The sewage of the two basins west of the water watershed line, the north-western (Sorek Basin) and the south-western (Refa’im Basin), is treated in the wastewater treatment plant at the Sorek Valley using the activated sludge method. The treatment plant purifies, on average, approximately 80,000 cubic meters a day, including sewage from residential areas around Jerusalem such as Mevasseret Zion, Giv’at Ze’ev, Zur Hadassa, Beitar Elit, Beit Jala etc. The plant is planned for treating 100,000 cubic meters sewage a day,
The cost of its construction amounted to 350 million shekels that was obtained from the European Bank and the Israel Government. The “West Management Israel” company planned and built the plant using the D.B.O. (design-build-operate) method.
The plant is one of the largest environmental-engineering projects to be built in Israel in recent years.
Connecting Refa’im sewage basin to Sorek basin, is carried out via a tunnel that was excavated out under Mount Ora, in a tunnel 2,100 meters long, ( 5 meters high and 5 meters wide) from the area of the Biblical Zoo, up to Kerem Intersection, and a 1 meter diameter pipe was laid in it. The flow of sewage to the treatment plant from the intersection of the Sorek and Refa’im Basins is carried out in a closed 1.4 meter diameter pipeline. The construction of the tunnel saved the laying of a long pipe and the construction of a separate wastewater treatment plant or a pumping station at the Refa’im Valley. Laying the pipeline and building the plant were implemented with maximal protection of the landscape. Certainly, the “Kerem Tunnel” enabled the cessation of raw sewage flow in the Refa’im Valley, and by connecting the basins,the construction of the plant at its present location was made possible.
How is sewage treated?
After arrival at the treatment plant, the sewage undergoes a primary treatment of screening out large components such as debris, diapers, sand, oils fats etc.
The next stage is a line of biological processes that are designed to remove the organic contaminants utilizing micro-organisms and bacteria. In the treatment process, the organic contaminants matters are separated from the water. The products of the process are sludge (organic matters) and effluent (treated wastewater)
At the Sorek Treatment Plant, the sludge formed during the sewage treatment process, and from which Methane gas is produced, and is utilized to produce about 70% of the electricity consumption for operating the treatment plant.. After the treatment, the sludge is turned into fertilizer to be employed for agricultural usages .The treated water flows out to the river bed and is utilized for irrigating agricultural crops in the Kibbutz Tzora area.