Analysis and description of sustainable solutions for wastewater treatment in small communities

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.