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Hydraulic retention time
About: Hydraulic retention time is a research topic. Over the lifetime, 6406 publications have been published within this topic receiving 151005 citations.
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TL;DR: Ethan oxidation was more inhibited by sulfide toxicity than the acetate oxidation, and the noncompetitive inhibition model described well the sulfide inhibition of the sulfate‐reducing culture.
Abstract: The effects of hydraulic retention time (HRT) and sulfide toxicity on ethanol and acetate utilization were studied in a sulfate-reducing fluidized-bed reactor (FBR) treating acidic metal-containing wastewater. The effects of HRT were determined with continuous flow FBR experiments. The percentage of ethanol oxidation was 99.9% even at a HRT of 6.5 h (loading of 2.6 g ethanol L−1 d−1), while acetate accumulated in the FBR with HRTs below 12 h (loading of 1.4 g ethanol L−1 d−1). Partial acetate utilization was accompanied by decreased concentrations of dissolved sulfide (DS) and alkalinity in the effluent, and eventually resulted in process failure when HRT was decreased to 6.1 h (loading of 2.7 g ethanol L−1 d−1). Zinc and iron precipitation rates increased to over 600 mg L−1 d−1 and 300 mg L−1 d−1, respectively, with decreasing HRT. At HRT of 6.5 h, percent metal precipitation was over 99.9%, and effluent metal concentrations remained below 0.08 mg L−1. Under these conditions, the alkalinity produced by substrate utilization increased the wastewater pH from 3 to 7.9–8.0. The percentage of electron flow from ethanol to sulfate reduction averaged 76 ± 10% and was not affected by the HRT. The lowest HRT did not result in significant biomass washout from the FBR. The effect of sulfide toxicity on the sulfate-reducing culture was studied with batch kinetic experiments in the FBR. Noncompetitive inhibition model described well the sulfide inhibition of the sulfate-reducing culture. (DS) inhibition constants (Ki) for ethanol and acetate oxidation were 248 mg S L−1 and 356 mg S L−1, respectively, and the corresponding Ki values for H2S were 84 mg S L−1 and 124 mg S L−1. In conclusion, ethanol oxidation was more inhibited by sulfide toxicity than the acetate oxidation. © 2004 Wiley Periodicals, Inc.
162 citations
TL;DR: In this article, a two-stage up-flow anaerobic sludge blanket (UASB) reactor was used to treat palm oil mill effluent (POME) achieving a high rate of acid production with a loading rate of 16.6 g l?1 d?1 COD.
160 citations
TL;DR: The efficiency of dissolved methane collection by degasification from the effluent of a bench-scale upflow anaerobic sludge blanket (UASB) reactor treating synthetic wastewater was investigated and total CH(4) recovery efficiency increased from 71% to 97% at 15 °C as a result of degAsification.
160 citations
TL;DR: The results indicate that a slow increase in the grease waste dose could be a strategy that favours biomass acclimation to fat-rich co-substrate, increases long chain fatty acid degradation and reduces the latter's inhibitory effect.
159 citations
TL;DR: Results of continuous flow experiments demonstrated that using the nonwovens could attain consistent high-rate p-nitrophenol degradation.
159 citations