Transcript Shafdan
Shafdan Wastewater Treatment Plant What is Shafdan? • The largest wastewater treatment plant in Israel • Located in the Dan Region (Dan Regional Association for environmental Infrastructure (IGUDAN) • Serves 2 million people • 17 municipalities • Treats 130 million cubic meters of wastewater a year. • Irrigates more than 60% of agriculture in the Negev Goals of Shafdan To minimize environmental pollution and avoid constructing a sewage collector and disposal system To prevent the discharge of raw sewage into rivers and the sea 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 for purposes of its reuse following further treatment in the ground-aquifer system (SAT) operated by Mekorot Percent of Water Recycled How it works: ON June 28, 2012 the UN cited Israeli wastewater treatment plant as global model for its unique method of using sand to naturally filter sewage 1. Waste undergoes pre-treatment 2. The mixture of waste is purified in the original facility 3. Recharged into the ground, undergoes an additional, natural filtration in the sands of Rishon Letzion and Yavne. 4. From these fields the effluent is recharged into groundwater reservoirs where it undergoes natural physical, biological and chemical processes that improve its quality and storage ability 5. 90 KM pipeline has in the Negev transports the water for irrigation of oranges, carrots, potatoes, lettuce, wheat, flowers, peppers, cherry tomatoes other vegetables! Evolution of Technology During the Temple days sewage was not recycled. Massive pipes like the one pictured below carried waste out to the seas. Now the pipes carry waste to the treatment facility to undergo purification where the water can be reused Sewage system beneath the City of David Modern Pipeline The Process and what we learned: Phase 1: Bar Screens: In the pretreatment phase particles, plastics, metal and other trash is separated from the wastewater by two stages of mechanical bar screening. 40 tons of waste is removed daily. Phase 2: Primary Clarifiers The clarifiers are circular tanks with concave bottoms and are equipped with large rake mechanisms. The mixed liquid flows into the clarifiers. The bacteria settle to the clarifier bottom and the sludge is scraped to the center, from where it is pumped the biological reactors for further separation. Phase 3: Biological Reactors There are 4 biological reactors, each with a volume of 55,000 m3. Each reactor is equipped with 36 mechanical reactors together with recycled bacterial. The bacteria digest the carbon and nutrients in aerators provide certain zones in the reactors with oxygen to drive bacteria’s digestive process. Phase 4: Secondary Clarifiers There are 12 secondary clarifiers, each with a volume of 7, 500 m3. The clarifiers are circular tanks with concave bottoms and are equipped with large rake mechanisms. The mixed liquid flows into the clarifiers. The bacteria settle to the clarifier bottom and the sludge is scraped to the center, from where it is pumped back to the biological reactors. The treated wastewater is defined as high quality effluent, and is transferred to Mekorot’s recharge fields for further treatment. Phase 5: Sludge Pumps Large metal screw pumps withdraw the settled sludge from the 12 secondary clarifier. 30% of the sludge flow is pumped to sludge thickening units while the remaining 70% is returned to the biological reactors. Global Impact and Future Shafdan and Mekorot are influencing innovative technology to purify water in other areas of the world, especially in arid areas of the Middle East surrounding Israel. Agricultural asset: DAN VIRO Sludge Treatment Plant, which serves as part of Shafdan’s integrated project, reduces 15% of the untreated sludge flow to the Mediterranean Sea. Preserving water in other areas: With this recharge system, Shafdan maximizes the use of aquifers as an underground water storage facility, minimizing the loss of surface water stored in the Sea of Galilee through evaporation or overflow to the lower Jordan River. Negative Impact: “Israel has responded to international pressure with self-imposed isolation. Acknowledging, rewarding, and cooperating with Israel’s successes are crucial to the UN’s legitimacy and ability to influence policy in the region,” says Haaretz, a reporter from the Green Prophet. Thank You Malena Price Jamie Bergstrom