Microthrix parvicella abundance associates with activated sludge settling velocity and rheology – Quantifying and modelling filamentous bulking

Wágner, Dorottya Sarolta; Ramin, Elham; Szabó, Péter; Dechesne, Arnaud; Plósz, Benedek G.

doi:10.1016/j.watres.2015.04.003

Cited by 49 publications

(15 citation statements)

References 38 publications

(35 reference statements)

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“…The results from more than one molecular method indicated that sludge bulking was caused by the overgrowth of several types of filamentous bacteria. A previous study has identified the 2 dominant groups of filamentous bacteria (Chloroflexi and Microthrix parvicella) in AS samples from filamentous bulking WWTPs (Wagner et al, 2015). Furthermore, Candidatus M. parvicella was confirmed to be the causative filamentous bacteria for sludge bulking in the investigated WWTP because its abundance gradually increased and its filaments became longer with the occurrence of sludge bulking.…”

Section: Biological and Environmental Factors Causing Sludge Bulkingmentioning

confidence: 71%

Detailed comparison of bacterial communities during seasonal sludge bulking in a municipal wastewater treatment plant

Wang

et al. 2016

Water Research

101

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a b s t r a c tIn this study, pyrosequencing combined with clone library analysis, qPCR, and fluorescent in situ hybridization (FISH) were performed to identify detailed changes of bacterial and filamentous bacterial communities in activated sludge (AS) in 3 types of typical AS samples: sludge bulking (B-AS), excessive bulking (EB-AS), and non-bulking (N-AS). Sludge bulking resulted in a decrease in total bacterial numbers from (6.4 ± 0.18) Â 10 8 gene copies/mL in N-AS to (2.4 ± 0.22) Â 10 8 in EB-AS and a decrease in bacterial diversity from 2757 OTUs in N-AS to 2217 OTUs in EB-AS. With the occurrence of sludge bulking, Actinobacteria and Firmicutes increased sharply, whereas Proteobacteria, which was the predominant phylum in N-AS, decreased markedly. In addition, Nitrospirae, a major lineage of the nitrite-oxidizing bacteria, had quite a low abundance in EB-AS (0.15%), while it was relatively high in N-AS (1.17%). On the other hand, filamentous bacteria accounted for 28.77% and 5.72% of total sequences in EB-AS and N-AS, respectively. More interestingly, 11 types of filamentous bacteria were always present in 3 types of typical AS samples from different stages of sludge bulking, and most of them enriched in EB-AS compared to N-AS. It is noteworthy that, in addition to the frequently reported filamentous bacteria such as Candidatus M. parvicella and Tetrasphaera, novel filamentous species of Trichococcus might exist in this bulking WWTP. Our results reveal that sludge bulking are derived from diverse taxa, which expands previous understanding and provides new insight into the underlying complications of the bulking phenomenon in AS.

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Section: Biological and Environmental Factors Causing Sludge Bulkingmentioning

confidence: 71%

Detailed comparison of bacterial communities during seasonal sludge bulking in a municipal wastewater treatment plant

Wang

et al. 2016

Water Research

101

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“…The qPCR data confirmed their important impact on sludge settleability in samples taken over 12 months. Yet Wágner et al (2015) 26 have questioned the role of the Chloroflexi in bulking. Although their FISH based study showed that their Chloroflexi were located predominately protruding from the floc surfaces, their modeling suggested they were less important than the floc bound actinobacterial "Ca.…”

Section: Discussionmentioning

confidence: 99%

Exploring the operating factors controlling Kouleothrix (type 1851), the dominant filamentous bacterial population, in a full-scale A2O plant

Nittami

Kasakura

Kobayashi

et al. 2020

Sci Rep

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This study reveals that the abundance of the filament Kouleothrix (Eikelboom type 1851) correlated positively with poor settleability of activated sludge biomass in a Japanese full-scale nutrient removal wastewater treatment plant sampled over a one-year period. 16S rRNA amplicon sequence data confirmed that Kouleothrix was the dominant filament in the plant, with a relative abundance of 3.06% positively correlated with sludge volume index (SVI) (R = 0.691). Moreover, Kouleothrix (type 1851) appeared to form interfloc bridges, typical of bulking sludge, regardless of season. Together with earlier studies that indicated the responsibility of Kouleothrix (type 1851) on bulking events, these data suggest that their high relative abundances alone may be responsible for sludge bulking. 16S rRNA qPCR data for this filament showed changes in its relative abundance correlated with changes in several operational parameters, including mixed liquor temperature, sludge retention time, and suspended solids concentration, and it may be that manipulating these may help control Kouleothrix bulking.The activated sludge process is the most popular method worldwide for the biological treatment of both municipal and industrial wastewaters. In conventional systems, solid-liquid phase separation is performed to produce ideally a final clear treated liquid effluent from the secondary settling tank 1 . Activated sludge bulking in the secondary settling tanks is a serious operational problem, which can lead to an outflow of suspended solids from the tank and decreasing biomass concentration in the reactor, resulting in a poor quality effluent, with poor thickening and dewatering characteristics 1 . Bulking is caused usually by excessive proliferation of filamentous bacteria, which appear to interfere with floc sedimentation and compaction 2 .Existing filamentous bulking control methods can be considered as specific and non-specific 3 . The latter usually consist of adding chemicals, including oxidizing agents (chlorine, ozone, hydrogen peroxide), weighting and flocculating agents (salts of iron and aluminium, lime, polymers and talc), and biocides 3 . These methods provide only temporary relief. They are useful when the cause of the filamentous bulking cannot be determined immediately, and when rapid resolution of a bulking problem is necessary 3 . On the other hand, specific targeted control methods if available are more attractive since high performing plants can operate with a limited filament proliferation 3 . Although the problem of bulking has attracted considerable interest, conclusions as to which individual ecological and physiological factors might favor excessive filament growth are still not available 3 . Quantitative PCR (qPCR) assays have identified correlations between "Ca. Microthrix parvicella" 4-6 , Thiothrix eikelboomii 7,8 , Sphaerotilus natans 9 and Haliscomenobacter hydrossis 10 16 S rRNA gene copy numbers and sludge settleability. However, such quantitative studies are rare.

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“…The settleability of activated sludge systems can also be monitored and controlled through microscopic observation [13,36]. Quantitative image analysis is a promising technique which has been used to study different problems in activated sludge systems [2,13,37,38]. In this research, SVI30 was used to determine settling performance along with a quantitative study for sludge samples which targeted the filamentous bacteria as this is considered one of the main reasons for sludge settling problems as mentioned earlier.…”

Section: Morphological Study and Image Analysis Procedures For The Sludgementioning

confidence: 99%

Improving sludge settleability by introducing an innovative, two-stage settling sequencing batch reactor

Alattabi

Harris

Alkhaddar

et al. 2017

Journal of Water Process Engineering

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Improving sludge settleability by introducing an innovative, two-stage settling sequencing batch reactor http://researchonline.ljmu.ac.uk/id/eprint/7679/ Article LJMU has developed LJMU Research Online for users to access the research output of the University more effectively. (2017) Improving sludge settleability by introducing an innovative, two-stage settling sequencing batch reactor. Journal of Water Process Engineering, 20. pp. 207-216. ISSN 2214-7144 LJMU Research Online Improving sludge settleability by introducing an innovative, two-stage settling sequencing batch reactor Abstract Sludge settleability is considered one of the main drawbacks of sequencing batch reactors. The aim of this study therefore is to improve sludge settleability by introducing a novel, two-stage settling sequencing batch reactor (TSSBR) separated by an anoxic stage. The performance of the TSSBR was compared with that of a normal operating sequencing batch reactor (NOSBR), operating with the same cycle time. The results show a significant improvement in sludge settleability and nitrogen compound removal rates for the TSSBR over the NOSBR. The average removal efficiencies of NH3-N, NO3-N and NO2-N have been improved from 76.6%,86.4% and 87.3% respectively for the NOSBR to 89.2%, 95.2% and 96% respectively for the TSSBR. In addition, the average SVI30 for the NOSBR has been reduced from 42.04 ml/g to 31.17 ml/g for the TSSBR. After three months of operation, there was an overgrowth of filamentous bacteria inside the NOSBR reactor, while the morphological characteristics of the sludge inside the TSSBR reactor indicated a better and homogenous growth of filamentous bacteria.

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Microthrix parvicella abundance associates with activated sludge settling velocity and rheology – Quantifying and modelling filamentous bulking

Cited by 49 publications

References 38 publications

Detailed comparison of bacterial communities during seasonal sludge bulking in a municipal wastewater treatment plant

Detailed comparison of bacterial communities during seasonal sludge bulking in a municipal wastewater treatment plant

Exploring the operating factors controlling Kouleothrix (type 1851), the dominant filamentous bacterial population, in a full-scale A2O plant

Improving sludge settleability by introducing an innovative, two-stage settling sequencing batch reactor

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