As a consequence, some compounds, like ammonia, potassium, sulfate, nitrate or phosphate, which are in sewage used for irrigation, are released again when it rains, so as they slowly arrive to the saturated area of the aquifer.
The thesis, entitled Impacto del riego con aguas residuales sobre el suelo de la zona no saturada de la Vega de Granada (Impact of sewage irrigation on soil of the non-saturated area of the Vega of Granada), has been carried out by Kaltoum El Mabrouki under the direction of Professors José Javier Cruz San Julián and José Miguel Rodríguez Maroto. In addition to laboratory experiences, the work has been prepared by means of trials carried out in an experimental area.
Due to the shortage of water resources, especially in arid or semi-arid areas like those of Andalusia and Granada, sewage irrigation, treated or not, has become a usual practice. The researchers from Granada intended to confirm or refute a stated opinion, according to which soil retains sewage compounds, so that polutants do not reach the saturated area of the aquifer.
To the contrary, the thesis has proved that, in El Mabrouki´s words, “there is a certain retention adsorption and a certain release desorption mechanism, since soil is a non-renewable resource and it adsorps and desorps the compounds, although this process is slower”. Professor Cruz stresses that “it has been proved that soil adsorps and retains a lot of sewage compounds, but they are released again when it rains, although this process is slower and, therefore, it will reach groundwaters some day”.
The thesis concludes that the natural attributes of soils to filter compounds are more effective when it is about organic and microbiological pollution, which is the most representative part of sewage; however, such decontamination “does not take place to the extent thought until today”. Soil receives other compounds like fertilizers, pesticides and nitrates, provided by farmers. Researchers specify that chlorination and drinking water treatment guarantee the helthiness of water when it reaches homes.
The authors of the research work recommend to use “with caution” sewage irrigation since “you can not irrigate with any sort of water, at any pace and in any season” and they insist that “the higher purification level, the better”. In this sense, they remind that in other Spanish towns, like Vitoria, water is so pure that it could be consumed by people thanks to its high quality, although nowadays it is used for irrigation.
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07.03.2017 | International Institute for Applied Systems Analysis (IIASA)
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
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