Stagnation trigger changes to tap water quality in winter season: Novel insights into bacterial community activity and composition

Aerobic Denitrification Enhanced by Immobilized Slow-Released Iron/Activated Carbon Aquagel Treatment of Low C/N Micropolluted Water: Denitrification Performance, Denitrifying Bacterial Community Co-occurrence, and Implications

“…1,14 Atomic absorption spectroscopy was used to determine the total iron concentrations. 27 Meanwhile, to explore the performance of the IACA in enhancing the denitrifying bacterial communities in the reduction of nitrogen from micropolluted water, 500 mL of the QJC, XQG, and CL sediment samples was combined with 15% of IACA cultivated in low C/N micropolluted water, named IACA-1, IACA-2, and IACA-3, respectively. During 16 days of operation, the concentrations of the nitrogen compounds and COD Mn were analyzed.…”

“…These reactors were aerated by the aeration pump that kept air dissolved in the systems. , The concentrations of NO 3 – -N, TN, ammonia (NH 4 + -N), and nitrite (NO 2 – -N) and the permanganate index (COD Mn ) were measured every day during the reactor operation based on standard methods . The pH values and DO concentrations were measured daily. , Atomic absorption spectroscopy was used to determine the total iron concentrations . Meanwhile, to explore the performance of the IACA in enhancing the denitrifying bacterial communities in the reduction of nitrogen from micropolluted water, 500 mL of the QJC, XQG, and CL sediment samples was combined with 15% of IACA cultivated in low C/N micropolluted water, named IACA-1, IACA-2, and IACA-3, respectively.…”

“…1,3,27 abundance distribution in the C reactors and IACA reactors, the species abundance distributions (SADs) were modeled by R software (version 3.6.1) with the vegan package. 27 The relationship among the environmental factors (including pH, DO, and total iron), carbon source, nitrogen source, and denitrifying bacterial community structure were probed by the structural equation modeling (SEM) using R software (version 4.0.2) with the lavaan package. − -N presented slight accumulation in C2 and C3.…”

“…20−22 As a common, inexpensive, and environment-friendly inorganic metal material with enhanced microbial activity performance, zero-valent iron is a potential substrate to enhance the denitrification performance of denitrifying bacteria. 1,10,23,27,28 Addition of zero-valent iron into a polluted water treatment system could enhance the function of gene abundance and relative enzyme concentrations. 1,29,30 However, exposure of zero-valent iron in water bodies directly would result in the fast release of iron ions, with no recycling properties, and be toxic for microorganisms.…”

“…It is meaningful to seek a suitable approach to promote nitrogen removal performance for aerobic denitrification . Due to the strict control of the concentrations of organic pollutants in natural water bodies, additional inorganic electron donors are the best choice to provide external electron donors for denitrifying bacteria. − As a common, inexpensive, and environment-friendly inorganic metal material with enhanced microbial activity performance, zero-valent iron is a potential substrate to enhance the denitrification performance of denitrifying bacteria. ,,,, …”