Rhinoflux Inc., a Kyoto University spinout, and Swing Corporation, a Japanese water treatment company, have begun a proof-of-concept trial in Japan to convert sewage sludge into electricity and capture high-purity carbon dioxide using Hydro Chemical Looping (HCL) technology, according to a release published 25 August 2026 by The National Law Review. The trial, announced from Kyoto, tests a non-combustion route for the country's roughly 2.34 million dry solids tons of annual sewage sludge.
Key takeaways
- Rhinoflux and Swing Corporation launched a proof-of-concept trial in July 2026 to test Hydro Chemical Looping on Japanese sewage sludge (The National Law Review).
- The process targets power generation and CO2 capture of 99.9%+ purity without combustion (The National Law Review).
- Japan is estimated to produce approximately 2.34 million dry solids tons of sewage sludge each year (The National Law Review).
- Rhinoflux's HCL is reported to offer approximately two to four times higher power generation efficiency than conventional biomass power systems (The National Law Review).
- The trial follows a feasibility study between the two companies that flagged HCL as potentially applicable and commercially viable for sewage sludge (The National Law Review).
What happened
The PoC trial, which began in July 2026, moves the partnership past a feasibility study in which Rhinoflux and Swing Corporation identified HCL as a candidate for sewage sludge treatment, according to The National Law Review. Alex Mazawa, Co-founder and CEO of Rhinoflux Inc., is leading the Kyoto University spinout that developed the aqueous chemical looping route, and Swing Corporation is providing the water and sludge treatment expertise. The two companies said they will collect practical data and assess the requirements for sewage sludge resource utilization at treatment facilities in Japan.
Why it matters for sludge management
Japan currently handles its sewage sludge mainly through landfilling, incineration, solid fuel conversion, anaerobic digestion for biogas, and use in construction materials such as cement, The National Law Review reported. Those routes face environmental and cost pressure, and the combustion-based power options leave room for lower-emission alternatives. HCL replaces combustion with chemical reactions in an aqueous solution, generating electricity while separating CO2 at reported purity above 99.9%, a stream the release said could be monetized through carbon dioxide removal credits or sold as liquefied CO2. The same release said the technology is particularly suited to high-moisture biomass such as sewage sludge, which has historically been difficult to use economically.
| Parameter | Reported figure |
|---|---|
| Annual Japanese sewage sludge output | Approximately 2.34 million dry solids tons/year |
| CO2 purity from HCL process | 99.9%+ |
| Power generation efficiency vs. conventional biomass | Approximately 2x to 4x |
| PoC start | July 2026 |
| Trial announcement | 25 August 2026 |
Specification read
At a sludge production rate of approximately 2.34 million dry solids tons per year, the national inventory implies a total wet sludge mass several times higher once typical dewatering cake moisture is included; a 25% dry-solids cake for example would correspond to roughly 9.36 million wet tons per year, or about 25,650 wet tons per day across Japan's fleet, which a single large works can handle by pairing Sludge Treatment trains of thickening, dewatering and either anaerobic digestion or thermal conversion. A facility receiving the HCL module would still need an upstream liquid train — screening, grit removal, primary clarification, and biological treatment such as A2O, MBR, MBBR, SBR or UASB, followed by tertiary and disinfection — and the HCL unit itself sits in the solids line, replacing or supplementing the digester-plus-incinerator combination on Municipal sites. The announcement positions it as an alternative to the conventional activated-sludge and incineration sequence on Integrated Sewage Treatment plants that also pursue energy recovery. If your plant treats municipal sewage in the order of 50,000 to 500,000 m³/day, runs BOD of roughly 150 to 300 mg/L in the influent, faces rising landfill and incineration costs, and is under decarbonization pressure, this PoC matters because the value proposition is on-site power plus a salable CO2 stream from your existing sludge, not a new discharge consent. For a Japanese context on residential flows, see Residential Wastewater Treatment in Japan: 2026 Engineering Guide — Regulations, Johkasou & Equipment Selection.
FAQ
What is Hydro Chemical Looping and how is it different from incineration?
It is Rhinoflux's non-combustion process that reacts biomass in an aqueous solution to generate electricity and separate CO2 at 99.9%+ purity, instead of burning the sludge. Reported efficiency is approximately two to four times higher than conventional biomass power systems (The National Law Review).
What scale of plant could the technology apply to?
The release does not give a specific flow range; the national sludge inventory of about 2.34 million dry solids tons per year suggests the technology is targeted at municipal-scale facilities, generally in the tens of thousands of m³/day range. A 50,000 to 500,000 m³/day plant is a typical fit (general industry range, not from the sources).
What is the development status and likely lead time?
As of 25 August 2026 the project is a PoC that started in July 2026, following a feasibility study. Commercial deployment timing was not disclosed, so procurement teams should treat it as a pilot-stage technology and plan for a multi-year qualification path before ordering (general industry range, not from the sources).
Who owns the technology and who is the integration partner?
Rhinoflux Inc., a Kyoto University spinout, owns the HCL technology, and Swing Corporation, a Japanese water treatment EPC and O&M contractor, is the integration partner for this trial (The National Law Review).
