Tokyo Waterworks supports the capital of Tokyo Tokyo, the Japanese capital, is the largest city in Japan with a population of about 13.16 million, which is about 10% of the country s entire population (as of October 1, 2010). Tokyo is the center of politics and business and with its concentration of national political functions and major companies. Also, it is an internationally important city with an abundance of information from internal or external sources. Tokyo Waterworks provides detailed and efficient water supply control and management to ensure a stable supply of water and has a total facility capacity of 6.86 million m 3 per day to support the residents of Tokyo and all urban functions. Population served: 12,948,248 (as of October 1, 2013) Annual total distributed amount: 1,523,491 1000 (as of FY 2013) Water Supply Operation Center The Water Supply Operation Center plays a central role in water supply control and management. The facilities of Tokyo Waterworks form a large-scale system consisting of water intakes at three main river systems, 11 main purification plants and 41 main water supply stations and transmission/distribution pipe networks. The center provides comprehensive control and management of the system. Water Supply Operation Center Purification Plants of Tokyo Waterworks 1
Tokyo water, the highest quality Japan is one of the few countries where tap water is drinkable directly from the faucet. Tokyo Waterworks strives for the world s highest level of potability and taste through a variety of different efforts. Water quality target for delicious water Tokyo Waterworks has established a unique water quality target for delicious water, which is stricter than national water quality standards and aims for the improvement of customer security and reliability. Tokyo High Quality Management Program (the Tokyo version of the Water Safety Plan) The Tokyo High Quality Management Program (the Tokyo version of the Water Safety Plan) is a comprehensive water quality management program that integrally controls and manages (1) the Water Safety Plan from water resources to faucets as a new water quality risk management method, (2) the ISO 9001 certified quality management method used at purification plants and (3) ISO/IEC 17025, in order to assure the reliability of water examinations. By consistently controlling and managing this program, we will realize a higher level of potability and taste while improving the reliability of tap water at the same time. Thorough water quality management We provide detailed water quality management, from water resources to faucets, to supply potable delicious water. Regular survey of water quality at water resources Water examination at purification plants for appropriate water treatment Continuous monitoring using automatic water quality meters and regular detailed examinations at 131 water taps in Tokyo Basic data of Tokyo Waterworks 2
Management of water conservation forest Tokyo Waterworks has been managing a forest of about 23,000 ha in the upper basin of the Tamagawa River for more than 100 years in order to assure a stable river flow rate in the Tamagawa River water resource area and to conserve the Ogouchi Reservoir (Lake Okutama), which is Tokyo s own water resource. We have developed new management plans for the water conservation forest for waterworks roughly every 10 years and have managed the forest according to these plans. Details of our efforts Conservation and management of forests Prevention of and recovery from mountain disasters Improvements in forest management infrastructure Connections and interactions in water resource areas The advancement of environmental measures Efforts relating to privately owned forests in the upper reaches of the Tamagawa River The history of water treatment methods in Tokyo Tokyo Waterworks takes raw water from various resources such as surface water from reservoirs and rivers, underground flows and groundwater and applies the water treatment appropriate to the quality of the water. Facility capacity ( 10,000m 3 per day) 800 700 600 500 400 300 200 100 0 Water treatment method Disinfection only Slow sand filtration method Rapid sand filtration method Advanced water treatment method Membrane filtration method Characteristics River surface water and ground water distributed with chlorination only. Raw water is filtrated at a slow speed of several meters per day. Microbes develop on the surfaces of the filtration sand and suspended organic substances are removed by the action of the microbes. After coagulation and sedimentation of impurities in water using chemicals, the water is filtrated at a speed of 120-180 meters per day through filtration sand. Ozone treatment and biological activated carbon treatment are added to a rapid sand filtration process. Impurities are separated by passing the raw water through microscopic holes. Start of water treatment Prevention of infectious diseases Although river surface water and groundwater were directly used for drinking by the first half of the Meiji era (1868~1912), water treatment started in the 1890s due to the spread of waterborne diseases, such as cholera and dysentery. Improvement in operating efficiency/space savings Slow sand filtration method Membrane filtration method This method is employed when clean water is used as the raw water or for a small purification plant in a mountainous area. Advanced water treatment method Progress of river pollution Since unpleasant tastes, odors, and toxic organic substances could not be completely removed as river pollution progressed during the high economic growth period, an advanced water treatment method was introduced. Rapid sand filtration method Expansion of the city With the increase in demand for tap water due to the development of Tokyo, the acquisition of the large amounts of land required for a slow sand filter became difficult. Therefore, the rapid sand filtration method was adopted, which requires less land than the slow sand filtration method. 1900 1920 1940 1960 1980 2000 year 3
State-of-the-art water treatment technologies Advanced water treatment Advanced water treatment processes, which combine ozonation and biological activated water carbon adsorption treatment with the rapid sand filtration method are in the process of being introduced. Since the first introduction of advanced water treatment to the Kanamachi purification plant in 1992, we have steadily promoted its development at other plants located along the Tonegawa River System. The development work at these plants was completed in 2014; currently all the water taken from the Tonegawa River System is treated through the advanced water treatment system. Figure : Advanced Water Treatment Facility System Membrane filtration treatment When water passes through a membrane with ultramicroscopic holes, the suspended substances and microbes, such as cryptosporidium in the raw water, can be removed. While Tokyo Waterworks introduced the largest membrane filtration facilities in the country at the Kinuta purification plant and the Kinutashimo purification plant as of FY2007, the eight small-scale purification plants in the Tama area also employ the same membrane filtration facilities. 4
Leakage Prevention Measures Although the leakage rate in Tokyo was more than 20% fifty years ago, it has improved to 2.2% in FY 2013. The total length of the distribution pipes in Tokyo is now 26,613 km, but the leakage rate is one of the lowest in the world. Additionally, the reduction in the leakage volume also contributes to a reduction in environmental burden through a reduction in the volume of carbon dioxide emissions. Planned replacement of water pipes and improvement of pipe materials Leakage prevention measures in Tokyo Ensuring a high Leakage detection standard of and early repair leakage prevention works technologies Leakage prevention measures in Tokyo Planned replacement of water pipes and improvement of pipe materials Leakage detection and early repair works Ensuring a high standard of leakage prevention technologies This level of reduction in the leakage rate is the result of active implementation of leakage prevention measures. Tokyo Waterworks repairs surface leaks on the same day they are found as a general rule and executes scheduled leakage volume measurements and patrol inspections for underground leaks. As for the replacement of aged distribution pipes with ductile iron pipes, we have completed 99% of the total planned replacement. In addition, we have accomplished material improvement work to replace lead service pipes with stainless steel pipes, with all being completed. In addition to our successive activities over many years, we have been improving the efficiency of our work through the development and improvement of leakage detection related equipment, such as electronic leak detectors, minimal flow measurement equipment, correlative leak detectors and time integration leak detectors. 5
Earthquake Disaster Measures Japan is one of the world leading countries having frequent earthquakes. The Great East Japan Earthquake occurred in upper 5 of seismic intensity. The imminence of a so-called epicentral earthquake in the capital area has been pointed out. According to the updated projection by the Tokyo Metropolitan Government Disaster Prevention Council, such epicentral earthquake once occurred may bring about seismic intensity of 7 at maximum in some area and average seismic intensity of upper 6 may be recorded in a large number of areas. This projection of disaster urges the necessity of views such as countermeasures against worse scenario earthquake and liquefaction risks. Since Tokyo Waterworks takes a role to support the lives of 13 million of Tokyo citizens, urban activities and central functions of the capital, we recognize the earthquake disaster countermeasures to be one of the highest priority agendas, and aims at establishment of earthquake-resistant system of water supply suitable for the capital city. Establishment of earthquake-resistant water supply system A i m i n g a t m i n i m i z a t i o n o f damages in the water supply system in case of any earthquake disaster and at maximization of securement of water supply s e r v i c e s, m e a s u r e s f o r earthquake-resistance in total system from water sources to water supply at end users are continued to be implemented effectively and efficiently, mainly in the following: [Major measures] Duplexing of water conveyance facilities and reinforcement of water transmission pipe networks Reinforcement of earthquake-resistance of water supply facilities Reinforcement of earthquake-resistance of pipelines Reinforcement of non-utility power generation facilities Securement of electric power sources for telemeters installed at water distribution mains and other relevant devices Reinforcement of backup functions In order to supply as much water as possible even in case of shutdown of specific facilities due to any earthquake disaster, reinforcement of backup functions shall be made particularly in installation of earthquake-resistance facilities, duplexing of conveyance facilities and networking of water transmission pipe system. Securement of drinking water In case of water stoppage or other accidents occurred in the earthquake disaster, emergency water supply shall be undertaken mainly in the following manners: (a)water supply at relevant points such as water purification plants/stations, water supply stations and emergency water supply tanks (b)water supply by vehicle transportation (c)water supply through temporary hydrants Figure: Duplexing Conveyance Facilities Figure: Network of the Water Transmission Figure : Installment of Earthquake-resistant Pipeline Joints on Supply Route to Important Facilities (Example of a project to install earthquake-resistant joints in pipelines) (Image) 6
International Development Acceptance of overseas trainees and overseas dispatch of our staff Utilizing its technology and know-how, Tokyo Waterworks has accepted trainees from overseas and dispatched its staff members overseas over the years in response to requests from other countries. Training Details Practice of water leakage prevention, provision of lectures on water quality management, customer service methods, etc., acceptance of visitors our facilities such as water purification plants Accepted about 2,000 trainees (FY 2009 FY 2013) Staff dispatch Details As requested by recipient countries (e.g. advice on project planning, implementation and evaluation) International development in cooperation with domestic and international stakeholders Tokyo Waterworks has been proceeding with international development utilizing the services of TSS Tokyo Water Co., Ltd. (TSS) 1 and TSS s subsidiary, Tokyo Waterworks International Co., Ltd. (TWI), in cooperation with public institutions and private enterprises, etc. For example: Participation in JICA s technical assistance projects Provision of technical assistance to overseas water utilities through mutual exchanges International business development in areas such as non-revenue water management, utilizing the strengths of Tokyo Waterworks and other Japanese entities Information transmission to the world Tokyo Waterworks transmits/shares its technology and know-how to/with the world by participating in and actively organizing international conferences. Hosting of the 4th IWA-ASPIRE Conference and Exhibition of 2011 Hosting of the 11th IWA World Water Congress and Exhibition 2 of 2018 (planned) For more details of Tokyo Waterworks efforts, updates and application for trainings related to international activities please go to the URL below. http://www.waterprofessionals.metro.tokyo.jp/ Edited and Published in Feb.2015 ( -676) Bureau of Waterworks Tokyo Metropolitan Government 2-8-1 Nishi-Shinjuku, Shinjuku-ku Tokyo, Japan http://www.waterprofessionals.metro.tokyo.jp/