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Conventional bioretention filters lack satisfactory performance in nitrogen removal. In this study, we used a mixture of cultivated soil and river sand as the bioretention filter to remove nitrogen pollutants from simulated rainwater runoff. To improve its permeability and nitrogen removal performance, both activated carbon and ceramsite were used as additives. The nitrogen removal processes and its mass accumulation in the modified bioretention filters were studied. The contribution of adsorption and biotransformation processes, together with the effects of percolate rate on nitrogen removal performance was explored. The results showed that an activated carbon layer in the bioretention filters could obviously improve nitrogen removal efficiencies, but its location made no significant difference in nitrogen removal performance. Bioretention filters modified with 20% of ceramsite could achieve the optimal percolate rate and nitrogen removal efficiencies. At given conditions, the average removal efficiencies of ammonium nitrogen (NH-N), nitrate-nitrogen (NO-N), and total nitrogen (TN) by the modified bioretention filter reached 80.27%, 41.48%, and 59.45%, respectively. During the leaching processes, organic nitrogen originated in the filter materials can be mineralised into NH-N, then be denitrified and completely removed in the anaerobic environment under flooding conditions. Biotransformation in the modified bioretention filters caused a reduction of NH-N removal efficiency by 15.41% and an increase of NO-N removal efficiency by 31.03%. The modified bioretention filter can withstand a long-term operation. Compared with NO-N and TN, the pollutant of NH-N in rainwater runoff is not easy to form a mass accumulation in the modified bioretention filter. The modified bioretention filter showed high percolation rate and nitrogen removal.Hydraulic residence time is a critical design parameter to achieve nitrogen removal.NH-N is not easy to form a mass accumulation in the filler media as NO-N.Biodegradation increased NO-N removal efficiency by 31.03% at given conditions.
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http://dx.doi.org/10.1080/09593330.2022.2057236 | DOI Listing |
Int J Biol Macromol
September 2025
School of Resource and Environmental Engineering, Jiangxi University of Science and Technology, Ganzhou, 341000, China; School of Resources and Civil Engineering, GanNan University of Science and Technology, Ganzhou, 341000, China.
Herein, organic/inorganic multiple adsorption sites were constructed on halloysite to intensify the selective adsorption performance of the adsorbent for Al(III) in rare earth solutions. The adsorption heat behavior and thermodynamics of the composite for different ion systems were investigated using microcalorimetry. The results showed that chitosan formed a mesoporous membrane on the acid-treated calcined halloysite (HalH) substrate through a strong electron interaction between the nitrogen atom of the amino group and the oxygen atom of SiO structure on HalH.
View Article and Find Full Text PDFSci Total Environ
September 2025
Department of Environmental Science, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark; WATEC, Centre for Water Technology, Aarhus University, Ny Munkegade 120, 8000 Aarhus C, Denmark.
Treatment wetlands (TW) are a popular choice for decentralized wastewater treatment, with substantial documentation on their capacity to manage conventionally monitored pollutants. However, most insights into their effectiveness against emerging contaminants come from lab and mesocosm studies with a limited number of compounds, highlighting knowledge gaps in their performance at full scale. This study provides a first long-term, full-scale assessment of TW ability to remove a large number of organic micropollutants (OMPs) and manage antibiotic resistance under real-world conditions.
View Article and Find Full Text PDFMicrobiol Spectr
September 2025
Guangdong Laboratory for Lingnan Modern Agriculture, College of Natural Resources and Environment, South China Agricultural University, Guangzhou, China.
Unlabelled: Microalgae treatment is regarded as a green and environmentally acceptable method of treating pig farm biogas slurry (BS). Numerous studies have been conducted on the use of microalgae to treat sterilized BS. Nevertheless, in large-scale application settings, this method will undoubtedly result in high costs and low efficiency.
View Article and Find Full Text PDFBioresour Technol
September 2025
Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu 610213, China. Electronic address:
Microbial desalination cells (MDCs) have traditionally employed simplified NaCl solutions as feedwater for synchronous desalination and bioenergy recovery. Nevertheless, the specific mechanisms by which MDCs remove complex multi-ions from saline wastewater remain obscure. This study thoroughly investigated ion migration, bioelectrochemical dynamics, and microbial ecological responses across three distinct configurations: monovalent ions - PMDC, divalent cations - CMDC and anions - AMDC.
View Article and Find Full Text PDFEnviron Sci Technol
September 2025
Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
Iron plaque (IP) on rice root surfaces has been extensively documented as a natural barrier that effectively reduces contaminant bioavailability and accumulation. However, its regulatory mechanisms in rhizospheric methane oxidation and biological nitrogen fixation (BNF) remain elusive. This study reveals a previously unrecognized function of IP: mediating methanotrophic nitrogen fixation through coupled aerobic methane oxidation and IP reduction (Fe-MOX).
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