Biological sulfate reduction using synthesis gas as energy and carbon source

Journal Article · Sat Apr 20 00:00:00 EDT 1996 · Biotechnology and Bioengineering

DOI:https://doi.org/10.1002/(SICI)1097-0290(19960420)50:2<136::AID-BIT3>3.3.CO;2-U· OSTI ID:227856

Houten, R.T. van; Spoel, H van der; Aelst, A.C. van; Pol, L W.H.; Lettinga, G ^[1]

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1. Wageningen Agricultural Univ. (Netherlands)

Several industries, in particular the chemical and mining industries, produce wastewater containing high amounts of oxidized inorganic sulfur compounds, such as sulfate, sulfite, or sulfuric acid. Due to the negative environmental impact, discharge of this wastewater to sewage systems is likely to be prohibited in the future. Therefore, recycling or (re)processing of this type of wastewater will become increasingly important. Biological sulfate reduction was studied in laboratory-scale gas-lift reactors. Synthesis gas (gas mixtures of H{sub 2}/CO/CO{sub 2}) was used as energy and carbon source. Special attention was paid to the effect of CO addition on the sulfate conversion rate, aggregation, and aggregate composition. Addition of 5% CO negatively affected the overall sulfate conversion rate; i.e., it dropped from 12--14 to 6--8 g SO{sub 4}{sup 2{minus}}/L{center_dot}day. However, a further increase of CO to 10 and 20% did not further deteriorate the process. With external biomass recycling the sulfate conversion rate could be improved to 10 g SO{sub 4}{sup 2{minus}}/L{center_dot}day. Therefore, biomass retention clearly could be regarded as the rate-limiting step. Furthermore, CO affected the aggregate shape and diameter. Scanning electron microscopy (SEM) photographs showed that rough aggregates pregrown on H{sub 2}/CO{sub 2} changed into smooth aggregates upon addition of CO. After addition of CO, a layered biomass structure developed. Acetobacterium sp. were mainly located at the outside of the aggregates, whereas Desulfovibrio sp. were located inside the aggregates.

• OSTI ID: 227856
• Journal Information: Biotechnology and Bioengineering, Vol. 50, Issue 2; Other Information: PBD: 20 Apr 1996
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
WASTE WATER
WASTE PROCESSING
SULFATES
BIODEGRADATION
SULFATE-REDUCING BACTERIA
GROWTH
CARBON MONOXIDE
CHEMICAL REACTION KINETICS
CARBON DIOXIDE
HYDROGEN
DESULFOVIBRIO