Effects of Cr(VI) on the performance and kinetics of the activated sludge process

Cheng, Li; Li, Xiaochen; Jiang, Ruixue; Wang, Chao; Yin, Hao

doi:10.1016/j.biortech.2010.08.116

Cited by 53 publications

(13 citation statements)

References 30 publications

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“…As shown in Fig. 2S (Cheng et al, 2011). Consequently, in this study, relationships between the NH 4 + -N removal efficiencies and the TTC-ETS activities in the control and the three AAMA + O 3 /US systems were investigated by statistical correlation analysis (Table 3).…”

Section: Effects Of Returned O 3 /Us Pretreated Sludge Lyses On Ttc-ementioning

confidence: 99%

Economical evaluation of sludge reduction and characterization of effluent organic matter in an alternating aeration activated sludge system combining ozone/ultrasound pretreatment

Yang

Guo

Chen

et al. 2015

Bioresource Technology

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Section: Effects Of Returned O 3 /Us Pretreated Sludge Lyses On Ttc-ementioning

confidence: 99%

Economical evaluation of sludge reduction and characterization of effluent organic matter in an alternating aeration activated sludge system combining ozone/ultrasound pretreatment

Yang

Guo

Chen

et al. 2015

Bioresource Technology

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“…It has been reported that nitrifying bacteria was more sensitive than heterotrophic bacteria to the toxicity of Cr(VI), and a Cr(VI) concentration of 0.5 mg L −1 caused significant inhibition of the nitrification process (up to 74% decrease in ammonia removal efficiency) [9]. Cheng et al [10] found that NH4 + -N removal decreased from 97% to 68% with the addition of Cr(VI) with 5 mg L −1 in an SBR. Fang et al [11] tested the acute tolerance of an enhanced biological phosphorus removal (EBPR) system on a high of concentration Cr(VI) and revealed that P removal performance was completely inhibited by Cr(VI) with a concentration higher than 5 mg L −1 , but the EBPR system could recover after a short Cr(VI) shock.…”

Section: Experimental Apparatus and Wastewater Compositionmentioning

confidence: 99%

“…Subsequently, Fang et al [2] studied the long-term effects (52-d systematic investigation) of a low concentration of Cr(VI) (0.3-0.8 mg L −1 ) on the P removal performance of a granule-based EBPR system, and found that a high Cr(VI) concentration (0.5 mg L −1 ) could significantly inhibit P removal; filamentous bacteria overgrew, and eventually sludge bulking occurred in long-term Cr (VI) loading. The discrepancy in results of Cr(VI) effects on microbial metabolic activities could be attributed both to metal speciation [12] and the types of assays used [10], which played an important role when comparing toxicity expressions by different studies [7]. Nevertheless, most of the above investigations studied the short-term and long-term toxicity of Cr(VI) on EBPR system, data from which cannot shed light on the likelihood of the long-term stable operation of a simple nitrifying activated sludge system.…”

Section: Introductionmentioning

confidence: 99%

Unraveling the Long-Term Effects of Cr(VI) on the Performance and Microbial Community of Nitrifying Activated Sludge System

Wang

Dai

Zhang

et al. 2017

Water

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Abstract:The long-term effects of different influent Cr(VI) concentrations (0-0.5 mg L −1 ) on the nitrification activities and microbial community structures of nitrifying activated sludge system were investigated in this study. Results showed that the performance of ammonia oxidation was significantly inhibited, and the effluent concentration of ammonia nitrogen (NH 4 + -N) increased markedly when the influent Cr(VI) loading was equal or greater than 0.2 mg L −1 . The specific oxygen utilization rate (SOUR), specific ammonium oxidation rate (SAOR), and specific nitrite oxidation rate (SNOR) of the system decreased from 53.24, 6.31, and 7.33 mg N g −1 VSS h −1 to 18.17, 1.68, and 2.88 mg N g −1 VSS h −1 , respectively, with an increase of Cr(VI) concentration from 0 to 0.5 mg L −1 . The protein/polysaccharide (PN/PS) ratio increased with the increasing Cr(VI) concentration, indicating that excessive PN secreted by microorganisms was conducive to resisting the toxicity of Cr(VI). High-throughput sequencing revealed that the relative abundance of ammonia-oxidizing bacteria (Nitrospira) and nitrite-oxidizing bacteria (Nitrosomonas and Nitrosospira) all decreased with the increasing Cr(VI) concentration, and ammonia-oxidizing bacteria were more sensitive to heavy metal toxicity than nitrite-oxidizing bacteria. The activities of nitrifying activated sludge system could not be completely recovered after a 30-d recovery process.

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“…A previous study demonstrated that the substrate removal performance depends on the microbial metabolism in the activated sludge system, and that the ETS activity is an important parameter for the evaluation of the microbial metabolic level [22]. In this study, the TTC-ETS of the aerobic granular sludge increased by 20.2% with the increasing Cr(VI) concentration of up to 5 mg/L.…”

Section: Discussionmentioning

confidence: 76%

“…(2) Specific ammonia utilization rate (sAUR) [22] was determined using the short-term batch reactors. The initial conditions (including the granular sludge and synthetic wastewater) and operational parameters (including pH, dissolved oxygen, and MLSS) of the batch assays were similar to those of the continuous flow reactors.…”

Section: Methodsmentioning

confidence: 99%

Effect of Cr(VI) on the microbial activity of aerobic granular sludge

Zheng¹,

Wang²,

Chen³

et al. 2016

Desalination and Water Treatment

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Cao (2015): Effect of Cr(VI) on the microbial activity of aerobic granular sludge, Desalination and Water Treatment, A B S T R A C TThe effects of different chromium (Cr(VI)) concentrations (0, 5, 10, 25, and 50 mg/L) on pollutant removal, nitrification ability, and microbial activity of aerobic granular sludge in sequencing batch reactors were analyzed. When compared with the control system, Cr(VI) decreased the average chemical oxygen demand (COD) and ammonia nitrogen removal rates. Significant correlations between the inhibitory rate of specific ammonia utilization rate (sAUR) and Cr(VI) concentration suggested that sAUR inhibition rate could be an effective indicator to predict the biological nitrification process in the aerobic granular sludge system. Although appropriate Cr(VI) concentration stimulated electron transport system activity of the granules, more than 25 mg/L Cr(VI) obviously inhibited the activity. The total polysaccharide and protein contents of the extracellular polymeric substances (EPS) linearly increased with increasing Cr(VI) concentrations of up to 25 mg/L. Furthermore, Cr(VI) exhibited greater inhibitory effects on the nitrification process than on the organic substrate removal process. This may be owing to the lower tolerance of nitrifying bacteria to Cr(VI), when compared with that of organics-degrading heterotrophic bacteria; distribution of nitrifying and heterotrophic bacteria, which occurred at the outer and inner layers of the granular sludge, respectively; and improvement in the COD removal rate of the micro-organisms as a result of EPS secretion.

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Effects of Cr(VI) on the performance and kinetics of the activated sludge process

Cited by 53 publications

References 30 publications

Economical evaluation of sludge reduction and characterization of effluent organic matter in an alternating aeration activated sludge system combining ozone/ultrasound pretreatment

Economical evaluation of sludge reduction and characterization of effluent organic matter in an alternating aeration activated sludge system combining ozone/ultrasound pretreatment

Unraveling the Long-Term Effects of Cr(VI) on the Performance and Microbial Community of Nitrifying Activated Sludge System

Effect of Cr(VI) on the microbial activity of aerobic granular sludge

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