Biological Cr(VI) reduction in a trickling filter under continuous operation with recirculation

Dermou, Eftychia; Vayenas, D.V.

doi:10.1002/jctb.1882

Cited by 11 publications

(10 citation statements)

References 22 publications

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“…The removal rates obtained by the works of Alam (2004), Middleton et al (2003), Dermou and Vayenas (2008), Philip (2009), Brunet et al (2006); Ekenberg et al (2005); Tziotzios et al (2008), and Ahmad et al (2010) were close to 100%. The removals obtained by this work were slightly lower except for experiment 13 (Table 2) in which the removal result was the same.…”

Section: Experimental Designmentioning

confidence: 62%

“…In agreement with Dermou and Vayenas (2008) the determination of the organic carbon concentration is of great importance, since carbon addition greatly increases the operational cost of the plant unit during industrial applications. They studied the Cr(VI) concentration of triplicate profiles along the filter depth for three different organic carbon concentrations of about 150, 175, and 200 mgC l -1 for constant Cr(VI) influent concentration at about 5.5 mg l -1 and found the presence of the organic substrate is a critical parameter for biological Cr(VI) extracellular reduction.…”

Section: Toc Removalmentioning

confidence: 90%

“…2, lower concentrations of sodium acetate (0-6 g l -1 ) and higher concentrations of ammonium chloride (0.5 to 1 g l -1 ) promoted the removal of Cr(VI). Dermou and Vayenas (2008) used three different organic carbon concentrations of about 150, 175, and 200 mg l -1 , to verify the effect of the organic carbon (electron donor) concentration for constant Cr(VI) influent concentration at about 5.5 mg l -1 and the carbon concentration of 200 mg.l -1 proved results more efficient as Cr(VI) was reduced completely at the reactor's effluent, resulting in values below the maximum permitted limit of 0.05 mg l -1 .The presence of the organic substrate is a critical parameter for biological Cr(VI) extracellular reduction. This difference is related to the fact that the authors did not consider the joint influence of the nitrogen concentration, carbon concentration, and initial Cr(VI) concentration.…”

Section: Cr(vi) Bioremovalmentioning

confidence: 97%

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Evaluation of the bioremoval of Cr(VI) and TOC in biofilters under continuous operation using response surface methodology

et al. 2011

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In the present study, the bioremoval of Cr(VI) and the removal of total organic carbon (TOC) were achieved with a system composed by an anaerobic filter and a submerged biofilter with intermittent aeration using a mixed culture of microorganisms originating from contaminated sludge. In the aforementioned biofilters, the concentrations of chromium, carbon, and nitrogen were optimized according to response surface methodology. The initial concentration of Cr(VI) was 137.35 mg l(-1), and a bioremoval of 85.23% was attained. The optimal conditions for the removal of TOC were 4 to 8 g l(-1) of sodium acetate, >0.8 g l(-1) of ammonium chloride and 60 to 100 mg l(-1) of Cr(VI). The results revealed that ammonium chloride had the strongest effect on the TOC removal, and 120 mg l(-1) of Cr(VI) could be removed after 156 h of operation. Moreover, 100% of the Cr(VI) and the total chromium content of the aerobic reactor output were removed, and TOC removals of 80 and 87% were attained after operating the anaerobic and aerobic reactors for 130 and 142 h, respectively. The concentrations of cells in both reactors remained nearly constant over time. The residence time distribution was obtained to evaluate the flow through the bioreactors.

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Section: Experimental Designmentioning

confidence: 62%

Section: Toc Removalmentioning

confidence: 90%

Section: Cr(vi) Bioremovalmentioning

confidence: 97%

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Evaluation of the bioremoval of Cr(VI) and TOC in biofilters under continuous operation using response surface methodology

et al. 2011

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“…The effect of the organic carbon concentration was examined for constant Cr(VI) influent concentration at about 5.5 mg/L and volumetric flow rates ranging from 60 to 900 mL/min. The highest reduction rate achieved was 1,117 g Cr(VI)/m 2 /day for a volumetric flow rate of 900 mL/min (Dermou and Vayenas 2008). Even though the system mandated frequent backwashing of the filter, the high reduction rates combined with low operating cost make this an option worth considering for the treatment of industrial chromate effluents.…”

Section: Purification and Characterization Of Bacterial Chromate Redumentioning

confidence: 99%

Remediation of chromium contaminants using bacteria

Kanmani¹,

Aravind²,

Preston

2011

Int. J. Environ. Sci. Technol.

124

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Chromium contaminants emanating from industrial activities pose a significant threat to human's wellbeing. Chromium (III) and Chromium (VI) are the forms in which they are commonly encountered, of which the trivalent form is relatively benign. Hence, biological reduction of hexavalent chromium has been widely explored by researchers, yielding fruitful outcomes, opening up exciting avenues and also throwing up new challenges. This article attempts to review this area of research. Microbes, especially bacteria capable of Chromium (VI) reduction, belonging to a heterogeneous group have been isolated from contaminated sites. They exhibit plasmid-mediated chromate resistance and the reduction is enzymatically mediated. Reduction studies have been carried out with free and immobilized enzymes as well as whole cells. Experiments have been carried out in specifically designed bioreactors operated in batch and continuous modes. Although significant progress has been made, much needs to be done for its successful in situ application as the organism may not withstand the Chromium concentration or may be impeded by the presence of other toxicants. With molecular engineering, it may be possible to derive strains with improved performance even under stressful field conditions.

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“…Two major types of biological Cr(VI) treatment processes exist: suspended growth [25,26] and attached growth [27,28]. Although there are several studies on Cr(VI) reduction in the literature, only a few use attached growth reactors especially under batch operating mode.…”

Section: Introductionmentioning

confidence: 99%