Paper Water Filter

Each page in the “drinkable book” is printed with instructions in local languages. (Brian Gartside/Courtesy of pAge Drinking Paper)

Imagine a book that has pages you can tear out and use to turn raw sewage into drinking water. Each page is implanted with silver or copper nanoparticles that kill bacteria when water passes through them. And each page is printed with a message in your local language: “The water in your village may contain deadly diseases. But each page of this book is a paper water filter that will make it safe to drink.”

That’s exactly what one postdoctoral researcher at Carnegie Mellon University says she’s created. She calls it the “drinkable book.”

“I originally starting working on it to help the environment — by using greener chemistry, and it’s evolved to have the noble goal of helping others,” Theresa Dankovich, who has been working on the product over the past several years, told The Washington Post in an e-mail.

The new water filtration system has been shown to eliminate 99 percent of bacteria in water during its first field trials at 25 contaminated water sources in South Africa, Ghana, Kenya, Haiti and Bangladesh, according to the researchers. The researchers, working with charities WATERisLIFE and iDE-Bangladesh, pulled pages from the book, put them into a holder and poured water from rivers and streams on top, straining away the bacteria. The findings were presented earlier this week at the 250th annual American Chemical Society conference in Boston.

“In Africa, we wanted to see if the filters would work on ‘real water,’ not water purposely contaminated in the lab,” Dankovich told the American Chemical Society. “One day, while we were filtering lightly contaminated water from an irrigation canal, nearby workers directed us to a ditch next to an elementary school where raw sewage had been dumped. We found millions of bacteria; it was a challenging sample.

“But even with highly contaminated water sources like that one, we can achieve 99.9 percent purity with our silver- and copper-nanoparticle paper, bringing bacteria levels comparable to those of U.S. drinking water.”

The pages are put into a holding device that allows water to pass through. (Brian Gartside/Courtesy of pAge Drinking Paper)

How does it work?

Dankovich said the microbes are killed when they absorb the silver or copper ions from the nanoparticles in the paper. “Only a few milligrams of silver are needed to be highly antibacterial,” she told The Post. Each filter can be used to purify 100 liters of liquid, meaning each page could last for weeks and each book could last for about a year, according to the researchers.

Some metal particles do seep through the paper, Dankovich said, but the amount is still “well below” the limits set by the Environmental Protection Agency and World Health Organization.

Paper Water Filter

Silver or copper ions from the nanopartricles in the paper kill bacteria in the water. (Brian Gartside/Courtesy of pAge Drinking Paper)

Kyle Doudrick, who studies sustainable water treatment at Notre Dame’s College of Engineering, told BBC News that although the science is important, the key is making sure people understand how to use the filters and when to replace them.

It’s also unclear whether the nanoparticles would kill other disease-causing microorganisms, including viruses.

“Overall, out of all the technologies that are available — ceramic filters, UV sterilization and so on — this is a promising one because it’s cheap and it’s a catchy idea that people can get hold of and understand,” Doudrick said.

Dankovich came up with the idea while working at McGill University in Montreal and developed it later at the University of Virginia.

The book is still in the development phase and will require many more laboratory tests and field trials over the next year, Dankovich said, but within the next couple years, Dankovich, working with students from Carnegie Mellon, hopes to have the product on the market. She said her goal is to provide each filter for less than 10 cents a piece.

“I hope that these filters will one day help improve the health of millions of people around the world,” she said.

Source:Washington Post August 19, 2015 

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“Membranes are selectively permeable barriers that can provide a filter for a range of processes, from removing salt from sea water in desalination plants, to filtering the blood of kidney patients in dialysis machines. Filtration processes using membranes could potentially reduce energy consumption compared to other separation methods.




The membrane is very thin, yet extremely strong

However, many industries use evaporation and distillation techniques rather than membranes, because membranes can be costly to scale up and they are not resistant to the organic solvents used in many industrial refining and chemical processes.

Now, researchers from Imperial College London have developed a prototype crumpled membrane that has the potential to be used widely across industry. The prototype is extremely thin – it would take a stack of ten thousand membranes to match the diameter of a human hair – making it very permeable. It is also strong, and is able to filter organic liquids at pressures of around 50 bar, which is the equivalent to the pressure at around 500 metres below the ocean’s surface. The membrane is durable and resistant in a range of organic solvents.

In a study detailed in the journal Science, the team created a membrane with nanoscale crumples and established that this provides an increased surface area for filtering substances that remains strong and does not buckle, even under extreme pressures. The prototype is 80 millimetres in diameter, but the team is confident that it can be scaled up to industrial areas.

Ultimately, the researchers believe that their prototype membrane could be used to improve or completely replace industrial processes that process organic solvents, which currently rely on evaporation and distillation techniques. Approximately 30 per cent of the world’s energy is currently used by industry, with a substantial fraction of that being used in evaporation and distillation processes. These industries could potentially make major energy savings if they used the membranes, with consequent reductions in carbon dioxide emissions.

Professor Andrew Livingston, co-author of the study from the Department of Chemical Engineering at Imperial College London, said: “Membranes are currently used for a range of important tasks such as making water drinkable and life-saving kidney filtering. The drawback has been that industry hasn’t been able to use membranes in organic liquid systems more widely because they’ve had cost and design limitations. Our research suggests that we can overcome these challenges, which could make these membranes useful for industries ranging from pharmaceutical companies to oil refining. The energy and environmental benefits could be massive.”

Dr Santanu Karan, co-author also from the Department of Chemical Engineering at Imperial College London, added: “I am really excited about this research breakthrough. We now want to work even more closely with industry to further refine our membranes so that they can meet their needs. We hope our work will lead to new collaborations and ultimately, improvements in the way industries use separation processes.”

To test the effectiveness of the membrane in the lab, they team mixed together a solution containing a solvent, alcohol, and dyed molecules of different colours and sizes. They then made the solution percolate through the membrane at high pressures, using a device called a dead-end cell, to see if they could filter out everything apart from the alcohol. The team observed the process using an absorption spectroscopy device, which uses light at different wavelengths to determine what molecules are passing through the membrane. They determined that the membrane was completely effective, with only the alcohol passing through.

The researchers then compared the crumpled membrane to a conventional membrane, carrying out the same experiment. Their aim was to determine how fast their membrane could purify and concentrate the solution compared to the conventional model. They found that the crumpled membrane could separate substances 400 times faster than the conventional membrane.

The team is now planning to further develop and optimise the membrane technology so that it can be scaled up for use in industries such as pharmaceuticals, manufacturing and oil refining.

The research was funded by the Engineering and Physical Sciences Research Council (EPSRC) and the BP International Centre for Advanced Materials.”


Written by Colin Smith 


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We have been learning so much reading all about compressed air energy storage online at We sampled some of our favorite questions and answers from their FAQ page.

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Why do we need energy storage?

The primary benefits are:

Risk of Power Outages:  Today’s electricity grid is increasingly vulnerable to threats from nature, terrorists, and accidents.  Millions of American families and businesses are victimized by outages (both sustained and monentary) each year.  Power outages cost as much as $130 billion annually, while hitting the job-creating commercial and industrial sectors the hardest.

Saving Consumers Money:  Sixty million Americans in thirteen states plus Washington, DC are saving money because energy storage systems are providing frequency regulation in PJM territory (the power transmission operator in the mid-Atlantic region).  PJM has projected that a 10-20% reduction in its frequency regulation capacity procurement could result in $25 million to $50 million savings to consumers.  Energy storage can also let customers avoid premium pricing that utilities charge during times of peak demand.  That’s like getting a cheap airline flight on Thanksgiving or a rush-hour subway pass at an off-peakprice.

Clean Energy Integration and Energy Independence: Energy storage supports the integration of renewable energy generation.  Energy storage can also help cut emissions as it takes more of the load off fossil-fuel generation.  Peaking generation is one of the most costly and wasteful aspects of the grid, so making existing generation go further and avoiding capital and resource-intensive new facilities would make a significant contribution to our environmental priorities.  By supporting an all-of-the-above energy strategy, storage will also help accelerate our drive to energy independence.

Economy and Jobs: In addition to reducing economic losses from major and minor annual outages, experts say that energy storage will be a critical technology in the electricity grids of the future.  They also predict that the long term-health of the U.S. economy, and tens of thousands of future U.S. jobs, depend in no small part on the ability of U.S. companies to at least remain competitive, if not to become leaders, in this critical technology.

Compressors use off-peak electricity to fill the cavern with compressed air. For peak demand, the compressed air is withdrawn from the cavern and used to power a wind turbine. Credit: Ridge Energy Storage & Grid Services LP Read more at:

Compressors use off-peak electricity to fill the cavern with compressed air. For peak demand, the compressed air is withdrawn from the cavern and used to power a wind turbine. Credit: Ridge Energy Storage & Grid Services LP
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Is energy storage clean?

Yes. Energy storage has no direct emissions. It requires no pipelines. Its systems typically require a minimal footprint.  It recycles electricity.  But energy storage will also help cut emissions as it takes more of the load off traditional generation.

How big is the energy storage market?

Energy storage systems currently make up approximately 2% of U.S. generation capacity.  That percentage is growing significantly, especially with the advent of more renewable energy.  Pumped hydroelectric power has played an important part of our electricity grid since the 1930s.  Yet today, electricity from wind, solar and other ‘intermittant’ sources have created urgent needs for additional energy storage.
World-wide demand for grid-scale energy storage is estimated to reach over 185.4 gigawatt-hours (GWh) by 2017 – which is approximately the amount of electricity New York City consumes in 17 days.  That represents a $113.5 billion incremental revenue opportunity for an industry that currently generates sales of $50-60 billion a year.

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Advanced-adiabatic compressed air energy storage (AA-CAES) is an evolution of traditional CAES, designed to deliver higher efficiencies via a zero-carbon process. Operation is similar to traditional CAES in that energy is stored by compressing air with turbomachinery and storing in an underground cavern. The difference lies in the treatment of the heat of compression.

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