Water purification: new technologies

Recent research on the treatment of water intended for human consumption have produced and are investigating, in a totally independent of each other, several new systems that are in addition to those classics, competing for originality, cost and possibility of use in developing countries .

The Moringa oleifera, also known as the miracle tree for its amazing quality and countless (provides food, water, fuel and other environmentally difficult), is a plant common in most of the tropical and equatorial band on the planet, and has been object of study by researchers funded by a program of the Environmental Protection Agency (EPA) to optimize a system for water treatment that exploits the seeds of the drumstick tree, another tree that epithet refers to the shape of its fruit.

Darrell Velegol, professor of chemical engineering engaged in research, explains that the seeds of the plant contain proteins, among which there is a cationic protein, which contains a sequence of a small peptide that acts as a molecular knife, a deadly weapon that passes through the cell wall of the bacteria and kills them, dissects them into practice. Also, because the protein is positively charged, it is able to wrap the solid particles in suspension, as the "carcasses" of microorganisms, allowing a rapid sedimentation.

This summer, Velegol, along with his wife Stephanie Velegol, professor of environmental engineering and Richard Schuhmann, they went in Tiout, Morocco, for assessing the water supply of a small village and to establish a better understanding of the people (and their culture ) that they hope to help.

The idea of ​​using Moringa seeds for the purification, it is not entirely new, however, presents some problems such as poor durability of the water thus treated. In fact, the many nutrients contained in the seeds offer a fertile ground for new contamination, and purified water does not remain unscathed for more than a day.

To prolong the shelf life of the treated water with Moringa seed, researchers are trying to disperse the proteins contained shattering in water, and adding sand as aggregating protein remained still active, it becomes easier to rinse away the rest of the protein and the organic matter source of further contamination. With this system, the researchers have shown to be able to obtain drinking water free from biological contaminants, and the sand so "functionalized" is recycled simply letting it rest out of the water.

Another interesting development comes to us from Stanford University, where he was quickly developed a filter that removes bacteria from water without clogging. The filter consists of a small cotton swab soaked by a dye in aqueous base containing a pigment composed of carbon nanotubes, which is fed with a weak electric field capable of killing the microorganisms consuming only 20% of the energy required by conventional filters pressure.

At least a billion people have access only to water contaminated by pathogens or severely polluted. The filter developed by researchers at Stanford University seeks to improve the systems for the removal of bacteria independently of centralized sewage treatment plants. There are two main chemical methods: adding chlorine to water to kill bacteria, or addition of iron, which causes the aggregation of the bacteria so that they can be easily removed. Chemical methods are penalized because they require staff training and a continuous supply of chemicals.

Filtration, on the contrary, is interesting because it is simple, but the current methods work discriminating the size of the microorganisms. Such filters become clogged with time, and work very slowly, less than consume energy to filter the water under pressure. The filter of Stanford, which depends on the force of gravity, has pores large enough to allow a high flow rate - about 100,000 liters per hour - and uses electrical pulses to inactivate bacteria by puncturing their cell walls. The research was conducted by professors of materials science and engineering Yi Cui and Sarah Heilshorn, of Stanford University.

On the research front Italian, has recently announced a new system to reduce the volume of sludge produced by the plants up to 20 times, cutting costs and reducing the supply of chemicals used for the treatment of wastewater.

Claudio Di Iaconi, IRSA-CNR researcher and head of research, says the system SBBGR (Sequencing Batch Biofilter Granular Reactor - enhanced ozone) is particularly useful in the case of treatment of industrial wastewater, where there are significant amounts of organic compounds toxic and readily biodegradable.

"Our technology" - says Dr. Di Iaconi - "would allow a company that produces 1,000 cubic meters of wastewater per day to save more than 2 -3 € per cubic meter. So 2000 - 3000 Euros per day, more than € 600,000 a year. "

This process developed within the project INNOWATECH (acronym for Innovative and Integrated Technologies for the Treatment of Industrial Wastewater: innovative technologies for industrial water purification) edited from the place of Bari IRSA, Water Research Institute of the National Council of research, he received an award at the international level by the European Commission through the LIFE program, funded with 700,000 € development of the technology demonstration scale.

Fortunately a special focus on water conservation and redistribution of water resources where you need to go back to be a topic worthy of attention, at least on the part of scientific research, when it is thought only to mere profits of privatization, the latter completely purely selfish and despicable.

 

19/09/2010

 

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Translated via software

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Source:

Italian version of CercaGeometra.it

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