BUSCADOR RECOLECTA

Investigadores del Programa Consolider Tragua “Tratamiento y Reutilización de Aguas Residuales para una Gestión Sostenible” han llevado a cabo un estudio sobre la viabilidad de cultivar en España Jatropha curcas L., cultivo no alimentario destinado a la producción de biodiésel, utilizando aguas regeneradas para su riego. Sus resultados y conclusiones se resumen a continuación. Researchers working on the Programa Consolider Tragua “Treatment and Reuse of Waste Water for Sustainable Management” have carried out a study on the feasibility of cultivating in Spain the non-edible crop for the production of biodiesel, Jatropha curcas L., using reclaimed water for its irrigation. The findings and conclusions of this study are described below.

Casas, A., Tapias, J., De Bustamante, I., Iglesias, J.A., De Miguel, A., Lillo, J., Leal, M., Candela, L., Cabrera, M.C., Palacios-Días, P., Salas, J.J., Martín, I., Mas, J. (2012). Guía metodológica para el uso de aguas regeneradas en riego y recarga de acuíferos. Ed. Consolider-Tragua. ISBN: 978-84-694-9258-1.

La tecnología de filtros verdes se plantea como una alternativa eficaz para el tratamiento, gestión y reutilización de los efluentes líquidos procedentes de aglomeraciones urbanas de pequeño tamaño. Para su implantación se hace imprescindible un buen conocimiento del medio geológico que nos permita asegurar, por un lado, la protección del medio natural, específicamente las masas de agua subterránea, y por otro, la eficacia de su aplicación como tecnología de regeneración, en el contexto normativo actual. Para ello, se propone la metodología a seguir en las etapas iniciales de un proyecto de aplicación de filtro verde como tecnología de regeneración de aguas residuales. Como caso de demostración, se presentan los resultados preliminares obtenidos con la metodología de caracterización propuesta obtenidos en la parcela experimental del filtro verde que se va a instalar en la planta experimental de Carrión de los Céspedes (Sevilla).

Virtual water is defined as the water needed to produce a product. We can use virtual water flow calculations to estimate the water efficiency of a country, as well as its economic dependence on water resources. Former studies on this area have focused on quantifying the virtual water flows between countries, in an international context. In this study we reduce the action framework to regions within a country, determining the virtual water balance between two Spanish regions: Castilla-La Mancha and Murcia. In 2004, Castilla-La Mancha exported to Murcia 2,453,442 tons of commercial products, from which 1,191,628 tons were agricultural goods. In terms of virtual water, it means 1,365 hm3, including food-processing, and industrial products. It is necessary to add 350 hm3 to the result, because of the water transfer (Tajo-Segura transfer) between the rivers basins of these regions, so the final virtual water number, in 2004, was 1,715 hm3. The other way round, Murcia exported in 2004 2,069,000 tons of products, from which 490,351 tons were agricultural goods. That supposes 712 hm3 of virtual water. Virtual water flow is unbalanced and displaced towards Murcia with a difference of 1,003 hm3.

In a growing concern of water and energy availability decrease, the sustainable growth of Jatropha curcas L. may be a feasible and complementary alternative within the local non-conventional energies field. This study emphasizes the idea of using reclaimed water agriculture implemented as a complementary local energy option. The main goal of this work focuses on monitoring the environmental affections and feasibility of treated water reuse for J. curcas L. irrigation. Two parcels were irrigated with two different water qualities: well groundwater (WG) and reclaimed water (RW). Differences were found in terms of nitrate, ammonia, sulphate, chloride, dissolved organic carbon (DOC), chemical oxygen demand (COD) and metals concentrations between the two irrigation water qualities. However, after one year of study, no significant differences in the leaves composition were measured with the exception of Fe (WG = 85.17 and RW = 102.63 mg/kg) and Mn (WG = 83.98 and RW = 43.51 mg/kg). The statistical analysis shows no significant differences in height, collar diameter and crown diameter (WG = 142.4, 5.7 and 157.1 cm; RW = 143.5, 5.4 and 154.7 cm, respectively). So far the aquifer water quality was only slightly affected in terms of total nitrogen (NT) after irrigation when rainfall took place. DOC and COD in groundwater were always below 5 and 15 mg/L, respectively. As a conclusion, wastewater reuse for irrigation does not provide a negative effect in J. curcas L. feasibility, becoming an alternative option in the renewable energy field. An environmental monitoring is necessary to guarantee a sustainable management.