaking down chemical pollutants. "We want to characterize it (this enzyme) further to see if we can better learn the mechanism underlying how DD4 degrades these contaminants." said Li.

Along with DD4's 1,1-DCE-resistance and ability to degrade the co-contaminants concurrently, Li says the bacterium possesses several other key traits that make it conducive as a potential bioremediation solution at contaminated groundwater sites -- such as its ability to disperse freely through water to remediate larger areas of contamination, rather than aggregating like other bacterial treatments. The microbe can also be cultured rapidly and can sustain for extended periods with limited nutrient source.

"We tested the bacterium in normal refrigerated temperature over three days and its viability remained above 80%," said Li. "After a week, half were still alive. This makes it even more desirable because it would be able to survive the delivery time from the lab to contaminated sites."

Li's lab is now conducting further tests of the bacterium in the lab to better understand how DD4 might perform at contaminated water sites. With feasibility tests already underway, Li says his team could begin field demonstrations of DD4 as a water treatment solution for 1,4-dioxane and 1,1-DCE contamination sites as early as next year.

"Ideally, we may inject the bacteria into the center of a contamination zone, or try growing them on the surface of bio-barriers that help stop spread of contamination," said Li. "First, we'd like to do more tests and possibly develop a gene marker that helps us assess the bacteria's performance. Then, we would like to move into the field."

Story Source:
New Jersey Institute of Technology. "Newly discovered bacterium rids problematic pair of toxic groundwater contaminants." ScienceDaily. ScienceDaily, 9 October 2018. https://www.sciencedaily.com/releases/2018/10/181009115019.htm

Rethinking Ketchup Packets: New Approach to Slippery Packaging Aims to Cut Food Waste

Benefits Also Include Consumer Safety and Comfort

Date: August 3, 2018
Source: Virginia Tech
Summary: New research aims to cut down on waste -- and consumer frustration -- with a novel approach to creating super slippery industrial packaging. The study establishes a method for wicking chemically compatible vegetable oils into the surfaces of common extruded plastics, like those used for ketchup packets and other condiments.

Virginia Tech doctoral student Ranit Mukherjee observes a dollop of ketchup as it moves on a super slippery plastic film. Mukherjee is the lead author on a study that yielded a novel approach to creating super slippery industrial packaging.
Credit: Virginia Tech

Almost everyone who eats fast food is familiar with the frustration of trying to squeeze every last drop of ketchup out of the small packets that accompany french fries.

What most consumers don't realize, however, is that food left behind in plastic packaging is not simply a nuisance. It also contributes to the millions of pounds of perfectly edible food that Americans throw out every year. These small, incremental amounts of sticky foods like condiments, dairy products, beverages, and some meat products that remain trapped in their packaging can add up to big numbers over time, even for a single household.

New research from Virginia Tech aims to cut down on that waste -- and consumer frustration -- with a novel approach to creating super slippery industrial packaging.

The study, which was published in Scientific Reports and has yielded a provisional patent, establishes a method for wicking chemically compatible vegetable oils into the surfaces of common extruded plastics.

Not only will the technique help sticky foods release from their packaging much more easily, but for the first time, it can also be applied to inexpensive and readily available plastics such as polyethylene and polypropylene.

These hydrocarbon-based polymers make up 55 percent of the total demand for plastics in the world today, meaning potential applications for the research stretch far beyond just ketchup packets. They're also among the easiest plastics to recycle.

"Previous SLIPS, or slippery liquid-infused porous surfaces, have been made using silicon- or fluorine-based polymers, which are very expensive," said Ranit Mukherjee, a doctoral student in the Department of Biomedical Engineering and Mechanics within the College of Engineering and the study's lead author. "But we can make our SLIPS out of these hydrocarbon-based polymers, which are widely applicable to everyday packaged products."

First created by Harvard University researchers in 2011, SLIPS are porous surfaces or absorbent polymers that can hold a chemically compatible oil within their surfaces via the process of wicking. These surfaces are not only very slippery, but they're also self-cleaning, self-healing, and more durable than traditional superhydrophobic surfaces.

In order for SLIPS to hold these oils, the surfaces must have some sort of nano- or micro-roughness, which keeps the oil in place by way of surface tension. This roughness can be achieved two ways: the surface material is roughened with a type of applied coating, or the surface material consists of an absorbent polymer. In the latter case, the molecular structure of the material itself exhibits the necessary nano-roughness.

Both techniques have recently gained traction with startups and in limited commercial applications. But current SLIPS that use silicone- and fluorine-based absorbent polymers aren't attractive for industrial applications due to their high cost, while the method of adding roughness to surfaces can likewise be an expensive and complicated process.

"We had two big breakthroughs," said Jonathan Boreyko, an assistant professor of biomedical engineering and mechanics and a study co-author. "Not only are we using these hydrocarbon-based polymers that are cheap and in high demand, but we don't have to add any surface roughness, either. We actually found oils that are naturally compatible with the plastics, so these oils are wicking into the plastic itself, not into a roughness we have to apply."

In addition to minimizing food waste, Boreyko cited other benefits to the improved design, including consumer safety and comfort.

"We're not adding any mystery nanoparticles to the surfaces of these plastics that could make people uncomfortable," he said. "We use natural oils like cottonseed oil, so there are no health concerns whatsoever. There's no fancy recipe required."

While the method has obvious implications for industrial food and product packaging, it could also find widespread use in the pharmaceutical industry. The oil-infused plastic surfaces are naturally anti-fouling, meaning they resist bacterial adhesion and growth.

Although the technique may sound very high-tech, it actually finds its roots in the pitcher plant, a carnivorous plant that entices insects to the edge of a deep cavity filled with nectar and digestive enzymes. The leaves that form the plant's eponymous shape have a slippery ring, created by a secreted liquid, around the periphery of the cavity. When the insects move onto this slippery ring, they slide into the belly of the plants.

"This slippery periphery on the pitcher plant actually inspired our SLIPS product," said Mukherjee.

The pitcher plant's innovation -- which engineers are now copying with great success -- is the combination of a lubricant with some type of surface roughness that can lock that lubricant into place very stably with surface tension.

"We're taking that same concept, but the roughness we're using is just a common attribute of everyday plastics, which means maximal practicality," said Boreyko.

This research was funded through an industrial collaboration with Bemis North America. Additional co-authors of the study include Mohammad Habibi, a Virginia Tech mechanical engineering graduate student; Ziad Rashed, an engineering science and mechanics 2018 graduate from Virginia Tech's undergraduate program; and Otacilio Berbert and Xiangke Shi, both of Bemis North America.



Reprinted From:
Virginia Tech. "Rethinking ketchup packets: New approach to slippery packaging aims to cut food waste: Benefits also include consumer safety and comfort." ScienceDaily. ScienceDaily, 3 August 2018. https://www.sciencedaily.com/releases/2018/08/180803103302.htm

Small Amounts of Pharmaceuticals Found in North Central Pa. Rural Well Water

Date: July 31, 2018
Source: Penn State
Summary: Drinking water from wells in rural north central Pennsylvania had low levels of pharmaceuticals, according to a new study.

While septic tanks are generally installed downgradient of wells, contaminant from septic systems can impact well water quality, especially if the septic systems are not maintained or were improperly installed. Pharmaceuticals that are incompletely degraded in septic tanks and leaching fields can travel with wastewater and infiltrate groundwater.
Credit: Heather Gall Research Group / Penn State

Drinking water from wells in rural north central Pennsylvania had low levels of pharmaceuticals, according to a study led by Penn State researchers.

Partnering with volunteers in the University's Pennsylvania Master Well Owner Network, researchers tested water samples from 26 households with private wells in nine counties in the basin of the West Branch of the Susquehanna River. All samples were analyzed for seven over-the-counter and prescription pharmaceuticals: acetaminophen, ampicillin, caffeine, naproxen, ofloxacin, sulfamethoxazole and trimethoprim.

At least one compound was detected at all sites. Ofloxacin and sulfamethoxazole -- antibiotics prescribed for the treatment of a number of bacterial infections -- were the most frequently detected compounds. Caffeine was detected in approximately half of the samples, while naproxen -- an anti-inflammatory drug used for the management of pain, fever and inflammation -- was not detected in any samples.

"It is now widely known that over-the-counter and prescription medications are routinely present at detectable levels in surface and groundwater bodies," said Heather Gall, assistant professor of agricultural and biological engineering, whose research group in the Penn State's College of Agricultural Sciences conducted the study. "The presence of these emerging contaminants has raised both environmental and public health concerns, particularly when these water supplies are used as drinking water sources."

The good news, Gall pointed out, is that the concentrations of the pharmaceuticals in groundwater sampled were extremely low -- at parts per billion levels. However, given that sampling with the Master Well Owner Network only occurred once, the frequency of occurrence, range of concentrations and potential health risks are not yet well understood, especially for these private groundwater supplies.

The researchers used a simple modeling approach based on the pharmaceuticals' physicochemical parameters -- degradation rates and sorption factors -- to provide insight into the differences in frequency of detection for the target pharmaceuticals, noted lead researcher Faith Kibuye, who will graduate with a doctoral degree in biorenewable systems next year.

She explained that calculations revealed that none of the concentrations observed in the groundwater wells posed any significant human health risk, with risk quotients that are well below the minimal value. However, the risk assessment does not address the potential effect of exposure to mixtures of pharmaceuticals that are likely present in water simultaneously, she said. For example, as many as six of the analyzed pharmaceuticals were detected in some groundwater samples.

"There remains a major concern that even at low concentrations, pharmaceuticals could interact together and influence the biochemical functioning of the human body, so even at very low concentrations they might have some kind of synergistic effect," Kibuye said. "We only analyzed for seven pharmaceuticals but the chances are that there may have been many more."

The findings of the research -- which Kibuye will present today (July 31) at the annual meeting of the American Association of Agricultural and Biological Engineers in Detroit -- should be of interest the world over because groundwater is a critical supply of drinking water globally.

It is estimated that half of the population accesses potable water from groundwater aquifers. In the United States, approximately 13 million households use private wells as their drinking water source, according to the U.S. Environmental Protection Agency. In Pennsylvania, approximately one-third of the residents receive their drinking water from private groundwater wells, Penn State Extension surveys show.

It is common for homeowners with private wells to also have septic tanks on their properties for treatment of their wastewater. And while septic tanks are generally installed downgradient of the well, it is possible that contaminant from septic systems can impact well-water quality, especially if the septic systems are not maintained or were improperly installed.

"While common contaminant issues include fecal coliform, E. coli and nitrate, pharmaceuticals and other compounds of emerging concern pose potential threats to well water quality," Kibuye said. "Pharmaceuticals that are incompletely degraded in septic tanks and leaching fields can therefore travel with wastewater plumes and impact groundwater, potentially making septic systems important point sources to surrounding domestic groundwater sources."

Story Source:

Penn State. "Small amounts of pharmaceuticals found in north central Pa. rural well water." ScienceDaily. ScienceDaily, 31 July 2018. https://www.sciencedaily.com/releases/2018/07/180731141630.htm

Could water-saving "shade balls" have a shady side?

By Ben Coxworth

July 17th, 2018

The shade balls getting dispersed into the LA Reservoir
(Credit: Eric Garcetti/CC 2.0)

Three years ago, the drought-stricken city of Los Angeles covered the surface of the LA Basin with 96 million shade-providing floating balls, in order to keep the water beneath from evaporating. Now, an international study suggests that the making of the plastic balls may have have used up more water than they saved.

The "shade balls" were left in place on the reservoir for approximately one and a half years, during the latter part of the 2011 - 2017 California drought. According to the study, they kept an estimated 1.7 million cubic meters (60 million cubic feet) of water from evaporating. Unfortunately, however, it is also estimated that production of the balls used up 2.9 million cubic meters of water (102 million cubic feet). This happened at locations where the oil and natural gas used to produce the plastic were refined, and where the electricity necessary for production was generated.

In order for the shade balls to save as much water as was used in manufacturing them, they would reportedly have to be left on the reservoir for at least two and a half years – and that's only if drought conditions persisted for the entire period.

Additionally, the study points out that the manufacturing process would have had other negative environmental costs, such as the generation of carbon emissions and water pollution.

"We are very good at quick technological fixes, but we often overlook the long-term and secondary impacts of our solutions," says study co-author Dr. Kaveh Madani, from Imperial College London. "This is how the engineering community has been solving problems; solving one problem somewhere and creating a new problem elsewhere … We are not suggesting that shade balls are bad and must not be used. We are just highlighting the fact that the environmental cost of shade balls must be considered together with their benefits."

The findings of the study, which also included scientists from MIT in the US and the University of Twente in the Netherlands, were recently published in the journal Nature Sustainability.

Source: Imperial College London
Story Source: https://newatlas.com/shade-balls-water-usage/55499/

Using Coal Waste to Create Sustainable Concrete

New Coal Concrete Reduces Energy Demand, Greenhouse Emissions

Date: July 12, 2018
Source: Washington State University
Summary: Researchers have created a sustainable alternative to traditional concrete using coal fly ash, a waste product of coal-based electricity generation.

Chemical engineering student Ka Fung Wong looks at the data log, which is used to gather data from sensors buried under the concrete test plot.
Credit: WSU

Washington State University researchers have created a sustainable alternative to traditional concrete using coal fly ash, a waste product of coal-based electricity generation.

The advance tackles two major environmental problems at once by making use of coal production waste and by significantly reducing the environmental impact of concrete production.

Xianming Shi, associate professor in WSU's Department of Civil and Environmental Engineering, and graduate student Gang Xu, have developed a strong, durable concrete that uses fly ash as a binder and eliminates the use of environmentally intensive cement. They report on their work in the August issue of the journal, Fuel.

Reduces Energy Demand, Greenhouse Emissions

Production of traditional concrete, which is made by combining cement with sand and gravel, contributes between five and eight percent of greenhouse gas emissions worldwide. That's because cement, the key ingredient in concrete, requires high temperatures and a tremendous amount of energy to produce.

Fly ash, the material that remains after coal dust is burned, meanwhile has become a significant waste management issue in the United States. More than 50 percent of fly ash ends up in landfills, where it can easily leach into the nearby environment.

While some researchers have used fly ash in concrete, they haven't been able to eliminate the intense heating methods that are traditionally needed to make a strong material.

"Our production method does not require heating or the use of any cement," said Xu.

Molecular Engineering

This work is also significant because the researchers are using nano-sized materials to engineer concrete at the molecular level.

"To sustainably advance the construction industry, we need to utilize the 'bottom-up' capability of nanomaterials," said Shi.

The team used graphene oxide, a recently discovered nanomaterial, to manipulate the reaction of fly ash with water and turn the activated fly ash into a strong cement-like material. The graphene oxide rearranges atoms and molecules in a solution of fly ash and chemical activators like sodium silicate and calcium oxide. The process creates a calcium-aluminate-silicate-hydrate molecule chain with strongly bonded atoms that form an inorganic polymer network more durable than (hydrated) cement.

Aids Groundwater, Mitigates Flooding

The team designed the fly ash concrete to be pervious, which means water can pass through it to replenish groundwater and to mitigate flooding potential.

Researchers have demonstrated the strength and behavior of the material in test plots on the WSU campus under a variety of load and temperature conditions. They are still conducting infiltration tests and gathering data using sensors buried under the concrete. They eventually hope to commercialize the patented technology.

"After further testing, we would like to build some structures with this concrete to serve as a proof of concept," said Xu.

The research was funded by the U.S. Department of Transportation's University Transportation Centers and the WSU Office of Commercialization.

Story Source: Washington State University. "Using coal waste to create sustainable concrete: New coal concrete reduces energy demand, greenhouse emissions." ScienceDaily. ScienceDaily, 12 July 2018. https://www.sciencedaily.com/releases/2018/07/180712100513.htm.

Wastewater Treatment Plants are Key Route into UK Rivers for Microplastics

Date: June 11, 2018
Source: University of Leeds
Summary: Water samples from UK rivers contained significantly higher concentrations of microplastics downstream from wastewater treatment plants, according to one of the first studies to determine potential sources of microplastics pollution.


Water samples from UK rivers contained significantly higher concentrations of microplastics downstream from wastewater treatment plants, according to one of the first studies to determine potential sources of microplastics pollution.

Scientists from the University of Leeds measured microplastics concentrations up and downstream of six wastewater treatment plants and found that all of the plants were linked to an increase in microplastics in the rivers -- on average up to three times higher but in one instance by a factor of 69.

Lead author Dr Paul Kay, from the School of Geography at Leeds, said: "Microplastics are one of the least studied groups of contaminants in river systems. These tiny plastic fragments and flakes may prove to be one of the biggest challenges in repairing the widespread environmental harm plastics have caused. Finding key entry points of microplastics, such as wastewater treatment plants, can provide focus points to combating their distribution.

"However, pervasive microplastics were also found in our upstream water samples. So while strengthening environmental procedures at treatment plants could be a big step in halting their spread, we cannot ignore the other ways microplastics are getting into our rivers."

Microplastics are pieces of plastic with a diameter less than five millimetres. They come from a wide range of materials including tiny plastic beads found in health and beauty products, plastic fibres from clothing and plastic flakes that break down from packaging.

In addition to exposing river ecosystems to the pollutants found in microplastics, a huge quantity continues to flow downstream and is then flushed into the ocean, posing a further threat to marine environments. Recent research has also found microplastics in fish stocks eaten by humans.

The researchers examined 28 river samples from six different field sites across Northern England. The treatment plants included in the study varied in the size of the population they served, the treatment technologies used and the river's characteristics. These variations allowed for a broader understanding of how different factors could affect how much wastewater treatment plants contribute to microplastic pollution.

In addition to treatment plants providing an entry point for microplastics found in both commercial and domestic wastewater, such as clothing and textile microfibers that shed into washing machines, wastewater treatment plants may also contribute secondary microplastics as a result of plastics caught in the treatment process breaking down further.

The study categorised the types of microplastics found, into pellets/beads, fibres and fragments/flakes. Fragment and fibres made up nearly 90% of the microplastics found in the river samples.

"By categorising the types of microplastics we can identify what aspects of our lifestyle are contributing to river pollution," said Dr Kay.

"Not that long ago microbeads in toiletries and cosmetics were the microplastics getting all the public attention. Seeing the amount of plastic microfibres from clothing and textiles polluting our rivers, we need to think seriously about the role of our synthetic fabrics in long-term environmental harm."

Story Source: University of Leeds. "Wastewater treatment plants are key route into UK rivers for microplastics." ScienceDaily. ScienceDaily, 11 June 2018. https://www.sciencedaily.com/releases/2018/06/180611133455.htm

Groundwater Pumping Can Increase Arsenic Levels in Irrigation and Drinking Water

Date: June 5, 2018
Source: Stanford University
Summary: Pumping an aquifer to the last drop squeezes out more than water. A new study finds it can also unlock dangerous arsenic from buried clays -- and reveals how sinking land can provide an early warning and measure of contamination.

For decades, intensive groundwater pumping has caused ground beneath California's San Joaquin Valley to sink, damaging infrastructure. Now research published in the journal Nature Communications suggests that as pumping makes the ground sink, it also unleashes an invisible threat to human health and food production: It allows arsenic to move into groundwater aquifers that supply drinking water for 1 million people and irrigation for crops in some of the nation's richest farmland.

The group found that satellite-derived measurements of ground sinking could predict arsenic concentrations in groundwater. This technique could be an early warning system to prevent dangerous levels of arsenic contamination in aquifers with certain characteristics worldwide.

"Arsenic in groundwater has been a problem for a really long time," said lead author Ryan Smith, a doctoral candidate in geophysics at the School of Earth, Energy & Environmental Sciences (Stanford Earth). It's naturally present in Earth's crust and a frequent concern in groundwater management because of its ubiquity and links to heart disease, diabetes, cancer and other illnesses. "But the idea that overpumping for irrigation could increase arsenic concentrations is new," Smith said.

Importantly, the group found signs that aquifers contaminated as a result of overpumping can recover if withdrawals stop. Areas that showed slower sinking compared to 15 years earlier also had lower arsenic levels. "Groundwater must have been largely turned over," said study co-author Scott Fendorf, a professor of Earth system science and a senior fellow at the Stanford Woods Institute for the Environment.

Releasing Arsenic from Clay

The research team analyzed arsenic data for hundreds of wells in two different drought periods alongside centimeter-level estimates of land subsidence, or sinking, captured by satellites. They found that when land in the San Joaquin Valley's Tulare basin sinks faster than 3 inches per year, the risk of finding hazardous arsenic levels in groundwater as much as triples.

Aquifers in the Tulare basin are made up of sand and gravel zones separated by thin layers of clay. The clay acts like a sponge, holding tight to water as well as arsenic soaked up from ancient river sediments. Unlike the sand and gravel layers, these clays contain relatively little oxygen, which creates conditions for arsenic to be in a form that dissolves easily in water.

When pumping draws too much water from the sand and gravel areas, the aquifer compresses and land sinks. "Sands and gravels that were being propped apart by water pressure are now starting to squeeze down on that sponge," Fendorf explained. Arsenic-rich water then starts to seep out and mix with water in the main aquifer.

When water pumping slows enough to put the brakes on subsidence -- and relieve the squeeze on trapped arsenic -- clean water soaking in from streams, rain and natural runoff at the surface can gradually flush the system clean.

However, study co-author Rosemary Knight, a professor of geophysics and affiliated faculty at the Woods Institute, warns against banking too much on a predictable recovery from overpumping. "How long it takes to recover is going to be highly variable and dependent upon so many factors," she said.

The researchers said overpumping in other aquifers could produce the same contamination issues seen in the San Joaquin Valley if they have three attributes: alternating layers of clay and sand; a source of arsenic; and relatively low oxygen content, which is common in aquifers located beneath thick clays.

The threat may be more widespread than once thought. Only in the last few years have scientists discovered that otherwise well-aerated aquifers considered largely immune to arsenic problems can in fact be laced with clays that have the low oxygen levels necessary for arsenic to move into most groundwater. "We're just starting to recognize that this is a danger," said Fendorf.

Satellite Insights

The revelation that remote sensing can raise an alarm before contamination threatens human health offers hope for better water monitoring. "Instead of having to drill wells and take water samples back to the lab, we have a satellite getting the data we need," said Knight.

While well data is important to validate and calibrate satellite data, she explained, on-the-ground monitoring can never match the breadth and speed of remote sensing. "You're never sampling a well frequently enough to catch that arsenic the moment it's in the well," said Knight. "So how fantastic to have this remote sensing early warning system to let people realize that they're approaching a critical point in terms of water quality."

The study builds on research led in 2013 by Laura Erban, then a doctoral student working in Vietnam's Mekong Delta. "That's where we started saying, 'Oh no,'" said Fendorf, who co-authored that paper.

As in the San Joaquin Valley, areas of the Mekong Delta where land was sinking more showed higher arsenic concentrations. "Now we have two sites in totally different geographic regions where the same mechanisms appear to be operating," said Fendorf. "That sends a trigger that we need to be thinking about managing groundwater and making sure that we're not overdrafting the aquifers."

Story Source:
Stanford University. "Groundwater pumping can increase arsenic levels in irrigation and drinking water." ScienceDaily. ScienceDaily, 5 June 2018.

Tiny Membrane Key to Safe Drinking Water

Date: February 14, 2018
Source: CSIRO Australia
Summary: Using their own specially designed form of graphene, 'Graphair' scientists have supercharged water purification, making it simpler, more effective and quicker.

Sydney's iconic harbour has played a starring role in the development of new CSIRO technology that could save lives around the world.

Using their own specially designed form of graphene, 'Graphair', CSIRO scientists have supercharged water purification, making it simpler, more effective and quicker.

The new filtering technique is so effective, water samples from Sydney Harbour were safe to drink after passing through the filter.

The breakthrough research was published today in Nature Communications.

"Almost a third of the world's population, some 2.1 billion people, don't have clean and safe drinking water," the paper's lead author, CSIRO scientist Dr Dong Han Seo said.

"As a result, millions -- mostly children -- die from diseases associated with inadequate water supply, sanitation and hygiene every year.

"In Graphair we've found a perfect filter for water purification. It can replace the complex, time consuming and multi-stage processes currently needed with a single step."

While graphene is the world's strongest material and can be just a single carbon atom thin, it is usually water repellent.

Using their Graphair process, CSIRO researchers were able to create a film with microscopic nano-channels that let water pass through, but stop pollutants.

As an added advantage Graphair is simpler, cheaper, faster and more environmentally friendly than graphene to make.

It consists of renewable soybean oil, more commonly found in vegetable oil.

Looking for a challenge, Dr Seo and his colleagues took water samples from Sydney Harbour and ran it through a commercially available water filter, coated with Graphair.

Researchers from QUT, the University of Sydney, UTS, and Victoria University then tested and analysed its water purification qualities.

The breakthrough potentially solves one of the great problems with current water filtering methods: fouling.

Over time chemical and oil based pollutants coat and impede water filters, meaning contaminants have to be removed before filtering can begin. Tests showed Graphair continued to work even when coated with pollutants.

Without Graphair, the membrane's filtration rate halved in 72 hours.

When the Graphair was added, the membrane filtered even more contaminants (99 per cent removal) faster.

"This technology can create clean drinking water, regardless of how dirty it is, in a single step," Dr Seo said.

"All that's needed is heat, our graphene, a membrane filter and a small water pump. We're hoping to commence field trials in a developing world community next year."

CSIRO is looking for industry partners to scale up the technology so it can be used to filter a home or even town's water supply.

It's also investigating other applications such as the treatment of seawater and industrial effluents.

Story Source: CSIRO Australia. "Tiny membrane key to safe drinking water." ScienceDaily. ScienceDaily, 14 February 2018. https://www.sciencedaily.com/releases/2018/02/180214181846.htm.

Pride Tops Guilt as a Motivator for Environmental Decisions

Date: February 13, 2018
Source: Princeton University, Woodrow Wilson School of Public and International Affairs
Summary: A lot of pro-environmental messages suggest that people will feel guilty if they don't make an effort to live more sustainably or takes steps to ameliorate climate change. But a recent study finds that highlighting the pride people will feel if they take such actions may be a better way to change environmental behaviors.

A lot of pro-environmental messages suggest that people will feel guilty if they don't make an effort to live more sustainably or takes steps to ameliorate climate change. But a recent study from Princeton University finds that highlighting the pride people will feel if they take such actions may be a better way to change environmental behaviors.

Elke U. Weber, a professor of psychology and public affairs at Princeton's Woodrow Wilson School of Public and International Affairs, conducted the study -- which appears in the academic journal PLOS ONE -- along with Ph.D. candidate Claudia R. Schneider (who is visiting Princeton's Department of Psychology through the Ivy League Exchange Scholar Program) and colleagues at Columbia University and the University of Massachusetts Amherst.

Past research has shown that anticipating how one will feel afterward plays a big role in decision-making -- particularly when making decisions that affect others. "In simple terms, people tend to avoid taking actions that could result in negative emotions, such as guilt and sadness, and to pursue those that will result in positive states, such as pride and joy," said Weber, who also is the Gerhard R. Andlinger Professor in Energy and the Environment.

Pro-environmental messaging sometimes emphasizes pride to spur people into action, Weber said, but it more often focuses on guilt. She and her colleagues wondered which is the better motivator in this area. To find out, they asked people from a sample of 987 diverse participants recruited through Amazon's Mechanical Turk platform to think about either the pride they would feel after taking pro-environmental actions or the guilt they would feel for not doing so, just before making a series of decisions related to the environment.

The participants were prompted to think about future pride or guilt by one of three methods. Some were given a one-sentence reminder -- which remained at the top of their computer screens as they completed a survey -- that their environmental choices might make them either proud or guilty. Others were given five environmentally friendly or unfriendly choice scenarios and asked to consider how making each choice might make them feel pride or guilt. Still others were asked to write a brief essay reflecting on their future feelings of pride or guilt over a real upcoming environmental decision. In the end, there were six groups: one for each of the three reflection methods and within each one section that considered future pride and another that reflected on future guilt.

Next, the participants were asked to make five sets of choices, each with "green" (environmentally friendly) or "brown" (environmentally unfriendly) options. In one scenario, for example, they could choose a sofa made from environmentally friendly fabric but available only in outdated styles, or they could pick a more modern style of sofa made from fabric produced with harsh chemicals. In another scenario, they could pick any or all of 14 green amenities for an apartment (such as an Energy Star-rated refrigerator), with the caveat that each one added $3 per month to the rent. A control group made the same decisions without being prompted to think about future pride or guilt.

The results revealed a clear pattern across all of the groups. "Overall," Weber said, "participants who were exposed to anticipation of pride consistently reported higher pro-environmental intentions than those exposed to anticipated guilt."

A likely explanation, she said -- one that's backed up by a great deal of past research -- is that some people react badly and get defensive when they're told they should feel guilty about something, making them less likely to follow a desired course of action. Thus, guilt-based environmental appeals run the risk of backfiring.

"Because most appeals for pro-environmental action rely on guilt to motivate their target audience, our findings suggest a rethinking of environmental and climate change messaging" to harness the power of positive emotions like pride, Weber said.

Story Source:
Princeton University, Woodrow Wilson School of Public and International Affairs. "Pride tops guilt as a motivator for environmental decisions." ScienceDaily. ScienceDaily, 13 February 2018. https://www.sciencedaily.com/releases/2018/02/180213120429.htm

A Biological Solution to Carbon Capture and Recycling?

E. coli bacteria shown to be excellent at CO₂ conversion

Date: January 8, 2018
Source: University of Dundee
Summary: Scientists have discovered that E. coli bacteria could hold the key to an efficient method of capturing and storing or recycling carbon dioxide. They have developed a process that enables the E. coli bacterium to act as a very efficient carbon capture device.

Rendering of bacteria.
Credit: © 7activestudio / Fotolia

Scientists at the University of Dundee have discovered that E. coli bacteria could hold the key to an efficient method of capturing and storing or recycling carbon dioxide.

Cutting carbon dioxide (CO₂) emissions to slow down and even reverse global warming has been posited as humankind's greatest challenge. It is a goal that is subject to considerable political and societal hurdles, but it also remains a technological challenge.

New ways of capturing and storing CO₂ will be needed. Now, normally harmless gut bacteria have been shown to have the ability to play a crucial role.

Professor Frank Sargent and colleagues at the University of Dundee's School of Life Sciences, working with local industry partners Sasol UK and Ingenza Ltd, have developed a process that enables the E. coli bacterium to act as a very efficient carbon capture device.

Professor Sargent said, "Reducing carbon dioxide emissions will require a basket of different solutions and nature offers some exciting options. Microscopic, single-celled bacteria are used to living in extreme environments and often perform chemical reactions that plants and animals cannot do.

"For example, the E. coli bacterium can grow in the complete absence of oxygen. When it does this it makes a special metal-containing enzyme, called 'FHL', which can interconvert gaseous carbon dioxide with liquid formic acid. This could provide an opportunity to capture carbon dioxide into a manageable product that is easily stored, controlled or even used to make other things. The trouble is, the normal conversion process is slow and sometime unreliable.

"What we have done is develop a process that enables the E. coli bacterium to operate as a very efficient biological carbon capture device. When the bacteria containing the FHL enzyme are placed under pressurised carbon dioxide and hydrogen gas mixtures -- up to 10 atmospheres of pressure -- then 100 per cent conversion of the carbon dioxide to formic acid is observed. The reaction happens quickly, over a few hours, and at ambient temperatures.

"This could be an important breakthrough in biotechnology. It should be possible to optimize the system still further and finally develop a 'microbial cell factory' that could be used to mop up carbon dioxide from many different types of industry.

"Not all bacteria are bad. Some might even save the planet."

Not only capturing carbon dioxide but storing or recycling it is a major issue. There are millions of tonnes of CO₂ being pumped into the atmosphere every year. For the UK alone, the net emission of CO₂ in 2015 was 404 million tonnes. There is a significant question of where can we put it all even if we capture it, with current suggestions including pumping it underground in to empty oil and gas fields.

"The E. coli solution we have found isn't only attractive as a carbon capture technology, it converts it into a liquid that is stable and comparatively easily stored," said Professor Sargent.

"Formic acid also has industrial uses, from a preservative and antibacterial agent in livestock feed, a coagulant in the production of rubber, and, in salt form, a de-icer for airport runways. It could also be potentially recycled into biological processes that produce CO₂, forming a virtuous loop."

Story Source:
University of Dundee. "A biological solution to carbon capture and recycling? E. coli bacteria shown to be excellent at CO₂ conversion." ScienceDaily. ScienceDaily, 8 January 2018. https://www.sciencedaily.com/releases/2018/01/180108101359.htm

One-Step Catalyst Turns Nitrates into Water and Air

Date: January 4, 2018
Source: Rice University
Summary: Engineers have found a catalyst the cleans toxic nitrates from drinking water by converting them into air and water.

Rice University's indium-palladium nanoparticle catalysts clean nitrates from drinking water by converting the toxic molecules into air and water.
Credit: Jeff Fitlow/Rice University

The research is available online in the American Chemical Society journal ACS Catalysis.

"Nitrates come mainly from agricultural runoff, which affects farming communities all over the world," said Rice chemical engineer Michael Wong, the lead scientist on the study. "Nitrates are both an environmental problem and health problem because they're toxic. There are ion-exchange filters that can remove them from water, but these need to be flushed every few months to reuse them, and when that happens, the flushed water just returns a concentrated dose of nitrates right back into the water supply."

Wong's lab specializes in developing nanoparticle-based catalysts, submicroscopic bits of metal that speed up chemical reactions. In 2013, his group showed that tiny gold spheres dotted with specks of palladium could break apart nitrites, the more toxic chemical cousins of nitrates.

"Nitrates are molecules that have one nitrogen atom and three oxygen atoms," Wong explained. "Nitrates turn into nitrites if they lose an oxygen, but nitrites are even more toxic than nitrates, so you don't want to stop with nitrites. Moreover, nitrates are the more prevalent problem.

"Ultimately, the best way to remove nitrates is a catalytic process that breaks them completely apart into nitrogen and oxygen, or in our case, nitrogen and water because we add a little hydrogen," he said. "More than 75 percent of Earth's atmosphere is gaseous nitrogen, so we're really turning nitrates into air and water."

Nitrates are toxic to infants and pregnant women and may also be carcinogenic. Nitrate pollution is common in agricultural communities, especially in the U.S. Corn Belt and California's Central Valley, where fertilizers are heavily used, and some studies have shown that nitrate pollution is on the rise due to changing land-use patterns.

Both nitrates and nitrites are regulated by the Environmental Protection Agency, which sets allowable limits for safe drinking water. In communities with polluted wells and lakes, that typically means pretreating drinking water with ion-exchange resins that trap and remove nitrates and nitrites without destroying them.

From their previous work, Wong's team knew that gold-palladium nanoparticles were not good catalysts for breaking apart nitrates. Co-author Kim Heck, a research scientist in Wong's lab, said a search of published scientific literature turned up another possibility: indium and palladium.

"We were able to optimize that, and we found that covering about 40 percent of a palladium sphere's surface with indium gave us our most active catalyst," Heck said. "It was about 50 percent more efficient than anything else we found in previously published studies. We could have stopped there, but we were really interested in understanding why it was better, and for that we had to explore the chemistry behind this reaction."

In collaboration with chemical engineering colleagues Jeffrey Miller of Purdue University and Lars Grabow of the University of Houston, the Rice team found that the indium speeds up the breakdown of nitrates while the palladium apparently keeps the indium from being permanently oxidized.

"Indium likes to be oxidized," Heck said. "From our in situ studies, we found that exposing the catalysts to solutions containing nitrate caused the indium to become oxidized. But when we added hydrogen-saturated water, the palladium prompted some of that oxygen to bond with the hydrogen and form water, and that resulted in the indium remaining in a reduced state where it's free to break apart more nitrates."

Wong said his team will work with industrial partners and other researchers to turn the process into a commercially viable water-treatment system.

"That's where NEWT comes in," he said. "NEWT is all about taking basic science discoveries and getting them deployed in real-world conditions. This is going to be an example within NEWT where we have the chemistry figured out, and the next step is to create a flow system to show proof of concept that the technology can be used in the field."

NEWT is a multi-institutional engineering research center based at Rice that was established by the National Science Foundation in 2015 to develop compact, mobile, off-grid water-treatment systems that can provide clean water to millions of people and make U.S. energy production more sustainable and cost-effective. NEWT is expected to leverage more than $40 million in federal and industrial support by 2025 and is focused on applications for humanitarian emergency response, rural water systems and wastewater treatment and reuse at remote sites, including both onshore and offshore drilling platforms for oil and gas exploration.

Additional study co-authors include Sujin Guo, Huifeng Qian and Zhun Zhao, all of Rice, and Sashank Kasiraju of the University of Houston. The research was funded by the National Science Foundation, the Department of Energy and the China Scholarship Council.

Source: Rice University. "One-step catalyst turns nitrates into water and air." ScienceDaily. ScienceDaily, 4 January 2018. www.sciencedaily.com/releases/2018/01/180104160819.htm