You’re speaking at World Water-Tech North America (November 2-3, Toronto) as part of the panel debate Energy and Resource Recovery; A New Paradigm for Utilities. Could you please tell us more about the pioneering Marselisborg Wastewater Treatment Plant and how Aarhus Vand is positioning itself as energy self-sufficient?
Aarhus Vand’s (Aarhus Water) vision is to become not only the leading water utility in Denmark, but also one of the leading water utilities in the world by developing and building the world´s most resource effective wastewater treatment plant by 2026. To us, being a leading water utility means that we are energy self-sufficient – or even better, that we are an energy net producer.
In 2016 the Marselisborg Wastewater Treatment Plant and the wastewater transportation to the plant had a total energy consumption of 3,9 GWh, while the energy production at the plant was 7,4 GWh. In this way, the energy self-sufficiency (power + heat) for the wastewater transportation and treatment was 190%. The industrial loading contribute with about 10% of the total organic loading. There is no co-digestion of organic waste.
If we look at the entire water circle (drinking water treatment and distribution and wastewater transport and treatment) in the catchment area of Marselisborg, the total energy consumption was 7,5 GWh, while the energy production was still 7,4 GWh. Our goal is to have total energy production at the same level at least as the total energy consumption.
Marselisborg WWTP was extended with biological and chemical treatment in the early 1990s to include sludge treatment and biogas utilization. Our current status has been achieved by, among other things, daily optimization and innovation of new biological process controls (side-stream deammonification and nitrite shunt in main process) through strategic collaboration with leading water utilities, companies, universities and organizations in Denmark and abroad since the early 1990s.
What were the drivers behind the utility’s decision to invest in the technology and infrastructure to convert its wastewater into energy?
When Marselisborg WWTP was extended in the early 1990s, we wanted to make sludge treatment more efficient. This was achieved by reducing the amount of sludge from the plant and increasing the reuse of biosolids in agriculture. At the same time, we wanted to make an operating income to produce electricity from biogas.
In 2007, the Aarhus city council decided that the municipality should actively participate in efforts to reduce CO2 emissions and set a target for CO2 neutrality by 2030. In order to back up this mission, Aarhus Water decided to work towards becoming energy and CO2 neutral.
To read the full interview, click here.
World Water-Tech North America is part of Ontario Water Innovation Week (October 30 – November 3). To register for this event and others, click here.