Water reuse in Israel - the Dan Region Project: evaluation of water quality and reliability of plant's operation

Israel is a semi-arid country with insufficient natural water resources. Wastewater effluent reuse and desalination have become the main source of water to compensate for the future water shortage. Today, between 65 and 70% of wastewater of urban and industrial origin is reused in agriculture after treatment in biological treatment plants around the country. The Dan Region Reclamation Project (Shafdan) is the largest wastewater treatment and reclamation project in Israel. 130 Mm³/yr of reclaimed water is used for unrestricted irrigation after soil aquifer treatment (SAT). Extensive water quality monitoring is performed to keep an efficient and safe wastewater reuse system. After 25 years of operation, the Shafdan deals with the following operational issues on an ongoing basis: Biofouling of the effluent pipelines from the wastewater treatment plant to the SAT, and a lack of capacity in the SAT system. Biofilm growth in the pipelines is controlled by intermittently applying chlorine based compounds at a 10 mg/L dosage for a few hours.