Messing A.1, Sela Y.2
1Balasha-Jalon Infrastructure Systems, Haifa, Israel
2Igudan-Dan Region Association for Environmental Infrastructure, Tel-Aviv, Israel(free)
The SHAFDAN is the largest wastewater treatment plant in Israel and currently treats 370,000 m3/day of municipal wastewater, about 92% of its treatment capacity. Waste sludge from the plant is discharged to the Mediterranean Sea through a marine outfall. The SHAFDAN is committed to ending the disposal of its sludge to the sea by the end of 2016 by providing a land-based biosolids management program that produces a Class A biosolids for agricultural use. In order to implement this strategy, a number of large-scale construction projects were undertaken.
These projects include a new sludge thickening and dewatering facility, updated headworks, a new primary treatment facility, and a new 3-stage thermophilic anaerobic digestion facility. The total capital cost of these projects is estimated to be US $300 million. This paper describes the principal components of these projects and their design parameters.
Keywords: Anaerobic thermophilic digestion, Primary clarifiers, Sludge thickening and dewatering.
|Figure 1: SHAFDAN Current Process Flow Diagram|
The SHAFDAN (Greater Tel Aviv Wastewater Treatment Plant) is the largest regional wastewater treatment plant in Israel. The plant treats wastewater from 35 municipalities. The population served by the SHAFDAN is approximately 2.3 million people. In 2015, the plant treated an average daily flow of about 370,000m³/d. The raw wastewater has a relatively high strength: BOD = 400 mg/l; TSS = 410 mg/l; TKN = 70 mg/l; P = 10mg/l (Mey Ezor Dan, 2014). The Shafdan was originally constructed in the 1960s as a large earth-lagoon oxidation pond system followed by lime-treatment and ammonia- stripping lagoons. The lagoon system was replaced by an extended aeration activated sludge facility, consisting of headworks, BNR bioreactors and final clarifiers. Primary clarifiers were not included in the facility. The secondary effluent meets very high quality standards with average values of BOD <6mg/l; TSS <6mg/l; TKN <6mg/l; TP <1mg/l. The effluent is infiltrated into a sand aquifer with an average retention time of 1 year, pumped and reused for unrestricted agricultural land application in the south of the country, supplying more than 70% of the irrigation needs