Sustainable Development Goals
PROJECT INFORMATION AT A GLANCE:
Project Status:
Operating commercial reference
Organizations Involved:
Kawaguchi City, Tokyo Electric Power, ORIX, Shimizu Corporation; EBARA (gasification and ash-melting technology)
Services / Equipment:
Design & Engineering, Consulting, Due Diligence
A city’s residual waste becomes electricity, recovered metals, construction material and heat for a public pool and bathing facility. With 420 tonnes per day of waste-treatment capacity and a 12 MW rated power system, Asahi Clean Center brings industrial resource recovery into the everyday life of the community it serves.
The Asahi Clean Center municipal waste gasification plant combines energy recovery and ash melting with a neighbouring Recycling Plaza. The wider complex includes a separate 95-tonne-per-day materials-recovery facility, environmental education spaces and SunR Asahi, a public heat-use facility on the Plaza’s fifth floor.
This is the commercial significance of the project: one municipal infrastructure complex connects waste treatment with several useful outputs and a visible public benefit. Its value comes from how those functions work together—across incoming waste, recovered materials, electricity and usable heat.
The Challenge
Solve the waste problem beyond the collection truck
Kawaguchi needed capacity for residual municipal waste, facilities for separately collected recyclables and a better destination for ash from existing treatment plants. Each stream presented a different challenge. Recyclables needed sorting and preparation; residual waste retained energy; mineral residues still required a managed outlet.
In a dense urban setting, these needs compete for land, infrastructure and public investment. The development question was how to bring them into a coordinated system while recovering useful resources and making the facility’s purpose understandable to residents.
Asahi’s design addressed that wider municipal requirement. It paired a substantial thermal-treatment plant with recycling, education and community heat use. For another city, this illustrates why the project boundary should include the surrounding waste network and potential energy users from the outset.
The Solution
Integrate gasification, ash melting and power recovery
The process consists of three lines rated at 140 tonnes per day each. Fluidized-bed gasification converts prepared residual waste into a combustible gas stream and solid fractions. The subsequent high-temperature combustion and melting stage recovers heat and transforms mineral material into a glass-like slag.
Klean’s technical account describes melting-stage temperatures of 1,300–1,450°C. Heat recovery produces steam for the turbine-generator, while the plant’s environmental-control systems treat the exhaust before discharge. This arrangement combines waste destruction, energy recovery and mineral treatment within one process.
The original facility specification also provides for 37 tonnes per day of external bottom ash, bringing a residue from another municipal treatment plant into the recovery system. That additional function matters: the development can improve the destination of material arising elsewhere in the city’s waste infrastructure.
Recover metals and put mineral residues to use
Ferrous metal and aluminium are separated from the solids discharged by the fluidized bed. Klean’s account describes further processing and return of the remaining mineral fraction, together with ash recirculation, to increase conversion into vitrified slag.
Klean reports an overall vitrification ratio above 90% under the documented recirculation conditions. The slag is described as suitable for construction use following quality assessment. This is an ash-treatment result, distinct from the proportion of incoming municipal waste recycled or diverted from landfill.
For a developer, the important connection is between equipment performance and a usable product. Slag quality, applicable testing requirements, local construction specifications and an identified outlet determine whether mineral recovery delivers its intended value.
Use the energy inside and outside the plant
The 12 MW rating defines the installed generation scale. Klean’s reported three-line operating example records approximately 8.3 MW generated, with approximately 3.8 MW exported after supplying the facility and Recycling Plaza. The project record identifies Tokyo Electric Power as the purchaser of surplus electricity.
Recovered heat also serves SunR Asahi. Residents use heated bathing and pool facilities within the same complex where their city recovers resources from waste. This makes heat utilization a tangible municipal service and provides a clear example of designing an energy customer into the development.
At the reported performance test, the waste’s own energy content sustained gasification and vitrification, with city gas used intermittently for the slag-outlet burner. That result demonstrates the importance of integrating the waste energy balance with the melting duty and plant services.
The Outcome
Industrial performance with a benefit residents can experience
Asahi’s operating reference combines municipal treatment capacity, exported electricity and materials recovery with an accessible community facility. The project’s principal figures describe different parts of that integrated system:
| Reference measure | Published figure and basis |
|---|---|
| Municipal waste capacity | 420 tonnes/day across three 140-tonne/day lines |
| External ash-treatment provision | 37 tonnes/day of bottom ash in the original specification |
| Separate Recycling Plaza capacity | 95 tonnes/day for source-separated materials |
| Rated electrical generation | 12 MW |
| Reported three-line operating example | Approximately 8.3 MW generated and 3.8 MW exported |
| Overall vitrification | Above 90% in Klean’s documented recirculation account |
| Historical availability reference | Above 90% annually, as reported in Klean’s project record |
The figures show the breadth of the facility’s role. Municipal waste, external ash and source-separated recyclables follow their respective treatment routes; their capacities describe separate duties within the complex.
Back the process with operating evidence
Klean’s account reports an average carbon monoxide concentration of 1.8 ppm, against a 10 ppm guarantee value, and dioxins/furans below 50 pg I-TEQ/m³ in the reported performance testing. It also records successful emergency-stop and power-failure shutdown/restart tests. These are specific historical test results supporting the technical reference.
The Recycling Plaza adds a further dimension: visitors can learn about resource recovery, participate in reuse activities and see how waste management connects with daily life. Klean’s record also describes a street-facing digital display of throughput and emissions information, bringing plant performance into public view.
For municipalities and infrastructure investors, Asahi demonstrates the value of planning the whole system. Waste treatment establishes the essential service. Electricity and heat create productive energy uses. Metal and mineral recovery reduce the final-residue burden. Public facilities give the community a direct connection to the infrastructure.
1. Design several useful outputs into one essential service. Asahi connects municipal waste treatment with electricity, recovered materials and community heat. Each outlet deserves its own technical specification and commercial arrangement.
2. Ash treatment can strengthen the wider municipal network. The external bottom-ash provision extends the plant’s role beyond its own waste intake. Regional residue flows can be part of the development opportunity.
3. A nearby heat user makes the energy proposition more complete. SunR Asahi turns recovered heat into a public amenity. Identify suitable heat demand early so the plant, distribution system and receiving facility can be designed together.
These are selected achievements and lessons. Further technical and commercial insights are available through an engagement with Klean.
WHAT DO THESE LESSONS MEAN FOR YOUR PROJECT?
For a city, waste company or infrastructure investor, the starting point is a map of the local resource flows: residual waste after recycling, ash requiring treatment, recoverable materials, electricity demand and nearby heat users. Klean can assess how those elements support an integrated development.
New equipment projects follow Detailed Equipment Quotation (DEQ) → Detailed Feasibility Study (DFS) → Front-End Engineering and Design (FEED). The engagement package outlines the work; the paid DEQ proposal establishes the preliminary technical and commercial basis. Existing-plant reviews and regional waste-system advisory assignments are scoped to their objectives.
Discuss Your Municipal Waste, Ash Recovery and Energy Project >> GO.
ABOUT THE INFORMATION PRESENTED
This case study shares selected project information and historical performance references. Commercial agreements, process details and proprietary know-how remain subject to confidentiality and the permissions of the parties involved. Project-specific disclosures and access are addressed within an agreed engagement.
This case connects with the Sustainable Development Goals through energy recovery (Goal 7), economic activity (Goal 8), industrial infrastructure (Goal 9), resource recovery (Goal 12), integrated energy and waste planning (Goal 13) and reduced demand for final disposal space (Goal 15).
