Systematic study of the effect of operating variables on reactor performance and microbial diversity in laboratory-scale activated sludge reactors

Pholchan, Mujalin K.; Baptista, Joana de C.; Davenport, Russell J.; Curtis, Tom

doi:10.1016/j.watres.2009.11.005

Cited by 83 publications

(67 citation statements)

References 39 publications

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Section: Introductionmentioning

confidence: 99%

“…However, system performance and microbial diversity are most influenced by operating conditions (for example, organic loading rate and feed composition) and reactor configuration (for example, batch-fed versus continuous; Pholchan et al, 2010). Pholchan et al (2010) found that microbial diversity and performance increased under a batchfed configuration, but diversity itself could not be systematically manipulated, which indicates a knowledge gap regarding the control of both the membership and structure of engineered microbial communities. The effects of other operational parameters on microbial diversity such as solids retention time (SRT), which represents the average time that microorganisms reside in a bioreactor, have yet to be investigated thoroughly and under realistic conditions (Saikaly et al, 2005;Tan et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

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Disturbance and temporal partitioning of the activated sludge metacommunity

et al. 2014

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The resilience of microbial communities to press disturbances and whether ecosystem function is governed by microbial composition or by the environment have not been empirically tested. To address these issues, a whole-ecosystem manipulation was performed in a full-scale activated sludge wastewater treatment plant. The parameter solids retention time (SRT) was used to manipulate microbial composition, which started at 30 days, then decreased to 12 and 3 days, before operation was restored to starting conditions (30-day SRT). Activated sludge samples were collected throughout the 313-day time series in parallel with bioreactor performance ('ecosystem function'). Bacterial small subunit (SSU) rRNA genes were surveyed from sludge samples resulting in a sequence library of 4417 000 SSU rRNA genes. A shift in community composition was observed for 12-and 3-day SRTs. The composition was altered such that r-strategists were enriched in the system during the 3-day SRT, whereas K-strategists were only present at SRTsX12 days. This shift corresponded to loss of ecosystem functions (nitrification, denitrification and biological phosphorus removal) for SRTsp12 days. Upon return to a 30-day SRT, complete recovery of the bioreactor performance was observed after 54 days despite an incomplete recovery of bacterial diversity. In addition, a different, yet phylogenetically related, community with fewer of its original rare members displaced the pre-disturbance community. Our results support the hypothesis that microbial ecosystems harbor functionally redundant phylotypes with regard to general ecosystem functions (carbon oxidation, nitrification, denitrification and phosphorus accumulation). However, the impacts of decreased rare phylotype membership on ecosystem stability and micropollutant removal remain unknown.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Disturbance and temporal partitioning of the activated sludge metacommunity

et al. 2014

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“…Generally, activated sludge flocs (ASF) are in the form of aggregates of microorganisms, suspended solids, and extracellular polymers (Jin et al, 2004). Removal of pollutants from wastewater mainly depends on the microbial composition and activity of activated sludge (Nadarajah et al, 2007;Pholchan et al, 2010;Wells et al, 2011). Thus flocs as microbiological units play an essential role in the operation of WWTPs.…”

Section: Introductionmentioning

confidence: 99%

Micro-environment characteristics and microbial communities in activated sludge flocs of different particle size

Han

Liu

Guo

et al. 2012

Bioresource Technology

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h i g h l i g h t s" Microelectrodes and molecular culture-independent techniques were applied. " The micro-environment and bacteria in flocs with different size were detected. " The DO, NH 4 + and NO 3 À concentration were distinct in flocs of different size." The bacterial population was closely related to the micro-environment in flocs.a r t i c l e i n f o b s t r a c tMicroorganisms in activated sludge flocs (ASF) play important roles in the wastewater treatment process. However, the interplay between micro-environmental variation and microbial responses within ASF is poorly understood. In this study, microelectrodes and molecular culture-independent techniques were applied to detect the internal environment, microbial composition, and distribution in flocs with different particle size. Results showed dissolved oxygen (DO) concentrations within the center of the flocs were less than at the surface, and the DO concentration distributions were distinct in flocs of different particle size. With floc particle size increasing from 100 to 250 lm, the DO concentrations in the floc centers decreased 10-55%, respectively, while no distinct change was observed in flocs of less than 100 lm.Similar phenomenon occurred for the distributions of NH 4 + and NO 3 À in flocs. Microbial structure indicated bacterial compositions and distributions were heterogeneous and responded to micro-environment variation in flocs of different particle size.

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“…It is known that culture-dependent methods have limitations for studying natural microbial community composition, because only a small part of bacteria in environmental samples are culturable under laboratory conditions [8]. Molecular techniques such as polymerase chain reaction-denaturing gradient gel electrophoresis) (PCR-DGGE) [9][10][11], amplified ribosomal DNA restriction analyses (ARDRA) [12], and fluorescence in situ hybridization (FISH) have been widely applied to study the diversity of microorganisms in natural samples [13]. These techniques have significantly overcome the weakness of traditional methods, but only elucidate the major microbial groups in wastewater treatments.…”

Section: Introductionmentioning

confidence: 99%

Sequencing Batch Reactor and Bacterial Community in Aerobic Granular Sludge for Wastewater Treatment of Noodle-Manufacturing Sector

et al. 2018

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Abstract:The sequencing batch reactor (SBR) has been increasingly applied in the control of high organic wastewater. In this study, SBR with aerobic granular sludge was used for wastewater treatment in a noodle-manufacturing village in Vietnam. The results showed that after two months of operation, the chemical oxygen demand, total nitrogen and total phosphorous removal efficiency of aerobic granular SBR reached 92%, 83% and 75%, respectively. Bacterial diversity and bacterial community in wastewater treatment were examined using Illumina Miseq sequencing to amplify the V3-V4 regions of the 16S rRNA gene. A high diversity of bacteria was observed in the activated sludge, with more than 400 bacterial genera and 700 species. The predominant genus was Lactococcus (21.35%) mainly containing Lactococcus chungangensis species. Predicted functional analysis showed a high representation of genes involved in membrane transport (12.217%), amino acid metabolism (10.067%), and carbohydrate metabolism (9.597%). Genes responsible for starch and sucrose metabolism accounted for 0.57% of the total reads and the composition of starch hydrolytic enzymes including α-amylase, starch phosphorylase, glucoamylase, pullulanase, α-galactosidase, β-galactosidase, α-glucosidase, β-glucosidase, and 1,4-α-glucan branching enzyme. The presence of these enzymes in the SBR system may improve the removal of starch pollutants in wastewater.

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Systematic study of the effect of operating variables on reactor performance and microbial diversity in laboratory-scale activated sludge reactors

Cited by 83 publications

References 39 publications

Disturbance and temporal partitioning of the activated sludge metacommunity

Disturbance and temporal partitioning of the activated sludge metacommunity

Micro-environment characteristics and microbial communities in activated sludge flocs of different particle size

Sequencing Batch Reactor and Bacterial Community in Aerobic Granular Sludge for Wastewater Treatment of Noodle-Manufacturing Sector

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