Research Paper Environmental assessment of underdrain designs for a sand media filter Josep Bov  e, Joan Pujol, Gerard Arbat, Miquel Duran-Ros, Francisco Ramı´rez de Cartagena, Jaume Puig-Bargu  es * Department of Chemical and Agricultural Engineering and Technology, University of Girona, C/Maria Aur elia Capmany 61, 17003 Girona, Spain article info Article history: Received 31 July 2017 Received in revised form 8 January 2018 Accepted 11 January 2018 Keywords: Drip irrigation Clogging Filtration Computational fluid dynamics Optimal design Life cycle assessment Increasing energy demand is the main problem linked with the adoption of more efficient irrigation techniques, particularly microirrigation. In microirrigation systems, important pressure losses and therefore energy consumption, occur at the filters, which are a key component in preventing emitter clogging. Previous studies have shown that the main pressure drop across sand media filters, which are widely used in microirrigation, occurs in the underdrain elements. To minimise this problem, new underdrains should be designed but an issue is how their environmental impact can be reduced. Two alternative design strategies were found: firstly, keeping the original filter dimensions and reducing energy consumption during operation by 30%; and, secondly, reducing filter size and reducing construction material by 25% but keeping the original pressure losses. A life cycle assessment transforming environmental effects into monetary values was carried out comparing a commercial sand filter with the two filters designed following the two aforementioned strategies. Results show that both alternatives reduce the environmental impact of the sand commercial filter. Reduction of filter size is the optimum strategy if filtered volumes are below 63,000 m 3 along the filter life, while reduction of energy con- sumption was the best alternative for higher filtered volumes. This work shows the use- fulness of life cycle assessment for assessing design strategies that could improve the sustainability of microirrigation equipment. © 2018 IAgrE. Published by Elsevier Ltd. All rights reserved. 1. Introduction Over the last 50 years, world agricultural production has grown to between 2.5 and 3 times, while the cultivated area has grown only by 12%. More than 40% of the increase in food production has come from irrigated areas, which have doubled in area. Over the same period, the cultivated area per person has gradually declined to less than 0.25 ha, a clear indicator of agricultural intensification. Irrigated agriculture currently uses 2.2% of the world's land surface and accounts for 70% of all water withdrawn from aquifers, streams and lakes (FAO, 2011). Within this context, irrigation sustainability assessment is important, especially in areas where rainfall is scarce and/or irregular. For example, Costa et al. (2016) noted that water is considered the most important and valuable resource in the Mediterranean basin. With the objective of increasing water use efficiency, a common strategy has been * Corresponding author. Fax: þ34 972 41 83 99. E-mail address: jaume.puig@udg.edu (J. Puig-Bargu es). Available online at www.sciencedirect.com ScienceDirect journal homepage: www.elsevier.com/locate/issn/15375110 biosystems engineering 167 (2018) 126 e136 https://doi.org/10.1016/j.biosystemseng.2018.01.005 1537-5110/© 2018 IAgrE. Published by Elsevier Ltd. All rights reserved.