Water and Fluid Separation News
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October 20, 2011
The simple act of machine washing our clothes may be causing serious environmental damage, according to a new study from University College Dublin. A research team led by Dr. Mark Browne has traced a path from washing machine wastewater to abnormally high concentrations of microplastic debris found all over the world. The problem arises because the synthetic fibers that many of today’s clothes are made of, polyester and acrylic, get rinsed by the machine. While we may not notice it, one cycle can strip as much 1,900 fibers off each piece of synthetic clothing! These dangerous fibers eventually make their way to the ocean and wash up on our beaches. Research also shows that the pollutants are eaten by mussels and locusts, which can then work their way up the food chain to humans. As a part of this study Dr. Browne’s team investigated 18 sites on six continents and through forensic analysis was able to match the proportions of polyester and acrylic fiber present in these sites with their
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September 29, 2011Today’s Laboratory Equipment newsletter features an interesting article on how Purdue researchers have created a water-disinfection system that uses ultraviolet radiation from the sun to remove pathogens. With 800 million people unable to access clean drinking water, the potential for water-cleaning system that can be powered by natural resources is tremendous. According to Water.org and the United Nations Human Development Report, every 20 seconds a child dies from a water-related disease. This water treatment device uses a parabolic reflector to capture sunlight and focus it onto a UV-transparent pipe through which the water flows. In a brilliant development, the reflector is made out of a type of wood, paulownia, which is inexpensive and
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August 29, 2011On September 1st a new web portal created specifically for water and wastewater management will officially launch to fill the industry’s need for a comprehensive database on water infrastructure in the United States. Dubbed WATERiD, this project is funded by Virginia Tech and it is the brainchild of Sunil Sinha, a National Science Foundation Career Award recipient for his work in sustainable water infrastructure management systems. One of the biggest problems in water utility management is figuring out when to replace pipelines and equipment, before things break and cause serious problems. It’s estimated that at least 2 million miles of the nation’s infrastructure is nearing the end of its useful life, and at present there is no singular resource for utilities to consult when making a decision on when to make replacements. This is the primary need WATERiD is looking to address. By collecting various technical papers, case studies, and research data
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August 17, 2011Western Biodiesel Inc. was fined $160,000 (Canadian dollars) yesterday by the Provincial Court of Alberta for releasing wastewater that contained methanol into the environment and for providing false or misleading statements to investigators. The fine is the outcome of an incident in October 2008 in which Western Biodiesel dumped around 16,000 liters of methanol-laced water onto its property. Problems arose for Western Biodiesel the day after this release occurred when an unsuspecting welder accidentally ignited the wastewater with his torch, causing a fire that luckily yielded no injuries. In what had to be an incredibly gutsy and foolish move, the (now former) plant manager denied the release occurred when investigators showed up. He was later sentenced to four months house arrest. So besides dumping it in a river and hoping nobody lights a match, what are the actual proper methods of methanol disposal? Methods for extracting methanol from biodiesel include: Vacuum stripping, flash
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July 20, 2011
The Silt Density Index is most frequently used to determine fouling potential prior to RO filtration. You can think of SDI as a bouncer, keeping the riff-raff out of the RO feed water. The higher the number, the greater the likelihood of fouling. The maximum SDI number allowed depends on the type of RO membrane being used; most manufacturers recommend a maximum SDI of 4 or 5. SDI is found by calculating the rate at which a membrane filter is plugged. ASTM standard D4189-07 defines that the nominal filter for this application is a white hydrophilic MCE membrane filter, with 0.45 ?m pore size and a 47 mm diameter. The reason this particular membrane is used is that it is more susceptible to plugging from colloidal material than from hard particles such as sand, therefore giving a better indication of the factors that might plug an RO membrane down the line. Other measures that
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July 11, 2011
This study from the ACS journal Applied Materials & Interfaces has been making headlinesrecently for introducing a new way to purify drinking water. Scientists from Rice University have created a new filter material, dubbed “super sand,” by coating regular sand with the nanomaterial graphite oxide. Their tests have shown that this super sand has the potential to be a cheap form of water filtration for developing areas.
The use of sand as a water filter isn’t anything new – it’s actually been done for around 6,000 years. However, by combining this old world technique with cutting edge nanotechnology scientists have made sand filtration at least 5 times more efficient. Their report indicates that the modified sand adsorbed 6 times the amount of liquid mercury and 5 times as much heavy metal and organic dye than regular sand.
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June 22, 2011
Biogas, a form of renewable energy this is produced through, among other things, animal and human waste (hey, it’s not like you were using it) is one of several developing energy sources whose proponents are exploring membrane separation techniques to improve their purification process. A recent study published in the “Applied Chemistry – A Journal of the Society of German Chemists” experimented with a new method of membrane separation called the “condensing-liquid membrane” (or CLM) in an effort to enrich raw biogas, which typically contains between 50-80% methane, to natural gas quality (at least 95% methane content), with favorable results. Common membrane materials like Cellulose Acetate and Polyimide have been tried for this application with some success, but the problem is that they can be ruined by the aggressive gases that are present in raw biogas, such as carbon dioxide and hydrogen sulfide. The CLM is a liquid (water in this case) layer that
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June 06, 2011After our last post discussing how experiments with carbon nanotubes (CNT’s) might greatly improve the effectiveness of reverse osmosis desalination now comes a new report from the Institute of Physics that shows researchers are getting closer to making this a reality. Already over a billion people do not have regular access to clean water and the problem will likely get worse as the demand for drinkable water is expected to grow dramatically in the near future. With natural sources increasingly scarce, this urgent need means there is an intense global interest in any potentially viable forms of water purification.
Right now the main issues preventing RO desalination on a large-scale basis are that the membranes used to perform seawater to freshwater separation do not remove salt ions with enough efficiency and they also -
June 01, 2011
One of the most promising new frontiers in filtration technology involves infusing different membrane types with nanomaterials in order to improve performance or to pass along certain material attributes. Here we will look into one prominent example from recent years, the incorporation of carbon nanotubes (CNTs) into ultrafiltration membranes used in water treatment. We’ll also look at how our stirred cells have aided in this specialized membrane manufacturing process. First off, what is there to gain by using CNT’s to manufacture water treatment membranes? While scientists have identified several potential advantages for CNT implementation, since the process is still in the R&D phase they have not necessarily been proven in all cases. One key possible benefit is that membranes made with these materials would be much stronger than traditional membranes, thus reducing instances of membrane breakage and fouling, two problems that contribute significantly to high maintenance costs in water
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May 24, 2011
An increase in salinity levels at the North Reverse Osmosis Water Plant in Kill Devil Hills (yes, that’s the town name) that had been creating stress for some local officials has been explained in a recent study. Researchers from nearby Duke University found that the rising salinity levels at this coastal aquifer are the result of fossil seawater and not seawater intrusion, as had been feared. Since the well’s installation in the late 1980’s salinity has more than doubled from about 1,000 mg/L to about 2,500 mg/L. There was much cause for relief however, when researchers were able to attribute the rise to fossilized seawater and not to seawater leaking in from the coast.
According to the director of the study, Duke Professor Avner Vengosh, knowing the source of the salinity increase is important because fossil seawater raises salinity, “At a relativelyf slow and steady rate that is more manageable and sustainable