TY - JOUR
T1 - Influence of filter age on Fe, Mn and NH4+ removal in dual media rapid sand filters used for drinking water production
AU - Haukelidsaeter, Signe
AU - Boersma, Alje S.
AU - Kirwan, Liam
AU - Corbetta, Alessia
AU - Gorres, Isaac D.
AU - Lenstra, Wytze K.
AU - Schoonenberg, Frank K.
AU - Borger, Karl
AU - Vos, Luuk
AU - van der Wielen, Paul W.J.J.
AU - van Kessel, Maartje A.H.J.
AU - Lücker, Sebastian
AU - Slomp, Caroline P.
N1 - Funding Information:
We are grateful to H. Doeve, M. Pipping and Vitens N.V. for their support and collaboration during the visits to the drinking water plants. We also thank L. Piso, N.A.G.M. van Helmond, J. Visser, E. Hellebrand and J.J. Mulder, A. Leeuwen-Tolboom, K. Pelsma and P. Kragt for analytical support, and T. Marcus for graphical design. This research was funded by the Netherlands Organisation for Scientific Research (NWO) partnership program Dunea–Vitens: Sand Filtration (grant 17841 ). MAHJvK and SL were funded by NWO (016.Veni.192.062 and 016.Vidi.189.050, respectively), CPS by the European Research Council (ERC Synergy Grant 694407 MARIX).
Publisher Copyright:
© 2023 The Authors
PY - 2023/8/15
Y1 - 2023/8/15
N2 - Rapid sand filtration is a common method for removal of iron (Fe), manganese (Mn) and ammonium (NH4+) from anoxic groundwaters used for drinking water production. In this study, we combine geochemical and microbiological data to assess how filter age influences Fe, Mn and NH4+ removal in dual media filters, consisting of anthracite overlying quartz sand, that have been in operation for between ∼2 months and ∼11 years. We show that the depth where dissolved Fe and Mn removal occurs is reflected in the filter medium coatings, with ferrihydrite forming in the anthracite in the top of the filters (< 1 m), while birnessite-type Mn oxides are mostly formed in the sand (> 1 m). Removal of NH4+ occurs through nitrification in both the anthracite and sand and is the key driver of oxygen loss. Removal of Fe is independent of filter age and is always efficient (> 97% removal). In contrast, for Mn, the removal efficiency varies with filter age, ranging from 9 to 28% at ∼2–3 months after filter replacement to 100% after 8 months. After 11 years, removal reduces to 60–80%. The lack of Mn removal in the youngest filters (at 2–3 months) is likely the result of a relatively low abundance of mineral coatings that adsorb Mn2+ and provide surfaces for the establishment of a microbial community. 16S rRNA gene amplicon sequencing shows that Gallionella, which are known Fe2+ oxidizers, are present after 2 months, yet Fe2+ removal is mostly chemical. Efficient NH4+ removal (> 90%) establishes within 3 months of operation but leakage occurs upon high NH4+loading (> 160 µM). Two-step nitrification by Nitrosomonas and Candidatus Nitrotoga is likely the most important NH4+ removal mechanism in younger filters during ripening (2 months), after which complete ammonia oxidation by Nitrospira and canonical two-step nitrification occur simultaneously in older filters. Our results highlight the strong effect of filter age on especially Mn2+but also NH4+ removal. We show that ageing of filter medium leads to the development of thick coatings, which we hypothesize leads to preferential flow, and breakthrough of Mn2+. Use of age-specific flow rates may increase the contact time with the filter medium in older filters and improve Mn2+ and NH4+ removal.
AB - Rapid sand filtration is a common method for removal of iron (Fe), manganese (Mn) and ammonium (NH4+) from anoxic groundwaters used for drinking water production. In this study, we combine geochemical and microbiological data to assess how filter age influences Fe, Mn and NH4+ removal in dual media filters, consisting of anthracite overlying quartz sand, that have been in operation for between ∼2 months and ∼11 years. We show that the depth where dissolved Fe and Mn removal occurs is reflected in the filter medium coatings, with ferrihydrite forming in the anthracite in the top of the filters (< 1 m), while birnessite-type Mn oxides are mostly formed in the sand (> 1 m). Removal of NH4+ occurs through nitrification in both the anthracite and sand and is the key driver of oxygen loss. Removal of Fe is independent of filter age and is always efficient (> 97% removal). In contrast, for Mn, the removal efficiency varies with filter age, ranging from 9 to 28% at ∼2–3 months after filter replacement to 100% after 8 months. After 11 years, removal reduces to 60–80%. The lack of Mn removal in the youngest filters (at 2–3 months) is likely the result of a relatively low abundance of mineral coatings that adsorb Mn2+ and provide surfaces for the establishment of a microbial community. 16S rRNA gene amplicon sequencing shows that Gallionella, which are known Fe2+ oxidizers, are present after 2 months, yet Fe2+ removal is mostly chemical. Efficient NH4+ removal (> 90%) establishes within 3 months of operation but leakage occurs upon high NH4+loading (> 160 µM). Two-step nitrification by Nitrosomonas and Candidatus Nitrotoga is likely the most important NH4+ removal mechanism in younger filters during ripening (2 months), after which complete ammonia oxidation by Nitrospira and canonical two-step nitrification occur simultaneously in older filters. Our results highlight the strong effect of filter age on especially Mn2+but also NH4+ removal. We show that ageing of filter medium leads to the development of thick coatings, which we hypothesize leads to preferential flow, and breakthrough of Mn2+. Use of age-specific flow rates may increase the contact time with the filter medium in older filters and improve Mn2+ and NH4+ removal.
UR - http://www.scopus.com/inward/record.url?scp=85164318633&partnerID=8YFLogxK
U2 - 10.1016/j.watres.2023.120184
DO - 10.1016/j.watres.2023.120184
M3 - Article
C2 - 37429136
AN - SCOPUS:85164318633
SN - 0043-1354
VL - 242
SP - 1
EP - 12
JO - Water Research
JF - Water Research
M1 - 120184
ER -