Extracting phosphorus and other elements from lake water: Chemical processes in a hypolimnetic withdrawal and treatment system

Silvonen, Soila; Niemistö, Juha; Myyryläinen, J.; Kinnunen, O; Huotari, Simo; Nurminen, Leena; Horppila, Jukka; Jilbert, Tom

doi:10.1016/j.watres.2022.118507

Cited by 6 publications

(3 citation statements)

References 34 publications

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“…Within the filters, P was mostly bound to amorphous Fe(III), regardless of the treatment method used. The main mechanism of P capture was the formation of Fe hydroxy-phosphates during oxidation of Fe(II) (Silvonen et al, 2022). However, Fe blocked the sand filters, requiring frequent filter maintenance.…”

Section: Potential Sustainable Lake Restoration and Circular Economy:...mentioning

confidence: 99%

“…The mean retention of total P by the sand filters used in Kymijärvi was 60% and varied between 30% and 85%, depending on how long the filter had been in use, while the retention of dissolved P was 71%–95% (Silvonen et al, 2022). Nitrogen was not effectively captured by the sand filters.…”

Section: Potential Sustainable Lake Restoration and Circular Economy:...mentioning

confidence: 99%

“…In the wetland located between the sand filter and the lake, P retention varied due to seasonal alterations in vegetation cover and biogeochemical cycling, but even with the lowest estimates of 33% P retention, the wetland added to the overall effectiveness of the closed‐circuit hypolimnetic withdrawal (Silvonen et al, 2022). With the wetland and filters, “good” ecological status (as defined in WFD) should be achieved in <20 years with 10 L s −1 pumping rate and in <10 years with 20 L s −1 rate (Silvonen et al, 2022). The wetland is also expected to intensify N removal via denitrification (Martínez‐Espinosa et al, 2021) and N retention via incorporation into biomass and organic matter burial in the sediments (Vymazal et al, 2020).…”

Section: Potential Sustainable Lake Restoration and Circular Economy:...mentioning

confidence: 99%

See 2 more Smart Citations

Sustainable lake restoration: From challenges to solutions

Tammeorg,

Chorus,

Spears

et al. 2023

WIREs Water

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Sustainable management of lakes requires us to overcome ecological, economic, and social challenges. These challenges can be addressed by focusing on achieving ecological improvement within a multifaceted, co‐beneficial context. In‐lake restoration measures may promote more rapid ecosystem responses than is feasible with catchment measures alone, even if multiple interventions are needed. In particular, we identify restoration methods that support the overarching societal target of a circular economy through the use of nutrients, sediments, or biomass that are removed from a lake, in agriculture, as food, or for biogas production. In this emerging field of sustainable restoration techniques, we show examples, discuss benefits and pitfalls, and flag areas for further research and development. Each lake should be assessed individually to ensure that restoration approaches will effectively address lake‐specific problems, do not harm the target lake or downstream ecosystems, are cost‐effective, promote delivery of valuable ecosystem services, minimize conflicts in public interests, and eliminate the necessity for repeated interventions. Achieving optimal, sustainable results from lake restoration relies on multidisciplinary research and close interactions between environmental, social, political, and economic sectors.This article is categorized under: Science of Water > Water Quality Water and Life > Stresses and Pressures on Ecosystems Water and Life > Conservation, Management, and Awareness

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Section: Potential Sustainable Lake Restoration and Circular Economy:...mentioning

confidence: 99%

Section: Potential Sustainable Lake Restoration and Circular Economy:...mentioning

confidence: 99%

Section: Potential Sustainable Lake Restoration and Circular Economy:...mentioning

confidence: 99%

See 1 more Smart Citation

Sustainable lake restoration: From challenges to solutions

Tammeorg,

Chorus,

Spears

et al. 2023

WIREs Water

View full text Add to dashboard Cite

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Closed-circuit hypolimnetic withdrawal and treatment: impact of effluent discharge on epilimnetic P and N concentrations

Silvonen,

Nurminen,

Horppila

et al. 2023

Limnology

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Closed-circuit hypolimnetic withdrawal and treatment systems (HWTS) represent a novel lake restoration technique in which nutrient-rich near-bottom water is pumped through a treatment system and returned to the same lake. However, the design of such systems is not yet standardized and routing of effluent waters must be planned carefully to minimize the risk of adverse water quality impacts. Here we assessed the risk of HWTS effluent to elevate epilimnetic nutrient concentrations under a range of withdrawal and effluent discharge scenarios (4.5–45 L/s, sand filtration only and sand filtration combined with wetland) at Lake Kymijärvi, Finland. The filter of the HWTS removed most of the phosphorus (67%), but only a small fraction of nitrogen (14%). For both nutrients, filter effluent concentrations were elevated with respect to the lake epilimnion. However, the results of our calculations suggest only minor increases (0–12%) in epilimnetic phosphorus concentrations in all withdrawal and discharge scenarios. For nitrogen, somewhat higher increases (1–17%) are expected unless the filter effluent is first discharged into a wetland as part of the HWTS circuit. We conclude that the impacts of the filter effluent on the epilimnion do not mask the benefits gained in the treated lake by the closed-circuit HWTS, but use of a buffering system such as a wetland decreases the risks further.

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Wintertime diffusion of sedimentary phosphorus – implications for under-ice phosphorus removal from eutrophic lakes

Silvonen,

Niemistö,

Jilbert

et al. 2024

J Soils Sediments

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Purpose Many eutrophic lakes are located in regions where lakes become ice-covered during the winter. This study aimed to find out if phosphorus (P) could be withdrawn from such lakes by utilizing the wintertime accumulation of P to the near-bottom water. Methods Data for water quality and sediment characteristics were collected from two eutrophic boreal lakes with tube samplers and sediment corers. Diffusion rates of P across the sediment-water interface (SWI) and within the active sediment layers, and potential export of P via wintertime withdrawal were calculated. Results In the stratifying Lake Kymijärvi, P concentration in the near-bottom water reached 66 µg L−1 and P diffusion across SWI in the hypoxic area 5.4 mg m−2 d−1. In the shallow Lake Savijärvi, maximum P concentration was 78 µg L−1 but P diffusion rate only 0.34 mg m−2 d−1. In Kymijärvi, the concentrations of Fe and Mn in the sediment were high relative to P. In Savijärvi, sediment P was bound to clay minerals and calcium carbonates, while Fe was bound in sulfides. Conclusion In Kymijärvi, a theoretical14.3% reduction in epilimnetic TP concentration could be achieved in 20 years with 20 L s−1 winter withdrawal. In Savijärvi, 10 L s−1 withdrawal could theoretically cause a 5.8% reduction in TP concentration in 5 years, but the low P diffusion rate across SWI, and the low discharge of the lake may limit P removal. In Kymijärvi, where summertime withdrawal is already applied, additional winter withdrawal could accelerate lake recovery.

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Extracting phosphorus and other elements from lake water: Chemical processes in a hypolimnetic withdrawal and treatment system

Cited by 6 publications

References 34 publications

Sustainable lake restoration: From challenges to solutions

Sustainable lake restoration: From challenges to solutions

Closed-circuit hypolimnetic withdrawal and treatment: impact of effluent discharge on epilimnetic P and N concentrations

Wintertime diffusion of sedimentary phosphorus – implications for under-ice phosphorus removal from eutrophic lakes

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