Mey Ezor Dan owns the Dan Region Wastewater Treatment Plant (SHAFDAN) in Rishon Letzion, approximately 10 km south of Tel Aviv. The plant currently treats 370,000 m3/d of municipal wastewater from a population of over 2.0 million in the Greater Tel Aviv area, and is designed for the biological nitrogen and phosphorus removal.
Secondary effluent from the SHAFDAN is polished in a series of rapid infiltration (RI) basins in the Yavne area, and used as irrigation water in the arid southern part of Israel.
There are a number of major plant upgrades currently underway at the SHAFDAN. These include a new preliminary treatment facility consisting of influent wastewater screening and vortex grit removal; a new primary treatment facility with 20 large rectangular primary clarifiers; a new digester facility with 3-stage thermophilic anaerobic digestion in 8 large digesters; and a new sludge thickening and dewatering building which includes gravity belt thickening of the waste activated sludge (WAS), and centrifuge dewatering of the digested sludge. Centrate from the thickening and dewatering building will be treated in a dedicated nitrogen and phosphorus removal facility before being returned to the treatment plant for treatment with the incoming wastewater.
Mey Ezor Dan recently completed a secondary treatment staging plan and a preliminary design for a 280,000 m3/d biological nutrient removal (BNR) expansion to the SHAFDAN. The expansion will includes 2 multi-cell, step-feed BNR bioreactors, 12 large secondary clarifiers, and a process air building.
Sludge is the residual solids produced by the wastewater treatment process, and is the microbiological mass that is created as a result of the decomposition of organic material in the wastewater. The quantity of sludge generated is dependent on the volume and organic load of the wastewater that reaches the treatment plant
The SHAFDAN produces about 15,000 m³ of WAS per day at a concentration of about 1% solids. Until recently, the WAS (secondary biological sludge only) was disposed of at sea through an 11 km long 360 mm diameter outfall pipe, of which 6 km is on land and 5 km is in the sea. The outfall ends at a depth of 38 m. The outfall is currently approved by the authorities as an excess sludge disposal solution, for which a marine discharge permit has been issued.
Mey Ezor Dan has developed a land-based solution for managing the primary sludge and WAS generated at the SHAFDAN. This is being done in coordination with government ministries, the Municipality of Rishon Lezion, and environmental organizations led by the Israel Union for Environmental Protection.
After investigating a range of options for a land-based sludge management solution, it was decided by the ministry of environment & the Association to promote an agricultural strategy for handling the sludge, which involves processing the sludge and spreading it on farmland as a soil conditioner and fertilizer, since it provides environmental, social and economic benefits. The strategy is based on the construction of 8 large thermophilic anaerobic digesters – 13,200 m3 each that stabilize the sludge to a level defined in the regulations as Type A sludge. This allows the treated sludge to be applied on farmland in the center and south of Israel without further treatment. Land application of the dewatered sludge is perform by an outside concessionaire which selected in a public tender published by the Association.
With the implementation of the land-based sludge management solution, the Association will become a body that recycles 100% of its wastewater and residual sludge in a manner which will be a model for other treatment facilities in Israel while ensuring a clean marine environment and better environment for the residents of the Dan Region.