TORWASH

TORWASH is turning sewage sludge from a cost into a resource.

TORWASH is a Dutch cleantech company and spin-off of TNO, founded in 2020 and based in North Holland. We develop and commercialise TORWASH®, a patented hydrothermal technology that turns sewage sludge, one of the most expensive waste streams in the water sector, into valuable circular products.

Challenge.
Wastewater treatment plants produce large volumes of sludge that consist mostly of water. Even modern centrifuges and filter presses typically reach only about 20–24% dry matter, and they usually need fossil-based polymers (flocculants) to do so. As a result, water authorities and industrial operators pay high costs to truck large volumes of wet sludge to incinerators. Meanwhile, the energy, nutrients and carbon in the sludge are largely lost, and agricultural use of sludge is being phased out.

Our solution: TORWASH-for-Sludge
TORWASH® is a mild hydrothermal treatment based on wet torrefaction. Sludge is treated at elevated temperature and pressure, without any chemical additives. This changes the structure of the sludge so that it can be mechanically dewatered far beyond what conventional technology achieves. The process delivers:

• Drastic volume reduction: pilot tests produced press cakes of around 50–65% dry matter, reducing the sludge volume to be disposed of by roughly 80–85%.

• No flocculants: dewatering is achieved without polymers, cutting chemical costs and their environmental footprint.

• Solid biofuel: the dewatered cake can be pressed into pellets with a calorific value of about 16–18 MJ/kg, suitable as a renewable fuel that replaces fossil fuels.

• Extra biogas: thanks to the mild process conditions, the liquid filtrate is easily digestible and yields additional biogas, which can supply heat for the process itself.

• Nutrient recovery: the process enables phosphate recovery for use as a fertiliser.

The technology requires no pre-treatment. It is modular: reactors can be scaled and switched on or off flexibly, and installed on site at the treatment plant, which reduces transport movements.

Track record

• Laboratory and pilot research at TNO, including a continuous 25 L/h pilot plant at the WWTP of Almere.

• A demonstration plant of about 0.5 tonne of sludge per hour at WWTP Land van Cuijk, developed together with Dutch water authorities and STOWA. It successfully proved the technology under real operating conditions.

• Coordinator of the EU LIFE project SLUDGE2VALUE, which applies TORWASH® to industrial wastewater sludge with the goal of an energy-positive, carbon-negative process.

• Backed by investments from Oost NL and the Brabant Development Agency (BOM).

Value for the water sector
For water authorities and industrial operators with their own treatment plants, TORWASH® means lower sludge disposal costs, fewer truck movements, no polymer use, extra biogas and a renewable fuel product, all contributing to energy-neutral and circular wastewater treatment. Earlier business case studies indicated a cost reduction of around 60-70% compared to conventional sludge processing and disposal.

What we are looking for

• Water authorities and municipalities interested in hosting a (first) commercial TORWASH® installation

• Industrial companies with their own wastewater treatment and sludge challenges (e.g. food & beverage)

• Investors and co-funding partners for commercial roll-out

Contact: Levien de Legé, CEO – levien@torwash.nl – www.torwash.com