Marselisborg WWTP - turning wastewater into green energy
At traditional wastewater treatment plants, the energy produced is nowhere near enough to cover the operation of the plant. In Aarhus it is. Marselisborg WWTP has an energy self-sufficiency far above 100 percent and the plant is in fact a power station, a bio refinery where energy is produced from wastewater.
In Aarhus, wastewater is no longer a waste product; it is a source of green energy. Marselisborg Wastewater Treatment Plant has been transformed from an energy consumer to an energy producing plant.
Production of energy from wastewater is no new invention. However, it is new that a wastewater treatment plant can produce this much.
Today the plant produces 50 percent more electricity than it needs and 2.9 GW of heat for the district heating system without adding external organic waste or carbon. This excess energy is enough to serve the needs of the drinking water supply and wastewater treatment facilities for the whole water cycle in the catchment area.
Acting as a showcase of these potentials, the Marselisborg plant is visited by energy experts and decision-makers from the entire world.
Minimizing energy consumption
Another important matter of the efficiency of this WWTP is a low energy consumption. To minimize energy consumption, every component and the influence on the driving process was evaluated and optimized: from pumps, mixers, aeration compressors to dosing equipment. A strong focus on the aeration system was the key change.
At Marselisborg Wastewater Treatment Plant, we have implemented energy-saving technologies such as an advanced dual-layer data management system and SCADA control system, a new turbo compressor, new CHP´s, sludge liquor treatment based on the anammox process, as well as optimized the fine bubble aeration system. This has resulted in a reduction in power consumption of approximately 1 GWh/year which corresponds to about 25 percent in total savings.
A dedicated staff is crucial
To follow the process improvements, it´s crucial to have dedicated and well educated of operators and sensor/lab staff to maintain and calibrate sensors and equipment deemed as critical in the control-system. Furthermore, Aarhus Vand have a dedicated staff regarding developing and maintaining the PLC/SCADA/DIMS system.