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Meta-omics profiling of full-scale groundwater rapid sand filters explains stratification of iron, ammonium and manganese removals

Corbera Rubio, F. (author), Laureni, M. (author), Koudijs, N. (author), Müller, S. (author), van Alen, Theo (author), Schoonenberg, Frank (author), Lücker, Sebastian (author), Pabst, Martin (author), van Loosdrecht, Mark C.M. (author), van Halem, D. (author)

Rapid sand filters (RSF) are an established and widely applied technology for groundwater treatment. Yet, the underlying interwoven biological and physical-chemical reactions controlling the sequential removal of iron, ammonia and manganese remain poorly understood. To resolve the contribution and interactions between the individual reactions...

journal article 2023

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Inactivation of Escherichia coli and somatic coliphage ΦX174 by oxidation of electrochemically produced Fe²⁺

Bicudo, Bruno (author), Medema, G.J. (author), van Halem, D. (author)

Electrochemical ferrous iron (Fe²⁺) wastewater treatment is gaining momentum for treating municipal wastewater due to its decreasing costs, environmental friendliness and capacity for removal of a wide range of contaminants. Disinfection by iron electrocoagulation (Fe-EC) has been occasionally reported in full scale industrial...

journal article 2022

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Groundwater-native Fe(II) oxidation prior to aeration with H₂O₂ to enhance As(III) removal

Roy, M. (author), van Genuchten, Case M. (author), Rietveld, L.C. (author), van Halem, D. (author)

Groundwater contaminated with arsenic (As) must be treated prior to drinking, as human exposure to As at toxic levels can cause various diseases including cancer. Conventional aeration-filtration applied to anaerobic arsenite (As(III)) contaminated groundwater can remove As(III) by co-oxidizing native iron (Fe(II)) and As(III) with oxygen (O...

journal article 2022

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Disinfection during Iron Electrocoagulation: Differentiating between Inactivation and Floc Entrapment for Escherichia coli and Somatic Coliphage Øx174

Bicudo, Bruno (author), Van Der Werff, Bart Jan (author), Medema, G.J. (author), van Halem, D. (author)

Electrochemical water treatment is gaining increasing popularity due to its wide range of potential applications, its decreasing costs, and its suitability as a decentralized treatment alternative, but mainly due to it being considered a "green technology". In the field of municipal wastewater treatment, the use of iron electrocoagulation (Fe...

journal article 2022

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Sequential Fe²⁺ oxidation to mitigate the inhibiting effect of phosphate and silicate on arsenic removal

Annaduzzaman, M. (author), Rietveld, L.C. (author), Hoque, Bilqis Amin (author), van Halem, D. (author)

Sequential iron (as Fe²⁺) oxidation has been found to yield improved arsenic (as As(III)) uptake than the single-step oxidation. The objective of this study was to gain a better understanding of interactions with phosphate (PO₄³⁻) and silicate (SiO₄²⁻) during sequential Fe²⁺...

journal article 2022

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Removal of Antibiotic Resistance From Municipal Secondary Effluents by Ozone-Activated Carbon Filtration

Spit, T.P.M. (author), van der Hoek, J.P. (author), de Jong, Coen (author), van Halem, D. (author), de Kreuk, M.K. (author), Bicudo, Bruno (author)

At wastewater treatment plants (WWTPs), additional steps are introduced for removal of organic micropollutants (OMPs) from the treated effluents, especially pharmaceutical residues. At the same time, a new concern is emerging: antibiotic resistance (AR). This research studied the effect of ozonation, coagulation and granular activated carbon ...

journal article 2022

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Vivianite precipitation for iron recovery from anaerobic groundwater

Goedhart, R.C. (author), Müller, S. (author), van Loosdrecht, Mark C.M. (author), van Halem, D. (author)

Iron in anaerobic groundwater is commonly removed by oxidation followed by sand filtration. This produces large volumes of iron(III)(hydr)oxide sludge with little value. Our research investigates the novel concept of anaerobic iron(II) recovery from groundwater as the valuable mineral vivianite (Fe₃(PO₄)₂ • 8...

journal article 2022

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Fluoride removal from water by Ca-Al-CO₃ layered double hydroxides and simultaneous acidification

Wei, L. (author), Zietzschmann, F.E. (author), Rietveld, L.C. (author), van Halem, D. (author)

Millions of people worldwide are exposed to excessive concentrations of fluoride (F⁻) from groundwater sources. Ca-Al-CO₃ layered double hydroxides (LDHs) have shown promising defluoridation efficiency; however, defluoridation by Ca-Al-CO₃ LDHs is highly pH sensitive. This study showed that simultaneous...

journal article 2021

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Integrating biological As(III) oxidation with Fe(0) electrocoagulation for arsenic removal from groundwater

Roy, M. (author), van Genuchten, Case M. (author), Rietveld, L.C. (author), van Halem, D. (author)

Arsenic (As) is a toxic element present in many (ground)water sources in the world. Most conventional As removal techniques require pre-oxidation of the neutral arsenite (As(III)) species to the negatively charged arsenate (As(V)) oxyanion to optimize As removal and minimize chemical use. In this work, a novel, continuous-flow As removal...

journal article 2021

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Low voltage iron electrocoagulation as a tertiary treatment of municipal wastewater: removal of enteric pathogen indicators and antibiotic-resistant bacteria

Bicudo, Bruno (author), van Halem, D. (author), Trikannad, S.A. (author), Ferrero, Giuliana (author), Medema, G.J. (author)

In this paper we analyse the feasibility of low voltage iron electrocoagulation as a means of municipal secondary effluent treatment with a focus on removal of microbial indicators, Antibiotic Resistant Bacteria (ARB) and nutrients. A laboratory scale batch unit equipped with iron electrodes was used on synthetic and real secondary effluent...

journal article 2021

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Comparative study of low-cost fluoride removal by layered double hydroxides, geopolymers, softening pellets and struvite

Wei, L. (author), Li, Z. (author), Ye, G. (author), Rietveld, L.C. (author), van Halem, D. (author)

Excessive F^- in drinking water due to natural and anthropogenic activities is a serious health hazard affecting humans worldwide. In this study, a comparative assessment was made of eight mineral-based materials with advantageous structural properties for F^- uptake: layered-double-hydroxides (LDHs), geopolymers,...

journal article 2021

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Arsenic removal from iron-containing groundwater by delayed aeration in dual-media sand filters

Annaduzzaman, M. (author), Rietveld, L.C. (author), Amin Hoque, Bilqis (author), Bari, Md Niamul (author), van Halem, D. (author)

Generally, abstracted groundwater is aerated, leading to iron (Fe²⁺) oxidation to Fe³⁺ and precipitation as Fe³⁺-(hydr)oxide (HFO) flocs. This practice of passive groundwater treatment, however, is not considered a barrier for arsenic (As), as removal efficiencies vary widely (15–95%), depending on Fe/As ratio...

journal article 2021

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Anoxic storage to promote arsenic removal with groundwater-native iron

Annaduzzaman, M. (author), Rietveld, L.C. (author), Ghosh, D. (author), Hoque, Bilqis A. (author), van Halem, D. (author)

Storage containers are usually used to provide a constant water head in decentralized, community groundwater treatment systems for the removal of iron (Fe) and arsenic (As). However, the commonly practiced aeration prior to storage assists in rapid and complete Fe²⁺ oxidation, resulting in poor As removal, despite sufficient native...

journal article 2021

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Inactivation of RNA and DNA viruses in water by copper and silver ions and their synergistic effect

Soliman, Mona Youssef Moawad (author), Medema, G.J. (author), Estrada Bonilla, B.A. (author), Brouns, S.J.J. (author), van Halem, D. (author)

Cu and Ag have been used as bactericidal agents since ancient times, yet their antiviral capacity in water remains poorly understood. This study tested the effect of copper (Cu) and silver (Ag) on model RNA and DNA viruses MS2 and PhiX 174 in solution at pH 6–8. Cu caused MS2 inactivation with similar rates at pH 6 and 7 but was inert towards...

journal article 2020

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Fluoride removal by Ca-Al-CO₃ layered double hydroxides at environmentally-relevant concentrations

Wei, L. (author), Zietzschmann, F.E. (author), Rietveld, L.C. (author), van Halem, D. (author)

In this study, F⁻ removal by Ca–Al–CO₃ layered double hydroxides (LDHs) was investigated at environmentally-relevant concentration ranges (2–12 mg/L) to below the WHO guideline, with an emphasis on the effect of LDHs’ modification, as well as the effects of initial F⁻ concentration, adsorbent dose, pH,...

journal article 2020

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Virus removal by ceramic pot filter disks: Effect of biofilm growth and surface cleaning

Soliman, Mona Youssef Moawad (author), van Halem, D. (author), Medema, G.J. (author)

Ceramic pot filters are household water treatment and safe storage (HWTS) systems designed to improve the microbial quality of drinking water. They yield high log reduction values (LRVs) for bacterial and protozoan pathogens but provide very little removal of viruses. This study investigated virus removal of ceramic filter discs (CFDs), using...

journal article 2020

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As(V) rejection by NF membranes using high temperature sources for drinking water production

Gonzalez Rodriquez, B.J. (author), Heijman, Sebastiaan (author), Rietveld, L.C. (author), van Halem, D. (author)

In Nicaragua, a Central American country, geothermally influenced waters are frequently found to be contaminated with arsenic (as As(V)). This study investigated the effect of high-temperatures (25–50 °C), as found in geothermally influenced source waters, on the rejection of monovalent H2AsO4 - and divalent HAsO4 2- species (at pH 6,7 and 8)...

journal article 2019

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Arsenic contamination of rural community wells in Nicaragua: A review of two decades of experience

Gonzalez Rodriquez, B.J. (author), Rietveld, L.C. (author), Longley, A. J. (author), van Halem, D. (author)

Several surveys have been conducted in Nicaragua between 1996 and 2015 confirming the presence of high levels of arsenic (>10 μg/L). In this paper, these peer-reviewed (n = 2) and non-peer reviewed sources (n = 14) have been combined to provide an extensive overview of the arsenic contamination of drinking water sources in Nicaragua. So...

review 2019

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Arsenic removal from geothermal influenced groundwater with low pressure NF pilot plant for drinking water production in Nicaraguan rural communities

Gonzalez Rodriquez, B.J. (author), Heijman, Sebastiaan (author), Rietveld, L.C. (author), van Halem, D. (author)

This research evaluated the effect of different fluxes (16, 23 & 30 L/m ² h) and temperatures (31,35 & 43 °C) on the rejection of As(V) during nanofiltration (NF) of natural geothermal influenced groundwater in Nicaragua. A NF pilot plant powered by solar panels was built and operated in rural community Telica, exposed to...

journal article 2019

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Natural recovery of infiltration capacity in simulated bank filtration of highly turbid waters

Gutiérrez, Juan Pablo (author), van Halem, D. (author), Uijttewaal, W.S.J. (author), del Risco, Efraín (author), Rietveld, L.C. (author)

As a consequence of the suspended sediments in river water, cake formation on the streambed and clogging of the aquifer may occur, leading to a decline in the production yield of riverbank filtration systems, particularly in highly turbid river waters. However, naturally occurring flow forces may induce sufficient scouring of the streambed,...

journal article 2018