INVESTIGATION OF THE EFFECTS OF FLUID FLOW ON SRB BIOFILM

摘要

Various studies have indicated that sessile bacteria in biofilms, not planktonic bacteria suspended in liquids, are directly responsible for pitting attack on metal surfaces in Microbiologically Influenced Corrosion (MIC). MIC has been detected not only in static fluid systems, but also in flow systems. Fluid flow directly impacts mass transfer and biofilm formation. A sufficiently high linear flow velocity can prevent biofilm establishment or even dislodge an established biofilm. It is difficult to perform experiments using a large flow loop to achieve high linear velocities. Instead, an electrochemical glass cell bioreactor with a cylindrical coupon on a rotating shaft can be used to simulate pipe flow with high linear velocities in MIC research. Mass transfer and wall shear stress similarities can be used to relate the coupon rotational speed in a glass cell and the average linear velocity in the corresponding pipe flow. In this work, ATCC 7757 strain of Desulfovibrio desulfuricans, a common strain of sulfate-reducing bacteria (SRB), was used in glass cell experiments to study biofilm behavior under flow conditions. The results confirmed that a high linear flow velocity could indeed prevent SRB biofilm formation.