The spatial distribution of nitrogen removal functional genes in multimedia biofilters for sewage treatment

Microbial structures and community functions of anaerobic sludge in six full-scale wastewater treatment plants as revealed by 454 high-throughput pyrosequencing

“…Pearson correlation coefficients (Ji et al, 2013) was also calculate using SPSS Statistics 20 (IBM, USA) to assess the ecological associations between microorganisms genes. Redundancy Analysis (RDA) (Gao et al, 2014), a direct gradient analysis, was used to analyze the relationships between the abundance of microorganisms genes and environmental parameters using R software 3.1.2 with the vegan library in the RStudio (Version 0.98).…”

“…The narG gene, encoding the membrane bound nitrate reductase enzyme (NAR), was the key gene for converting NO 3 À to NO 2 À (Ji et al, 2013). It consumed NO 3 À and provided substrate NO 2 À for converting NO 2 À to NO.…”

“…anaerobic treatment. The nitrogen removal processes included aerobic ammonium oxidation (AOB), archaea ammonium oxidation (AOA), anaerobic ammonium oxidation (anammox), nitrite oxidation, anaerobic denitrification and heterotrophic nitrification, as well as dissimilatory nitrate reduction to ammonium (DNRA) (Graham et al, 2014;Ji et al, 2013), while the organic matter degradation processes included anaerobic methane formation, sulfate reduction and so on. These processes were mainly catalyzed by different 16S rRNAs and functional genes, such as anammox 16S rRNA, nitrite oxidation bacteria (NOB) 16S rRNA, ammonia monooxygenase (amoA), archaea ammonia monooxygenase (amoA), periplasmic (napA), membrane-bound nitrate reductase (narG), nitrous oxide reductase (nosZ), copper-containing nitrite reductase (nirK), nitrite reductase (nirS), dissimilatory nitrate reductase (nrfA), methyl coenzyme-M reductase (mcrA) and sulfate reductase (mcrA) (Nakamura et al, 2009;Wang et al, 2014).…”

Enhanced long-term ammonium removal and its ranked contribution of microbial genes associated with nitrogen cycling in a lab-scale multimedia biofilter

“…), respectively. These COD removal efficiencies are higher than those of filter systems with high air-based aeration costs, which are commonly constructed to treat drinking water (COD = 6-107 mg/L) with typical removal efficiencies ranging from 42% to 94% (Hasan et al, 2014;Ji et al, 2011Ji et al, , 2013Van den Akker et al, 2008). Influent and effluent DO content during the start-up phase was 8.98 ± 0.15 mg/L and 10.31 ± 0.20 mg/L, respectively.…”

“…Biofilters are engineered systems designed for NH 4 + -N removal from drinking water (Ji et al, 2013;Ryu and Lee, 2009 Akker et al, 2008). However, in practice, both domestic and industrial effluents released into rivers are subject to fluctuations in both quality and quantity, leading to variations in COD and NH 4 + -N loading.…”