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Abstract

Nonylphenol polyethoxylate (NPnEO) surfactants, ubiquitous contaminants in sewage processing facilities, continue to receive attention due to their recalcitrance and diverse toxicity concerns. How the addition of nonylphenol diethoxylate (NP2EO) and its biodegradation products affect microbial community structure in anaerobic semi-continuous digesters was investigated by molecular techniques. Fluorescence in situ hybridization (FISH) and quantitative PCR (qPCR) were used in parallel to monitor total Bacteria, four classes of Proteobacteria, total Archaea, and two genera of acetoclastic methanogens (Methanosarcina and Methanosaeta). Beta- and Gammaproteobacteria were the dominant phyla and the relative abundances of both groups were roughly doubled following NP2EO addition. While Methanosaeta was dominant over Methanosarcina throughout, NP2EO addition and accumulation of NP nearly doubled the relative abundance of Methanosarcina. While digester performance was not affected, this study revealed that relative abundances of the key players in anaerobic digestion were altered by the addition of NP2EO.

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... Goel et al. (2003) reported lower removal (30 -50%) for similar NP10EO concentration (5 mg L -1 ) in a lab-scale anaerobic reactor fed with synthetic substrate. On the other hand, Murdoch et al. (2018) reported removal of approximately 90% for 3 mgNP2EO L - In phase III, a significant decrease of the removal efficiency (60 ± 18%) was observed when the specific load of NPEO was increased to 9.8 ± 2.9 mg gVS -1 d -1 . Consequently, the strategy was to reduce the load by 50% for the following phases and this way, loads of 4.8 ± 1.8 mg gVS -1 d -1 and 4.7 ± 1.9 mg gVS -1 d -1 were applied in phases IV and V, respectively. ...
... The greatest methane content was observed in the phase I (without NPEO), which continuously decreased throughout the operation after NPEO entered the system. Murdoch et al. (2018) reported slightly higher methane production (0.38 ± 0.001 LCH 4 gCOD -1 removed and CH 4 content 57.3 ± 0.8%) in a lab-scale anaerobic reactor fed with waste activated sludge and lower NPEO concentration (3 mg L -1 ). The observed values after microorganisms adapted to the NPEO (phase V), were relatively high compared with previous investigations on anaerobic treatment of wastewater containing toxic compounds. ...
Article
Nonylphenol Ethoxylate (NPEO) is a non-ionic surfactant used worldwide in the formulation of cleaning products. Removal of these compounds from domestic sewage is difficult to achieve. In this study, the degradation of NPEO from the co-digestion of domestic sewage (DS) and commercial laundry wastewater (CLW) was evaluated using a pilot-scale expanded granular sludge bed (EGSB) reactor operated for 637 days. In phase I, the reactor was fed with synthetic substrate (SS) – without NPEO, phases II and III with SS plus 3.5 ± 1.0 mgNPEO L-1 and 7.6 ± 2.1 mgNPEO L-1, respectively. Phase IV with SS plus CLW containing 4.0 ± 1.1 mgNPEO L-1, phase V with DS plus CLW and 3.7 ± 1.3 mgNPEO L-1. Nearly 60% of NPEO was biodegraded and chemical oxygen demand (COD) removal varied from 90 ± 5% to 97 ± 2% (for up to 573.8 ± 130.1 mgCOD L-1). Spirochaetacea exhibit the greatest relative abundance (from 65.3% to 90.7%) throughout the operation. NPEO addition negatively affected methanogenic activity, such that CH4 yield decreased 91% even at high COD removal. Surprisingly, after 549 days of operation, a CH4 yield of 0.30 ± 0.14 LCH4 gCOD-1 removed was observed.
... Motteran, Braga [6] reported high removal of linear alkylbenzene sulfonate (LAS) from laundry wastewater (~71 % for 47 mg L -1 ) in batch reactors using sucrose as carbon source. For NPEO, removal of up to 90% has been observed in lab-scale anaerobic digester fed with waste activated sludge [7]. Despite the mentioned progress, complete degradation is still difficult to achieve, hence it is necessary to study the factors involved in the process and their effects to obtain better treatment efficiencies. ...
... Paterakis, Chiu [39] studied anaerobic degradation of NPEO (7 -10 mg d -1 ) in mesophilic and thermophilic temperature in lab-scale reactors and observed removal of 58% and 90%, respectively. Murdoch, Murdoch [7] reported removal of 90% for 3 mg L -1 of NP2EO in a lab-scale semicontinuous anaerobic reactor. ...
Article
Nonylphenol ethoxylathe (NPEO) is a non-ionic surfactant of increasing concern, used in the formulation of laundry detergents and is frequently found in aquatic environments. The purpose of this study was to evaluate the effects of yeast extract (YE) and sodium fumarate (SF) in NPEO removal from domestic sewage under anaerobic conditions via central composite rotatable design (CCRD) and response surface methodology (RSM). Experiments were designed by varying concentrations of NPEO (1.6 - 5.8 mg L-1), YE (131.8 - 468.2 mg L-1) and SF (97.7 - 602.3 mg L-1) in batch reactors. SF and YE addition significantly influenced NPEO removal and CH4 production. Optimal values of YE (400 mg L-1) and SF (200 mg L-1) result in removal efficiency of 97% for 5 mg L-1 of NPEO, being mostly removed by biodegradation (86%). Meanwhile COD removal was 95% and methane yield was 134 ± 4 NmLCH4 g⁻¹CODremoved. The most abundant Bacteria genus identified were Macellibacteroides, Longilinea, Petrimonas and Proteiniphilum, while for Archaea, Methanosaeta and Methanoregula were the genera identified in higher relative abundances in optimized conditions.
... respectively (Fig. 4). The betaproteobacteria was reported to degrade polyaromatic hydrocarbons, surfactants, pharmaceuticals, and other emerging contaminants [27,28]. Kara Murdoch et al. [27] demonstrated that the addition of chemical surfactant resulted in increased abundance of Beta-proteobacteria and they have the tendency to adapt to the sudden change in the environment. ...
... The betaproteobacteria was reported to degrade polyaromatic hydrocarbons, surfactants, pharmaceuticals, and other emerging contaminants [27,28]. Kara Murdoch et al. [27] demonstrated that the addition of chemical surfactant resulted in increased abundance of Beta-proteobacteria and they have the tendency to adapt to the sudden change in the environment. Thus, the dominance of Beta-proteobacteria in MBR treating pharmaceutical wastewater might be due to its inherent ability to survive in stress conditions. ...
Article
The study was conducted to investigate the effect of sludge retention on bacterial community composition of membrane bioreactor (MBR) treating synthetic hospital wastewater. The removal of four pharmaceuticals, namely carbamazepine, estradiol, venlafaxine, and ibuprofen in MBR, was studied at varying sludge retention time (SRT) duration of 100, 45, and 15 days and hydraulic retention time (HRT) of 18 h. The removal of ibuprofen and estradiol was constant at varying SRT; however, a negligible removal of carbamazepine and low removal of venlafaxine was observed (< 20%). The study suggested that the SRT of 45 days in MBR could provide maximum treatment efficiency via decreasing membrane clogging. The effect of sludge age and pharmaceutical presence on the bacterial community was investigated via high-throughput sequencing. The study reveals that the variation in SRT affects the dynamics of the bacterial community significantly. For instance, the dominant bacterium Caldimonas of SRT 100 was disappeared at lower SRTs. Moreover, the profile of the dominant genus of the SRTs varied greatly from each other.
... A Q test revealed an increase in the proportion of anaerobic methanogens of the genus Methanosarcina in the NP + BuT treatment (D240) to 7.1% against 2.6% in control (A240) ( Table 2S). The addition of nonylphenol diethoxylate and its biodegradation products caused the relative abundance of Methanosarcina in anaerobic semi-continuous digesters to nearly double (Murdoch et al. 2018). ...
Article
Full-text available
Pollution of aquatic ecosystems with nonylphenol (NP) and butyltins (BuTs) is of great concern due to their effects on endocrine activity, toxicity to aquatic organisms, and extended persistence in sediments. The impact of contamination with NP and/or BuTs on the microbial community structure in marine sediments was investigated using microcosms and high-throughput sequencing. Sediment microcosms with NP (300 mg/kg) and/or BuTs (95 mg/kg) were constructed. Complete removal of monobutyltin (MBT) occurred in the microcosms after 240 days of incubation, while a residual NP rate was 40%. The content of toxic tributyltin (TBT) and dibutyltin (DBT) in the sediments did not change notably. Co-contamination of the sediments with NP and BuTs did not affect the processes of their degradation. The pollutants in the microcosms could have been biodegraded by autochthonous microorganisms. Significantly different and less diverse bacterial communities were observed in the contaminated sediments compared to non-contaminated control. Firmicutes and Gammaproteobacteria dominated in the NP treatment, Actinobacteria and Alphaproteobacteria in the BuT treatment, and Gammaproteobacteria, Alphaproteobacteria, Firmicutes, and Acidobacteria in the NP-BuT mixture treatment. The prevalence of microorganisms from the bacterial genera Halothiobacillus, Geothrix, Methanosarcina, Dyella, Parvibaculum, Pseudomonas, Proteiniclasticum, and bacteria affiliated with the order Rhizobiales may indicate their role in biodegradation of NP and BuTs in the co-contaminated sediments. This study can provide some new insights towards NP and BuT biodegradation and microbial ecology in NP-BuT co-contaminated environment.
... The importance of these tasks is highlighted by several comprehensive reviews regarding the fate of surfactants in the environment (Mungray and Kumar 2009;Könnecker et al. 2011;Cowan-Ellsberry et al. 2014;Jackson et al. 2016). The relevance of this topic is confirmed by the fact that numerous scientific reports focused on the biodegradation of surfactants were published to date (Kara Murdoch et al. 2018;Fedeila et al. 2018;Barra Caracciolo et al. 2019;Nguyen and Oh 2019). ...
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Surfactants are widely used in biotechnological processes, but also constitute significant contaminants of the modern world. Among many reports there is a shortage of works which summarize the issue of surfactant sorption to biomass in a way that would elucidate the biological factors for analysts, and analytical factors for microbiologists. The main factor, which is not as obvious as one would expect, is associated with the susceptibility of analytical approaches to errors resulting from incorrect handling of biomass. In case of several publications reviewed in the framework of this study, it was not possible to establish whether the decrease of the analytical signal observed by the authors actually resulted from biodegradation of the surfactant. This review emphasizes the necessity to consider the possibility of surfactant sorption to microbial cells, which may result in significant detection errors as well as conceptual inconsistency. In addition, a reference study regarding representative surfactants (cationic, anionic and non-ionic) as well as yeast, Gram-negative, Gram-positive bacteria and activated sludge was provided to highlight the possible errors which may arise from disregarding sorption processes when determining degradation of surfactants. This particularly applies to systems which include ionic surfactants and activated sludge as sorption may account for 90% of the observed depletion of the surfactant. Therefore, a systematic approach was proposed in order to improve the credibility of the obtained results. Finally, the need to employ additional procedures was highlighted which may be required in order to verify that the decrease of surfactant concentration results from biodegradation processes.
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Anaerobic digestion is a promising approach for waste activated sludge (WAS) disposal. However, a wide range of exogenous pollutants (e.g. heavy metals, nanoparticles) exists in WAS and their influences on anaerobic digestion are neglected. This study investigates the correlations between exogenous pollutants and anaerobic digestion performance. The results indicate that exogenous pollutants exhibit dose-dependent influences on WAS digestion. Most of the pollutants improve the performance of anaerobic digestion by partially or wholly promoting the hydrolysis, acidification and methanogenesis processes at low dose, but exhibit negative effects at high levels due to their toxicity. Generally, methanogens are more vulnerable than those hydrolytic and acidogenic bacteria. Poly-aluminum chloride and polyacrylamide show strong inhibition on WAS digestion, which are primarily attributed to their physical enmeshments of organic matters in WAS. The synergistic effects of different mixed pollutants and the mitigating strategies for typical pollutants inhibition deserve more attention in light of WAS anaerobic digestion.
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