It can be years before an innovation achieves its first success, and this was the case with SewerThermal. About 5 years ago, following a joint study tour with district water boards and district councils in Switzerland, Tauw examined whether SewerThermal could also become a success in the Netherlands. The technology had to be adapted to Dutch conditions: a SewerThermalsystem which was both suitable for pressure lines and also able to compete with the low natural gas prices.
In the first few years local councils and water boards showed considerable interest, but things did not progress beyond feasibility studies and opportunities maps. The next step for the development and construction of the system failed to materialize. Until the town of Urk decided to take the plunge. Urk decided to install a riothermal system in the pressure line system to heat their (to be renovated) swimming pool at the end of 2014. The extra costs for the riothermal system amounted to half a million Euros with a payback period of 12 years. The riothermal system became operational at the beginning of 2016 making this the first pressure line based system. The heat is recovered from the raw sewage which is discharged via the pressure line. The situation in Urk is typical of many municipalities; pressure lines are in the vicinity of swimming pools or other units requiring heat. The monitoring plan in Urk will not only show how efficient the system is, but also if the water is cooled down and how this affects purification efficiency.
This brings us to a point where many municipalities will follow the example of Urk, with SewerThermal regarded as a serious option for sustainable heating. We are currently working on various concrete assignments, including outside the Netherlands. Together with Tauw Belgium we have fully explored the applicability of SewerThermal for the city of Antwerp. The main advantage of riothermics is that, unlike wood pellet or other burners, there is only an electricity demand to be dealt with. The success in Urk marks the beginning of a period of new and sustainable heat technology in the Netherlands and Europe.