V. Uberoi et Sk. Bhattacharya, SULFATE-REDUCING BACTERIA IN ANAEROBIC PROPIONATE SYSTEMS, Journal of environmental engineering, 123(7), 1997, pp. 675-682
The design of anaerobic treatment systems for sulfate containing high-
strength wastewater requires the understanding of interactions between
sulfate reducers and other anaerobes. The objectives of this research
were to study the effects of the feed propionate:sulfate ratio on the
interactions among the sulfate-reducing bacteria (SRB), acetogens, an
d methanogens, and to determine the kinetics of anaerobic biological r
eactions for propionate degradation under sulfate-limited and sulfate-
rich conditions. Both continuous and batch experiments were conducted
to meet these objectives. In sulfate-limited chemostats with propionat
e as the sole carbon source, the effluent sulfate concentration was go
verned by the propionate utilizing SRB and was below 10 mg/L. In sulfa
te-rich systems the effluent sulfate concentration was governed by ace
tate utilizing SRB and could not be maintained below 400 mg/L without
controlling the sulfide concentration. Under these sulfate-rich condit
ions, a decrease in SRT from 30 to 13 d decreased the extent of acetat
e utilization by SRB. The propionate utilizing SRB outcompeted the pro
pionate utilizing acetogens in the chemostats. This was attributed to
lower Monod-half velocity coefficient, K-s, for propionate utilization
by SRB (4.5 mg-Pm), than the K-s for propionate utilization by acetog
ens (20.4 mg-Pr/L). The rate constants (k) for SRB and acetogens in te
rms of mg of propionate/mg of volatile suspended solids (VSS) per day
were approximately 5.2 and 3.1 mg-Pr/mg-VSS-d, respectively. In sulfat
e-rich conditions, propionate was utilized by SRB, and the intermediat
e acetate was utilized by both SRB and methanogens.