Project no. 427
The Effect of Copper: A Diagnostic Tool for Improved
A. H. Thomsen
DTU Environment, Technical University of Denmark
Clean drinking water is a vital element for healthy and sustainable living. Drinking water
production based on groundwater abstraction undergoing simple treatment through
biological sand filters is one of the most cost and energy efficient methods available.
Biological sand filters lower the ammonium concentrations through the microbial process of
nitrification. High concentrations of ammonium present in drinking water can lead to
regrowth of microbes causing corrosive conditions and formation of toxic chloramines
(Zhang et al., 2009). In recent years water works have struggled to effectively lower the
ammonium concentrations, and as a result 6 % of Danish water works exceed the guideline
standard (DEA, 2017). This has emphasized the need to further investigate and improve the
current treatment technique – nitrification in biological sand filters.
The aim of this project is to develop a diagnostic tool for water works to identify and
overcome the challenges of ammonium removal in biological sand filters. This could
ultimately lead to a more efficient and sustainable production of drinking water without
compromising the water quality.
The removal of ammonium is a biochemical reaction catalyzed by the AMO enzyme, which
has been suggested to be activated by free copper ions (Ensign et al., 1993). The principle
of the applied method is to determine the effect of copper on nitrification by microbes in
biological sand filters. The activity of the microbial culture is analyzed through substrate
utilization and product formation, assessing the change in nitrification rate when introduced
to different water qualities and different copper concentrations. The applied methods include
continuous flow analysis and mass spectrophotometry according to ISO standards.
The findings of the project indicate that dosing of copper can improve ammonium removal.
The experimental research shows that nitrification rates can be enhanced by 174%, if
copper is dosed at a concentration of 1 μg/L. The project successfully designed a diagnostic
tool through which the availability of copper in a water source can be assessed, with the aim
to identify whether copper depletion limits the ammonium removal.
DEA - Danish Environmental Agency (2017). Quality of the Danish drinking water for the
period 2014- 2016, in Danish (“Kvaliteten af det danske drikkevand for perioden 2014-
Ensign, S. A., Hyman, M. R., & Arp, D. J. (1993). In vitro activation of ammonia
monooxygenase from Nitrosomonas europaea by copper. Journal of bacteriology, 175(7),
Zhang, Y., Love, N., & Edwards, M. (2009). Nitrification in drinking water systems. Critical
Reviews in Environmental Science and Technology, 39(3), 153-208.