海外投資家の皆様へ ; For Overseas Investors

Original Engineering Consultants Co., Ltd. (OEC) is a leading Japanese engineering consultancy specializing in water and environmental infrastructure. Established in 1962, the company has built a strong track record in the planning, design, and implementation of public infrastructure projects across Japan and overseas.

OEC provides comprehensive consulting services covering water supply, sewerage, sanitation, solid waste management, industrial wastewater treatment, flood prevention, urban runoff control, and related environmental engineering fields. Based on decades of accumulated experience, OEC supports clients through prefeasibility and feasibility studies, investigations, master planning, detailed design, diagnosis and rehabilitation planning, construction supervision, and associated engineering services.

Since its early years, OEC has actively introduced computerization into engineering practice. Today, the firm develops and applies proprietary software and digital tools for hydraulic analysis, flood control planning, supervisory control systems, mapping, and high-accuracy engineering calculations, enhancing efficiency and reliability throughout the project lifecycle.

OEC operates 54 offices across Japan and works closely with affiliated companies. The OEC Group employs professionals, including civil, environmental, and mechanical engineers, planners, and project management specialists.

Helping people around the world lead better lives through water.

Born in rural Ibaraki in 1967, he devoted his youth to basketball, cycling 12 kilometers daily to high school. After studying at Waseda University, he joined Yamaichi Securities in 1990, spending two years visiting small businesses across Tokyo and learning the passion of entrepreneurship firsthand. In 1992, he married into a construction consulting family, entering an industry where he had no technical background. Through night school and relentless study, he mastered civil engineering, earned his Professional Engineer license on the fourth attempt, and later completed a Master’s degree in San Francisco. That experience in diversity and openness transformed his worldview. Returning to Japan, he became President in 2012 during a severe business crisis.

He rebuilt the company through transparency, direct dialogue, and annual meetings with every employee across the nation. Today, he leads with a philosophy rooted in face-to-face communication, continuous learning, and responsibility to employees, customers, and society. His journey from athlete to salesman to engineer to president embodies perseverance, humility, and the power of human connection.

OEC provides comprehensive engineering consultancy services in the following fields:

Water Supply / Wastewater Collection Systems / Wastewater and Sludge Treatment (including industrial wastewater, septage, and night soil treatment) / Septic Tank and On-site Sanitation Planning / Urban Runoff and Flood Control Planning / Digital Engineering Solutions (GIS, AI, Metaverse) 

OEC has experienced in the planning, design, and supervision of wastewater collection systems since 1962. The company has designed hundreds of pump stations and sewer networks, delivering optimized solutions based on hydraulic performance, constructability, lifecycle cost, and system resilience.

Key services: feasibility studies and master planning, sewer network planning and diagnostics, hydraulic and network modeling, gravity/pressure/vacuum sewerage systems, pump stations and special structures, combined sewer overflow (CSO) reduction, EPCM services, project management, and construction supervision.

OEC delivers integrated consulting services for wastewater and sludge treatment plants by combining multidisciplinary expertise in chemistry, biology, hydraulics, civil and structural engineering, mechanical and electrical systems, and instrumentation and control.

The firm has completed numerous wastewater and sludge treatment projects, including major municipal facilities with treatment capacity. OEC also supports sustainable sludge management solutions, including biosolids utilization, energy recovery, and treated wastewater reuse.

Key services: feasibility studies and master planning, process design and optimization, alternatives analysis and life-cycle assessment, biosolids and sludge management planning, conceptual and detailed design, design–build owner’s engineering support, project management, and construction supervision.

OEC is advancing digital engineering to enhance infrastructure planning, operation, and stakeholder engagement. The company develops and applies:

• GIS-based asset management systems for water and wastewater utilities
• AI-assisted analysis and forecasting for planning, flood risk assessment, and operational optimization
• Digital twin and metaverse applications for visualization, training, and scenario-based decision-making

By integrating engineering expertise with advanced digital technologies, OEC continues to improve the efficiency, reliability, and sustainability of water infrastructure projects.

OEC has extensive experience in overseas infrastructure development. Its first international engagement began in 1979 with the preparation of a sewerage master plan for Seoul, Republic of Korea. Since then, the company has undertaken numerous water supply and sanitation projects throughout Asia, particularly in the Philippines, Viet Nam, and the Republic of Korea, the Pacific Islands, the Middle East, and South America. To date, we have completed approximately 70 projects overseas.

Many of these projects have been financed by international development partners such as the World Bank, Asian Development Bank (ADB), International Bank for Reconstruction and Development (IBRD), Japan International Cooperation Agency (JICA), and local governments.

Reflecting the rapid global expansion of the water infrastructure market, OEC actively participates in Public–Private Partnership (PPP) initiatives. The company is a member of the “PPP Council for Overseas Water Infrastructure,” organized by the Government of Japan, and contributes to project formulation by conducting feasibility studies and technical evaluations as part of international consortia.