Effects of Chlorophenols and Nitrophenols on the Kinetics of Propionate Degradation in Sulfate-Reducing Anaerobic Systems

Abstract

The ability of sulfate-reducing bacteria (SRB) to effectively degrade several substituted and non-substituted aromatic and aliphatic compounds offers a promising alternative for the treatment of sulfate-containing industrial wastewaters and landfill leachates. For the design of sulfate-reducing anaerobic treatment systems for such wastewaters, it is important to determine the effects of toxicants on the kinetics of sulfate-reducing and methanogenic reactions. Batch kinetic experiments were conducted in the presence and absence of selected organic toxicants with a sulfate-reducing propionate enrichment culture. Fourteen chlorophenols and four nitrophenols were selected for this study. Toxicity due to dichlorophenols and trichlorophenols to both propionate and acetate degradation was dependent on the substitution position of chlorine atoms on the benzene ring. Among the dichlorophenols, 2,3-dichlorophenol and 2,6-dichlorophenol were the least toxic and 3,5-dichlorophenol was the most toxic. Among the trichlorophenols, 2,3,5-trichlorophenol and 2,4,5-trichlorophenol were more toxic as compared to 2,3,6-trichlorophenol and 2,4,6-trichlorophenol. Toxicity due to the mononitrophenols was also dependent on the substitution position showing 4-nitrophenol as the least toxic. All of the selected nitrophenols were more toxic to acetate utilization by methanogens than propionate utilization by the SRB.

Effect of shocked nitrobenzene concentrations on the operational performance of anaerobic sequential batch reactor

“…Therefore, it is likely that the shocked influent NB lowered the propionate consumption in this study. This result agrees with the previous research, which reported that nitrophenols, one kind of NACs, had an inhibitory effect on SRB, thereby lowering the propionate consumption in sulfate-reducing systems [42].…”

Inhibitory concentrations of 2,4D and its possible intermediates in sulfate reducing biofilms

“…These results can be compared to those obtained by Uberoi and Bhattacharya [9] on propionate utilization by a sulfate reducing consortium, where 2,4DCP turned out to be more toxic than 2CP and 4CP, although 4CP was more toxic than 2CP. In this case, the paraisomer was more toxic than the ortho-isomer, while a disubstituted phenol in the ortho-and the para-positions resulted more toxic than de monosubstituted compounds.…”

“…Many SRB are able to metabolize hydroxybenzoate isomers or benzoic acid through the benzoyl coenzyme A pathway, but are not known to degrade phenols or chlorophenols until exposed to these compounds for long periods of time [8]. Moreover, Uberoi and Bhattacharya [9] determined the relative toxicity concentrations of several chlorophenols for propionate degrading SRB.…”

Kinetics of biochemically driven metal precipitation in synthetic landfill leachate

“…The observation of increasing concentrations of dissolved inorganic carbon in the batch reactor suggested that under sulphate-limited conditions, net acetate accumulation was the result of bacterial activity, possibly non-sulphate-reducing acetogenic bacteria and SRB (Uberoi & Battacharya, 1997), which produce carbon dioxide and methane. Methane gas was detected after 60 days for the duration of the study.…”