Is it true that almost all short-term lab tests are in the charge transfer control region?
Most pit depth data from lab tests lasting a few weeks are shallow (say 5 – 20 microns). Sulfate concentrations are high (above 20 mM in most SRB media). In such cases, MICORP simulation will show that mass transfer is not limiting. This means sulfate concentration variations have no impact on pit depth. There are exceptions. For example, some researchers grow SRB biofilms in a rich culture medium and then switch to wastewater that contains less than 1 mM sulfate. In such a case, it is likely that charge transfer and mass transfer are both important.
