Our biggest wastewater treatment plant in Marselisborg produced 30 % more electricity than the amount consumed by the plant itself on average between 2015-2019. At the same time the treatment plant produced 75 % more heat than it consumed, resulting in a total net energy production of 150 %.
Over the past five years, Aarhus Vand has put great focus on energy savings and energy production. At Marselisborg WWTP, we have implemented energy-saving technologies such as an advanced SCADA control system, a new turbo compressor, sludge liquor treatment based on the anammox process, as well as optimised the fine bubble aeration system.
This has resulted in a reduction in power consumption of approximately 1GWh/year which corresponds to about 25% in total savings. During the same time period, the energy production has been improved through implementation of new energy efficient biogas engines (CHP), resulting in an increase in electricity production of approximately 1 GWh/year. Furthermore, a new heat exchanger has been installed with the aim of selling surplus heat to the district heating grid, which represents approx. 2 GWh/year.
Between 2015 and 2019, Marselisborg WWTP had an average total energy production of 9,6 MWh/year and an energy consumption of 6,4 MWh/year, equivalent to a net energy production of 150%. Most of the installed technologies have a payback time of less than 5 years.