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Aragon C.A.,A-D Technologies | Salas J.J.,A-D Technologies | Ortega E.,Center for Studies and Experimentation of Public Works | Ferrer Y.,Center for Studies and Experimentation of Public Works
Water Practice and Technology | Year: 2011

Wastewater treatment in small communities, with less of 2,000 population equivalent, is one of the priorities of the new Spanish National Plan for Water Quality: Sanitation and Purification (2007-2015). Due to the peculiarities of the small agglomerations, the treatment solutions used in medium and large cities usually do not give satisfactory results if they are implanted directly into those communities. It is therefore necessary to adapt these technologies to the small towns or to search for new treatment solutions. In this regard, R&D activities play a key role. In fact, many research groups address their activities to the study of sanitation and treatment of small populations. In relation to the technologies studied there is a wide range that includes both extensive and intensive technologies. In the case of Spain, as in other countries, constructed wetlands seem to be the most studied technology in the recent years to sewage treatment in small settlements. However, there are still areas of study to be promoted in order to solve the current problems of sanitation and wastewater treatment in small settlements. © IWA Publishing 2011.


Salas J.J.,A-D Technologies | Aragon C.A.,A-D Technologies | Real A.,A-D Technologies | Ortega E.,Center for Studies and Experimentation of Public Works | Ferrer Y.,Center for Studies and Experimentation of Public Works
Water Practice and Technology | Year: 2011

In Spain, the current level of conformity with the Directive 91/271/EEC, concerning urban wastewater treatment, has achieved an 80%. The remaining 20% are mainly agglomerations with less than 10,000 p.e., and more exactly, under 2,000 p.e. Only a 40-50% of the small populations have their sewage appropriately treated. It is estimated that the population not served at the moment is about 3-4 million p.e. In order to correct this non-desirable situation, the new National Plan for Water Quality, Sanitation and Purification 2007- 2015 (NPWQ), provides concrete actions in small settlements (less than 2,000 p.e). Due to the peculiarities of the small agglomerations, the treatment solutions used in medium and large cities usually do not give satisfactory results if they are implanted directly into those communities. It is therefore necessary to adapt these technologies to the small settlements or to develop new treatment diagrams that allow obtaining a good quality effluent in a sustainable way. In this sense, the Centre for Studies and Experimentation of Public Works (CEDEX) and the Foundation Centre for New Water Technologies (CENTA) have prepared a "Manual for the implementation of treatment systems in small populations". In this work, some of the most relevant issues included in the Manual are exposed. © IWA Publishing 2011.


Norambuena-Contreras J.,Empa - Swiss Federal Laboratories for Materials Science and Technology | Asanza Izquierdo E.,Center for Studies and Experimentation of Public Works | Castro-Fresno D.,University of Cantabria | Partl M.N.,Empa - Swiss Federal Laboratories for Materials Science and Technology | Garcia A.,Empa - Swiss Federal Laboratories for Materials Science and Technology
International Journal of Pavement Research and Technology | Year: 2013

It is well known that asphalt mixtures with different air void contents will present different drainage capacity, but until now there is not a model that evaluates its water infiltration capacity considering its air void content value. For this reason, a new model to predict the hydraulic conductivity (permeability) of asphalt mixtures as a function of its air void content has been proposed in this paper. Additionally, this paper presents the laboratory results and procedures used to measure the hydraulic conductivity of asphalt mixtures with a wide range of air void content. With this purpose, four types of asphalt mixtures with different aggregate distribution (dense, semidense, discontinuous and porous), amounts of bitumen (from 4.5 to 5.2%) and air void content (from 4 to 20%), have been tested. The average hydraulic conductivity of the asphalt mixtures analyzed ranged from 5.2×10-6 to 3.0×10-2 cm/s. Besides, it has been found that the hydraulic conductivity model is valid for all ranges of air void content existing in the compacted asphalt mixture. In addition, the model has been checked through experimental and literature data, presenting a good fit to data. Therefore, the results of this study can be used as reference values of the hydraulic conductivity of asphalt mixtures used in the road pavement construction. © Chinese Society of Pavement Engineering.

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