Challenges in the Use of Greenhouse Water Desalination Systems**

Agricultural crop production in greenhouses and controlled environments, due to the possibility of increasing the productivity of water and other agricultural inputs, employment creation, value-added off-season production and etc. is among the items that have been considered in the agenda of the agricultural and horticultural authorities of Iran. At the same time and as the result of decreasing in the quantity and quality of available irrigation water, issues have arisen in the established greenhouses. These conditions have led the greenhouse owners to use water desalination systems. The use of these systems is associated with the production of low quality brine, which has some problems with disposal. Therefore, the status of some greenhouses with water desalination system in Isfahan, Qazvin and Alborz provinces was studied for their saline effluent disposal. The results showed that the main alternative for brine disposal of desalination systems was unregulated land evacuation around the greenhouses and then, combined use with well water for outdoor farming, recharge of local wells and discharge into infiltrated trenches and ponds were in the following ranks. Unfortunately, due to the lack of a definite organization to control and monitor the implementation and operation of these equipments and lack of such brine disposal considerations, inappropriate situation is occurring in the surveyed areas. It seems that as the current trend continues, serious problems in means of water and soil resources contamination are not unexpected and may impose irreversible conditions on the country's environment. Therefore, this situation must be fundamentally addressed as soon as possible.