Results for “aerobic granular sludge”

PubMed2026

Boosting domestic wastewater treatment with quorum signal-augmented heterotrophic nitrification-aerobic denitrification bacterial-algal aerobic granular sludge.

The aerobic bacterial-algal granular sludge (ABGS) enhanced with heterotrophic nitrification-aerobic denitrification (HN-AD) bacteria, as a novel symbiotic technology, exhibits fluctuating treatment efficiency and unstable performance primarily due to the unstable symbiotic relationship. This study proposes an innovative approach to strengthening the bacteria-algae symbiosis by introducing exogenous signaling molecules. Concurrently, high-throughput, correlation analysis of environmental factors and metagenomic sequencing techniques are employed to elucidate the enhancement mechanisms of the signaling molecules. The results demonstrate that signaling molecule enhancement boosted total nitrogen (TN) removal efficiency by 24.51 % in the bacteria-algae symbiotic system (X1). Scanning electron microscopy (SEM) characterization revealed that the addition of signaling molecules resulted in more compact aerobic granular sludge (AGS) and markedly improved stability. High-throughput sequencing showed signaling molecules enriched denitrifying bacteria (Hydrogenophaga, Pseudoxanthomonas, Thauera, Zoogloea) and organic-degrading Desulfomicrobium, optimizing microbial diversity and enhancing nitrogen/organic removal. Correlation analysis of environmental factors indicate that the addition of C8-HSL facilitates the enrichment and functional activation of specific genera. Metagenomic analysis revealed that signaling molecules enhanced the system's denitrification performance by modulating gene expression and associated metabolic pathways. Quantitative polymerase chain reaction (qPCR) analysis further confirmed that the signaling molecules upregulated the expression of the napA, nirK, and nirS genes. An increased abundance of the napA gene facilitated aerobic denitrification (NO₃⁻-N→NO₂⁻-N), while upregulated abundance of the nirK and nirS genes accelerated nitrite reduction (NO₂⁻-N→N₂). This study aims to provide theoretical and practical foundations for implementing advanced bacteria-algae symbiotic technologies.

Denitrification↗

PubMed2026

Genome-Resolved Metagenomics Revealed the Functional Potential of Core Novel and Known Genera Key to Processes in Full-Scale Aerobic Granular Sludge Plants.

Microbial communities are critical for nutrient removal in aerobic granular sludge (AGS) wastewater treatment plants (WWTPs). Despite the stable long-term operation of full-scale AGS WWTPs, the microbial populations and functional traits sustaining stable long-term performance remain poorly resolved. To address this gap, the recovered MAG catalog from nine full-scale AGS WWTPs across five countries was analyzed. From this catalog, 74 high-quality core MAGs were identified and used for downstream taxonomic characterization and functional analyses. These high-quality core MAGs spanned 48 established and 7 novel genera, representing 31 known and 43 novel species. Functional analysis linked core MAGs to key WWTP processes: polyphosphate accumulation (9), glycogen accumulation (12), denitrification (62), and nitrification (1). These included four novel MAGs with glycogen-accumulating (3) and polyphosphate-accumulating (1) potential and 11 capable of nitrous oxide reduction, critical for mitigating greenhouse gas emissions. Ca. Phosphoribacter was the most abundant genus, highlighting its underestimated role caused by misclassification as Tetrasphaera in 16S rRNA surveys. Specifically, Ca. P. hodrii was the dominant species, exhibiting enhanced sugar uptake and amino acid synthesis as likely drivers of its enrichment in the AGS WWTPs. Overall, this study resolves for the first time the taxa and functional traits consistently enriched in full-scale AGS systems, enabling a shift from an empirical performance assessment toward biologically informed process interpretation.

Sewage↗