Solutions for Water Supply and Sewerage Systems
Water supply and sewerage facilities are crucial social infrastructure for our life to pursue a stable water supply, to maintain a drinkable water quality, to protect the water quality at water sources and to protect public health through proper waste water treatment.
Toshiba designs entire facilities to enable efficient and stable operations and to prevent various problems concerning water supply and sewerage systems. In addition, Toshiba endeavors to offer the best solutions for improving the energy efficiency of facilities, streamlining operations and adding extra values to our services.
Because water supply and sewerage facilities are important for safe and comfortable lives, they must be properly managed and operated.
Supervisory Control and Data Acquisition (SCADA) is a technique for quickly and accurately identifying the operational status of water supply and sewerage facilities. Automatic control enables smooth and smart operation of the facilities, making it easy to achieve the target water quality and conserve energy.
In addition, SCADA allows a management center to keep track of facilities such as purification and sewerage treatment plants dispersed across a wide area via external communication lines. Therefore, SCADA can be adapted to various applications in a flexible manner such as wide-area management of plants and unattended operations.
Toshiba offers easy-to-use operation systems for operators by leveraging its expertise and decades of experience in the monitoring and control of water supply and sewerage plants. These operation systems allow quick and accurate monitoring of the real-time operating states of power receiving and transforming equipment, components, devices and instruments in water supply and sewerage facilities.
The water sources of rivers and lakes are facing various problems regarding water quality such as musty odors caused by algae and generation of trihalomethane. These problems are caused by such conditions as eutrophication, discharge of domestic waste water and inflow of agricultural chemicals. The conventional water disinfection by chlorination are becoming unable to cope with the deteriorating water quality at these water sources.
The water quality deterioration at water sources such as particularly musty odors in summer and ammonium nitrogen in winter is becoming serious.
When bromide ions are present, excessive ozone injection generates bromic acid, which is one of the parameters of the water quality standard. Feed-forward and feedback control to improve ozone injection based on the fluorescence intensity of water is useful to pursue a safe water quality level (reduced bromate ions) and energy-efficient operations (less energy required for ozone generation).
Our system can also be used to control the injection of powdered activated carbon.
As demand for securing tap water quality is increasing, water quality management at purification plants is becoming more rigorous than ever before to supply safe and good quality water. Under such circumstances, Toshiba has developed a feedback control system for coagulant injection equipped with a streaming current meter, which is being used in actual plants.
The conventional coagulant injection control systems relies on feed-forward control based on the raw water turbidity versus coagulant injection rate curve derived from past injection records. However, the conventional systems are unable to respond to rapid fluctuations in the quality of raw water and tends to inject excessive coagulant to pursue coagulation. To address this issue, Toshiba's coagulant injection control system combines feed-forward control with feedback control using streaming current which is related to the coagulation conditions. This system enables suitable injection control and thus reduces the amount of coagulant injected.
In addition to stable water supply, efficient use of water resources has been becoming important in recent years. As water supply facilities are being integrated and abolished, proposals for wide-area water operation are becoming necessary.
Toshiba's water distribution management system is designed to realize efficient operation of water distribution networks. It gathers, accumulates and monitors measured values in real time such as fluctuating water distribution flow rates, pressures and water quality factors, and issues an alarm when it detects any abnormal values. This enables an integrated operation including quick decision-making for the handling of abnormalities as well as the reporting of operations such as an analysis and implementation of countermeasures.
Conserving energy and improving the quality of discharged water (reducing nitrogen and phosphorus concentrations) usually have a trade-off relationship in sewerage treatment. This means that more electrical energy is required to improve water quality while water quality may be lowered if energy is spared. To address this issue, Toshiba has developed an energy-efficient aeration air flow control system that improves both energy efficiency and the discharged water quality.
The electricity cost required for aeration accounts for about 30 to 60% of the total electricity cost of a sewerage treatment plant. Thus, there is a need for control technologies for improving energy efficiency and reducing the emission of greenhouse gases. There is also a need for technologies for efficiently removing nitrogen and phosphorus from the treated water discharged from sewerage treatment plants to prevent eutrophication in closed water areas. Toshiba's energy-efficient aeration air flow control system for removing nitrogen effectively removes nitrogen at low energy consumption.
Toshiba globally conducts business by leveraging its expertise and rich experience in the construction of water supply and sewerage infrastructure in Japan. We operate worldwide, offering end to end and customized solutions to meet our customers' needs. We are committed to assisting in the establishment of sustainable water circulation systems and the realization of advanced environmentally sound communities using our expertise and affiliates.