Principles and potential of the anaerobic digestion of waste-activated sludge

The corrosion of sewers and the control of odor are the major operational and maintenance problems in wastewater collection systems. The generation of hydrogen sulfide and subsequent sulfuric acid results from microbially mediated reactions, by sulfate‐reducing bacteria (SBR) and sulfide‐oxidizing bacteria. This review covers pertinent information about sulfate reduction‐induced problems in general and SBR in particular. Metabolism with respect to carbon, energy, and sulfur sources, ecology, growth factors (dissolved oxygen, temperature, pH, and sulfide), and the competitive effects of methane‐producing bacteria on SBR are discussed. Because metals react with sulfide to form metal sulfide precipitates with extremely low solubilities, metal interactions in sulfate reduction environments are discussed.

Sulfate‐reducing bacteria

Until recently, biological treatment of sulphate-rich wastewater was rather unpopular because of the production of H2S under anaerobic conditions. Gaseous and dissolved sulphides cause physical-chemical (corrosion, odour, increased effluent chemical oxygen demand) or biological (toxicity) constraints, which may lead to process failure. Anaerobic treatment of sulphate-rich wastewater can nevertheless be applied successfully provided a proper treatment strategy is selected. The strategies currently available are discussed in relation to the aim of the treatment: i) removal of organic matter, ii) removal of sulphate or iii) removal of both. Also a whole spectrum of new biotechnological applications (removal of organic chemical oxygen demand, sulphur, nitrogen and heavy metals), recently developed based on a better insight in sulphur transformations, are discussed.

Anaerobic treatment of sulphate-rich wastewaters.

Sulfide inhibition of anaerobic degradation of lactate and acetate

Biotechnology in the petroleum industry: An overview

Screening growth inhibitors of sulfate-reducing bacteria and their effects on methane fermentation

Effects of volatile fatty acids on methanogenesis of methanol and of pregrowth with methanol on acetate utilization by methanogens

Enzyme activity for monitoring the stability in a thermophilic anaerobic digestion of wastewater containing methanol

Influence of pH on methane and sulfide production from methanol

PURPOSE:To prevent the generation of sulfide ions hindering methane fermentation by adding a surfactant selectively hindering the growth of sulfate reducing bacteria coexisting with methane bacteria to org. waste water contg. sulfate ions and by carrying out anaerobic fermentation. CONSTITUTION:The surfactant selectively hindering the growth of sulfate reducing bacteria coexisting with methane bacteria is added to org. waste liquor contg. sulfate ions such as waste water from an alcohol distilling stage or waste liquor from a pulp mill and the waste liquor is treated by anaerobic fermentation. The surfactant may be tween-60, octadecyltrimethylammonium chloride, dodecylbenzenesulfonic acid, cetyltrimethylammonium bromide or cetylpyridium bromide. By this method, the generation of sulfide ions hindering methane fermentation is prevented and the consumption of hydrogen necessary for methane formation by sulfate reducing bacteria is also prevented.

Yuichi Tanimoto

Papers

Screening growth inhibitors of sulfate-reducing bacteria and their effects on methane fermentation

Effects of volatile fatty acids on methanogenesis of methanol and of pregrowth with methanol on acetate utilization by methanogens

Enzyme activity for monitoring the stability in a thermophilic anaerobic digestion of wastewater containing methanol

Influence of pH on methane and sulfide production from methanol

Method for inhibiting reduction of sulfate in anaerobic treatment and coloring matter hindering growth of sulfate reducing bacteria