Management of eutrophication in Lake De Kuil (The Netherlands) using combined flocculant - lanthanum modified bentonite treatment

G. Waaijen, F. van Oosterhout, G.C. Douglas, M.F.L.L.W. Lurling

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Abstract

Eutrophication of Lake De Kuil (The Netherlands, 6.7 ha, maximum depth 9 m) has frequently caused cyanobacterial blooms resulting in swimming bans or the issue of water quality warnings during summer. The eutrophication was mainly driven by sediment phosphorus (P)-release. The external P-loading was in the range of the critical loading for phytoplankton blooms. Hence, the reduction of the internal P-loading provided a promising way to reduce cyanobacterial blooms. To mitigate the cyanobacterial blooms, the combination of a low dose flocculant (iron(III)chloride; Flock) and a solid phase phosphate fixative (lanthanum modified bentonite; Lock) was applied in May 2009. This combined approach both removed cyanobacterial biomass from the water column and also intercepted P released from the bottom sediments. Immediately after treatment, the Secchi depth increased from 1.5 m up to 5 m. Sediment P-release decreased from 5.2 mg P m−2 d−1 (2009) to 0.4 mg P m−2 d−1 (2010) but increased in later years. Mean summer concentrations of total P decreased from 0.05 mg L−1 (1992–2008) to 0.02 mg L−1 (2009–2014) and chlorophyll-a from 16 μg L−1 (1992–2008) to 6 μg L−1 (2009–2014). Mean summer Secchi depth increased from 2.31 m (1992–2008) to 3.12 m (2009–2014). The coverage of macrophytes tripled from 2009 to 2011. In the winter of 2010/2011 Planktothrix rubescens bloomed, but cyanobacterial biomass decreased during the summers after the Flock and Lock treatment in comparison to prior years. After the Flock & Lock the bathing water requirements have been fulfilled for six consecutive summers. As the sediment P-release has gradually increased in recent years, there is a risk of a reversion from the present mesotrophic state to a eutrophic state.
LanguageEnglish
Pages83-95
JournalWater Research
Volume97
DOIs
Publication statusPublished - 2016

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Eutrophication
Bentonite
Lanthanum
bentonite
Lakes
eutrophication
Sediments
algal bloom
lake
summer
Biomass
sediment
Phytoplankton
bathing water
Chlorophyll
Water quality
biomass
Phosphorus
Water
Phosphates

Cite this

@article{7121f17912a54761a7efddee7dd37465,
title = "Management of eutrophication in Lake De Kuil (The Netherlands) using combined flocculant - lanthanum modified bentonite treatment",
abstract = "Eutrophication of Lake De Kuil (The Netherlands, 6.7 ha, maximum depth 9 m) has frequently caused cyanobacterial blooms resulting in swimming bans or the issue of water quality warnings during summer. The eutrophication was mainly driven by sediment phosphorus (P)-release. The external P-loading was in the range of the critical loading for phytoplankton blooms. Hence, the reduction of the internal P-loading provided a promising way to reduce cyanobacterial blooms. To mitigate the cyanobacterial blooms, the combination of a low dose flocculant (iron(III)chloride; Flock) and a solid phase phosphate fixative (lanthanum modified bentonite; Lock) was applied in May 2009. This combined approach both removed cyanobacterial biomass from the water column and also intercepted P released from the bottom sediments. Immediately after treatment, the Secchi depth increased from 1.5 m up to 5 m. Sediment P-release decreased from 5.2 mg P m−2 d−1 (2009) to 0.4 mg P m−2 d−1 (2010) but increased in later years. Mean summer concentrations of total P decreased from 0.05 mg L−1 (1992–2008) to 0.02 mg L−1 (2009–2014) and chlorophyll-a from 16 μg L−1 (1992–2008) to 6 μg L−1 (2009–2014). Mean summer Secchi depth increased from 2.31 m (1992–2008) to 3.12 m (2009–2014). The coverage of macrophytes tripled from 2009 to 2011. In the winter of 2010/2011 Planktothrix rubescens bloomed, but cyanobacterial biomass decreased during the summers after the Flock and Lock treatment in comparison to prior years. After the Flock & Lock the bathing water requirements have been fulfilled for six consecutive summers. As the sediment P-release has gradually increased in recent years, there is a risk of a reversion from the present mesotrophic state to a eutrophic state.",
author = "G. Waaijen and {van Oosterhout}, F. and G.C. Douglas and M.F.L.L.W. Lurling",
year = "2016",
doi = "10.1016/j.watres.2015.11.034",
language = "English",
volume = "97",
pages = "83--95",
journal = "Water Research",
issn = "0043-1354",
publisher = "IWA Publishing",

}

Management of eutrophication in Lake De Kuil (The Netherlands) using combined flocculant - lanthanum modified bentonite treatment. / Waaijen, G.; van Oosterhout, F.; Douglas, G.C.; Lurling, M.F.L.L.W.

In: Water Research, Vol. 97, 2016, p. 83-95.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Management of eutrophication in Lake De Kuil (The Netherlands) using combined flocculant - lanthanum modified bentonite treatment

AU - Waaijen, G.

AU - van Oosterhout, F.

AU - Douglas, G.C.

AU - Lurling, M.F.L.L.W.

PY - 2016

Y1 - 2016

N2 - Eutrophication of Lake De Kuil (The Netherlands, 6.7 ha, maximum depth 9 m) has frequently caused cyanobacterial blooms resulting in swimming bans or the issue of water quality warnings during summer. The eutrophication was mainly driven by sediment phosphorus (P)-release. The external P-loading was in the range of the critical loading for phytoplankton blooms. Hence, the reduction of the internal P-loading provided a promising way to reduce cyanobacterial blooms. To mitigate the cyanobacterial blooms, the combination of a low dose flocculant (iron(III)chloride; Flock) and a solid phase phosphate fixative (lanthanum modified bentonite; Lock) was applied in May 2009. This combined approach both removed cyanobacterial biomass from the water column and also intercepted P released from the bottom sediments. Immediately after treatment, the Secchi depth increased from 1.5 m up to 5 m. Sediment P-release decreased from 5.2 mg P m−2 d−1 (2009) to 0.4 mg P m−2 d−1 (2010) but increased in later years. Mean summer concentrations of total P decreased from 0.05 mg L−1 (1992–2008) to 0.02 mg L−1 (2009–2014) and chlorophyll-a from 16 μg L−1 (1992–2008) to 6 μg L−1 (2009–2014). Mean summer Secchi depth increased from 2.31 m (1992–2008) to 3.12 m (2009–2014). The coverage of macrophytes tripled from 2009 to 2011. In the winter of 2010/2011 Planktothrix rubescens bloomed, but cyanobacterial biomass decreased during the summers after the Flock and Lock treatment in comparison to prior years. After the Flock & Lock the bathing water requirements have been fulfilled for six consecutive summers. As the sediment P-release has gradually increased in recent years, there is a risk of a reversion from the present mesotrophic state to a eutrophic state.

AB - Eutrophication of Lake De Kuil (The Netherlands, 6.7 ha, maximum depth 9 m) has frequently caused cyanobacterial blooms resulting in swimming bans or the issue of water quality warnings during summer. The eutrophication was mainly driven by sediment phosphorus (P)-release. The external P-loading was in the range of the critical loading for phytoplankton blooms. Hence, the reduction of the internal P-loading provided a promising way to reduce cyanobacterial blooms. To mitigate the cyanobacterial blooms, the combination of a low dose flocculant (iron(III)chloride; Flock) and a solid phase phosphate fixative (lanthanum modified bentonite; Lock) was applied in May 2009. This combined approach both removed cyanobacterial biomass from the water column and also intercepted P released from the bottom sediments. Immediately after treatment, the Secchi depth increased from 1.5 m up to 5 m. Sediment P-release decreased from 5.2 mg P m−2 d−1 (2009) to 0.4 mg P m−2 d−1 (2010) but increased in later years. Mean summer concentrations of total P decreased from 0.05 mg L−1 (1992–2008) to 0.02 mg L−1 (2009–2014) and chlorophyll-a from 16 μg L−1 (1992–2008) to 6 μg L−1 (2009–2014). Mean summer Secchi depth increased from 2.31 m (1992–2008) to 3.12 m (2009–2014). The coverage of macrophytes tripled from 2009 to 2011. In the winter of 2010/2011 Planktothrix rubescens bloomed, but cyanobacterial biomass decreased during the summers after the Flock and Lock treatment in comparison to prior years. After the Flock & Lock the bathing water requirements have been fulfilled for six consecutive summers. As the sediment P-release has gradually increased in recent years, there is a risk of a reversion from the present mesotrophic state to a eutrophic state.

U2 - 10.1016/j.watres.2015.11.034

DO - 10.1016/j.watres.2015.11.034

M3 - Article

VL - 97

SP - 83

EP - 95

JO - Water Research

T2 - Water Research

JF - Water Research

SN - 0043-1354

ER -