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Wastewater Treatment and Effluent Reuse Mekorot, Israel National Water Company, Public Relations Unit, Lincoln st Tel Aviv 61201, ISRAEL Tel: 972-3-6230705, Fax: 972-3-6230641, Website: www.mekorot.co.il MEKOROT WATER IS A BUSINESS FOR LEADERS Initiated and Produced: Public Relations Unit Head Office Professional Contents: Dan Region Unit - Central District Waste Water Treatment and Reuse Division - Head Office Districts' Process Engineers Copywriter: Zohar Lidovsky Translation: SET Group Graphic Design and Production: Trigon Design Photographers: Albatros, Moshe Barkon, Eli Dgani, Israel Sun, David Tzadok, Moshe Shai May 2006 Effluent Reuse Project - Ayalon-Latrun Introduction Since its establishment the State of Israel has been confronting water shortage due to the dry climate, the desert expanse and the scarse water sources Mekorot, the national water company, has been constantly searching for solutions in order to increase the water supply, whether by improving the utilization of the existing sources or by finding additional ones Within the framework of its activities, the company deals with wastewater treatment and effluent reuse for agricultural purposes Mekorot considers the improvement of the wastewater treatment level and the expansion of the uses of reclaimed water as most important professional and ecological challenges The replacement of fresh water with reclaimed effluent for agricultural irrigation permits the supply of additional drinking water to the population, while maintaining environmental quality by reducing the ecological damages caused by wastewater Mekorot is responsible for 40% of the treated wastewater in Israel and for more than 50% of effluent reuse for agricultural needs in the country The quantities and quality of the reclaimed effluent are among the highest in the world The company invests a lot of efforts and capital in research and development of related areas such as effluent desalination, treatment by membranes and development of alternative methods for chlorine disinfection, in cooperation with leading companies throughout the world One of Mekorot's main goals for the coming decade is to utilize all the effluent in Israel, thereby to stop the disposal of 110 million cu.m./Year of effluent to the environment ± Wastewater Treatment What is the principle of wastewater treatment? Wastewater treatment in Mekorot's facilities is based on the principle according to which very high concentrations of the microorganisms meet with high-load wastewater, under a massive supply of oxygen (aerobic conditions) This process significantly shortens the natural treatment duration that takes place in the streams - from weeks and months to less than 24 hours! P ertiary treatment – This advanced treatment ensures the removal of contaminants, suspended matter, bacterial and other microorganisms found in the secondary effluent This is done by filtering the effluent through a deep granular (sand) bed filtration and disinfection by the addition of chlorine or other disinfectants At the completion of the treatment, the result is very high-quality effluent, sent to the reclamation systems for unlimited agricultural use, or to streams rimary treatment – A physical process intended to reduce the load on the biological treatment (the secondary), which consumes great amounts of energy During the primary treatment, approximately 30%-35% of the organic materials and 40% to 60% of the suspended solids are removed by gravitational sedimentation What are the wastewater treatment methods? What are the stages of wastewater treatment? re-treatment – In this stage coarse materials such as sand, rags, stones and plastics are removed This stage also includes coarse filtration by bar screens and removal of sand and oils in grit chambers T P econdary treatment – A biological process intended to treat the dissolved organic materials in the wastewater This process takes place by utilizing bacteria and microorganisms that digest the waste products, while introducing oxygen into the liquid by mechanical means (aerators or air difussion) In order to remove the contaminants from the wastewater, the bacteria population is multiplied to the extent that there are enough bacteria to digest the contaminants within a given time The organic matter found in the wastewater and the oxygen supplied are requisites for these aerobic bacteria’s existence During the digestive process the bacteria develop into larger colonies, which can be separated from the fluid using secondary sedimentation After sedimentation high-quality effluent result, suitable for agricultural use in accordance with the Ministry of Health regulations S Yavne recharge fields ≤ xidation Ponds – Until the beginning of the 90’s, this method was the cheapest and most used According to this method, wastewater is sent to shallow ponds for several weeks, until alga grows and multiplies The alga releases large quantities of oxygen during photosynthesis, utilized by the bacteria to remove the organic materials in the wastewater O ctivated Sludge – During the 90’s the Ministry of Health determined on "20/30 regulations", according to which each municipality is obligated to treat its wastewater in order to obtain effluent quality of no more then 20 mg/l BOD and no more than 30 mg/l suspended solids) As a result, many facilities (Wastewater Treatment Plants - S.T.P) have adopted this mechanical-biological method, that was found more advanced and efficient than the Oxidation Ponds By this method, a dense population of microorganisms is maintained in a constant state of mixture/circulation in the reactors to which the raw wastewater A Effluent Reuse Project - Ayalon-Latrun Ashkelon S.T.P Ashkelon S.T.P is introduced The microorganisms digest the organic material and the nitrogen and phosphorus compounds, and utilize the oxygen supplied In this form the microorganisms multiply their number at a very rapid rate, so that the process continues for 12-18 hours only After their stay in the reactors, the multiplying bacteria (biological sludge) are separated from the effluent in sedimentation clarifiers ludge treatment – The sludge treatment stream generally includes a thickning system for the sludge, before entering S into the digesters In the digesters, which are generally anaerobic, the bacterial digestion process takes place, without oxygen, and at a temperature of 35°-37°C The sludge is transferred to dewatering facilities for water extraction and the sludge (with 20%-25% solids content) can be disposed of in containers for agricultural use The gas produced in the digesters, mostly methane, can be utilized to generate electricity with a biogenerator The residual heat of this process is used to heat the sludge in the digesters ≥ Facts & Figures £ £ Wastewater Treatment by Mekorot Mekorot treats approximately 40% of the wastewater treated in Israel every year In 2005 the company operated purification plants around the country S.T.P Population Equivalent Value Daily flow (M3) Annual flow (millions of M3) Safdan Beer-sheeba Natanya Ashdod Karmiel Ashkelon Afula Rahat 2,000,000 280,000 240,000 180,000 120,000 110,000 55,000 30,000 340,000 40,000 36,000 33,000 22,000 20,000 8,000 3,500 127 14.4 13.2 12 7.3 Total 3,005,000 502,000 Effluent Reclamation by Mekorot Mekorot aspires to return all of Israel’s effluent to agriculture, thereby to contribute to the water resources in the country At present, Mekorot returns over 50% of the reclaimed effluent to agriculture through reclamation plants which are among the largest and most advanced in Israel: Plant Connected Wastewater Facilities The Third Line to the Negev Dan Region Association of Towns (D.R.A.T) Haifa and Afula Netanya and Local Drillings Ayalon (Lod-Ramla) Hadera Nahal Og (East Jerusalem) Karmiel Safed Gush Etzion Kishon Complex Emek Hefer Ayalon-Latrun Hadera Jordan Valley Karmiel Safed Gush Eztion Total ¥ 185.9 Annual Consumption (millions of M3) 145 28 18 5.5 2.5 1.5 0.9 0.2 205.6 £ Drinking water consumption in the urban and industrial sectors in Israel is 800 million cu.m per year (Data from year 2005) 470 million cu m of wastewater are created every year in Israel 430 million cu.m of wastewater are treated every year (about 90%) 340 million cu.m of effluent (treated wastewater) are reused every year for agriculture (about 70%) 110 million cu.m of non-reused effluent are returned to the environment (about 26%) Karmiel S.T.P µ Shafdan The Shafdan - the Dan Region Wastewater Treatment Plant - is owned by the Dan Region Association of Towns (D.R.A.T), which includes seven municipalities and many other settlements The facility Is one of the largest and complex plants in Israel, and is considered to be the largest and most advanced of its type in the Middle East The Shafdan treats about 130 million cubic meters of wastewater annually, and returns the reclaimed water to the Negev through “The Third Line to the Negev” reclamation system The facility serves a population of about millions of people, in the most crowded and densely populated area in the country - the Dan Region Mekorot is responsibe for the operation of the facility, guarantees the desired quality level of the effluent; recharges them to confined aquiter through infiltration fields in order to improve their quality, pumps the reclaimed water through recovery wells and supply them to the Negev at a quality permitting unlimited agricultural crop irrigation In this way Mekorot provides a solution for Israel’s increasing water needs, by turning more fresh water to urban use The fruitful cooperation that has lasted for many decades between the two public organizations: The Dan Region Association of Towns and Mekorot, has guaranteed and will guarantee in the future efficient wastewater treatment and reuse, at a very high professional level ∂ “The Third Line to the Negev” Effluent Recharge and recovery After the biological treatment (secondary stage) in the Shafdan plant, the effluent are sent to infiltration fields in the sands of Rishon Le-Zion and Yavneh, where they are recharged into the aquifer (ground water reservoir) by alternate regime of flooding and drying As it seeps through the ground, the water undergoes physical, biological and chemical processes that improve their quality In addition, the underground stay serves as a seasonal and multi-annual storage for large quantities of water, that are used for irrigation during “dry” periods After the transfer to the aquifer, and during the stay and flow there, the water is pumped by about 150 recovery wells Their purpose is to pump the reclaimed water and prevent it from penetrating into other wells in the area, which are used for drinking water supply The quality of the reclaimed water is very high, suitable for unlimited irrigation The “Third Line to the Negev” enterprise consists of a combined system of pipes, resevoirs and pumping stations whose purpose is to improve the quality of the Shafdan effluent and transfer it for agricultural use to the Negev The reclaimed water are suitable for unlimited irrigation, without fear for the customer’s health The third pipeline is separated from the two other pipelines that supply drinking water to the Negev (the eastern “Yarkon-Negev” and the western “Yarkon-Negev” pipelines), and is intended to transfer only reclaimed water for unlimited irrigation for all types of crops in the Negev The system is made up of three main pipe sections, whose total length is 90 kilometers, six operational “floating” reservoirs and three end reservoirs in the Negev, in order to collect the stored reclaimed water during the winter and increase the quantity of water supplied for irrigation during the summer months ∑ Goals By returning reclaimed water to the Negev, Mekorot has achieved the following goals: Full utilization of Shafdan effluent and prevention of wasting one of the most precious resources in Israel – water Improvement of the water balance in Israel by diversion of a larger quantity of fresh water for domestic and industrial use Transferring large agricultural areas from the congested center of the country to the expanses of the Negev Creation of green groves and fertile agricultural fields in previously arid and desolate areas Reduction of the potential contamination of ground water and the spreading of disease to the population due to lack of appropriate wastewater treatment and disposal ∏ Initiated and Produced: Public Relations Unit Head Office Professional Contents: Dan Region Unit - Central District Waste Water Treatment and Reuse Division - Head Office Districts' Process Engineers Copywriter: Zohar Lidovsky Translation: SET Group Graphic Design and Production: Trigon Design Photographers: Albatros, Moshe Barkon, Eli Dgani, Israel Sun, David Tzadok, Moshe Shai May 2006 Wastewater Treatment and Effluent Reuse Mekorot, Israel National Water Company, Public Relations Unit, Lincoln st Tel Aviv 61201, ISRAEL Tel: 972-3-6230705, Fax: 972-3-6230641, Website: www.mekorot.co.il MEKOROT WATER IS A BUSINESS FOR LEADERS ... activities, the company deals with wastewater treatment and effluent reuse for agricultural purposes Mekorot considers the improvement of the wastewater treatment level and the expansion of the uses... the effluent in Israel, thereby to stop the disposal of 110 million cu.m./Year of effluent to the environment ± Wastewater Treatment What is the principle of wastewater treatment? Wastewater treatment. .. Towns and Mekorot, has guaranteed and will guarantee in the future efficient wastewater treatment and reuse, at a very high professional level ∂ “The Third Line to the Negev” Effluent Recharge and