Aeration effects on Beggiatoa in a laboratory fixed‐film growth system

Abstract

The enrichment of Beggiatoa was derived in a lab‐scale continuous flow fixed‐film growth system. Under a low aeration and high BOD organic loading condition, the enrichment of Beggiatoa was easily achieved on the glucose‐fed slime while it took fairly long time on the acetate‐fed one. An increased aeration resulted in a decrease in the Beggiatoa population for the acetate‐fed slime, but not for the glucose‐fed slime, except slightly at very high aeration level. Sulfate removal rate in both Beggiatoa dominated slimes was generally low, between 10–30%. The glucose‐fed slime showed a much higher sulfate removal at high organic loading. The aeration effects on Beggiatoa and sulfate removal were understandable in the context of the Beggiatoa‐Desuljouibrio interaction, diffusion and uptake rate of substrate. Glucose diffusion and uptake rate may more rapid, thus air could not penetrate as efficiently into the sulfide‐emitting anaerobic layer inhabited by sulfate reducing bacteria such as Desuljombrio. This may have resulted in less inhibitory effects on the sulfate reducing bacteria.