Reuse of treated municipal wastewater in agriculture in MENA countries: the Lebanese case study

The Middle East and North Africa (MENA) is the most arid region on Earth. Due to water scarcity, combined with over population, inefficient water use especially in the agricultural sector, climate change, and mass migration of humans from to various regional conflicts, recycling wastewater has become a necessity for many. Furthermore, with this growing population comes the increase in food demand; the region does not have the natural water resources to withstand this phenomenon and needs be proactive in its environmental and agricultural policy. This paper describes the activities carried out in Lebanon by the ENEA Agency in order to set some conditions for the safe reuse of treated wastewater in agriculture such as (i) identification of the most suitable guidelines for agriculture wastewater reuse and (ii) assessment of the performance capacity of municipal wastewater treatment plants (WWTPs) so as to achieve the discharge limit values (LVs) previously identified. With reference to the first point, several international guidelines, WHO, FAO, US approach, as well as those for Mediterranean countries, were addressed. With reference to the second one, WWTPs located in the Bekaa valley, inner part of Lebanon with agricultural vocation, were considered. After the identification of each plant, a simple methodology to assess the WWTP capacity to achieve targets imposed by the FAO proposal guideline (2010) was implemented. The obtained results showed how, at first, it is necessary to adapt the Lebanese WWTPs in order to ensure the targets imposed by Lebanese Law for the discharge of the treated wastewater in surface and sea waters and then, adapt the plants in order to ensure the standards by WHO 2006. Finally, based on the energy availability, evaluate the possibility to adopt other approach using more sophisticated wastewater reuse technologies (from WHO to US approach).