PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 15137409

Factors affecting nitrogen removal by nitritation/denitritation.

P Jenicek·P Svehla·J Zabranska·M Dohanyos
View original source ↗Export metadata ↓

Abstract

Nitrogen removal from wastewater with high nitrogen concentration and low COD/N ratio via nitrite is advantageous. The specific character of the sludge liquor enables the application of such a method. The factors affecting process efficiency were studied. From the factors followed pH, NH4+/NH3 and NO2-/HNO2 concentration and distribution seem to be most important, using sequencing batch reactor technology and treating wastewater with high NH4+ concentration (above 1 g/l). The efficient oxidation of N-NH4+ to nitrite was achieved at a minimal nitrate production. Primary sludge was used as an internal source of substrate for the denitritation because of the organic substrate deficiency of the sludge liquor. The denitritation can be controlled by dosing of the primary sludge and can be complete. There are two operational alternatives of sludge liquor pretreatment: without pH control--lower operational costs and N-removal up to 65% and with pH control--higher operational costs and N-removal close to complete.

Explore related subjects

AmmoniaBioreactorsHydrogen-Ion ConcentrationNitratesNitrogenOxygenSewageWaste Disposal, FluidJournal ArticleResearch Support, Non-U.S. Gov't

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

P Jenicek, P Svehla, J Zabranska, M Dohanyos. 2004. Factors affecting nitrogen removal by nitritation/denitritation.. https://pubmed.ncbi.nlm.nih.gov/15137409/

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2026

Adaptive Evolution Reveals Metabolic Plasticity and Functional Redundancy in an Anaerobic Microbiome under Extreme Ammonia Stress.

Ammonia toxicity represents a primary biochemical bottleneck governing microbial community structure and performance during the anaerobic digestion of the organic fraction of municipal solid waste. However, the mechanistic basis of microbial adaptation to chronic ammonia levels remains poorly characterized. In this study, a long-term sequential enrichment strategy under progressively increasing ammonia concentrations (350-1500 mgN L-1), integrated with genome-centric metagenomics and metatranscriptomics, was employed to resolve the response of an organic waste-degrading microbiome over a 240 day period. Increasing ammonia pressure induced a progressive decline in methanogenesis and accumulation of volatile fatty acids, particularly acetate. Despite these inhibitory pressures, methane production was only halved relative to the initial baseline reflecting a resilient methanogenic community. This stability was driven by a restructuring of the microbiome, where functional redundancy across divergent taxa preserved core metabolic functions. Key adaptive responses included the reconfiguration of carbon fixation pathways, specifically via a variant of the Wood-Ljungdahl pathway coupled with the glycine cleavage system acting as an alternative acetate oxidation route, as well as sustained osmoprotectant biosynthesis. Cellular homeostasis was preserved through H+ replenishment via multiple energy-converting complexes and K+ influx to maintain cation-proton balance. Collectively, these findings demonstrate that metabolic plasticity and the preservation of core metabolic functions are the primary determinants of ammonia resilience, sustaining methane production under inhibitory conditions.

Ammonia↗
PubMed2026

Potential survival strategies of novel comammox and nitrite-oxidizing Nitrospira synthesizing osmoprotectants in a wastewater microbiome treating high-ammonia brackish landfill leachate.

BACKGROUND: In the late stages of landfill operation, leachate becomes brackish and contains high concentrations of ammonia with limited organic carbon. At leachate treatment facilities, it is typically subjected to nitrification followed by denitrification, with methanol supplied as an external electron donor. This unique environment may harbor novel microorganisms, including nitrifiers. Although a variety of microorganisms are involved in nitrification, their substrate specificity and salinity tolerance remain insufficiently understood. In this study, a genome-centric metagenome analysis was conducted on the microbiome from a leachate treatment facility at a closed landfill. RESULTS: A total of 68 metagenome-assembled genomes (MAGs) were reconstructed, including 64 putative novel species. Among these, two Nitrospira MAGs were recovered: a novel complete ammonia-oxidizing bacterium (comammox), Nitrospira LAS72 (88.72% completeness, 2.10% contamination), and canonical nitrite-oxidizing Nitrospira LAS18 (99.98% completeness, 2.29% contamination). Comparative genomic analysis with 260 publicly available Nitrospira genomes revealed that LAS18 represents a new sub-lineage within lineage VII of the Nitrospira genus. Two ammonia-oxidizing archaea (AOA), Candidatus Nitrosocosmicus LAS21 and Nitrosarchaeum LAS73, were also identified, while canonical ammonia-oxidizing bacteria were not detected. Given the brackish conditions (1.23% salinity) and the methanol-fed operation of the treatment facility, the genomic potential for osmotic stress adaptation and methanol metabolism was investigated. Comammox Nitrospira LAS72 harbors biosynthetic pathways for several compatible solutes (osmoprotectants), including glycine betaine, proline, trehalose, and L-glutamate. Moreover, comammox Nitrospira LAS72 possesses genetic potential for oxidizing formaldehyde, suggesting that it may exploit these methanol-derived intermediates as energy sources. These features indicate that LAS72 may withstand osmotic fluctuations through the production of various osmoprotectants and thrive under the unique conditions of a methanol-fed environment. CONCLUSIONS: The discovery of novel comammox Nitrospira and canonical Nitrospira forming a new sub-lineage within lineage VII of the Nitrospira genus in an ammonia-rich brackish environment provides the first genomic evidence for evolutionary adaptation among nitrifiers to saline, methanol-fed environments. These findings enhance our understanding of the ecological and evolutionary dynamics shaping nitrifier communities in complex treatment ecosystems. Video Abstract.

Ammonia↗
PubMed2026

Hypoosmolarity inhibits ammonia oxidation by terrestrial and freshwater Nitrosopumilaceae members.

Salinity strongly influences the physiology and distribution of nitrifying microorganisms, yet the effects of low salinity remain understudied. This study investigates the impact of hypoosmolarity on different groups of ammonia oxidizers in soil and freshwater reservoirs, as well as in pure culture isolates. In soil microcosms amended with ammonium, at low salinity levels (~120 μS/cm), comparable to values commonly found in pristine terrestrial and freshwater environments, the abundance of ammonia-oxidizing bacteria (AOB), dominated by Nitrosomonas oligotropha, significantly increased. In contrast, the growth of ammonia-oxidizing archaea (AOA), dominated by "Candidatus Nitrosotenuis" of the Nitrosopumilaceae family, was stimulated by high salinity (~760 μS/cm). In ammonium-fed freshwater microcosms, the abundance of AOB, dominated by N. oligotropha, significantly increased under both low (~170 μS/cm) and high salinity (~850 μS/cm) conditions. In the presence of allylthiourea (50 μM), used to inhibit bacterial ammonia oxidation, AOA were sensitive to low salinity in both soil and freshwater microcosms. Consistently, culture-dependent studies revealed marked growth inhibition of terrestrial AOA, especially members of Nitrosopumilaceae, under hypoosmolarity, unlike AOB and complete ammonia oxidizer (comammox) strains. Genomic analyses, along with transcriptomic studies, suggested that the sensitivity of AOA to hypoosmolarity stress was possibly due to a lack of osmoregulatory transport systems and their S-layer cell wall structure. Overall, this study indicates hypoosmolarity as an important factor shaping the ecological niches and distribution of ammonia oxidizers, as well as nitrification activities, in terrestrial and freshwater environments that are increasingly affected by intensified water cycles due to global change.

Ammonia↗