Stanford University researchers have created a water-purifying nanoparticle, which they are able to recover, rendering the treated water safe for human consumption.

The engineers made a nanoscavenger with a synthetic core that is ultraresponsive to magnetism, enabling the purifying substance to be easily and efficiently recovered.

The addition of nanoparticles to water is not a new approach for cleaning it from contaminating substances such as bacteria, heavy metals, or other pollutants. Current commercial technologies use iron oxide, but it typically remains in the water once it is cleaned because it is not “absolutely responsive to magnetism,” according to the researchers, who say about 20% of the material can be removed. Thus, the water is too contaminated for human consumption.

The Stanford scientists solved the challenge of removing the nanoscavenging material from the water by changing the materials used in the particle. The iron oxide core is replaced with various layers of material, including a magnetic outer layer of synthetic material.

Mingliang Zhang, a doctoral candidate in material science and engineering, explained:

The magnetic moments of the two outer layers are opposed. The direction of the magnetic force in the top layer and the bottom layer point in opposite directions, effectively canceling the magnetic properties of the material.

The core material is covered with silver, titanium dioxide, or another reactive material. This varies based on the contaminant needing to be removed from the water.

If the particles are placed near a strong permanent magnet, the magnetic layers in each particle turn into alignment. This creates a very strong attraction to the magnet that enables almost all of the nanoscavengers to be safely removed from the water.

Shan Wang, the study’s senior author and a professor of material science as well as engineering and electrical engineering, explained:

In contaminated water, nanoscavengers float around, randomly bumping into and killing bacteria or attaching themselves to the molecular pollutants they are after. When the contaminants are either stuck to the nanoscavenger or dead, the magnet is turned on and the particles vanish.

The Stanford researchers were able to clean water contaminated with E.coli bacteria in 20 minutes using a silver-impregnated nanoscavenger material. The engineered material killed 99.9% of the bacteria, and all of it was removed from the water.

The researchers say they will explore creating a single nanoscavenger able to clean a wide variety of pollutants from water. This would enable a single type of nanoparticle to be added to the water for cleaning rather than determining the contaminants in the water and having to select the proper cleaning material.

Xing Xie, a doctoral candidate in civil and environmental engineering at Stanford who worked on the project, stated:

Our hope is to one day create a ‘one-pot solution’ that tackles water afflicted by a diverse mixture of contaminants. A purification technology like that could be very useful in recycling water in developing nations and arid climates where water quality and quantity are of critical importance.

The researchers published their work in Nature Communications.

Images by Mingliang Zhang, Stanford School of Engineering.

Many challenges are associated with growing water scarcity, not the least of which is the pressing question about how restricted water availability may change the global energy industry.

The energy industry reportedly uses 23% of fresh water globally and 40% of water in the United States.

Growing demand for water in the face of ongoing drought and dwindling reserves is creating an imbalance that could ultimately affect the energy industry. Eli Hinckley writes in The Christian Science Monitor:

Fuel extraction is water intensive, especially for mining and fracking extraction — for fracked natural gas, about a gallon of water is required to extract one [MMBtu]. Electric generation from fossil fuels also requires large amounts of water. The average kWh produced from coal-fired electric generation uses a gallon of water, and while natural gas averages less water use, nuclear uses significantly more.

This intertwined dependence is commonly referred to as the water-energy nexus. As Sandia National Laboratory explains, “These two critical resources are inextricably and reciprocally linked; the production of energy requires large volumes of water while the treatment and distribution of water is equally dependent upon readily available, low-cost energy.”

The shortage of water for energy production may be ameliorated by placing a premium on water, says Hinckley. In particular, he says, pricing of water for energy, industrial, and agricultural use may be “the most politically viable place to increase costs” to slow water use.

He adds:

Historically, the prices paid for water are so low as to be of little concern to most energy businesses, even if they were to double, but given the high cost of disruption from shortages, real, significant increases in prices are a possibility in the future. Pricing cuts both ways, it will add to the cost of energy, but it would also provide certainty as to availability. There are already markets in which doubts about the absolute availability of water has limited the ability of developers to finance new power generation.

Those energy production methods with a low-water use profile — wind, solar, and conventionally produced natural gas – should eventually expand. They may ultimately “gain some advantage” relative to coal and nuclear energy, says Hinckley.

Water utilities are also contributing to the energy-water problem, notes Mark LeChevallier, director of innovation and environmental stewardship for American Water, writing in Environmental Leader:

The technology used for advanced water treatment processes is energy intensive, meaning treatment plants contribute to greenhouse gas emissions, creating an unfortunate link between improved water quality and climate change. Impaired water quality due to climate change, reuse or desalination will require the increased use of advanced water treatment processes that will increase the energy intensity of potable water systems.

There are many possible solutions for water utilities to practically reduce their environmental footprint, starting with tracking their emissions. Once the amount of greenhouse gas emissions has been quantified, a plan can be developed. Regular energy audits are certainly one metric that can be checked. An action plan for energy reduction, says LeChevallier, may include using new technologies, using energy-efficient pumps, or adding renewable energy sources such as solar, wind, and biofuels.

Image by flattop341.

Scientists from the Institute for Frontier Materials at Deakin University in Australia and France’s Pierre and Marie Curie University created nanosheets of boron nitride, also known as white graphene. These are wavy, single-atom layers of boron nitride that look like a coarse white powder.

The material reportedly “vastly outperformed sheets that did not have the pores, and commercially available chunks of boron nitride that is not made up of the tiny sheets,” noted the BBC News.

The powdery substance reportedly soaked up as much as 33 times its own weight in ethylene glycol and 29 times its own weight in engine oil. It continues to float, even when fully saturated, say the researchers. Comparatively, materials now used for cleaning oil spills collect roughly 10 times their weight in oil.

The researchers reportedly tested the nanosheets’ ability to absorb oils as well as chemical solvents and dyes commonly used in industries including the production of textiles and in tanneries and found the sheets take up the pollutants in about two minutes.

Liat Clark, writing on Wired UK, observed:

In the wake of the BP oil spill disaster in 2010, more and more novel methods for cleaning our oceans have been experimented with. Last year MIT also suggested using nanoparticles, this time developing a method for magnetically charging oil spills and turning them into ferrofluids that can be lifted out of the water. Other tactics touted have included self-propelled microsubmarines that attract oil and repel water.

Another promising substance in the war against water pollutants is graphene aerogel, developed by researchers at Zhejiang University in Hangzhou, China. Created using a freeze-drying method, the super-light material reportedly soaks up 900 times its weight in oil and is capable of absorbing 68.8 grams of organic material per second.

Ian Chen, a researcher at Deakin University and co-author of the newly published research, told AFP:

The new material and related technology will have [an] important impact on environmental protection […] and they are not expensive…

The researchers add:

The saturated boron nitride nanosheets can be readily cleaned for reuse by burning or heating in air because of their strong resistance to oxidation. This easy recyclability further demonstrates the potential of porous boron nitride nanosheets for water purification and treatment.

They published their findings in Nature Communications.

Image by polandeze (Andrew).

Their complaint? Water tastes too much like, well, water.

This is spurring the growth of a new beverage product — sugar-free water additives. When dropped into water, these fruity, liquid concoctions magically make water taste better.

“[P]owder and liquid enhancers have further cemented their positions in the beverage industry, symbolizing the new-age thirst for portable interaction and healthy products,” writes BevNet’s Max Rothman. Kraft Foods netted more than $200 million in sales in 2012 from its MiO additive. On its heels, other beverage giants launched competing products. This includes Kool-Aid, which is offering a sugar-free, squeezable liquid drink mix.

These additives target a specific group, according to The Wall Street Journal:

People who know they should drink more water but don’t always like the taste. These water-fussy drinkers are a quiet but large group — about 20% of Americans, say drinks companies and consumer research firms. Some complain water tastes metallic or chlorinated. Others say water is too boring.

As Grist explains:

This does not mean stuff like Vitamin Water, by the way. That has calories, which are almost as gross as water. It means new stuff, like a no-cal Vitamin Water spin-off called Fruitwater. And Mio, which is some tasty stuff you can squirt into water. (YUM.) And Dasani Drops. One of the selling points on the additives, according to the Wall Street Journal, is that they are ‘simpler to carry in a purse.’ OK, next time I tell you I’ve purchased something because it’s “simpler to carry in a purse” please take me out back and shoot me.

Most blind taste tests of water find no taste difference between tap and bottled waters, states World of Psychology. In a 2001 taste-testing, “Good Morning America” found 45% of its blind tasters preferred New York City tap water. A survey of 2,800 people in Yorkshire, England, found that 60% of those polled couldn’t determine the difference between the local tap water and bottled water.

Which begs the question, can we even taste water?

What does water taste like? When people taste water, they are most often reacting to its mineral taste. This includes trace substances such as calcium, magnesium, sodium, potassium, and silica. Without a “a tasting vocabulary for water” as have been developed for wine and foods such as olive oils, notes Matching Food and Wine, people cannot readily define what it is they are tasting.

But what younger consumers want to taste is their very own water-based concoction. Bill McKay, founder of Ecosentials LLC, makers of the powdered additive Vitamin Squeeze, told BevNet:

The do-it-yourself flavor is what the millennials are looking for. [...] People are customizing everything from their facebook page to their iPhone. They want their food customized and they want their beverages customized.

Image by archeoseby.

The precisely engineered silica material, created by University of South Australia School of Engineering researchers with scientists from Mawson Institute, acts as a magnet for any oil in the water. When the silica particles are spread over the water, they attract oils — motor oil, crude oil, gasoline, or kerosene — and repel water.

Professor Peter Majewski, head of school, in the university’s school of engineering, says the technology could be used in agriculture and manufacturing, but could particularly prove useful for cleaning oil spills in various bodies of water. He explains:

Oils are among the major pollutants in drinking water reservoirs. […] Contamination may occur through natural spills, cracked pipe lines and run off of oil from land-based sources. The toxic effects of these pollutants can lead to conditions including narcosis and cancer. By applying plasma polymerisation technology to develop surface engineered silica particles for oil removal, these adsorbents can remove more than 99.9 per cent of the oil from both fresh and sea waters.

When the silica particles are sprinkled onto an oil spill, the oil binds to those particles and falls to the ocean floor, he explains. This material could then be collected and removed.

The material has additional water treatment uses, according to Majewski:

The use of the silica particles in small quantities, such as in filters for farms could aid water purification in remote and rural communities. In large quantities filters for industrial outlets could help in the treatment of waste water. […] As the absorbent material is based on silica particles or simple quartz sand, it is very easy to use, store, and transport. In addition, it can be used in already existing conventional sand filters.

These types of novel materials have interested researchers in recent years. They have pursued their use for decentralized water treatment, specifically for the removal of organic contaminants such as iron and iron oxides.

The new work builds on previous work by the University of South Australia researchers. They analyzed the efficacy of coating of silica particles with an extremely thin layer of hydrocarbon-based surface active material. This previous technology, which is essentially a chemically-engineered silica in powder form, could remove substances from drinking water — including pathogens, bacteria such as Escherichia coli, and the water-borne parasite Cryptosporidium parvum — simply by stirring it into water, then filtering it. Those findings were ultimately published in the International Journal of Nanotechnology in 2008.

Although this new material is still in the early development stages, the researchers are seeking industrial partners and are planning to commercialize it through ITEK, the University of South Australia’s technology commercialization firm.

Image by the University of South Australia.

An 11-member advisory panel, which consists of hydrologists, microbiologists, and physicians, has not been able to reach consensus on its recommendations to the city council, the Arizona Daily Sun reported.

The issue was raised after a 2012 study coordinated by a Virginia Tech researcher found the city of Flagstaff’s reclaimed water system may be a breeding ground for antibiotic-resistant bacteria; however, opinions diverge as to whether the bacteria could ultimately harm residents.

Some panel members, including a former state epidemiologist, say the city should conduct a public health study to determine how many city residents have illnesses or injuries not responding to antibiotics. Such studies could be green-lighted by the city manager, provided they cost less than $50,000; otherwise, the Flagstaff City Council would need to vote on the issue.

A greater number of panel participants contend other agencies are adequately tracking chemicals in the city’s drinking water that could cause cancer and health problems; however, in response to a suggestion that the city rely on other those agencies for guidance and answers, Kevin Burke, the city manager, said residents are ultimately going to hold his feet to the fire:

Here’s the question I’m going to get from our community: ‘Why are you going to wait for someone else to determine if there’s a health effect?’ [...] I don’t think I’m going to be allowed to do nothing.

Panel members also suggested, according to the Arizona Daily Sun, “Tracking antibiotic-resistance via hospital data, comparing local hospital data to areas that don’t have reclaimed wastewater, and attempting to establish how often people here were resistant to antibiotics some 20 years ago, before reclaimed wastewater was widely used in irrigation.”

When the study was originally released, Amy Pruden, the author of the study and an associate professor of civil and environmental engineering at Virginia Tech, told the Arizona Daily Sun that the bacteria might be living and breeding in the city’s reclaimed water system, “except we cannot say for sure to what extent bacteria ‘acquired’ resistance in the purple pipes themselves, or if it was acquired upstream of the purple pipes. […] It is not necessarily a surprise that bacteria are growing […] bacteria grow everywhere and most of them are harmless.”

Pruden is now suggesting a comparison of those areas with patients hospitalized with antibiotic-resistant infections with the substances found in the Flagstaff water. She says it isn’t well known where those people who become ill actually came into contact with antibiotic-resistant bacteria.

Flagstaff’s wastewater is treated in multiple stages, which includes UV treatment and the addition of bleach before it is distributed to irrigate local golf courses, the grounds of city schools such as Northern Arizona University, and municipal parks. The city of Flagstaff was compelled to study the matter after Robin Silver, a local physician, and other residents presented their concerns. Neither the state of Arizona nor the United States Environmental Protection Agency regulates antibiotic-resistant genes in water.

The newspaper noted this latest meeting was not well attended by residents since the public notice was “not widely distributed until less than one hour before the meeting began.”

Image by 5u5.

The proposed rule change was submitted in April 2013 and covers wastewater discharges from those power plants operating as utilities.

The discharges from steam-electric power plants reportedly contribute half the toxic pollutants found in U.S. water bodies. This includes substances such as arsenic and mercury as well as lead and selenium.

Compliance could reportedly cost between $185 million and $954 million, depending upon the number and sources of waste — such as fly ash handling or emissions-control wastes — ultimately included under the rulemaking. Another of the various options could also include the stringency of treatments.

The EPA guidelines were originally established in 1974. The Steam Electric Power Generating effluent guidelines and standards were subsequently amended in 1977, 1978, 1980, and 1982.

As the agency explains, these guidelines apply to most power generating plants in the United States, whether they are fueled by either fossil fuels or are nuclear-powered:

Steam electric plants use nuclear or fossil fuels (such as coal, oil and natural gas) to heat water in boilers, which generates steam. The steam is used to drive turbines connected to electric generators. The plants generate wastewater in the form of chemical pollutants and thermal pollution (heated water) from their water treatment, power cycle, ash handling and air pollution control systems, as well as from coal piles, yard and floor drainage, and other miscellaneous wastes.

The EPA estimates there are approximately 1,200 of these facilities located throughout the United States, roughly 500 of which are coal-fired: the primary fuel source targeted by the revisions.

The limits would apply to seven types of power plant wastewater streams, according to Electric Light & Power/POWERGRID International, adding that the rules proposed have “the potential to add a financial and operational burden to an industry already in transition and facing numerous other challenges,” according to the Edison Electric Institute.

Tom Kuhn, president of the Edison Electric Institute, which represents shareholder-owned electric companies in the United States, stated:

This is a very complex rulemaking, and we’re still in the process of reviewing EPA’s proposed guidelines. […] The new guidelines come at a time when the industry is already adapting to EPA’s new Mercury and Air Toxics Standards (MATS) and other new federal and state rules. Many power plant operators are in the process of transitioning to meet new standards, including extensive and expensive retrofits at coal plants, retirement of some units, and fuel switching from coal to gas-based generation. We look forward to working with EPA to develop a final rule that achieves the goal of cleaner water, while minimizing the economic impact on the industry and its customers.

The proposed rules may also change how coal ash is regulated. It could be considered as non-hazardous municipal and solid waste, rather than a hazardous substance. “According to the EPA, its proposal curbing water discharges from power plants would prod many utilities to switch to so-called dry handling of coal ash,” notes Bloomberg, “thus curbing or eliminating the use of the ash ponds. Those ash ponds can rupture or leak.”

Bob Perciasepe, the acting EPA administrator, stated:

America’s waterways are vital to the health and well-being of our communities. […] Reducing the pollution of our waters through effective but flexible controls such as we are proposing today is a win-win for our public health and our economic vitality. We look forward to hearing from all stakeholders on the best way forward.

Michael Brune, executive director of the Sierra Club, stated that the coal plant water pollution standards are “commonsense and affordable standards” that “will save lives, prevent children from getting sick, and ensure our water is safe to drink and our fish safe to eat… We will work to ensure these standards are not weakened by baseless industry attacks.”

The EPA intends to complete the rulemaking by May 22, 2014. Any new requirements would be phased in between 2017 and 2022. Those facilities generating less than 50 MW of power would not be subject to the rules.

Image by futureatlas.com.

The Northern Arizona ski resort became the first facility in the world to create artificial snow from the city of Flagstaff’s wastewater in 2012 following a decade-long legal fight. The plan was opposed by both environmental and Native American groups concerned that the wastewater-snow could damage wildlife and human health.

Arizona Snowbowl, which opened for business in 1938, is located 14 miles from Flagstaff and has 777 skiable acres. The addition of artificial snow was expected to add as much as $35 million to the local economy in winter months.

The area is considered sacred by 13 Indian tribes, including the Navajo and Hopi whose representatives have continually objected, stating the wastewater would desecrate the land. In 2005, Joe Shirley Jr., president of the Navajo Nation, told High Country News, “To Native Americans, desecrating the San Francisco Peaks with wastewater is like flushing the Koran down the toilet.”

“This opens the door for the tribe to file a new case challenging the city’s 2002 decision to sell reclaimed wastewater to the ski area, on assertions that the water sale works against the public’s interests,” notes the Arizona Daily Sun. The newspaper also stated the tribe’s arguments centered on procedural questions; however:

The Appeals Court ruled that the tribe can raise questions about whether making snow causes a public nuisance — or something that ‘interferes with the comfortable enjoyment of life or property by an entire community or neighborhood or by a considerable number of persons,’ in the eyes of the law.

“The Court of Appeals ruling is significant because it suggests that courts haven’t yet considered the effects of the snowmaking on the environment or the public interest,” noted Indian Country Today Media Network.

The court did find the 2011 lawsuit against the city of Flagstaff was filed too early since snowmaking started in December 2012. It also stated that the action was presenting new arguments regarding the matter, namely whether selling reclaimed water to the resort was in the public’s best interest. Previous lawsuits centered on issues including whether snowmaking would harm Native American religious ceremonies and possible environmental impacts on the watershed.

LeRoy Shingoitewa, chair of the Hopi tribe, told the Arizona Daily Sun:

The Hopi Tribe, as well as many others, has always maintained that snowmaking with reclaimed wastewater on the San Francisco Peaks is simply wrong. Using wastewater harms the use and enjoyment of these areas and degrades the pristine nature of the Kachina Peaks Wilderness Area. […] We look forward to presenting our environmental and public health evidence to the court.

The tribe may now refile its claim in Coconino County Superior Court.

Image by fredcamino (Frederick Dennstedt).

Nubian announces strategic partnership with Nirosoft

Nubian Water Systems and Israel-based Nirosoft announce a partnership that will enable them to provide complete end-to-end water solutions in Australia

Australia, Sydney 7th May: Nubian Water Systems, Australia’s leading provider of sustainable water solutions to the urban environment, today announces its strategic partnership with Nirosoft, an RWL Water Group  company and a global provider of water treatment solutions for the industrial, manufacturing, municipal, power and resources sectors.

This partnership is part of Nubian’s strategy to build a facility-centric, end-to-end water solutions company in Australia that will drive water balance and reduce Australia’s water footprint.

Barry Porter, CEO Nubian Water Systems comments on the partnership, “Nubian is now the only company in Australia that can claim to provide total water solutions. We can now take water from its source, optimise its value through recycling, and see it through to its environmentally sustainable discharge.

Nirosoft is a leader in providing membrane-based water treatment solutions and combining their expertise with Nubian’s leadership in recycling and disinfection will allow us to offer the market a truly unique proposition.”

Owned by The RWL Water Group, a fully integrated holding company founded by Ronald S. Lauder, Nirosoft specialises in the design, manufacturing and operation of advanced water treatment systems. Nirosoft’s state-of-the-art membrane technology is also used to create ultra-pure water, essential to the manufacturing industry, especially in the food & beverage, electrical and pharmaceutical sectors where ultra-pure water is essential in the creation of safe products and consumables.

CEO Nirosoft, Avi Bonibay comments, “We are in the business of providing advanced water treatment solutions wherever they are needed.  Nirosoft is focused on creating a global water business that will meet the growing need for clean water.

We feel the best way to bring our solutions to the Australian market is to partner with a local company that has the same ideals and objectives as Nirosoft. It is clear to us that, not only is Nubian a leader in providing innovative solutions to the Australian market, the company is also committed to providing water wherever it is needed.”

Gary Zamel, Nubian’s Executive Chairman comments, “Ronald Lauder and I both recognize that there is an urgent need for sustainable water solutions globally and we see an opportunity that managing urban water requires. Nirosoft has a deep and strong understanding of Australia’s water needs and we have the expertise to penetrate the Australian market.

This partnership between Nirosoft and Nubian Water Systems strengthens economic ties between Israel and Australia. We are glad to work together in protecting the world’s most precious resource — water.  Nubian appreciates the introduction to Nirosoft through an initiative provided by the Australia-Israel Chamber of Commerce.  The initiative is designed to improve trade links between Israeli and Australian companies.”

Nirosoft has thousands of systems implemented globally including 30 systems here in Australia. Notably, Australia’s power stations in Cape Preston, the Australian Air Force and the Australian Antarctic Station use Nirosoft technologies.

“When organizations with water-intensive applications go to suppliers for complete facility solutions, they find that companies usually specialize in only one technology whereas the key differentiator with Nubian is that we provide an end-to-end approach. We can now say to our customers ‘come to Nubian and tell us what your objectives and challenges are’, whether it’s excess unusable water, not enough water, need for ultra-pure water for manufacturing or green stars for your building – with RWL Water Nirosoft, we can do it,” says Barry Porter.

ENDS

For more information visit:
www.nubian.com.au
www.nirosoft.com
www.RWLwater.com

For any further media information or an interview, contact:    
Boleyn Iles, Taurus Marketing
Phone: +61 2 9415 4528
Email: boleyn@taurusmarketing.com.au

About Nubian
Nubian Water Systems is an Australian-owned company that develops and markets end-to-end solutions for water-intensive applications across both domestic and commercial markets in the urban environment. Nubian is committed to helping homes, offices and industrial facilities improve their water balance and move towards the objective of achieving net zero water. The business has developed and patented world-leading technology and integrates this with best of breed technology from around the world. Headquartered in Sydney, Australia and with offices in Melbourne and Perth, Nubian’s mission is to lead the way in the protection of and management of the world’s water supplies.

About Nirosoft
Nirosoft, a member of the RWL Water Group, creates cost–effective, custom solutions for challenging water and wastewater treatment projects anywhere in the world. With its focus on meeting the unique requirements and site-specific conditions of industrial, municipal, non-government and military customers, Nirosoft uses advanced technologies to solve water-related problems quickly. Nirosoft provides a range of solutions, including desalination, demineralization, effluent reclamation, mobile water purification and industrial wastewater treatment systems to all types of environments — from densely populated areas to remote communities as well as complex industrial applications. Founded in Israel, Nirosoft has operations throughout Africa, Asia, Australia, Europe and South America.

www.nirosoft.com

About RWL Water Group
RWL Water is a water, wastewater and waste-to-energy systems integrator.   Founded by Ronald S. Lauder, the RWL Water Group is a rapidly growing global water solutions provider that will meet the world’s increasing need for clean water through the utilization of advanced water purification and recycling technologies.

The company designs plants for clients on all seven continents to help industrial and municipal clients treat their complex water and wastewater effluents in affordable, energy efficient ways. With more than 4,000 sites installed in over 70 countries around the world, RWL Water has a reputation for superb engineering and fast deployment – all at an affordable price.

The company’s core operations are strategically located in North America, the Middle East and Europe to provide rapid response through its network of sales, service, technical and engineering professionals worldwide.

For more information on RWL Water Group, please visit www.RWLwater.com.

The problem exists in several mining sites in that nation as well as worldwide. University researchers say the problem is “significant” throughout the world, “with thousands of kilometres of streams and rivers severely affected each year.”

The development of an environmentally friendly treatment system able to remove acid and metals from the mining effluent is being investigated by doctoral candidate Benjamin Uster, who explained:

Polluted mining water impacts aquatic systems downstream from a mining site. Streams affected by acid mine drainage typically support little if any living organisms and are unsuitable for recreational water activities.

The problem is caused when rainfall flushes metals from mining sites. The toxic runoff is extremely acidic. When it reaches waterways, these also become acidic.

Typically, quarried limestone — a form of calcium carbonate — reacts with the acidic water and raises the water’s pH level, the researchers explained to the Marlborough Express. The resulting increase in pH causes any dissolved metals in the water to sink, naturally removing them from the water.

The University of Canterbury has been investigating the use of mussel shells, which are another form of calcium carbonate, since 2005. Uster’s work is the second project to investigate the material. He explains:

I am conducting several lab-scale experiments using waste mussel shells that neutralize the acidity and remove the metals from the mining wastewater. I am also using other waste products including compost and wood bark mulch that feed the bacteria responsible for the treatment. No synthetic products or any chemical re-agents are used in this treatment system so it is a relatively sustainable strategy.

Mussels are an obvious material for researchers to explore since the shellfish has been farmed commercially in New Zealand since 1969. The industry exploded in the 1980s. There are now about 645 mussel farms in the nation growing the New Zealand Greenshell Mussel or Perna canaliculus.

Exports of mussels in 2011 totaled NZ$218 million, making it the number two seafood export after rock lobster. By the third quarter of 2012, mussel exports fell 12%, behind rock lobster and hoki.

The researchers estimate that waste mussel shells could be more efficient for treatment as well as less expensive than limestone. Uster says he should be able to confirm this by year’s end.

The research is being funded by CRL Energy Ltd and by the University of Lausanne, Switzerland. Uster is scheduled to present his research to the Australasian Institute of Mining and Metallurgy in August.

Image courtesy University of Canterbury.