Abstract
A toolbox of methods must be available for the remediation of lakes and water bodies suffering from eutrophication. One method suggested is hypolimnetic withdrawal based on a closed-circuit system. Prior to the start of a pilot-scale test at Lake Hönsan, Sweden, a laboratory trial with containers filled with water and bottom sediment from this lake was performed. A peristaltic pump distributed equal bottom water volume to four columns, two filled with glass beads and two with the filter material Polonite, and then back to the surface of the containers. The reactive filter medium (RFM) removed phosphate (PO4-P) efficiently (98.6%), despite the relatively low influent concentration (390 µg L−1). The control column filled with glass beads, removed 2.9% of the PO4-P. The anoxic sediment, containing 2.47 mg P g−1, released PO4-P, which was indicated by the increased concentration in near-bottom water. The redirected water after RFM filtration had high pH (x¯=11.1); however, an equalization took place in the water mass to a lower but still increased pH value (x¯=8.7) compared to the control (x¯=7.02). This article reports the pros and cons of a full-scale system using the proposed method.
Highlights
Despite large and costly measures to counteract the effects of lake eutrophication, many of the water bodies in Europe still have poor ecological status
A method that addresses the possibility of saving the P resource and applying cycling of P and circular economy is hypolimnetic withdrawal (HW) of water from lakes integrated with reactive media filtration [7–9]
This bench-scale experiment lasted only 32 days; the results indicate promising possibilities for using hypolimnetic water recirculation combined with filtration in reactive filter media (HWRFM) as a P-trap (Figure 1)
Summary
Despite large and costly measures to counteract the effects of lake eutrophication, many of the water bodies in Europe still have poor ecological status. Silvonen et al [10] discussed a solution where withdrawn water would flow through a P-capturing purification unit and subsequently return into the same water body This method involved, in its original version, withdrawing of the lake’s hypolimnetic water directly through a pipeline and discharging into a downstream water body [8,11]. The control of P inputs from catchments can be a successful tool for the recovery of many lakes; stored P in the bottom sediment promotes internal loading, which can prevent lakes from being free of algal blooms Motivated by this fact, and that P is historically buried in lake sediments and occurs in high concentrations in hypolimnion in stratified lakes, we developed an original
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
