The emission of sulphur compounds into the environment is undesirable because of their acidifying characteristics. The processing of sulphidic ores, oil refining and sulphuric acid production are major sources of SO2 emissions. Hydrogen sulphide is emitted into the environment as dissolved sulphide in wastewater or as H2S in natural gas, biogas, syngas or refinery gases. Waste streams containing sulphate are generated by many industries, including mining, metallurgical, pulp and paper and petrochemical industries. Applying process technologies that rely on the biological sulphur cycle can prevent environmental pollution. In nature sulphur compounds may cycle through a series of oxidation states (-2, 0, +2, +4, +6). Bacteria of a wide range of genera gain metabolic energy from either oxidising or reducing sulphur compounds. Paques B.V. develops and constructs reactor systems to remove sulphur compounds from aqueous and gaseous streams by utilising naturally occurring bacteria from the sulphur cycle. Due to the presence of sulphide, heavy metal removal is also achieved with very high removal efficiencies. Ten years of extensive laboratory and pilot plant research has, to date, resulted in the construction of over 30 full-scale installations. This paper presents key processes from the sulphur cycle and discusses recent developments about their application in industry.
[1]
F. Widdel,et al.
Gram-Negative Mesophilic Sulfate-Reducing Bacteria
,
1992
.
[2]
A. Janssen,et al.
Surface characteristics and aggregation of microbiologically produced sulphur particles in relation to the process conditions
,
1996
.
[3]
A. Rinzema,et al.
Anaerobic treatment of sulfate containing wastewater.
,
1988
.
[4]
J. Kuenen.
Colourless sulfur bacteria and their role in the sulfur cycle
,
1975,
Plant and Soil.
[5]
J. Visser.
Sulfur compound oxidation and sulfur production by Thiobacillus sp. W5
,
1997
.
[6]
C. Buisman,et al.
Optimization of sulphur production in a biotechnological sulphide‐removing reactor
,
1990,
Biotechnology and bioengineering.
[7]
R. Tichý,et al.
Possibilities for using biologically-produced sulphur for cultivation of Thiobacilli with respect to bioleaching processes
,
1994
.
[8]
C. L. Brierley,et al.
Present and future commercial applications of biohydrometallurgy
,
1999
.