FUJI ELECTRIC JOURNAL 2001 Vol.74-No.8

Water processing technology which watches a water cycle system

Present Status and Prospects for the Circulating Water Environment
 Masakazu Usui, Tomoyasu Kida, Hiroshi Tada
In Japan s water environments, pollutants still continue to accumulate and concentrate in the water system due to the repeated use of water and various chemical substances discharged into the environment. It is necessary in the future to control the discharge load into environment lower than nature s own purification capacity and stop environmental deterioration. Fuji Electric supplies water environment technologies, such as sensor groups to on-line monitor the momentarily changing water environment, the simulation of algae multiplication in closed water areas, and process control technology to operate water/sewage treatment plant capacity to the maximum.

Water Quality Maintenance System for Lakes and Marshes
 Manabu Sagawa, Ikuo Myose, Naohiro Noda
Lakes, marshes, and reservoirs play an important role in reserving water resources and supplying drinking water. Recent natural or artificial pollutant inflow from the upstream area has rapidly made these water resources eutrophic and caused various obstacles to water utilization. This paper describes the following solution technologies for preventing lakes and marshes from eutrophication and maintaining the valuable water resources for the future: (1) simulation for water quality prediction using an ecosystem model (2) monitoring of lake and marsh water quality (3) direct purification technology for lakes and marshes.

Water Quality Sensor Technologies for Various Environments (Lakes, Rivers, and Drinking Water)
 Takashi Aoki, Mutsuhisa Hiraoka, Satofumi Kikuchi
Recent environmental problems to water quality have been diversified. For example, sudden water quality accidents; algae multiplication caused by eutrophication; raw water and underground water pollution caused by agricultural chemicals, endocrine disrupter and organic chemicals; reduction of by-products from disinfection; and risk management against pathogenic microbe such as cryptosporidium. Fuji Electric has developed various water quality sensors and solution technologies for safety improvement and labor saving by automated monitoring. This paper describes the newly developed hybrid particle counter, trihalomethane formation potential meter and oil-on-water sensor, as well as their application systems.

Ozone Injection Control System Against Bromate Formation
 Yasuhiro Kato, Takayuki Morioka, Hiroshi Hoshikawa
Ozonations of water containing bromide leads to the formation of bromate as a by-product. The experimental investigation showed that the reaction of decreasing trihalomethane formation potential is prior to and faster than that of bromate formation. This paper suggests that bromate formation can fully be controlled by monitoring dissolved ozone concentration and controlling ozone injection at the necessary minimum. Also it proposes an operation support system to minimize risk of bromate formation.

Advanced Microfiltration System with Ozonation
 Norimasa Nonaka, Naruaki Kadokawa, Nobuyuki Motoyama
Ozone application was investigated to prevent the foulant of membrane, an important technical problem in applying membrane filtration to drinking water systems. As the result, the permeate flux was 5m3/(m2day) with ozone pretreatment under the condition of residual ozone in the permeate, and 2 to 3 m3/(m2day) when injected into back-washing water. The flux in the system with ozonation was several times higher than that without ozonation. The ozone dosage was adjusted in order to maintain the required dissolved ozone concentration in the permeate or backwashing water.

Water Purification Plants Using Self-Supply Energy
 Souichirou Yamamoto, Yoshinori Nagakura, Hajime Ito
Water service utilities are tackling the introduction of new energy facilities to improve energy consumption and environmental preservation using environment-friendly energy, as well as in case of a disaster, maintain the water service function as a lifeline ensuring their own power supply by these facilities. This paper describes the hydroelectric power generating equipment, cogeneration system, and solar power generating equipment so far supplied to the Higashi-murayama water purification plant of the Tokyo Metropolitan Waterworks Bureau.

Sensor Technologies Monitoring the Environmental Water Quality of Sewerage
 Koju Miyairi, Masanori Sato, Yoshiharu Tanaka
Recent advance in urbanization and industrial development have caused various environmental problems. The role of sewage treatment plants in the water environment has become important. Harmful chemicals flowing into sewage treatment plants obstruct the biological function of sewage. This paper describes the importance of toxicant monitor installation to discover harmful chemicals in advance as well as its principle. It also introduces a supersonic sludge interface meter that advances the reduction and recycling of sludge and strictly controls the amount of sludge in the plant, and an optical water level meter for efficient pump control in the rainwater pumping plant against a heavy rain in large cities.

Advanced Sewage Treatment Control for Water Environment
 Noboru Okuda, Yoshitaka Okada, Kousei Sasaki
Recently, the bad smell and taste of service water and fishery damage from red tides due to the eutrophication of lakes, marshes, and inland seas have become a problem. Because eutrophication is accelerated by nutritious salts of nitrogen and phosphorus contained in waste water flowing into rivers, marshes, and seas, advanced sewage treatment mainly aiming at nitrogen and phosphorus removal has been promoted. From among Fuji Electric's activities to meet advanced sewage treatment, this paper describes the method of controlling the advanced treatment process, examples supplied, and trials using simulation to improve treated water quality.

Open Supervisory Control and Data Acquisition System with Web Technology in Waterworks and Sewerage
 Shinji Takamisawa, Kenji Kawato, Hiroshi Motoyama
In recent waterworks and sewerage, their diffusion has caused the shortage of operators as well as strong claims for improvement in labor environment. This paper describes the required functions and introduced examples of the next-generation open supervisory control and data acquisition (SCA DA) system using information technology as a help to solve the problems. Then it gives descriptions of Fuji Electrics system components applicable to the system construction, classifying them into management stations, wide-area stations, operator stations, controller stations, PIO stations and networks.

Energy Conservation and Recycling in Waterworks and Sewerage
 Souichirou Yamamoto, Eiichi Masuzawa, Osamu Sato
Taking the opportunity of The Third Session of the Conference of the Parties to the United Nations Framework Convention on Climate Change, plans for reducing environmental load have been going on. Revised Law Concerning Rational Use of Energy and Law on Promotion of Green Purchasing were prepared and completed and it is expected that inplementation of the plans is accelerated further. In relation to energy conservation and recycling that support environmental accounts, this paper introduces products that meet these laws and suggests an example of a method of coping with the future situation.

Solutions for the Operation and Management of Waterworks Facilities
 Makoto Kakei, Tomofumi Maruyama, Hirohide Akiyama
Many water supply utilities are suffering from deficit operation. Amendments to the Waterworks Law in June, 2001 aims to integrate water supply utilities to wide-area ones and systemize of management contracts to third parties as well as to disclosure information to consumers and improve quality by stricter regulation to water supply to receiving tanks. In this circumstance, Fuji Electric has prepared a solution menu for work analysis, operation control and water quality control to receive management contracts from water supply utilities as well as proposes the planning of a management center to support wide-area operation.

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