Modeling of anaerobic corrosion influenced by sulfate‐reducing bacteria

Abstract

A laboratory experiment was conducted to investigate the corrosion influenced by sulfate‐reducing bacteria (SRB). A mathematical model was developed and fitted to the pitting depths measured at 0.1 and 0.5 mM sulfate concentrations. The model was successful in predicting the pitting depth at two different sulfate concentrations when the kinetic variables reported in the literature were used. The deepest pitting depths were observed to be approximately 0.19 and 0.39 mm for bulk sulfate concentrations of 0.1 and 0.5 mM after 150 days of exposure, respectively. The pitting depths were predicted to be 0.17 and 0.36 mm for bulk sulfate concentrations of 0.1 and 0.5 mM after 150 days of simulation, respectively. The steady‐state pitting depth was predicted to be 0.48 mm for a bulk sulfate concentration of 0.5 mM after 400 days of simulation. The model was most sensitive to the sulfate diffusion coefficient (DSO42−), closely followed by the maximum sulfate utilization rate (q), and the biomass concentration (Xc), but it was less sensitive to the half‐velocity coefficient (Km). At the initial stage, the pitting depth was affected only by q and Xc. As the pitting depth increased, however, the diffusion of sulfate in the reaction zone became one of the dominant limiting factors. The decrease in the q or Xc value by 20% resulted in the increase in the pitting depth by 19%.

Theoretical aspects of antibiotic diffusion into microbial biofilms

“…The biofilm contains cells (volume fraction ε c ), extracellular polysaccharide (volume fraction ε p ), and water (volume fraction ε w , ε w ϭ 1 Ϫ ε p Ϫ ε c ). Mathematical models with some of the same features as those described below have been derived to analyze solute diffusion in dental plaque (11), in biofilms occurring in wastewater treatment processes (13), and in biofilms implicated in microbially induced corrosion (27).…”

General Theory for Integrated Analysis of Growth, Gene, and Protein Expression in Biofilms

“…Biofilm models incorporating reaction-diffusion analyses date back to the mid-1970s [17] – [19] ). These models have been used to simulate and understand such phenomena as overall substrate fluxes in wastewater treatment processes [20] , [21] , species competition and coexistence [21] , [22] , the heterogeneous architecture of biofilms [23] , [24] , antimicrobial penetration and efficacy [25] , [26] , microbially influenced corrosion [27] , [28] , pH gradients in dental plaque [29] , and mineral precipitation [30] . Apart from certain models of quorum sensing in biofilms [31] , [32] , there have not been attempts to model the dynamic spatiotemporal expression of specific genes or proteins in microbial biofilms.…”

Removal of Dissolved Heavy Metals from Acid Rock Drainage Using Iron Metal

“…Chemical reactions spontaneously, but slowly, reduce oxidized sulfur to H 2S under reduced, anaerobic conditions. Microbial processes, involving sulfate reducing bacteria (SRB) such as Desulfovibrio desulfuricans or Clostridium desulfuricans, rapidly induce corrosion of metals in anaerobic conditions and use sulfate as the terminal electron acceptor in respiration, reducing it to sulfide (20,23,24). Therefore, a viable SRB population may yield an end-result of precipitated metal sulfides as a way of remediating ARD.…”