Metagenomic analysis reveals enhanced nutrients removal from low C/N municipal wastewater in a pilot-scale modified AAO system coupling electrolysis
| Autor: | Lei He, Benzhou Gong, Ziyuan Lin, Qiang He, Jian Zhou, Wei Huang, Yingmu Wang |
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| Rok vydání: | 2019 |
| Předmět: |
Environmental Engineering
Denitrification Nitrogen 0208 environmental biotechnology Heterotroph chemistry.chemical_element 02 engineering and technology 010501 environmental sciences Wastewater 01 natural sciences Waste Disposal Fluid Electrolysis Nutrient Bioreactors Autotroph Waste Management and Disposal 0105 earth and related environmental sciences Water Science and Technology Civil and Structural Engineering biology Chemistry Ecological Modeling Phosphorus Nutrients biology.organism_classification Pollution Anoxic waters Carbon 020801 environmental engineering Nitrifying bacteria Environmental chemistry |
| Zdroj: | Water research. 173 |
| ISSN: | 1879-2448 |
| Popis: | The conventional biological nutrients removal process is challenged by insufficient organic carbon in influent. To cross such an organic-dependent barrier, a pilot-scale electrolysis-integrated anaerobic/anoxic/oxic (AAO) process was developed for enhanced removal of nitrogen (N) and phosphorus (P) from low carbon/nitrogen (C/N) municipal wastewater. Average removal efficiencies of total nitrogen (TN) and total phosphorus (TP) in the electrolysis-AAO reached to 77.24% and 95.08% respectively, showing increases of 13.88% and 21.87%, as compared to the control reactor. Spatial variations of N and P showed that NH4+-N removal rate was promoted in aerobic zone of electrolysis-AAO. The intensified TN elimination, which was mostly reflected by abatement of NO3−-N with the concomitant slight accumulation of NH4+-N and NO2−-N, mainly occurred in anoxic2 compartment as the electrons supplied by electrolysis. Furthermore, minor P contents were measured and remained almost unchanged along the reaction units, indicating that chemical precipitation should be the dominant mechanism of P-removal in electrolysis-AAO. From the metagenomic-based taxonomy, phylum Actinobacteria was dramatically inhibited, and phylum Proteobacteria dominated the electrolysis-AAO. Particularly, nitrifying bacteria and multifarious autotrophic denitrifiers were enriched, meanwhile, a significant evolution of heterotrophic denitrifiers was found in electrolysis-AAO compared to control, which was mostly reflected by the inhibition of genus Candidatus Microthrix. Batch tests further confirmed that autotrophic denitrifiers using H2 and Fe2+ as essential electron sinks were mainly responsible for the electrolysis-induced denitrification. Differential metabolic capacities were revealed from the perspectives of functional enzymes and genes, and network analysis allowed insight of microbial taxa-functional genes associations and shed light on stronger relevance between autotrophic denitrifiers and denitrification-associated genes in the electrolysis-AAO system. |
| Databáze: | OpenAIRE |
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