Torwash: waste sludge from cost item to source of revenue

Method optimised

Torwash has been developed to the extent that TNO wants to work with market parties to make the application a commercial product. The processing method was optimised at laboratory scale and subsequently proved itself in practice in a test with a reactor. The pilot was carried out in cooperation with the Zuiderzeeland water board in Almere. Scaling up to semi-production level is next on the programme.

Savings and revenues

The crux of the Torwash method is to initiate a chemical reaction under high pressure and temperature without additives, which almost completely squeezes the water out of the sludge and removes salt. Dewatering waste sludge in this way works much better than existing techniques such as centrifugation and decantation. What remains is a largely dry substance that is suitable for making fuel pellets. The remaining aqueous material can be efficiently fermented into biogas. Thus, in addition to savings, the method generates two derived products and thus revenues.

Global market

Water treatment is the most important market for Torwash application. For water boards, for example, reducing the volume of sludge to around 15% is financially attractive. A second potential customer is evident in companies that have their own water treatment plant and currently spend a lot of money on disposing the sludge. Thirdly, Torwash is perfectly suitable for manure processing. Meanwhile, foreign parties have also registered interest. Torwash is applicable worldwide.

Future

In collaboration with several water boards and STOWA, the TNO spin-off TORWASH BV is now scaling up to a capacity of 1 ton of sludge per hour at the RWZI Land van Cuijk. After a final scale-up to 20 tons per hour, TORWASH hopes to bring the technology to the market within three years