91福利

In the "Breakthrough by Dynamic Approach in Sewage High Technology Project (B-DASH project)"*1 undertaken by the Ministry of Land, Infrastructure, Transport and Tourism (MLIT), "Demonstration Project for Advanced Wastewater Treatment Technology in Single Tank Nitrification Denitrification Process using ICT and AI Control" (hereinafter "Proposal") was selected as an implementation project for FY2019. The Proposal was made by a consortium composed of three entities: Machida City (Mayor: Jouichi Ishizaka), Japan Sewage Works Agency (President: Toshihiro Tsujihara, Headquarters: Bunkyo-ku, Tokyo; hereinafter "JS"), and METAWATER Co., Ltd. (President: Yasushi Nakamura, Headquarters: Chiyoda-ku, Tokyo; hereinafter "Company").

Presently, many wastewater treatment facilities in Japan exceed their serviceable life and deterioration is becoming a serious issue. With sewage inflows also expected to decrease due to the fall in population, streamlining needs of treatment facilities are increasing. The sewage inflow to treatment facilities will increase after streamlining and, therefore, transition to a system allowing all inflow treatment will be in need. Yet, when looking into future population decease, setting up additional associated treatment facilities should be held at a minimum level. Furthermore, while introduction of advanced wastewater treatment to preserve water quality is raised in the "New Sewerage Vision"*2, it is accompanied by issues such as a significant increase in accompanying costs (facility construction cost, maintenance and operation cost), and a decrease in treatment capacity compared to the conventional activated sludge process*3 when introducing to existing facilities.

In consideration of these circumstances, the Proposal will enable the securing of water quality equivalent to that with advanced wastewater treatment without having to increase power equipment, and while utilizing the existing framework. Treatment capacity will also increase by reducing the retention period (detention time) of the sewage inflow in the tank, as compared to that of the A2O process*4, which is the previous advanced wastewater treatment. Furthermore, stable treated wastewater quality and minimization of system-wide energy use will be realized without any advanced operational management technologies. Such will be done through integrated management utilizing ICT and AI in a series of equipment that have each been previously optimized.

1. Outline of the proposal

Demonstration of a single tank nitrification denitrification process utilizing ICT and AI

• Realization of treated wastewater quality equivalent to that of the A2O process in short HRT by air quantity control, which corresponds to the inflow load fluctuation of aeration tanks
• Reduction in electrical power consumption by automatic computing and control of discharge pressure for blowers interlocked with air quantity control

2. Characteristics

• Realization of short retention period (detention time) by air quantity control utilizing ICTs
  • Calculate air quantity corresponding to load fluctuation with NOx meter* and NH4 meter, and flexibly create an optimum aerobic anoxic zone within a single tank* sensor measuring total concentration of NO2-N and NO3-N
  • Power cost reduced due to unnecessary recirculation pumps and mixers
• Realization of blower power reduction by coordinating equipment and reducing pressure by utilizing ICT
  • Conduct integrated control of aeration tank and blower equipment
  • Automatically calculate optimum discharge pressure for blowers from required air quantity on a real time basis, reducing blower power
• Realization of response to seasonal fluctuation and reduction in burden on operational adjustment by utilizing AI
  • Conduct automatic tuning of control parameters for necessary air quantity calculation by utilizing AI (machine learning function)
  • Realization of stable treated wastewater quality while reducing burden of tuning

3. Technological effects

Contribution to the promotion of advanced wastewater treatment

• Control of construction costs (decrease in tank capacity by creating optimum aerobic anoxic zone)
• Realization of energy saving (elimination of mixers and recirculation pumps, reduction in blower power)
• Reduction in burden on persons in charge of operation and maintenance (automatic operation corresponding to seasonal fluctuations, etc.)

4. Overview of project

Machida City will provide, operate and maintain the demonstration area, and coordinate matters related to effective utilization measures of demonstrated technologies. JS will design, construct, and supervise demonstration facilities, manage research studies, propose research plans, analyze and evaluate data, and widely expand both within and outside Japan. The Company, as a total solution company in the water environment field, will design, construct, comprehensively operate, and collate research. Under mutual cooperation of the three entities, Machida City, JS and the Company, the Company aims to establish innovative technologies that will contribute to the development and secured sustainability of the sewage works business.

• Demonstrators：Consortium composed of METAWATER Co., Ltd., Japan Sewage Works Agency, and Machida City
• Demonstration areas：Naruse Clean Center, Machida City, Tokyo (8-1-1 Minaminaruse, Machida City, Tokyo)

*1 B-DASH is the abbreviation for Breakthrough by Dynamic Approach in Sewage High Technology Project.
This is a demonstration project carried out by the Ministry of Land, Infrastructure, Transport and Tourism to help reduce sewage business costs and create renewable energy, etc. by 　accelerating the research, development and practical application of new technologies, and to support overseas water business development by Japanese companies.
*2 Jointly developed by the Ministry of Land, Infrastructure, Transport and Tourism (MLIT) and the Japan Sewage Works Association (released on July 15, 2014)
*3 A method to treat contaminants in wastewater, such as organic substances, by combining inflow sewage with activated sludge and further conducting aeration
*4 A treatment method to remove nitrogen and phosphorus by placing aeration tanks in the order of anaerobic tanks, anoxic tanks, and aerobic tanks, and recirculating parts of nitrified mixed liquor in the aerobic tank to the anoxic tank