acidregions alternative aridregions aridregionsecology aridregionsnaturalresourcesmanagement civil congresses desertecology deserts déserts eau eausouterraine engineering environmentalscience exploitation épuration filtration general geomorphology groundwater hc55 management naturalresources photovoltaicpowergeneration photovoltaicpowersystems powerresources purification renewable research science tec031000tec031010 technology thardesert(indiaandpakistan) turkmenistan water