Comparison of dredging, lanthanum-modified bentonite, aluminium-modified zeolite, and FeCl2 in controlling internal nutrient loading

Li Kang; Sina Haasler; Maíra Mucci; Leon Korving; Achim Iulian Dugulan; Thomas Prot; Guido Waajen; Miquel Lürling

doi:10.1016/j.watres.2023.120391

Comparison of dredging, lanthanum-modified bentonite, aluminium-modified zeolite, and FeCl₂ in controlling internal nutrient loading

Water Res. 2023 Oct 1:244:120391. doi: 10.1016/j.watres.2023.120391. Epub 2023 Jul 23.

Authors

Li Kang¹, Sina Haasler², Maíra Mucci¹, Leon Korving³, Achim Iulian Dugulan⁴, Thomas Prot³, Guido Waajen⁵, Miquel Lürling⁶

Affiliations

¹ Aquatic Ecology & Water Quality Management Group, Department of Environmental Sciences, Wageningen University, P.O. Box 47, 6700 AA, Wageningen, The Netherlands.
² Freshwater Ecology Group, Department of Biology, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark.
³ Wetsus, European Centre Of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA, Leeuwarden, The Netherlands.
⁴ Delft University of Technology, Radiation Science & Technology, Fundamental Aspects of Materials and Energy, Mekelweg 15, 2629 JB, Delft, The Netherlands.
⁵ Water Authority Brabantse Delta, Team Knowledge, P.O. Box 5520, 4801 DZ, Breda, The Netherlands.
⁶ Aquatic Ecology & Water Quality Management Group, Department of Environmental Sciences, Wageningen University, P.O. Box 47, 6700 AA, Wageningen, The Netherlands. Electronic address: miquel.lurling@wur.nl.

PMID: 37544119
DOI: 10.1016/j.watres.2023.120391

Abstract

The eutrophic Bouvigne pond (Breda, The Netherlands) regularly suffers from cyanobacterial blooms. To improve the water quality, the external nutrient loading and the nutrient release from the pond sediment have to be reduced. An enclosure experiment was performed in the pond between March 9 and July 29, 2020 to compare the efficiency of dredging, addition of the lanthanum-modified bentonite clay Phoslock® (LMB), the aluminum-modified zeolite Aqual-P™ (AMZ) and FeCl₂ to mitigate nutrient release from the sediment. The treatments improved water quality. Mean total phosphorus (TP) concentrations in water were 0.091, 0.058, 0.032, 0.031, and 0.030 mg P L^-1 in controls, dredged, FeCl₂, LMB and AMZ treated enclosures, respectively. Mean filterable P (FP) concentrations were 0.056, 0.010, 0.009, 0.005, and 0.005 mg P L^-1 in controls, dredged, FeCl₂, LMB and AMZ treatments, respectively. Total nitrogen (TN) and dissolved inorganic nitrogen (DIN) were similar among treatments; lanthanum was elevated in LMB treatments, Fe and Cl in FeCl₂ treatments, and Al and Cl in AMZ treatments. After 112 days, sediment was collected from each enclosure, and subsequent sequential P extraction revealed that the mobile P pool in the sediments had reduced by 71.4%, 60.2%, 38%, and 5.2% in dredged, AMZ, LMB, and FeCl₂ treatments compared to the controls. A sediment core incubation laboratory experiment done simultaneously with the enclosure experiment revealed that FP fluxes were positive in controls and cores from the dredged area, while negative in LMB, AMZ and FeCl₂ treated cores. Dissolved inorganic nitrogen (DIN) release rate in LMB treated cores was 3.6 times higher than in controls. Overall, the applied in-lake treatments improved water quality in the enclosures. Based on this study, from effectiveness, application, stakeholders engagement, costs and environmental safety, LMB treatment would be the preferred option to reduce the internal nutrient loading of the Bouvigne pond, but additional arguments also have to be considered when preparing a restoration.

Keywords: Geo-engineering techniques; Lake restoration; Nutrients; Sediment; Water quality.

MeSH terms

Aluminum
Bentonite
Eutrophication
Geologic Sediments
Lakes
Lanthanum
Nutrients
Phosphorus
Water Pollutants, Chemical* / analysis
Zeolites*

Substances

Bentonite
Aluminum
Zeolites
Lanthanum
Phosphorus
Water Pollutants, Chemical