Water & Wastewater Asia May/June 2019

INSIGHT | 41
Utilisation of biogas from wastewater utilities
Marselisborg is a traditional city area,
where water supply is based on
groundwater supply which in average
is pumped from depths of 35 metres,
and traditional household wastewater
in a relatively flat geographic
region.
The concept used has been a two-step
strategy, covering:
• Reduce energy consumption throughout
both the water and wastewater facilities
to highest sensible level
• Increase energy production from the
wastewater facility
On the water supply side, energy savings
have been obtained by reducing leakage to
six to eight per cent (from above 14 per cent)
and splitting the city into pressure zones.
The Marselisborg wastewater facility is
a traditional activated sludge treatment
plant with mesophilic digestion based on
household wastewater from Marselisborg
catchment area.
The wastewater facility has been upgraded
with both more energy efficient equipment
and especially with advanced real-time
process control based on a much wide use of
online sensors and VSD than normally seen.
This much more efficient control combined
with process as “carbon harvesting”,
“simultaneous Nitrification/Denitrification”,
“Anammox on side-stream” and partly
“Nitrite-shunt” resulted in 2016 into a
complete energy neutral situation for the
whole catchment area and isolated for the
wastewater facility to a 234 per cent energy
production. (See also table 1)
The ROI has in average been less than five
years for the upgrade of the Marselisborg
facility. WWA
Table 1: Energy consumption and production overview for the Marselisborg catchment area
Water & Wastewater Asia • May / June 2019