Managing Eutrophic Waters in Artificial Recharge Plants

Project: DissertationInterdisciplinary research

Research areas and keywords

UKÄ subject classification

  • Engineering and Technology


  • Drinking water, Cyanobacterial blooms, Cyanotoxin, Nutrients, Total Phosphorus, DIN/TP, quick test kit


In the last decades, the frequency and intensity of cyanobacterial blooms have been
of increasing concern. They have become a direct threat to the drinking water supply
by clogging filters, bringing odour and unpleasant taste to the treated water and
worst of all, causing elevated cyanotoxins, which can be difficult to remove, yet
lead to severe health issues. This thesis aims to present a comprehensive knowledge
base and tools for water managers and operators to understand cyanobacterial risk
in their water so that bloom problems can be prevented or mitigated. Firstly, an
adaptive approach for cyanobacteria management in drinking water supply is
proposed, starting with an overview of this problem and resulting in a conceptual
management tool design, a Cyanobacteria Management Tool (CMT) by which
multi-indicators for actions are provided. Secondly, the magnitude of this problem
in Swedish freshwaters was studied both on a national and local scale, including
their geographical distribution, species dynamics, bloom seasonal pattern and their
connection with eutrophication status, land use, and other factors. Thirdly, the study
highlights impact of nutrients on cyanobacteria formation, including testing two
hypothesizes, 1) if Total Phosphorus (TP) can be used to predict cyanobacteria risk
and 2) if the Dissolved Inorganic Nitrogen and Phosphorus ratio (DIN/TP) is a better
indicator for cyanobacteria risk than TN/TP. The results were also verified by a fullscale
on-site experiment study of pre-treating eutrophic water at a local water
treatment plant. Lastly, cyanotoxin detection challenges and strategies are
presented. The key findings are:
• Local target levels for TP for preventing cyanobacterial blooms are possible to be
assessed by applying quantile regression analysis;
• DIN/TP is a better indicator than TN/TP in predicting high levels of cyanobacteria;
high levels of cyanobacteria coincide with DIN/TP <10;
• Most problematic lakes that experience intensive cyanobacterial blooms are
located in southern Sweden; and the lakes are eutrophic or hypereutrophic due to
intensive land use;
• Clear seasonal patterns of cyanobacteria biomass and percentage in phytoplankton
community can be derived by applying long-term series analysis. Analysis results
show that regarding cyanobacteria risk, special attention should be paid in the
months of May through November;
• Cyanotoxin screening tools such as enzyme-linked immunosorbent assay (ELISA)
or lateral flow immunoassay (LFA) are useful for early screening of certain toxins
such as microcystins and saxitoxins; advanced analytical tools such as LC–MS/MS
are required for the confirmation of toxin profiles.
Research findings presented in this thesis can be used to update a locally based CMT
and applied as a workflow for water operators to improve their monitoring routines
and develop their strategies. Measures to control nutrients in freshwaters are
necessary to protect our drinking waters from intensive cyanobacterial blooms.
Effective start/end date2017/04/012020/03/27

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Related research output

Li, J., 2020 Mar 27, Lund: Department of Water Resources Engineering, Lund Institute of Technology, Lund University. 81 p.

Research output: ThesisDoctoral Thesis (compilation)

Li, J., Kristofer Hägg, Kenneth M Persson & L-A Hansson, 2019 Sep 24, In : Water (Switzerland). 11, 10, 17 p., 1991.

Research output: Contribution to journalArticle

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