Monday, September 29, 2014

Solar Energy-Driven Process Could Revolutionize Oil Sands Tailings Reclamation

Source: University of Alberta
Summary: A civil engineering research team has developed a new way to clean oil sands process affected water and reclaim tailings ponds in Alberta's oil sands industry. Using sunlight as a renewable energy source instead of UV lamps, and adding chlorine to the tailings, oil sands process affected water is decontaminated and detoxified -- immediately.

Civil engineering graduate student Zengquan Shu simulates the solar UV/chlorine treatment process. Laboratory-scale tests found the solar UV/chlorine treatment process removed 75 to 84 per cent of the toxins found in tailings ponds.
Credit: Image courtesy of University of Alberta

Cleaning up oil sands tailings has just gotten a lot greener thanks to a novel technique developed by University of Alberta civil engineering professors that uses solar energy to accelerate tailings pond reclamation efforts by industry.

Instead of using UV lamps as a light source to treat oil sands process affected water (OSPW) retained in tailings ponds, professors Mohamed Gamal El-Din and James Bolton have found that using the sunlight as a renewable energy source treats the wastewater just as efficiently but at a much lower cost.

"We know it works, so now the challenge is to transfer it into the field," says Gamal El-Din, who also worked on the project with graduate students Zengquan Shu, Chao Li, post doctorate fellow Arvinder Singh and biological sciences professor Miodrag Belosevic.

"This alternative process not only addresses the need for managing these tailings ponds, but it may further be applied to treat municipal wastewater as well. Being a solar-driven process, the cost would be minimal compared to what's being used in the field now."

Oilsands tailings ponds contain a mixture of suspended solids, salts, and other dissolvable compounds like benzene, acids, and hydrocarbons. Typically, these tailings ponds take 20 plus years before they can be reclaimed. The solar UV/chlorine treatment process when applied to the tailings ponds would make OSPW decontamination and detoxification immediate.

The sun's energy will partially remove these organic contaminants due to the direct sunlight. But, when the sunlight reacts with the chlorine (or bleach) added to the wastewater, it produces hydroxyl radicals (powerful oxidative reagents) that remove the remaining toxins more efficiently. The chlorine leaves no residuals as the sunlight causes it to decompose.

In laboratory-scale tests the solar UV/chlorine treatment process was found to remove 75 to 84 per cent of these toxins.

"With this solar process, right now, the wastewater on the top of the tailings ponds is being treated. But because we have nothing in place at the moment to circulate the water, the process isn't being applied to the rest of the pond," says Gamal El-Din.

"Because we are limited by the sunlight's penetration of the water, we now must come up with an innovative design for a mixing system like rafts floating on the ponds that would circulate the water. Installing this would still be much more cost effective for companies. It is expected that the UV/chlorine process will treat the OSPW to the point that the effluent can be fed to a municipal wastewater treatment plant, which will then complete the purification process sufficiently so the water can be discharged safely into rivers.

"This process has been gaining a lot of attention from the oil sands industry. We're now seeking funds for a pilot-pant demonstration and are looking at commercializing the technology."

Their findings were published in the Environmental Science & Technology journal.

Story Source: The above story is based on materials provided by University of Alberta. The original article was written by Tarwinder Rai.

Tuesday, September 23, 2014

Unique Waste Cleanup for Rural Areas Developed

Source: Washington State University
Summary: A unique method has been developed to use microbes buried in pond sediment to power waste cleanup in rural areas. The first microbe-powered, self-sustaining wastewater treatment system could lead to an inexpensive and quick way to clean up waste from large farming operations and rural sewage treatment plants while reducing pollution.

Washington State University researchers have developed a unique method to use microbes buried in pond sediment to power waste cleanup in rural areas.

The first microbe-powered, self-sustaining wastewater treatment system could lead to an inexpensive and quick way to clean up waste from large farming operations and rural sewage treatment plants while reducing pollution.

Professor Haluk Beyenal and graduate student Timothy Ewing in the Voiland College of Engineering and Architecture discuss the system in the online edition of Journal of Power Sources and have filed for a patent.

Cutting Greenhouse Gases

Traditionally, waste from dairy farms in rural areas is placed in a series of ponds to be eaten by bacteria, generating carbon dioxide and methane pollution, until the waste is safely treated. In urban areas with larger infrastructure, electrically powered aerators mix water in the ponds, allowing for the waste to be cleaned faster and with fewer harmful emissions.

As much as 5 percent of energy used in the U.S. goes for waste water treatment, said Beyenal. Most rural communities and farmers, meanwhile, can't afford the cleaner, electrically powered aerators.

Microbial fuel cells use biological reactions from microbes in water to create electricity. The WSU researchers developed a microbial fuel cell that does the work of the aerator, using only the power of microbes in the sewage lagoons to generate electricity.

The researchers created favorable conditions for growth of microbes that are able to naturally generate electrons as part of their metabolic processes. The microbes were able to successfully power aerators in the lab for more than a year, and the researchers are hoping to test a full-scale pilot for eventual commercialization.

Hope for Dairies

The researchers believe that the microbial fuel cell technology is on the cusp of providing useful power solutions for communities.

"Everyone is looking to improve dairies to keep them in business and to keep these family businesses going,'' said Ewing.

The technology could also be used in underdeveloped countries to more effectively clean polluted water: "This is the first step towards sustainable wastewater treatment,'' Ewing said.

Beyenal has been conducting research for several years on microbial fuel cells for low-power electronic devices, particularly for use in remote areas or underwater where using batteries is challenging. Last year, he and his graduate students used the microbes to power lights for a holiday tree.

Story Source: Washington State University. "Unique waste cleanup for rural areas developed." ScienceDaily. ScienceDaily, 18 September 2014.

Monday, September 15, 2014

Nuclear Waste Eaters: Scientists Discover Hazardous Waste-Eating Bacteria

Source: University of Manchester
Summary: Tiny single-cell organisms discovered living underground could help with the problem of nuclear waste disposal, say researchers. Although bacteria with waste-eating properties have been discovered in relatively pristine soils before, this is the first time that microbes that can survive in the very harsh conditions expected in radioactive waste disposal sites have been found.

The bacterium (inset) was found in soil samples in the Peak District.
Credit: Image courtesy of University of Manchester

Tiny single-cell organisms discovered living underground could help with the problem of nuclear waste disposal, say researchers involved in a study at The University of Manchester.

Although bacteria with waste-eating properties have been discovered in relatively pristine soils before, this is the first time that microbes that can survive in the very harsh conditions expected in radioactive waste disposal sites have been found. The findings are published in the ISME (Multidisciplinary Journal of Microbial Ecology) journal.

The disposal of our nuclear waste is very challenging, with very large volumes destined for burial deep underground. The largest volume of radioactive waste, termed 'intermediate level' and comprising of 364,000m3 (enough to fill four Albert Halls), will be encased in concrete prior to disposal into underground vaults. When ground waters eventually reach these waste materials, they will react with the cement and become highly alkaline. This change drives a series of chemical reactions, triggering the breakdown of the various 'cellulose' based materials that are present in these complex wastes.

One such product linked to these activities, isosaccharinic acid (ISA), causes much concern as it can react with a wide range of radionuclides -- unstable and toxic elements that are formed during the production of nuclear power and make up the radioactive component of nuclear waste. If the ISA binds to radionuclides, such as uranium, then the radionuclides will become far more soluble and more likely to flow out of the underground vaults to surface environments, where they could enter drinking water or the food chain. However, the researchers' new findings indicate that microorganisms may prevent this becoming a problem.

Working on soil samples from a highly alkaline industrial site in the Peak District, which is not radioactive but does suffer from severe contamination with highly alkaline lime kiln wastes, they discovered specialist "extremophile" bacteria that thrive under the alkaline conditions expected in cement-based radioactive waste. The organisms are not only superbly adapted to live in the highly alkaline lime wastes, but they can use the ISA as a source of food and energy under conditions that mimic those expected in and around intermediate level radwaste disposal sites. For example, when there is no oxygen (a likely scenario in underground disposal vaults) to help these bacteria "breath" and break down the ISA, these simple single-cell microorganisms are able to switch their metabolism to breathe using other chemicals in the water, such as nitrate or iron.

The fascinating biological processes that they use to support life under such extreme conditions are being studied by the Manchester group, as well as the stabilizing effects of these humble bacteria on radioactive waste. The ultimate aim of this work is to improve our understanding of the safe disposal of radioactive waste underground by studying the unusual diet of these hazardous waste eating microbes. One of the researchers, Professor Jonathan Lloyd, from the University's School of Earth, Atmospheric and Environmental Sciences, said: "We are very interested in these Peak District microorganisms. Given that they must have evolved to thrive at the highly alkaline lime-kiln site in only a few decades, it is highly likely that similar bacteria will behave in the same way and adapt to living off ISA in and around buried cement-based nuclear waste quite quickly.

"Nuclear waste will remain buried deep underground for many thousands of years so there is plenty of time for the bacteria to become adapted. Our next step will be to see what impact they have on radioactive materials. We expect them to help keep radioactive materials fixed underground through their unusual dietary habits, and their ability to naturally degrade ISA."

Story Source: The above story is based on materials provided by University of Manchester.

Thursday, September 11, 2014

To Clean Air and Beyond: Catching Greenhouse Gases with Advanced Membranes

Source: Institute for Integrated Cell-Material Sciences, Kyoto University
Summary: An advanced membrane has been developed for the purpose of cleaning up greenhouse gases. The membranes are cheaper, long-lasting, selective and highly permeable compared to commercially available ones.

PIM-1 is a highly permeable membrane compared with commercially available ones. The orange balloon on the left illustrates this point as a higher volume of nitrogen gas is able to pass through PIM-1 into the balloon compared with the membrane on the right, connected to the pink balloon.

Greenhouse gases, originating from industrial processes and the burning of fossil fuels, blanket the Earth and are the culprits behind current global warming woes. The most abundant among them is carbon dioxide, which made up 84% of the United States' greenhouse gases in 2012, and can linger in Earth's atmosphere for up to thousands of years.

Countries all over the world are looking to reduce their carbon dioxide footprint. However, carbon dioxide is essentially a waste product with little immediate commercial value and large treatment costs. Therefore, new low-cost technologies are sorely needed to incentivize greenhouse gas capture by industry.

Easan Sivaniah -- an associate professor at Kyoto University's Institute for Integrated Cell-Material Sciences (iCeMS) -- led an international team of researchers from iCeMS and the University of Cambridge to create an advanced membrane capable of rapidly separating gases.

The membrane they worked on, referred to as PIM-1, is "typically embedded with a network of channels and cavities less than 2 nm in diameter that can trap gases of interest once they enter," said Qilei Song, who was involved in the study. "The only problem is that their intrinsic properties make them rather flimsy and their starting selectivity is weak."

To overcome PIM-1's weaknesses, Sivaniah's team heated PIM-1 at temperatures ranging from 120 to 450 °C in the presence of oxygen, a process referred to as thermal oxidation. "Oxygen, under high temperatures, chemically reacts with PIM-1 to reinforce the strength of channels while controlling the size of so-called gate openings leading into the cavities, which allows for higher selectivity," said Song.

The resulting improved PIM-1 was found to be twice as selective for carbon dioxide while allowing air to pass through it 100 times faster compared with commercially available polymers. PIM-1 can also be used for other applications such as capturing carbon dioxide from the burning of fossil fuels, enriching the oxygen content in air for efficient combustion engines, hydrogen gas production, and processes to generate plastic.

"Basically, we developed a method for making a polymer that can truly contribute to a sustainable environment," said Sivaniah. "And because it is affordable and long-lasting, our polymer could potentially cut the cost of capturing carbon dioxide by as much as 1000 times."

Story Source: The above story is based on materials provided by Institute for Integrated Cell-Material Sciences, Kyoto University.

Thursday, September 4, 2014

Clean Air Halves Health Costs in Chinese City

Air pollution regulations over the last decade in Taiyuan, China, have substantially improved the health of people living there, accounting for a greater than 50% reduction in costs associated with loss of life and disability between 2001 and 2010, according to researchers at the Columbia Center for Children's Environmental Health (CCCEH) at the Mailman School of Public Health, the Shanxi Medical University, the Center of Diseases Control and Prevention of Taiyuan Municipality, and Shanghai Fudan University School of Public Health.

The study is the first to document the health and economic benefits of policies to reduce the burden of air pollution in a highly polluted area of China, and provides a model to measure how policies to improve air quality can protect human health. Results appear online in the journal Environment International.

Taiyuan, the capital of Shanxi Province, is a major center in China for energy production and metallurgical industries. To combat air pollution, the Shanxi Provincial Government implemented many new environmental policies and regulations. Between 2000 and 2012, these included mandating the closure of many polluting sources, auditing companies that produced large amounts of toxic and hazardous materials, setting pollutant emissions standards, and promoting energy efficiency and pollution reduction. As a result, concentrations of particulate matter (PM10) declined by more than half, from 196 µg/m3 in 2001 to 89 µg/m3 in 2010, as measured at eight sites throughout the city.

Reductions in particulate matter between 2001 and 2010 were associated with 2,810 fewer premature deaths, 31,810 fewer hospital admissions, 141,457 fewer outpatient visits, 969 fewer ER visits, and 951 fewer cases of bronchitis. The team estimated that there were more than 30,000 fewer DALYs -- disability-adjusted life years, a standard measure of the loss of healthy years -- attributed to air pollution in Taiyuan in 2010 compared to 2001. The cost of premature death due to air pollution decreased by 3.83 billion Yuan, or approximately $621 million.

Particulate matter is released by coal-burning plants and other sources. These small particles can lodge themselves deeply in human lungs, and are associated with heart and lung conditions and premature death.

"Our results suggest that the air quality improvement from 2001 to 2010 resulted in substantial health benefits. In fact, the health and financial impacts of air pollution could potentially be greater than those reported due to our selection of only a few health outcomes that could be quantitatively estimated and translated into monetary values," says lead investigator Deliang Tang, DrPH, associate professor of Environmental Health Sciences at the Mailman School of Public Health.

The study builds on similar research from CCCEH in China, showing improvements in air quality were linked with improved childhood developmental scores.

"Over the last ten years, our research in two Chinese cities have demonstrated that strong government policies to reduce air pollution can result in substantial health benefits for children and adults," says Frederica Perera, PhD, director of the Columbia Center for Children's Environmental Health at the Mailman School of Public Health. "These findings make the argument for stronger and broader regulations in Chinese cities where air pollution remains a serious health problem."

According to the Chinese Ministry of Environmental Protection, only three of 74 cities the government monitors meet minimum air standards. In March, Premier Li Kequiang announced that the country would "declare war against pollution," by reducing particulate matter and closing outdated industrial plants.

Story Source: Columbia University's Mailman School of Public Health.