Design of the Shafdan Digestion and Cogeneration Facility

Israel is a leader in water reuse and reclaims more than 75 percent of its wastewater. A state of the art solids processing facility is being designed at its largest wastewater treatment facility to compliment its water reclamation leadership. MED (“Mey Ezor Dan” Cooperative Agriculture Water Society LTD) owns the 80-MGD (300,000 m3/day) Dan Region Wastewater Treatment Plant (SHAFDAN) located in Rishon Letzion, approximately 10 kilometers south of Tel Aviv, serves two million people and reclaims the water for agricultural purposes. SHAFDAN's wastewater treatment capacity is being expanded to handle 2030 maximum month flows of 110-MGD (420,000 m3/day). A 310 dry tons per day (dtpd) (280 tonne per day) anaerobic digestion and a 10 MW cogeneration facility is being designed for SHAFDAN. This bioenergy facility is part of a land based biosolids management program that will end the current practice of discharging sludge into the Mediterranean Sea through a long ocean outfall. Class A Biosolids, as defined by the Israel Ministry of Environment, will be produced along with electric power and heat. Recovered heat will be used for solids processing. Other elements of this biosolids program include a new sludge thickening and dewatering facility that has recently been constructed and a new headworks and primary sedimentation facility that has been designed. Class A biosolids will be beneficially used for agricultural applications.Design of the SHAFDAN Digestion and Cogeneration Facility gives a global perspective to solids processing and power generation. Trends in sludge screening, anaerobic digestion technologies, digester mixing, biogas treatment and use are applied throughout the design. Class A Biosolids will be produced using batch pasteurization in conjunction with acid gas anaerobic digestion and provide a soil amendment to the local agricultural region. The biogas produced will be treated and beneficially used in the cogeneration system to produce 10 MW of power. Instead of sludge being disposed of into the Mediterranean Sea, it will be processed and beneficially used. Upon completion, it is expected that SHAFDAN will serve as a model for water reuse, solids processing, and biogas use for other wastewater treatment plants.