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

2021 ◽  
Vol 9 ◽  
Author(s):  
Ana M. S. Paulo ◽  
Catarina L. Amorim ◽  
Joana Costa ◽  
Daniela P. Mesquita ◽  
Eugénio C. Ferreira ◽  
...  
Keyword(s):  
Microbial Community ◽  
Industrial Wastewater ◽  
Structural Changes ◽  
Microbial Community Composition ◽  
Granular Sludge ◽  
Aerobic Granular Sludge ◽  
Organic Loading Rate ◽  
Second Phase ◽  
Metabolic Versatility ◽  
Two Phases

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.

scholarly journals Changes in BNR Microbial Community in Response to Different Selection Pressure

Nitrogen ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 474-490
Author(s):  
Roya Pishgar ◽  
John Albino Dominic ◽  
Joo Hwa Tay ◽  
Angus Chu
Keyword(s):  
Microbial Community ◽  
Structural Changes ◽  
Morphological Characteristics ◽  
Granular Sludge ◽  
Phosphate Removal ◽  
Biological Nutrient Removal ◽  
Aerobic Granular Sludge ◽  
Sequencing Data ◽  
Phosphate Release ◽  
Starting Point

This study investigated structural changes in microbial community of biological nutrient removal (BNR) in response to changes in substrate composition (ammonium and phosphate), redox condition, and morphological characteristics (flocs to granules), with a focus on nitrification and phosphate removal. Analyzing treatment performance and 16S rRNA phylogenetic gene sequencing data suggested that heterotrophic nitrification (HN) and autotrophic nitrification (AN) potentially happened in aerobic organic-rich (HN_AS) and aerobic organic-deficient (AN_AS) activated sludge batch reactors, respectively. However, phosphate release and uptake were not observed under alternating anaerobic/aerobic regime. Phosphate release could not be induced even when anaerobic phase was extended, although Accumulibacter existed in the inoculum (5.1% of total bacteria). Some potential HN (e.g., Thauera, Acinetobacter, Flavobacterium), AN (e.g., Nitrosomonas (3.2%) and Nitrospira), and unconventional phosphate-accumulating organisms (PAOs) were identified. Putative HN bacteria (i.e., Thauera (29–36%) and Flavobacterium (18–25%)) were enriched in aerobic granular sludge (AGS) regardless of the granular reactor operation mode. Enrichment of HN organisms in the AGS was suspected to be mainly due to granulation, possibly due to the floc-forming ability of HN species. Thus, HN is likely to play a role in nitrogen removal in AGS reactors. This study is supposed to serve as a starting point for the investigation of the microbial communities of AS- and AGS-based BNR processes. It is recommended that the identified roles for the isolated bacteria are further investigated in future works.

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

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1472
Author(s):  
Sara Toja Ortega ◽  
Mario Pronk ◽  
Merle K. de Kreuk
Keyword(s):  
Microbial Community ◽  
Nutrient Removal ◽  
Microbial Community Composition ◽  
Treatment Plant ◽  
Granular Sludge ◽  
Full Scale ◽  
Test Period ◽  
Normal Operation ◽  
Aerobic Granular Sludge ◽  
Hydrolytic Activities

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.

Performance and Microbial Community of Aerobic Granular Sludge Bioreactor

2014 ◽  
Vol 522-524 ◽  
pp. 405-410
Author(s):  
Xia Zhao ◽  
Ji Min Shen ◽  
Zhong Lin Chen ◽  
Xiao Chun Wang
Keyword(s):  
Microbial Community ◽  
Activated Sludge ◽  
Removal Efficiency ◽  
Batch Reactor ◽  
Dynamic Balance ◽  
Granular Sludge ◽  
Aerobic Granular Sludge ◽  
Organic Loading Rate ◽  
Balance System ◽  
Microbial Species

Aerobic granular sludge was cultivated from activated-sludge in sequencing batch reactor. The change of physical properties and the effect of treatment of organic substance and microbial community were studied in the process of the different influent organic loading rate. The results showed that the formation process of aerobic granulation was rapid but the granular sludge was not stable and existed a disintegration-reunion dynamic balance system. The value of MLSS descended from 5.12g/L to 1.03g/L. The removal efficiency of NH4+-N decreased to 74.17% and total phosphorous (TP) removal efficiency maintained beyond 90% all the while. The CODCr removal was over 85% which higher than that of after adding in methanol, then reduced but had trend of rise to 31.89% at last. Microbial species in granulation were speculated by detecting polyhydroxyalkan- oates between granular sludge and activated sludge in the reactor. The results showed that microbial species of activated sludge are more diverse.

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