Ammonium oxidation to nitrite and then to nitrate (nitrification) is a key process in many waterworks treating groundwater to make it potable. In rapid sand filters, nitrifying microbial communities may evolve naturally from groundwater bacteria entering the filters. However, in new filters this may take several months, and in some cases the nitrification process is never sufficiently rapid to be efficient or is only performed partially, with nitrite as an undesired end product. The present study reports the first successful priming of nitrification in a rapid sand filter treating groundwater. It is shown that nitrifying communities could be enriched by microbiomes from well-functioning rapid sand filters in waterworks and that the enriched nitrifying consortium could be used to inoculate fresh filters, significantly shortening the time taken for the nitrification process to start. The key nitrifiers in the enrichment were different from those in the well-functioning filter, but similar to those that initiated the nitrification process in fresh filters without inoculation. Whether or not the nitrification was primed with the enriched nitrifying consortium, the bacteria performing the nitrification process during start-up appeared to be slowly outcompeted by Nitrospira, the dominant nitrifying bacterium in well-functioning rapid sand filters.
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http://dx.doi.org/10.1016/j.watres.2017.11.009 | DOI Listing |
Sci Rep
January 2025
College of Civil Engineering and Architecture, China Three Gorges University, Yichang, 443002, Hubei, China.
With the rapid development of infrastructure construction on oceanic reefs, calcareous sand, as the primary medium of these reefs, exhibits unique physical and mechanical properties such as high void ratio, low strength, and susceptibility to particle breakage. These characteristics reduce the bearing capacity and stability of pile foundations in calcareous sand foundations. This study investigates the bearing characteristics of high-strength preloaded expansion piles in calcareous sand foundations, taking into account the influence of HSCA high-performance expansion agent dosage through a series of indoor model tests and in-situ tests.
View Article and Find Full Text PDFEnviron Technol
January 2025
College of Architecture & Civil Engineering, Beijing University of Technology, Beijing, People's Republic of China.
The release of algal organic matter (AOM) during seasonal algal blooms increases the complexity and heterogeneity of natural organic matter (NOM) in water sources, altering its hydrophilic-hydrophobic balance and posing significant challenges to conventional water treatment processes. This study aims to verify whether the (Granular activated carbon) GAC selected for the adsorption of NOM in sand filtration effluent can adapt to water quality fluctuations caused by AOM release, and identify the criteria influencing GAC adsorption performance. Results indicated that external surface area, mesopore volume, pore size and surface functional groups were key indicators of GAC adsorption performance.
View Article and Find Full Text PDFSci Total Environ
January 2025
Laboratorio de Geografía Física, Escuela de Geografía, Universidad de Costa Rica, Costa Rica.
Human interventions in the form of riverbed sand mining are escalating worldwide, especially in the humid tropics with excess population pressure exerting an elevated demand for sand as construction materials. Naturally, channel morphological alterations are observed for the tropical fluvial systems to a large extent. The present work examines the riverbed sand mining of the Mayurakshi River (India) during the last fifty years (1970-2020) using topographical maps, satellite images and field-based cross-sectional measurements.
View Article and Find Full Text PDFEnviron Technol
January 2025
Department of Civil Engineering, The University of Hong Kong, Hong Kong SAR, People's Republic of China.
The remediation of oil-contaminated soil poses significant environmental challenges, often necessitating innovative approaches for effective and sustainable solutions. This study focuses on the synthesis, characterisation, and application of biodegradable capsules loaded with surfactant for enhanced oil remediation of a clean sand. By controlling the release properties of capsules, the research aims to overcome the limitations of conventional surfactant-based remediation methods, such as rapid washout and reduced efficacy over time.
View Article and Find Full Text PDFEnviron Sci Pollut Res Int
January 2025
CERENA - Civil Engineering Research and Innovation for Sustainability, IST-ID, Av. António José de Almeida 12, 1049-001, Lisbon, Portugal.
Polypropylene (PP) disposable face masks (DFMs) are essential for limiting airborne infectious diseases. This study examines the behavior of DFMs under three scenarios: (i) exposure to the natural environment, (ii) simulated high-energy aquatic environments through an abrasion test, and (iii) incorporation into cement-based mortars. In the natural weathering experiment, after 117 days, the DFMs exhibited photodegradation, resulting in chemical alterations in carbonyl and hydroxyl groups.
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