Toshiba’s Sewage Pretreatment Technology with a Rotating Fiber Unit for Oxidation Ditch Method Selected as New Technology Category I by Japan Sewage Works Agency

Toshiba Infrastructure Systems & Solutions Corporation’s^*1 (Toshiba) pretreatment technology with a rotating fiber unit for use in sewage treatment facilities with an oxidation ditch (OD)^*2 has been selected by the Japan Sewage Works Agency (JS) as a New Technology Category I. The designation indicates a technology jointly developed with JS that has either been completed or reached the point of practical application, and selected by JS as suitable for construction projects that it commissions. This is the first time a Toshiba technology has been selected.

The technology enhances the treatment capacity of OD tanks by as much as 150-190%^*3 and cuts power consumption for aeration^*4 by about 20%. Toshiba expects to see it introduced in JS construction projects as a solution for optimizing efficient sewage treatment while cutting energy consumption.

Pretreatment technology with a rotating fiber unit for the OD

1) Pretreatment technology for the OD with a rotating fiber unit shaped to form a three-dimensional mesh, a type of biofilm method.

2) The rotating fiber unit can hold a large number of microorganisms, realizing high-load operation.

3) Lower power consumption than a typical OD for removed BOD^*5.

4) The rotating fiber unit biofilm has a long solid retention time that reduces excess sludge generated through self-decomposition

5) Can be installed while the OD is operating

• Target: Urban sewage, mainly consisting of domestic wastewater
• Water temperature: 13°C or higher (annual minimum monthly average water temperature)
• BOD/N ratio of the sewage flowing into the OD tank: 3.0 or higher (when applied to advanced OD processing)
• Feasibility study: Advance assessment of effects of introduction on capacity enhancement and economic efficiency.

1) Enhanced treatment capacity
    Treatment capacity of the OD tanks raised by approximately 150-190%.
-   No need for additional OD tanks, even if inflow sewage volume increases.
-   If inflow sewage volume decreases relative to facility capacity, the number of operating OD tanks can be reduced.

2) Lower energy consumption
    Lower organic load inflow reduces the required oxygen level in OD tanks.
-   Power consumption for aeration reduced by about 20%.

3) Lower life cycle cost (LCC) for sewage treatment facilities
    Construction and maintenance costs are reduced by eliminating the need for additional OD tanks and by reducing power consumption and surplus sludge, lowering the LCC of sewage treatment facilities by up to 22%.

Toshiba commercialized the new technology in July 2024 as Habuki™^*6. The company will continue to leverage long cultivated expertise and extensive experience in water treatment technologies to support water companies and sewage operators as a partner in developing solutions for safe and secure water resources and the environment.

JS New Tech Implementation Program:
https://www.jswa.go.jp/en/rd/ip/ip.html

Habuki™ product information:
https://www.global.toshiba/ww/products-solutions/social/water-environmental/solution-product/municipal-field/sewage-treatment/habuki.html

Note 1: Toshiba Infrastructure Systems & Solutions Corporation will be integrated into Toshiba Corporation on April 1, 2025.
Note 2: A method in which activated sludge is treated using a non-terminal waterway as a reaction tank, and sludge and treated water are separated in the final sedimentation tank.
Note 3: Estimated value under conditions of water temperature 16-20°C and MLSS 3,000 mg/L.
Note 4: A type of sewage treatment process that involves injecting air into the reaction tank.
Note 5: Biochemical Oxygen Demand. The amount of oxygen consumed when microorganisms oxidize and decompose organic matter in water over a certain period (5 days) and at a certain temperature (20°C). It indicates the level of organic pollution in the water.
Note 6: Habuki™ is the product name in Japan. It may be marketed under a different name when sold overseas.