Sulphur and sulphate reduction with acetate and propionate in an aerobic process for sulphide removal

Abstract

Sulphide production rates of sulphurand sulphate-reducing bacteria up to 50 mg per biomass support particle per day were observed in an aerated sulphide-removal reactor with polyurethane (PUR) foam as carrier material. The optimal pH and temperature for the sulphide-producing bacteria were 8.0 and 30°C respectively. Raschig rings and four types of cube-shaped PUR particles were tested as carrier materials. When using PUR particles, the sulphide production rate was always between 3% and 4% of the sulphide removal rate, dependent on the dimensions and pore size of the polyurethane support particles. With the Raschig rings this ratio was only 2% and for reactors in which no carrier materials were present it was even lower (0.6%). Media containing different mixtures of acetate, propionate, sulphur and sulphate inoculated under anoxic conditions with sludge from the aerated reactor showed the presence of acetate-degrading sulphur-reducing, but not of acetate-degrading sulphate-reducing, bacteria. With propionate as sole electron donor no degradation occurred in the presence of sulphur within 2 weeks, whereas sulphate-dependent propionate oxidation started after 5-6 days incubation. Bacteria were isolated and resembled Desulfuromonas acetoxidans and DesulfobuIbus propionicus morphologically and physiologically.

Effect of organic substrates on biological sulphide oxidation

“…This was probably due to an inhibitory effect of sulphide on the heterotrophic organisms present. At 30°C a slight increase in the sulphide effluent concentration was found when fatty acid removal started up, but this effect is due to sulphide production from sulphur and sulphate reduction (Buisman et al 1989c) rather than to an inhibitory effect of the fatty acids.…”

“…Previously (Buisman et al 1989c) we have shown that anaerobic acetate and propionate oxidation with sulphur and sulphate, respectively, is possible in an aerobic sulphide-removing reactor. The acetate and propionate removal shown in Table 1, however, cannot be due to sulphate-and sulphur-reducing bacteria, because this reducing activity was found to be very low in cell suspensions.…”

“…Besides aerobic oxidation of acetate and propionate, anaerobic oxidation is also possible. We have already described the anaerobic oxidation of acetate with sulphur and propionate with sulphate by Desulfuromonas and Desulfobulbus respectively (Buisman et al 1989c).…”

Influence of acetate and propionate on sulphate-reducing bacteria activity

“…The effect of acetate and propionate on SRB performance got limited attention so far, and if discussed, it was for other objectives (Buisman et al . ; Omil et al . ; Finke et al .…”

Phenol and sulfide oxidation in a denitrifying biofilm reactor and its microbial community analysis

“…However, Reyes-Á vila et al [21] using acetate as electron donor indicated that the lithoautotrophic process is faster. Sulfide can be removed via anaerobic processes by chemolithoautotrophic microorganisms such as Thiobacillus denitrificans, which has been extensively studied under anoxic or aerobic conditions [22][23][24]. Sulfide in presence of an organic molecule such as acetate can be removed via denitrification process either in continuous or batch mode [21,25].…”