Studies on activated sludge response to variations in the composition of a synthetic surfactant-containing feed effluent

Carvalho, Gilda; Paul, Etienne; Novais, J.M.; Pinheiro, H.M.

doi:10.2166/wst.2000.0507

Cited by 14 publications

(7 citation statements)

References 13 publications

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“…At the same time, for anionics, the dehydrogenase activity was three or even four times lower than for nonionics at the same initial concentration of surfactant in wastewater. These results confirmed the observations made by Carvalho et al that, though nonacclimatized, the sludge was not inhibited by APE and their biodegradation products during batch and sequencing batch laboratory tests [25]. Also in the papers reviewing the fate and the ecotoxicity of the synthetic surfactants in the environment, anionics are usually believed to be more toxic than nonionics towards aquatic organisms excluding some products of APE breakdown, i.e.…”

Section: Discussionsupporting

confidence: 88%

Effect of Selected Nonionic Surfactants on the Activated Sludge Morphology and Activity in a Batch System

Liwarska-Bizukojć

Drews

Kraume

2008

J Surfact & Detergents

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In this study, two nonionic surfactants, one alcohol ethoxylate (AE) and one alkylphenol ethoxylate (APE) were investigated with regard to their influence on the morphology of activated sludge flocs, microbial activity and wastewater treatment efficiency in a laboratory batch system. The experiments were carried out for a range of nonionic surfactants concentrations in wastewater from 5 to 500 mg L -1 . Additionally, these results were compared to the data obtained in previous experiments on anionics and performed under the same conditions. Both nonionics tested caused a decrease in the size of activated sludge flocs but they did not affect the shape of the flocs. The circularity index and convexity of flocs remained similar to the control run, containing no surfactant. The presence of nonionic surfactants within the tested concentrations range caused a decrease in biomass activity. In spite of morphological changes of activated sludge flocs and a decrease in microbial activity, only higher concentrations of nonionics in wastewater starting with the level of 50 mg L -1 can induce pinpoint flocs and decrease wastewater treatment efficiency. APE showed a stronger impact on the decrease in floc size and microbial activity than alcohol ethoxylate did. APE was also more difficult to biodegrade than AE. Comparing the efficiency of wastewater treatment (in terms of COD removal) in the presence of nonionic and anionic surfactants at the same concentration of 50 mg L -1 , the degree of organic pollutant removal was found to be higher by about 10% for anionics than for nonionics.

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Section: Discussionsupporting

confidence: 88%

Effect of Selected Nonionic Surfactants on the Activated Sludge Morphology and Activity in a Batch System

Liwarska-Bizukojć

Drews

Kraume

2008

J Surfact & Detergents

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“…However, at full operation (F1: 800 m 3 /day, F2: 2800 m 3 /day), HRT values would be shortened to 18 h and 9 h for F1 and F2, respectively. In that case, F1 may be still on the safe side regarding nonylphenolic removal, but F2 may be at risk in terms of complete mineralization of NPEO metabolites, as suggested by Birkett and Lester [109], Carvalho et al [123], Maki et al [125], and Petrie et al [108].…”

Section: The Role Of the Secondary Activated Sludge Processmentioning

confidence: 99%

“…Firstly, the oxidation of ethoxylate chain as primary degradation may take place as quickly as within 10 h of aeration [123,124]. The next phase as mineralization of decomposed products may consume an additional 10 h for the induction of specialized enzymes or shifts in bacterial inoculum that may degrade those substances via different mechanisms [109,123,125]. Consequently, an ultimate degradation time of about 20 h at the F/M (substrate/biomass) ratio of 0.24-0.86 is suggested by Carvalho et al [123].…”

Section: Persistence Of Np and Npeo Metabolites And The Implication Omentioning

confidence: 99%

“…The next phase as mineralization of decomposed products may consume an additional 10 h for the induction of specialized enzymes or shifts in bacterial inoculum that may degrade those substances via different mechanisms [109,123,125]. Consequently, an ultimate degradation time of about 20 h at the F/M (substrate/biomass) ratio of 0.24-0.86 is suggested by Carvalho et al [123]. Nevertheless, Petrie et al [108] argues that the shortening of medium-to-long nonylphenolics (NP 4-12 EO) may not be dependent on the HRT, whereas the degradation of short-chain compounds (NP 1-4 EO) and NP is probably mediated by increasing HTR from 8 to 24 h.…”

Section: The Role Of the Secondary Activated Sludge Processmentioning

confidence: 99%

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Distribution and Removal of Nonylphenol Ethoxylates and Nonylphenol from Textile Wastewater—A Comparison of a Cotton and a Synthetic Fiber Factory in Vietnam

Watanabe

2017

Water

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Abstract:The textile industry is a significant source of nonyphenol and their ethoxylates, which are suggested to be responsible for endocrine disruption in wildlife and humans. This study is a comparison of two conventional wastewater treatment processes in a cotton and a synthetic fiber factory in Vietnam, with regard to the distribution and removal of nonyphenol ethoxylates and nonyphenol throughout each process. Diverse trends in the distribution of nonyphenol ethoxylates in wastewater from factories, distinguished by their raw materials, could be revealed. Primary coagulation might not perfectly facilitate nitrification in the secondary activated sludge process regarding pH. Nevertheless, satisfactory removals were achieved during coagulation and activated sludge processes in both systems. The roles of long hydraulic retention times (21 and 16 h, respectively), low organic loadings (0.1 and 0.2 gCOD/gMLVSS.day, respectively), extended solids retention times (61 and 66 days, respectively), and mixed liquor suspended solids of greater than 2000 mg/L have been demonstrated. The findings provide evidence and a better understanding of nonyphenol ethoxylate and nonyphenol removal efficacy as well as influencing factors in Vietnamese textile wastewater treatment. The results are beneficial for the textile industry in Vietnam regarding investment decisions for wastewater treatment.

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“…Recent work (7) has indicated the continued existence of marine pollution with alkylphenol polyethoxylates. Studies on the response of activated sludge to variations in the composition of feed effluent (8) have indicated that alkyl ethoxylateadapted biomass was more capable of adaptation to alkylphenol ethoxylate than the reverse. Overall, there are conflicting views on the fate and effect of the present class of alkylphenol polyethoxylates in the environment.…”

mentioning

confidence: 99%

Surfactant properties and biodegradation of polyethoxylates from phenolic lipids

Tyman

Bruce

2004

J Surfact & Detergents

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The surface tension of aqueous solutions of cardanol and cardol polyethoxylates derived from technical cashew nut-shell liquid were examined to determine their relative surfactancy. The compositions with the greatest surface tension reduction, or optimal surfactancy, were selected for biodegradation testing, in terms of total organic carbon, using a soil inoculum. The experimental surfactants in this study were compared with commercial t-nonyl polyethoxylate and glucose as reference materials. Over a period of 28 d, cardanol polyethoxylate and its saturated analog were degraded to 17 and 25%, respectively, and cardol polyethoxylate and its saturated analog were degraded approximately half that extent (37 and 46%). t-Nonylphenyl polyethoxylate remained substantially undegraded (77%), whereas glucose was almost completely degraded (5%).Technical cashew nut-shell liquid (CNSL), obtained by the industrial processing of phenolic lipids in the natural material Anacardium occidentale, which contains principally anacardic acid 1, cardol 2, and 2-methylcardol 3. Decarboxylation gives cardanol 4, together with unchanged cardol, as shown in Scheme 1. The polyethoxylates 5 and 6, depicted in Scheme 2, were obtained by the reaction of cardanol and cardol with ethylene oxide (1). t-Nonylphenol polyethoxylate 7 is shown for comparison. In each case, they contain a profile of oligomers in which m ranges from 1 to about 48. The ethoxylates were deemed ideal candidates for further surfactant and biodegradation studies, specifically, by first determining the optimal number of ethoxylate (EO) groups required for surfactancy, as judged by their relative reduction of the surface tension of water. With this information, biodegradation studies were carried out on the sample in each series exhibiting the highest surfactancy.Studies on the environmental occurrence of alkylphenols and alkylphenol ethoxylates (2) and their persistence in aquatic environments have both been reviewed extensively (3). Commercial alkylphenol polyethoxylates have received criticism on environmental and toxicological grounds (4), and although subsequent studies have suggested their accumulation is not significant (5), there also have been indications that they could be gradually phased out (6). Recent work (7) has indicated the continued existence of marine pollution with alkylphenol polyethoxylates. Studies on the response of activated sludge to variations in the composition of feed effluent (8) have indicated that alkyl ethoxylateadapted biomass was more capable of adaptation to alkylphenol ethoxylate than the reverse. Overall, there are conflicting views on the fate and effect of the present class of alkylphenol polyethoxylates in the environment.Since approximately 90% of the alkylphenol ethoxylates in the European Union are based on the petrochemical intermediate t-nonylphenol, it is of interest to examine the use of natural alkylphenols, based on the supposition that a biosynthesized compound might prove to be more biodegradable and environmentally acceptab...

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Studies on activated sludge response to variations in the composition of a synthetic surfactant-containing feed effluent

Cited by 14 publications

References 13 publications

Effect of Selected Nonionic Surfactants on the Activated Sludge Morphology and Activity in a Batch System

Effect of Selected Nonionic Surfactants on the Activated Sludge Morphology and Activity in a Batch System

Distribution and Removal of Nonylphenol Ethoxylates and Nonylphenol from Textile Wastewater—A Comparison of a Cotton and a Synthetic Fiber Factory in Vietnam

Surfactant properties and biodegradation of polyethoxylates from phenolic lipids

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