Innovation award for Basel district heating and St. Gallen wastewater treatment plant

This year, President Filippo Lombardi was able to present the InfraWatt-Two innovation prizes were presented at the 18th Annual General Meeting in Berne.

Innovation Award 2020, Waste Sector

The project of the two-stage flue gas condensation of the Industriellen Werke Basel (IWB) is so far unique in Switzerland and was planned and realized together with the company Ramboll AG.

IWB operates a district heating network in Basel that is around 118 kilometers long and is considered the largest "urban central heating" system in Switzerland. At the waste incineration plant (KVA) and the two wood-fired power plants, waste heat utilization has been significantly increased thanks to a new type of flue gas condensation: warm flue gases are cooled in so-called condensation scrubbers and the condensation heat released is used for preheating the district heating water by means of direct condensation on the one hand and absorption heat pumps on the other. A total of around 13 million Swiss francs was invested. The system increases waste heat utilization by 60 million kWh/a, which means that, comparatively speaking, an additional 4,000 single-family homes of 4 persons each (cf. Energieheld, mean value: heat consumption EFH, 4 persons, approx. 15,000 kWh/a) can be supplied with CO2-neutral district heating.

The deciding factor in the choice of the innovation prize was the novelty, the great effect and the fact that this system could be applied to many of the approximately 30 MWIPs in Switzerland and that about 350 million kWh/a of heat could be gained with it, as InfraWatt writes in its media release.

In addition to IWB, two other innovative projects stood out, according to InfraWatt: the Zofingen region's ERZO waste-to-energy plant, which heats an indoor swimming pool using latent heat storage, and designwerk's 25-ton electric vehicle for waste collection in the city of Thun.

Innovation Award 2021, Wastewater Division

Those responsible for the Hofen wastewater treatment plant (ARA) were pioneers in the past and had already installed a wastewater power plant in 1917. The energy strategy systematically implemented in recent years also has pioneering character. Currently, efficient combined heat and power plants (CHP) combined with a heat pump have been installed. The biology, the largest consumer of electricity at a wastewater treatment plant, was equipped with modern turbo-compressors and a dynamic control system was developed with the ETH Zurich, which improves the oxygen input and thus minimizes electricity consumption. At the same time, this doubled the cleaning capacity and avoided an expensive enlargement of the biology basins. In addition, nitrous oxide emissions, which are around 260 times more harmful than CO2, could be reduced to one fifth. With all these measures, the self-sufficiency of electricity could be increased from 70 % to over 130 %. This comprehensive approach can also be applied to many other 700+ wastewater treatment plants in Switzerland.

The jury found the project of the Altenrhein AVA wastewater association on Lake Constance (2nd place), which breeds local edible fish on the site of the wastewater treatment plant and brings it to market without long transport routes, particularly original. In the case of the Altstetten Höngg energy network, a collaboration between the city of Zurich's electricity company and Entsorgung + Recycling Zürich ERZ (3rd place), the dimensions are impressive. In the final stage of development in 2035 (areas of Altstetten North, East and West as well as Höngg), the network should be able to supply around 30,000 households with heating and cooling and save 13 million liters of heating oil per year.

Source: InfraWatt

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