Article for WC&P Magazine
The Annual Water Conference of the Israeli Water Association is the largest event of its kind in the water community in Israel, and its central subject this year was research, technology and implementation. The Israeli Water Association is a professional and inter-disciplinary volunteer organization active with other parties engaged in the field of water, and helping them liaise for the purposes of sharing information, discussions and problem solving. The Association represents Israel in the International Water Association (IWA) and the American Water Environment Federation (WEF). The Association has hundreds of members from academia, design and consulting firms, industry, economics, management, operation, media, government institutions and more. The main goal of the Association is to serve as a professional center for all the institutions and organizations in Israel involved in water, with an emphasis on the implementation of advanced technologies and improving the operation and maintenance of purification systems. The two-day conference was divided into two parts: on the first day, 35 papers were presented during four sessions, dealing with topics such as: water treatment technologies; projects in the field of water and water environment; security, law and water; waste treatment; policies and economics1. On the second day, a tour was conducted entitled “Water supply facilities to Jerusalem – past and present”. The conference was attended by 350 participants. This article presents a summary of selected papers and provides a review of some of the sites included in the tour.
As part of the sessions on water security and policies, papers were delivered dealing with the issues of water security and international standards. A paper entitled “The State of Israel’s Preparations Relating to Water Security” dealt with apprehensions associated with belligerent acts that may damage the water sources or water supply facilities. The 9/11attacks on the Twin Towers in New York have significantly changed the security perception that was widely held until this event, and it was realized that the scope of threats against which defences are needed, must be expanded. In addition, the Water Commissioner, who is also responsible for the country’s water security, has decided to reinforce this area with a special unit that will be responsible for security. The work presented at the conference reviewed the Water Commission’s attitude towards water security and the steps taken by the Commission to advance the subject, including (a) preparations and prevention (b) event handling, and (c) purification and rehabilitation of a damaged system. It is understood that handling of emergency water events requires integration of numerous parties that during routine times are not used to working in coordination, and this includes the Ministry of Health, the Police, Army, Information service, and more. This understanding emphasized the need to extend the scope of the operational methodology that had been in place, so that the new methodology would cover new threats and proper collaboration between the parties involved in handling an emergency event.
Another lecture related to water security was entitled “Added value of a standard for a management system for water facility security”. This was presented by the head of the National Robustness branch at the Standards Institute of Israel. He stressed the fact that organizations with awareness of the need for environmental protection have taken the management system one step further by integrating risk analysis and increasing awareness of the need to prevent damage to the environment. The integration of risk analysis into the management system, in addition to creating management programs for the prevention of environmental damage, has resulted in the creation of an Environmental Management System. Furthermore, a new standard has been prepared for Security Robustness Management: Israeli Standard 24001. It is estimated that implementation of this standard in organizations engaged in the field of natural resources can improve the organizations’ preparedness and shorten the recovery time after the occurrence of an event. During the conference, the standard was presented in outline form, as well as the advantages of its implementation2.
A paper in the Policy and Economics session dealt with “International standards as advancing the exporting of water solution technologies”. A review was presented of the Government program entitled Lakes 10, which includes a policy directed at turning the State of Israel into a leader in advanced water solutions. This includes decisions relating to execution of actions for reinforcing Israel’s integration with international standards in these fields. The integration model in the field of water will attempt to duplicate the success of Israel’s integration of international standards in the field of irrigation equipment that began 30 years ago and continues to this day. Israel initiated and established an international committee for irrigation and drainage equipment, known as ISO TC23/SC18. The committee is managed and headed by an Israeli representative. This committee has advanced new standards in the field, and has published 36 standards, 28 of which are based on Israeli standards3.
A presentation on “Inactivation of micro-organisms in water using the UV/H2O2 advanced oxidation process” was given as part of the Water Treatment Technologies session. It was given by by Dr. Hadas Mamane from the School of Mechanical Engineering and the Porter School of Environmental Studies at Tel Aviv University, based on research conducted in collaboration with the Department of Civil and Environmental Engineering at Duke University, North Carolina. The theme of the paper evaluation of the potential of using highly reactive hydroxyl radicals (•OH) generated by the Advanced Oxidation Process (AOP) to inactivate bacteria and viruses in drinking water. The micro-organisms selected for the study were MS2, T4 and T7, as well as Bacillus subtillis and Escherichia coli. The •OH type radicals in this study were created when a wide spectrum ultraviolet (UV) light (200-400 nm wavelength (λ)) was absorbed directly by hydrogen peroxide (H2O2). By using H2O2 in the presence of filtered UV irradiation to generate wavelengths above 295 nm, the direct UV photolysis disinfection mechanism was minimized while disinfection by H2O2 was also negligible. Results indicated that the T4 virus and E. coli in water were sensitive to UV irradiation at λ>295 nm (without H2O2) while MS2 was very resistant to those wavelengths. Addition of H2O2 at 25 mg/l in the presence of filtered UV irradiation over a 15 min reaction time did not result in any additional disinfection of T4, while an additional 1 log inactivation for T7 and 2.5 logs for MS2 were obtained. B. subtilis spores did not show any inactivation at any of the conditions used in this study. With E. coli only a slight additional effect was observed when H2O2 was added. These results indicate that for an UV-based AOP process, the disinfection due to the presence of OH radicals is very small compared to the damage from the UV irradiation in water, although for viruses, there may be some oxidative enhancements that can assist disinfection efficacy, possibly relevant for UV- resistant viruses4.
Tour of Water Supply Works for Jerusalem – Past and Present
The second part of the conference included a tour of Jerusalem and its surroundings, and presentation of a historical review of water supply facilities to Jerusalem, past and present. Jerusalem is situated on the edge of a desert. The city itself has no sources of fresh water, and throughout its history it was necessary to transfer water into the city from adjacent areas via canals, aqueducts, tunnels and underground passages. This part of the article focuses on the Visitors Center for the transporting of water to Jerusalem and the water facilities in the historical City of David.
Visitors Center for the Transport of Water to Jerusalem
At the beginning of the 1930s, the British Mandate resolved to implement a far-reaching solution for water supply to the city – laying a waterline of a relatively large diameter at that time – 18 inches (0.45 meter), which was later detonated by the Jordanian army during the Israeli War of Independence (1948). Throughout the generations, Jerusalem has suffered from a shortage of water and has been forced to make do with water from adjacent wells and springs. It was only during the British Mandate, in 1936, that the city began to receive a supply of running water through pipes via a modern water distribution facility constructed by the British and named The First Waterline to Jerusalem. During the British Mandate, the restoration of the city in general and of its water system in particular was begun. It was at this time that the 18 inch diameter water line was laid, pumps were put into operation, and taps installed to partially replace the historic wells. Despite all this, Jerusalem remained thirsty and required larger quantities of water.
During the War of Independence, and particularly during the siege of the city, the situation became dire. Convoys of food and water no longer reached Jerusalem, as the city suffered constant shelling, day and night, by the Trans-Jordan Arab Legion. The IDF (Israel Defense Forces), founded at the time, endeavored to break a route into the city, but the Jordanians prevented their progress. As a result, the paving of a bypass road began, dubbed the Burma Road, named after the road from Burma to China paved during World War II. During cessations in the fighting, supplies, equipment and weapons convoys ascended to Jerusalem through the Burma Road. In June 1948, the water shortage worsened, and the city had water reserves for only 30 days. An emergency meeting was held between Jerusalem’s city engineer, personnel of the Defense Ministry and Mekorot (the National Water Company) personnel, and it was decided to utilize the Burma Road to lay a waterline (Figure 1). Despite the war and fighting, 250 workers were enlisted to execute the job, and within less than two months, under very difficult conditions, and sometimes under Jordanian fire, the waterline was laid along the Burma Road. Moments before the wells of Jerusalem dried up; water began to flow up the mountains and into besieged Jerusalem. The amount of water was small (between 100 – 120 m3/h), but its contribution to the morale of the residents was tremendous. The waterline was named the Shiloach Line – after the ancient water works built during the time of the First Temple (completed in the 10th century BCE, and destroyed by the Babylonians in 586 BCE). Mekorot won special acclaim for this operation from the Israeli Defense Ministry.
Figure 1: Laying the Shiloach Waterline, 1948
Since that historic waterline, Mekorot has laid four more waterlines, three of which are active to this day (Figures 2 and 3, Table 1). Currently, an additional large and complex system is planned, that will improve the water supply to the city. It is called the Fifth System for Jerusalem. In light of the growth of the population and increased demand for water, Mekorot is planning this fifth waterline system, which will address the future needs of the region. The 80 inch (2 m) diameter line will, at peak operation, supply up to 0.5 million m3/d of water. Desalinated water will also be integrated into the system. The system will supply the additional water needed for Jerusalem and its environs, and will augment the water supply to neighboring plants.
The Jerusalem Mountains region is characterized by a mountainous and divided landscape, and extensive areas of woodlands and forests. The route of the waterline passes through areas of high landscape sensitivity, and spots declared to be of historic value. So as not to damage these important areas, the design process of the waterline includes a landscape architect, environmental consultant and ecologist. Due to its importance, the Fifth Waterline to Jerusalem was declared a national infrastructure project.
Figure 2: Visitors Center for Water Supply to Jerusalem – the five waterlines from the shore to Jerusalem, from 1936, and up to planning for 2010-2020
|4 million m3||Blown up by Jordanians in 1948|
|Shiloach line||1948||10-12 inch
|0.7 million m3||Operated temporarily during the War of Independence|
|Second line||1953||24 inch
|10 million m3||Active|
|Third line||1979||36 inch
|14 million m3||Active|
|Fourth line||1994||42-50 inch
|50 million m3||Active|
|Fifth line||2010-2020||80 – 100 inch
|150 million m3||Under design|
Table 1: Waterlines to Jerusalem from 1936 to 2020
Figure 3: Waterlines to Jerusalem from 1936 to 2020
At the end of the tour of the Visitors Center, conference attendees were taken for a visit that took them back 3000 years, and included the water works in the City of David.
Underground waterworks in the City of David
The City of David is a small hill to the south of the Temple Mount, which is located between the Kidron stream to the east and a valley to the west. In this city, King David constructed the capital of his kingdom 3000 years ago. Although the City of David was not endowed with the finest topographical, strategic or economic attributes, an important factor in its selection as a capital was its proximity to the Gichon spring – one of Jerusalem’s largest springs which served as a source of life, and supplied water to its inhabitants. The City of David (Figure 4) is the ancient nucleus of Jerusalem, from which the city grew and developed throughout its history. The Gichon spring, that supplied the residents of the City of David with water, is located outside the fortified borders of the city. This fact posed a severe difficulty in planning the city’s defences, since its residents could be cut off from their regular water source during times of siege.
Figure 4: City of David Hill, source – Path of Land, Stone, Clay and Man, published by the Ministry of Defense, 1996
The engineering/military solution proposed by the national planners at the time was the creation of a tunnel quarried in the stone that lead to a hidden water source. Through this tunnel, residents were provided with access to water, and the city’s water supply was guaranteed both in times of war and of peace. Another difficulty in ensuring the water supply to Jerusalem in ancient times was due to the character of the Gichon spring, which was different from the other springs that were based on a water carrying layer (aquifer). The Gichon spring was a pulsing spring, whose water burst forth once every few hours. This required users to plan the capture of water as it burst out, collect the water in pools, and use the water cautiously.
Over the past 100 years, various segments of the underground water works were discovered and examined in relation to utilization of the Gichon water. The most widely known segment is the Hezekiah tunnel (Figure 5), through which visitors pass to this day. This tunnel was quarried in stone, running a length of 533 m, from the spring to the south-western edge of the City of David, where a large reservoir pool was constructed – the Shiloach pool. The Hezekiah tunnel is part of the water works constructed by King Hezekiah during his preparations for the revolt against the Assyrian empire (before 701 BCE). Quarrying for the water works is described by the miners in an inscription engraved into the wall of the tunnel, near its southern opening, and it reads: “Now the rest of the acts of Hezekiah, and all his might, and how he made the pool, and the conduit, and brought water into the city, are they not written…” (Kings 2, 20:20).
Figure 5: Hezekiah tunnel, source: www.cityofdavid.org.il
This water project resolved the problem of the location of the Gichon spring. Spring water was transported through the tunnel into the walls of the besieged city, so that enemies were unable to find it. In addition, the supply of water to the water pool put an end to dependence on the irregular pulsing of the spring.
As one exits the tunnel, one reaches the Shiloach Pool (Figure 6). The remains of columns in the pool are remnants of the Shiloach church. During the period of the Second Temple (516 BCE to 70 CE), water continued to flow northwards, and was collected in the Shiloach pool that was uncovered in excavations conducted in the summer of 2004. The size of the pool was 3000 m2, and the impressive remains of the street and stairs leading to the pool are visible to this day.
Figure 6: Shiloach Pool, source: www.cityofdavid.org.il
The objective of this 2-day conference was to exchange and share information pertinent to the Israeli water industry. Over 3000 years ago, the City of David was selected as the capital city of Israel due to its proximity to the Gichon spring, one of the largest springs in Jerusalem that was a source of its vitality, and supplied residents of the City of David with water. The problematic location of the spring, and making it accessible, required the excavation of an underground tunnel to lead the water through the tunnel and into a deep pool, quarried in stone, from which numerous people drew water simultaneously. This bears fascinating archeological testimony to the historical water system. But the establishment of the State of Israel in 1948 did not end the difficulties, and it was necessary to lay waterlines from the shore to the capital, of increasingly larger diameters, to supply water to the residents of Jerusalem. Currently, work is underway to lay a waterline with a diameter of 80 inches (2 m), to supply approximately 500,000 cubic m3 /d. This waterline is planned to begin operation between 2010 and 2020.
1. The Fourth Conference of the Israeli Water Association, Book of Abstracts, 21 March
2007 Kfar Hammacabia Hotel Israel Tel-Aviv.
2. The Added Value of a Standard for a Management System for Water Facility Safety, Yitzhak Ekerman, Manager of the National Robustness Branch of the Standard’s Institute of Israel, 42 Haim Lavon St., Tel Aviv.
3. International standards for the advancement of the exporting of water solution technologies, Ari Yaron, Manager of the Water Technologies Branch of the Standard’s Institute of Israel, 42 Haim Lavon St., Tel Aviv.
4. Inactivation of E. coli, B. subtilis spores, and MS2, T4, and T7 phages using UV/H2O2 advanced oxidation, Hadas Mamane, School of Mechanical Engineering, Tel Aviv University; Hilla Shemer and Karl G Linden, Department of Civil and Environmental Engineering, Duke University, NC, USA. The 4th Conference of the Israeli Water Association, Book of Abstracts.
5. Path of Land, Stone, Clay and Man, IDF Chief Education Officer, BaMahame, Ministry of Defense, 1996, p. 16-18
The author would like to thank Professor Ronald Gehr of the Department of Civil Engineering at McGill University in Montreal, Quebec, Canada, for his assistance in writing this paper, as well as Danny Targan, Chief Executive Officer and Eldad Maziel, Chief Technology Officer at Tana Water, for their encouragement and support.
About the company
Tana Water has been a major force in the provision of drinking water systems for over 30 years and is one of the world’s most advanced developers and manufacturers of point-of-use systems. Leading-edge products are matched by a focus on customer service, which comes from long-lasting partnerships with clients.
About the author
Anat Kartaginer is the head of the Water Treatment Department at Tana Water, of Emek Haela, Israel. She is a member of the Israeli Water Association (IWA), International Ultraviolet Association (IUVA) and European Point-Of-Use Drinking Water Association (EPDWA). She can be reached at +972 2 990 0222 (phone), fax +972 2 990 0500, e-mail firstname.lastname@example.org or through the company’s website http://www.tanawater.com/, www.tanawater.com.