In many cities, towns and villages, maximum power consumption is generated from water supply and drainage facilities, which is about 25-40% of the total energy consumption. In Aarhus City, a city in Denmark, a regional water company carried out renovation to a drainage facility that also functions as a heat generating power generation function as a single function drainage plant.

In 2014, the drainage plant in Aarhus City produced 140% electricity and 2.5 GWh of surplus heat, and it was able to reduce carbon dioxide emissions by using it in the city’s district heating system. The total production of heat and electricity is comparable to 190-200% of energy production, which is 90% higher than that of the factory.

This is achieved by advanced processing optimization. It was realized by using more than 120 Danfoss water speed conversion devices for almost all rotating equipment. This converter (inverter) made it possible to adapt to the load fluctuation of drainage facilities in the 24-hour cycle. By being optimized, sludge / carbon used for the digestor (digestion processor) is also produced to the maximum amount, and it generates gas used for electricity and heat production.

The future image of Aarhus’ water use is the further progress of energy production and the expansion of surplus energy production from wastewater treatment plants. It can also satisfy the energy required for the city’s drinking water supply. In the future, it is expected that the largest consumer in the city alone will be transformed into a middle class of energy consumption.

If you would like to read more about the conversion speed drive used for water and drainage applications, click here.

Lasse Bastkjær Jensen