Filamentous bulking sludge—a critical review

Martins, António; Pagilla, Krishna; Heijnen, Joseph J.; Loosdrecht, M.C.M. van

doi:10.1016/j.watres.2003.11.005

Cited by 470 publications

(271 citation statements)

References 138 publications

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“…Sludge bulking is a global menace to wastewater treatment plants (WWTPs), since its occurrence often leads to poor sludge settleability and bad effluent quality (Martins et al, 2004). For example, in northern China, the problem occurs in over 50% activated sludge (AS) WWTPs every year (Wang et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

“…For example, more than 30 different filament morphotypes were found in AS systems and their excessive growth was associated with sludge bulking (Nielsen et al, 2009). Among them, members of Actinobacteria such as Candidatus M. parvicella and Tetrasphaera were often the causative organisms of sludge bulking by plant surveys conducted around the world (Martins et al, 2004;Seviour et al, 2008). In addition to Actinobacteria, members of Proteobacteria such as Meganema perideroedes, Thiothrix eikelboomii, Leucothrix mucor, and type 021N (Nielsen et al, 2009;Asvapathanagul et al, 2015) could cause sludge bulking.…”

Section: Introductionmentioning

confidence: 99%

“…Some studies related to filamentous bulking have been performed for solving sludge bulking problems (Martins et al, 2004). Sludge bulking is always controlled by nonspecific measures such as the addition of chlorine (Ramírez et al, 2000), ozone (Caravelli et al, 2006), metal salts (Agridiotis et al, 2007), and even cetyltrimethyl ammonium bromide .…”

Section: Introductionmentioning

confidence: 99%

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

Wang

et al. 2016

Water Research

104

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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: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Wang

et al. 2016

Water Research

104

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“…However, an excessive growth of filamentous bacteria in activated sludge wastewater treatment plants (WWTPs) can cause serious operational problems (Martins et al, 2004). An overgrowth of some filaments, an event called sludge bulking, can prevent adequate flocculation and settling of the biomass.…”

Section: Introductionmentioning

confidence: 99%

“…Several global surveys have shown that Candidatus Microthrix parvicella (hereinafter referred to as M. parvicella) is most frequently responsible for the problems of solid-liquid separation in bulking and foaming (Jenkins et al, 2004;Martins et al, 2004;Wanner, 1994).…”

Section: Introductionmentioning

confidence: 99%

Development and evaluation of a TaqMan duplex real-time PCR quantification method for reliable enumeration of Candidatus Microthrix

Vanysacker

Denis

Roels

et al. 2014

Journal of Microbiological Methods

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Candidatus Microtrhix parvicella is one of the most common filamentous bacteria reported to be involved in bulking and foaming problems in activated sludge plants worldwide. In order to detect and quantify both M. parvicella and Microthrix calida by quantitative PCR (qPCR), primers targeting 16S rDNA genes were designed. The qPCR reaction was optimized by using the TaqMan technology and an internal positive control was included to ensure the absence of PCR inhibitors. A total of 29 samples originating from different wastewater treatment plants were analyzed and the results were compared by using conventional microscopy, fluorescent in situ hybridization and an existing SYBR Green-based assay. Our assay showed a 100% specificity for both M. parvicella and M. calida, a sensitivity of 2.93 × 10 9 to 29 copy numbers/reaction, an amplification efficiency of 93% and no PCR inhibition. By performing a spiking experiment including different Microthrix concentrations, recovery rates ranging from 65 to 98% were obtained. A positive correlation with the SYBR Green assay (R 2 = 0.85) was found and most of the samples were in accordance with the microscopical observation. In comparison with SYBR Green assay, the probe-based TaqMan assay had a much lower detection limit. Compared with microscopy, some samples had a lower or higher enumeration when using qPCR. In conclusion, a qPCR method is forwarded here that could be useful as an early warning tool for fast and reliable detection of Microthrix in for instance sludge bulking events.

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