Annals of West University of Timişoara, ser. Biology, 2014, vol XVII (2), pp.95-110 95 REUSE OF TREATED WASTEWATER IN AGRICULTURE: SOLVING WATER DEFICIT PROBLEMS IN ARID AREAS (REVIEW) Faissal AZIZ 1 , Mohamed FARISSI* 2 1 National Center for Research and Study on Water and Energy, University Cadi Ayyad, Marrakesh, Morocco 2 Unit of Plant Biotechnology and Symbiosis Agro-physiology, Faculty of Sciences and Techniques, Marrakesh, Morocco. Corresponding author e-mail: farissimohamed@gmail.com Received 9 September 2014; accepted 1 November 2014 ABSTRACT In the arid and semiarid areas, the availability and the management of irrigation water have become priorities of great importance. The successive years of drought, induced by climate change and population growth, increasingly reduced the amount of water reserved for agriculture. Consequently, many countries have included wastewater reuse as an important dimension of water resources planning. In the more arid areas wastewater is used in agriculture, releasing high resource of water supplies. In this context, the present work is a review focusing the reuse of treated wastewater in agriculture as an important strategy for solving water deficit problems in arid areas. Much information concerning the wastewater reuse in different regions of the world and in Morocco, the different wastewater treatment technologies existing in Morocco were discussed. The review focused also the fertilizing potential of wastewater in agriculture, the role of nutrients and their concentrations in wastewater and their advantages effects on plant growth and yield. KEY WORDS: wastewater, reuse, drought, fertilizing potential, agriculture INTRODUCTION In recent years, the wastewater reuse has experienced very rapid growth with an increase in volumes of wastewater reuse in the order of 10-29% per year, in Europe, the United States and China, and up to 41% in Australia. The current daily volume of water used reaches a staggering 1.5-1.7 million m 3 per day in several countries, such as California, Florida, Mexico and China (Lazarova & Brissaud, 2007). Reuse of wastewater is spread around the world with several types of recovery. There are thousands of projects using wastewater (Bixio et al., 2008). Bixio et al. (2005) are classified different types of reuse in 4 categories 1) agricultural use, 2) urban and periurban use and replenishing the aquifer 3) industrial use, 4) mixed uses. Globally, the reuse of treated wastewater for agriculture, industry and domestic use cover respectively 70%, 20%, 10% of water demand (Ecosse, 2001), however, these proportions vary across regions of the world (Figure 1).