Limited simultaneous nitrification-denitrification (SND) in aerobic granular sludge systems treating municipal wastewater: Mechanisms and practical implications

Layer, Manuel; Villodres, Mercedes Garcia; Hernández, Antonio; Reynaert, Eva; Morgenroth, Eberhard; Derlon, Nicolas

doi:10.1016/j.wroa.2020.100048

Cited by 106 publications

(52 citation statements)

References 52 publications

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“…Also detected in the AGS biomass, Taibaiella, Leadbetterella, Terrimonas, and Chryseolinea are associated to the hydrolysis and degradation of organic compounds (Abdullah et al, 2013;Szabó et al, 2017;Xu et al, 2018;Layer et al, 2020). Mariniflexile, a bacterium mostly found in saline water, might have been already present in the inoculum, a biomass previously adapted to fish canning wastewater.…”

Section: Discussionmentioning

confidence: 99%

“…Simultaneous nitrification and denitrification (SND) is expected to occur within the granule (De Kreuk et al, 2005). However, to achieve this, both processes need to meet favourable conditions, mostly related to the absence/presence of carbon source, which should be diffusible, and to the amount of dissolved oxygen concentration in the bulk liquid (Layer et al, 2020). Nevertheless, nitrification must be firstly assured for achieving nitrogen removal.…”

Section: Introductionmentioning

confidence: 99%

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High Carbon Load in Food Processing Industrial Wastewater is a Driver for Metabolic Competition in Aerobic Granular Sludge

Paulo

Amorim

Costa

et al. 2021

Front. Environ. Sci.

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Aerobic granular sludge (AGS) processes are among the most robust wastewater treatments. One of their greatest advantages is related to the granules multi-layered structure, which creates a protective barrier against organic shock loads and variable wastewater composition, particularly attractive for the treatment of industrial wastewater. However, when treating a wastewater with variable and complex composition, the difficulty in identifying factors that most affect a specific biological process increases. In this study, the effect of organic loading rate (OLR), namely carbon content, on nitrification in an AGS process treating fish canning wastewater was investigated. Besides process performance, also biomass structural changes, and microbial community composition were analysed. Reactor operation lasted for 107 days and was divided in three phases during which different OLR and C/N ratios were applied. A higher OLR was applied during the first two phases (ca. 1.1 and 1.5 kg COD m−3 day−1, respectively) compared to the third phase (between 0.12 and 0.78 kg COD m−3 day−1) and the C/N ratios also varied (ca. 4.4, 7.8, and 2.9, respectively). Throughout the operation, COD concentration in the outlet was lower than 100 mg O2 L−1. Nitrification was inhibited during the second phase and recovered afterwards. Principal component analysis (PCA) of quantitative image analysis (QIA) and performance data allowed to distinguish process changes over the three operational phases. During the first two phases, the decrease in the biomass robustness occurred, but recovered during the last phase, indicating that the high content of organic matter had possibly an effect on the aerobic granules structural characteristics. The composition of the AGS microbiome did not change substantially after the end of the higher OLR periods. The main microbial diversity shifts were mostly associated to adaptation to higher or lower carbon availability. Bacteria and inferred enzymes associated to nitrogen and phosphorous removal were identified. Chryseobacterium, a bacterium with high metabolic versatility, was able to adapt to the organic shock load, becoming dominant over operation. Despite the variable composition of the fish canning wastewater, carbon was identified as the main driver for nitrification inhibition, while promoting changes in the physical characteristics and on the microbial community of granules.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

High Carbon Load in Food Processing Industrial Wastewater is a Driver for Metabolic Competition in Aerobic Granular Sludge

Paulo

Amorim

Costa

et al. 2021

Front. Environ. Sci.

View full text Add to dashboard Cite

show abstract

“…Even if the anaerobic uptake of particulates by granules would be limited, SND can be enhanced by applying optimised aeration strategies. Layer et al proposed to apply alternating aeration (intermittent switching on and off) or 2-step aeration (a pulse of high aeration followed by low DO for the rest of the reaction phase) to improve SND when AGS was fed with complex wastewater [60]. This way, with an increased particulate COD load such as the one in the present study it is likely possible to enhance SND, as well as to reduce the post-denitrification phase length and achieve lower effluent N.…”

Section: Impact Of Particulates On Wastewater Treatment and Granular Sludge Growthmentioning

confidence: 99%

Effect of an Increased Particulate COD Load on the Aerobic Granular Sludge Process: A Full Scale Study

2021

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High concentrations of particulate COD (pCOD) in the influent of aerobic granular sludge (AGS) systems are often associated to small granule diameter and a large fraction of flocculent sludge. At high particulate concentrations even granule stability and process performance might be compromised. However, pilot- or full-scale studies focusing on the effect of real wastewater particulates on AGS are scarce. This study describes a 3-month period of increased particulate loading at a municipal AGS wastewater treatment plant. The pCOD concentration of the influent increased from 0.5 g COD/L to 1.3 g COD/L, by adding an untreated slaughterhouse wastewater source to the influent. Sludge concentration, waste sludge production and COD and nutrient removal performance were monitored. Furthermore, to investigate how the sludge acclimatises to a higher influent particulate content, lipase and protease hydrolytic activities were studied, as well as the microbial community composition of the sludge. The composition of the granule bed and nutrient removal efficiency did not change considerably by the increased pCOD. Interestingly, the biomass-specific hydrolytic activities of the sludge did not increase during the test period either. However, already during normal operation the aerobic granules and flocs exhibited a hydrolytic potential that exceeded the influent concentrations of proteins and lipids. Microbial community analysis also revealed a high proportion of putative hydrolysing and fermenting organisms in the sludge, both during normal operation and during the test period. The results of this study highlight the robustness of the full-scale AGS process, which can bear a substantial increase in the influent pCOD concentration during an extended period.

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“…Di Bellaa & Torregrossa (2014) reported denitrifying activity in AGR, which could decrease NO 3 -N concentration in the e uent. The anoxic zone in the core of aerobic granules due to the inability of oxygen diffusion promotes simultaneous nitri cation and denitri cation in AGR (Layer et al 2020).…”

Section: Nh -N Removalmentioning

confidence: 99%

Simultaneous removal of carbon, nitrogen, and phosphorus from landfill leachate using an aerobic granular reactor

Saxena

Padhi

Bhatt

et al. 2021

Preprint

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In this study, aerobic granular reactor (AGR) was used to treat landfill leachate by changing the concentrations of chemical oxygen demand (COD) (668 ± 110–1149 ± 93 mg/L), ammonia (NH3-N) (30 ± 3.3–48 ± 1.3 mg/L), and phosphorus (PO4-P) (147 ± 18–221 ± 17 mg/L). The average COD removal was gradually reduced from 81 to 75%, increasing COD concentrations from 668 ± 110 to 1149 ± 93 mg/L. In phase I, the maximum removal of COD (94%) and NH3-N (85%) were observed at influent concentrations of 668 ± 110 mg/L and 30 ± 3.3 mg/L, respectively. Significant removal of PO4-P was observed, resulting in a maximum of up to 87%, further reducing up to 34% due to an increase in influent PO4-P concentration. The SVI30 reduced from 77 mL/g to 24.15 mL/g towards the end of phase III indicates the formation of granular biomass. The stability of AGR was also investigated in extreme conditions like shut-down and shock-loading phases. The treatment of real leachate diluted with wastewater (~ 20:80% v/v) using AGR showed a significant COD, NH3-N, and PO4-P removal of 62–65%, 61–93%, and 56–64%, respectively. Proteobacteria and Planctomycetes were identified as the predominant (80%) bacterial community in aerobic granules responsible for removing COD, NH3-N, and PO4-P from leachate using AGR. The maximum biodegradation rate (rmax) and half-saturation constant (Ks) in AGR were determined as 123.5 mg/L h and 309 mg/L, respectively.

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Limited simultaneous nitrification-denitrification (SND) in aerobic granular sludge systems treating municipal wastewater: Mechanisms and practical implications

Cited by 106 publications

References 52 publications

High Carbon Load in Food Processing Industrial Wastewater is a Driver for Metabolic Competition in Aerobic Granular Sludge

High Carbon Load in Food Processing Industrial Wastewater is a Driver for Metabolic Competition in Aerobic Granular Sludge

Effect of an Increased Particulate COD Load on the Aerobic Granular Sludge Process: A Full Scale Study

Simultaneous removal of carbon, nitrogen, and phosphorus from landfill leachate using an aerobic granular reactor

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