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Effluent Reclamation

Effluent Reclamation

The Mekorot Group works to improve Israel’s water balance through a variety of activities, including wastewater treatment and reclamation for agricultural crop irrigation.  The Group supplies over 60% of the treated wastewater for Israel’s agricultural needs.

 
Mekorot considers the improvement of the quality of treated wastewater and the expansion of the variety of its uses a professional and ecological challenge of the highest order:  replacing freshwater with treated wastewater for agricultural irrigation diverts additional freshwater for the population and protects the environment by reducing ecological damages  caused by untreated and unused wastewater. 

 
The amount of reused treated wastewater in Israel is among the highest in the world (80%).


In order to meet the targets of high quality water, Mekorot invests substantial efforts in research and development, and it develops and implements treated wastewater desalination, advanced Oxidation Processes (AOP), various membrane treatments and development of alternative methods for disinfection.  These activities, executed in cooperation with leading global institutions, are designed to improve and upgrade wastewater treatment and reclamation.


Mekorot’s goals in the field of wastewater reclamation for the coming decade are to achieve  full utilization of all of Israel’s treated wastewater, and to stop the annual flow of 50-70 million cubic meters of unutilized wastewater into the environment.

 
The Third Line to the Negev


Mekorot is responsible for the operation of the Dan region’s wastewater treatment plant (SHAFDAN), considered as the largest and most advanced of its kind in the Middle East.  The wastewater treatment plant treats about 130 million cubic meters of wastewater annually.
After the treatment at Shafdan, the treated wastewater is transferred to infiltration fields in Rishon L’Zion and Yavne, is recharged into the confined groundwater through a flooding and drying process. As it seeps into the groundwater, the water undergoes physical, biological and chemical processes which significantly contribute to the improvement of its quality. 
Its high quality is suitable for the unlimited irrigation of agricultural crops.
Additionally, this serves as a method for seasonal and multiannual storage of large quantities of water to be used for irrigation during ‘dry’ periods.  After the storage in the groundwater reservoir and while it is stored, the reclaimed water is pumped by a peripheral system of 150 recovery wells. whose aim is to prevent the leakage of this water into other drinking water wells in the region .  The system is managed in such a way as to facilitate the total separation between the treated wastewater that was infiltrated into the groundwater and the natural groundwater, through pumping that controls the water levels and prevents the infiltrated water from mixing with the natural water.


The reclaimed water is  supplied for  irrigation of agricultural lands in the Negev, through Mekorot’s reclamation plant - The Third Line System to the Negev.  The plant began operation in a limited format in 1977, and was launched in its expanded format in November, 1989.  The plant is comprised of a fully integrated system that includes 150 recovery well, a main pipeline of about 90 kilometers and a diameter of 70 inches, six ‘floating’ operational reservoirs and five seasonal reservoirs in the Negev, with a total volume of about 18 Million CM, designed to store the surplus water reclaimed during the winter in order to increase the amount of water supplied for irrigation during the summer months. 
The treated wastewater is suitable for unlimited agricultural irrigation, without sanitary concerns for the customer.  Reclamation of wastewater frees up additional freshwater for urban use, thereby providing a solution to Israel’s increase in water consumption.


The Third Line to the Negev is separated from the two other lines that supply drinking water to the Negev:  the eastern Yarkon-Negev line and the Western Yarkon-Negev line.
By supplying  the reclaimed water to the Negev, Mekorot achieves a number of goals:
• Full utilization of the Dan Region’s wastewater and preventing wastage of one of Israel’s most precious resources - water.
• Improving the water balance in Israel by diverting larger amounts of freshwater for domestic and industrial consumption.
• Relocating agricultural processing areas from the overcrowded center of the country to the expanses of the Negev.
• Creating green groves and fertile agricultural fields in areas that were previously completely arid and desolate.
• Reducing the potential for contamination of the groundwater and the spreading of diseases as a result of proper treatment and disposal of wastewater.

 

Research Studies at the Shafdan Reclamation System


As part of the plans for the regular supply of high quality water in the future, Mekorot invests in research and development of new technologies for water desalination and treatment, using various types of membranes, in order to optimally utilize the water sources. The company works to improve the treated wastewater by desalinating secondary wastewater up to drinking water level, for agricultural use, unlimited irrigation, enriching the aquifer and for industrial use.

 
With the increase of the amounts of treated wastewater at Shafdan, a surplus of treated wastewater is expected that cannot be infiltrated into the SAT (soil-aquifer treatment) system.  In order to find solutions for the surplus treated wastewater, a pilot system was established at Shafdan for membrane treatment of surplus wastewater.  At the end of the process, the quality of the treated wastewater is close to the quality of the water following the SAT treatment currently conducted at Shafdan, which is based on the infiltration of secondary effluents in sandy seepage basins into the aquifer.

 
At the plant, Mekorot is designing a method for producing reclaimed water that is close in quality to that of the water of the Third Line to the Negev (water that may be used for unlimited irrigation of all types of agricultural crops).  Using this method, a membrane treatment will be used for surplus wastewater that has undergone secondary treatment.  This surplus cannot be infiltrated in the infiltration fields using the SAT method, because the infiltration fields are limited.  This method uses a different process, the results of which are close in quality to the water produced with Shafdan’s existing tertiary treatment.