Shafdan’s Wastewater Treatment System The Shafdan Plant
The Dan Region Wastewater Treatment Plant (Shafdan) is a complex inter-regional system that collects, treats and reclaims municipal wastewater in high density urban areas and industrial zones. Igudan Environmental Infrastructure’s principal collection and carrier systems are comprised of the Hayarkon Collector Main, the Ayalon Main Collector and the Shoreline Collector Main. These lines together have a total length of about 70 km of principal and secondary carrier piping that range in diameter from 60 cm to 2.2 m. Igudan’s principal carrier system for transporting raw wastewater begins at the Reading Pumping Station in north Tel Aviv, continues along the Tel Aviv beaches until reaching the Bessa Pumping Station at the entrance to Yafo, and from there through Yafo and Bat Yam to the treatment facility at Sorek.
Where does the water go?
Shower water is collected into a drain and disappears down the pipes, as does water that flows down the kitchen sink and the toilet, and from the dishwasher and the washing machine… Most of us have no idea where this sewage water is taken and how it disappears. Without a sophisticated and state-of-the-art system for collecting household sewage and wastewater and its removal, sewage would run through the streets and would become impossible to bear, creating bad odors, breeding mosquitoes, transmitting serious diseases and having other serious effects. Our natural environment would also be gravely damaged: wadis, river courses, beaches, groundwater, vegetation and wildlife… would all suffer irreversible damage.
Stopping the discharge of wastewater into the Mediterranean Sea
The phase stage of the system was operated through February 1987, in which wastewater from Holon, Bat Yam, Rishon Lezion and south Tel Aviv-Yafo only was sent for biological treatment at the flocculation circulation aeration ponds at the Sorek Site, totaling about 20,000,000 m³ per year. Stage 1 of the construction and operation of the mechanical-biological wastewater treatment facility at the Sorek Site was completed in February 1987, while Stage 2 of the plant began operations in March 1996. Since then, the facility has been handling all of the wastewater from the Metropolitan Dan Region, amounting to about 120,000,000 m³ per year, so that wastewater is no longer discharged into the Mediterranean Sea.
The wastewater treatment facility and principles of the treatment process
The treatment facility is operated by the Shafdan Unit of the Central District of the Mekorot Water Company, Ltd., which acts as a contract operator for the Association.
Shafdan’s main goals:
1. To minimize environmental pollution and avoid health risks by constructing a sewage collector and disposal system.
2. To prevent the discharge of raw sewage into rivers and the sea.
3. To contribute toward protecting and preserving the state's dwindling water resources through appropriate treatment of sewage water for purposes of its reuse. The reclaimed water is supplied for agricultural use following further treatment in the ground-aquifer system (SAT) operated by Mekorot.
Purification of the wastewater is performed through natural biological processes that bring about the removal and decomposition of organic materials in the water. The household sector in Israel discharges primarily sodium and boron into the wastewater, the source of which is household detergents. Reduction in the concentration of these materials in detergents marketed in Israel as a result of legislation that has been recently enacted is bringing about a continual reduction in these pollutants in the wastewater. The industrial sector discharges salt-rich solutions (brines) into the sewage system from the following sources: the refurbishing of ion exchangers used in water softening, cloth dyeing processes used in the textile industry, meat preparation processes, the manufacture of pickles and canned goods, fish processing, leather tanning, the cheese industry and brines stemming from industrial equipment cleaning processes.
Reducing brines in effluents
The upgrading of effluents in wastewater treatment facilities for purposes of reducing chloride in brines to levels under 250 mg per liter is very expensive. Brines in wastewater from industrial sources can be reduced at the source by changing manufacturing processes or by transitioning to technologies that don’t require the addition of salt, such as water softening by reverse osmosis rather than by using ion exchangers. Another method is to separate the discharge of brines at the factory from other discharges, collecting the brine in ponds and discharging them into the sea at approved sites, subject to the provisions of law that prevent marine pollution from land sources.
Recycling, that’s the whole story
The Shafdan system was constructed by Igudan Environmental Infrastructure in order to treat wastewater in the Dan Region and to recycle it into water that can be used for agricultural irrigation for all types of crops in Israel, without limitation. The population of the Dan Region, which now numbers about 2½ million residents, today benefits from Shafdan’s water purification and recycling services. Next to the National Water Carrier, the Shafdan system has become the largest water producer in Israel from a single source and the most advanced system of its kind throughout the eastern Mediterranean Basin. The treated wastewater is sent to the Negev Desert and contributes to its development. More than 60% of agriculture in the Negev is irrigated by Shafdan water. The establishment of the Shafdan system began with the operation of aeration ponds having a total area of about 2,000 dunams (about 2,000,000 m²). Today, only the mechanical-biological plant is operating, making possible discontinuation of activity at the aeration ponds. These ponds will be dried and turned into a municipal park in the near future.