Solution provider
Frederiksberg Forsyning is the local utility company in Frederiksberg.
Case
Water management
Industrial water treatment
Frederiksberg Forsyning is the local utility company in Frederiksberg.
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Frederiksberg’s aging waterworks, built in 1999, faced the need for modernization to better meet residents’ needs and environmental standards. One primary demand was to soften Frederiksberg’s exceptionally hard water, which causes scaling issues for residents and businesses. However, given Frederiksberg’s dense urban setting and limited space, expanding horizontally was not an option. To address these challenges, Frederiksberg Forsyning reimagined the waterworks in a vertical format, creating Denmark’s first high-rise waterworks to optimize water softening within a compact footprint.
In November 2022, Frederiksberg unveiled its new four-story high-rise waterworks, a modern and space-efficient facility capable of softening 5.4 million cubic meters of water annually. Through this softening process, water hardness is reduced from 30 °dH (degrees of German hardness) to 10 °dH, resulting in medium-hard water. This carefully calibrated hardness level was selected to minimize corrosion risks in water pipes and installations, which can occur when water is softened below 8 °dH.
The water softening process uses a pellet method: calcium is removed by precipitating it on sand granules using sodium hydroxide (NaOH), which crystallizes calcium around the sand, forming small pellets that settle and are removed. As this process raises the water’s pH level, CO₂ is subsequently added to restore pH balance to neutral.
In addition to its softening capabilities, the high-rise waterworks includes advanced treatment technologies such as activated carbon filters and UV treatment to ensure water quality. The facility also integrates heat pumps, which capture thermal energy from drinking water, cooling the water while transferring the extracted heat to Frederiksberg’s district heating system. This innovative approach contributes 3% of Frederiksberg’s district heating supply, providing a sustainable energy source that would otherwise go unused.
The new high-rise waterworks represents a major leap in resource efficiency and sustainable urban infrastructure: