Bioaugmentation for low C/N ratio wastewater treatment by combining endogenous partial denitrification (EPD) and denitrifying phosphorous removal (DPR) in the continuous A2/O - MBBR system. (15th June 2022)

• Record Type: Journal Article
• Authors: Zhang, Miao; Wan, Jiajie; Fan, Yajun; Yong, Daming; Liu, Yizhong; Ji, Junjie; Wu, Qichao; Sun, Hongwei; Wu, Jun
• Is Part Of: Journal of environmental management. Volume 312(2022)
• Publication Date: 2022-06-15
• Subjects: Low C/N ratio wastewater -- Endogenous partial denitrification -- Denitrifying phosphorous removal -- Nitrite accumulation -- Stoichiometry analysis -- Microbial community; Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2022.114920
• Languages: English
• ISSNs: 0301-4797

Abstract

Abstract: Endogenous partial denitrification (EPD) and denitrifying phosphorous removal (DPR) were combined in a novel A 2 /O - MBBR (Anaerobic Anoxic Oxic - Moving Bed Biofilm Reactor) system for low carbon/nitrogen (C/N) ratio wastewater treatment. The DPR performance was compared and the nutrient metabolism was elucidated based on the optimization of hydraulic retention time (HRT, 4–12 h) and nitrate recycling (R, 200%–600%). In the continuous-flow, the nitrate (NO3 − ) denitrification accompanied by nitrite (NO2 −, via EPD) accumulation with the nitrate-to-nitrite transformation ratio (NTR) of 35.87%–43.31% in the anoxic zones. At HRT of 12 h with R of 500%, batch test initially revealed the DPR mechanism using both NO3 − and NO2 − as electron acceptor, where denitrifying phosphorus accumulation organisms (DPAOs) and denitrifying glycogen accumulation organisms (DGAOs) were the main contributors for EPD with incomplete denitrification (NO3 − → NO2 − ). Furthermore, stoichiometry-based functional bacteria analysis displayed that higher bioactivity of DPAOs (NO2 − →N2, 57.30%; NO3 − →N2, 35.85%) over DGAOs (NO3 − →N2, 6.85%) facilitated the anoxic NO3 − reduction. Microbial community analysis suggested that Cluster I of Defluviicoccus -GAO group (∼4%) was responsible for stable NO2 − accumulation performance via EPD, while increased Accumulibacter -PAO group (by ∼15%) contributed to the advanced nutrient removal. Based on the achievement of NO2 − accumulation, the application feasibility of integrated EPD - DPR - Anammox for deep-level nutrient removal was discussed. Highlights: The optimal TN (84.77%) and PO4 3− (96.48%) removals were achieved. Stoichiometry methodology was adopted to quantify substrate transformation. Enriched Cluster I of Defluviicoccus (4.90%) was responsible for NO2 − accumulation. The functional contribution via NO2 − .→N2 metabolic pathway was up to 57.30%.