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Removal of hydrogen sulfide by sulfate-resistant Acidithiobacillus thiooxidans AZ11

Paper ID Volume ID Publish Year Pages File Format Full-Text
22163 43258 2006 6 PDF Available
Title
Removal of hydrogen sulfide by sulfate-resistant Acidithiobacillus thiooxidans AZ11
Abstract

Toxic H2S gas is an important industrial pollutant that is applied to biofiltration. Here, we examined the effects of factors such as inlet concentration and space velocity on the removal efficiency of a bacterial strain capable of tolerating high sulfate concentrations and low pH conditions. We examined three strains of Acidithiobacillus thiooxidans known to have sulfur-oxidizing activity, and identified strain AZ11 as having the highest tolerance for sulfate. A. thiooxidans AZ11 could grow at pH 0.2 in the presence of 74 g l−1 sulfate, the final oxidation product of elemental sulfur, in the culture broth. Under these conditions, the specific sulfur oxidation rate was 2.9 g-S g-DCW (dry cell weight)−1 d−1. The maximum specific sulfur oxidation rate of A. thiooxidans AZ11 was 21.2 g-S g-DCW−1 d−1, which was observed in the presence of 4.2 g-SO42−l−1 and pH 1.5, in the culture medium. To test the effects of various factors on biofiltration by this strain, A. thiooxidans AZ11 was inoculated into a porous ceramic biofilter. First, a maximum inlet loading of 670 g-S m−3 h−1 was applied with a constant space velocity (SV) of 200 h−1 (residence time, 18 s) and the inlet concentration of H2S was experimentally increased from 200 ppmv to 2200 ppmv. Under these conditions, less than 0.1 ppmv H2S was detected at the biofilter outlet. When the inlet H2S was maintained at a constant concentration of 200 ppmv and the SV was increased from 200 h−1 to 400 h−1 (residence time, 9 s), an H2S removal of 99.9% was obtained. However, H2S removal efficiencies decreased to 98% and 94% when the SV was set to 500 h−1 (residence time, 7.2 s) and 600 h−1 (residence time, 6 s), respectively. The critical elimination capacity guaranteeing 96% removal of the inlet H2S was determined to be 160 g-S m−3 h−1 at a space velocity of 600 h−1. Collectively, these findings show for the first time that a sulfur oxidizing bacterium has a high sulfate tolerance and a high sulfur oxidizing activity below pH 1.

Keywords
sulfate tolerance; Acidithiobacillus thiooxidans; biofilter; hydrogen sulfide
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Removal of hydrogen sulfide by sulfate-resistant Acidithiobacillus thiooxidans AZ11
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Bioscience and Bioengineering - Volume 101, Issue 4, April 2006, Pages 309–314
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us