ABSTRACT
JUAN C. DURÁN-ÁLVAREZ and BLANCA JIMÉNEZ-CISNEROS
6.1 Introduction .................................................................................. 148 6.2 Impacts of Wastewater Reuse in Agriculture ............................... 152 6.3 Negative Impacts of Wastewater Reuse in Irrigation ................... 166 6.4 Scope for Further Research .......................................................... 202 6.5 Summary ...................................................................................... 204 Keywords .............................................................................................. 207 References ............................................................................................. 213
6.1 INTRODUCTION
The scarcity of water for human use, such as food and energy production, manufacturing, drinking water and ecosystem conservation is a global problem for which the solution goes beyond merely the preservation of freshwater sources [60, 170]. Although three quarters of the Earth’s surface is covered by water, most of this water is either contained in oceans or confined in glaciers [199]. The volume of freshwater (FW) available for human activities (less than 1%) is unequally distributed throughout the globe; in some cases this water is confined to the deep sub-soil or is polluted [182]. Furthermore, the desertification of large areas caused by climate change has intensified the lack of water sources in cities and rural areas throughout the world [70]. Water scarcity results in food scarcity, since 70% of the water withdrawn for human activities goes to agriculture [58]. In zones where rain-fed agriculture is practiced, decay in crop yields is observed when droughts occur, which results not only in the scarcity of food but also the decrease in incomes due to falling crop sales [160]. The use of freshwater for irrigation limits the volume of freshwater available for human consumption; therefore, recycling of water becomes necessary for irrigation in dry zones [56, 90]. The idea of reusing wastewater (WW) to irrigate is not new; it actually originated around 3000 B.C. People in these ancient civilizations knew that WW contained both water and compounds that benefited the soil and thus they used it in a planned way to increase crop yields [52].
