| dc.description.abstract | Microbially Influenced Corrosion (MIC), also known as biocorrosion, has significant impacts on the environment and economy. Typical systems to study biocorrosion are either dynamic (once-through flow) or static (serum bottle incubations). Dynamic systems can be materials, cost and personnel intensive, while static systems quickly become nutrient limiting and exhibit long incubations. A semi- continuous biocorrosion cell was developed to address these issues. Low carbon shim steel was used as a test surface. Initial results revealed that 50 ppm glutaraldehyde (GLT), a common oil field biocide, in an abiotic cell (24.5 x 10-3 mm/y) was 3.6 times more corrosive than a biocorrosion cell inoculated with a sulfate-reducing bacteria (SRB) enrichment (6.73 x 10-3 mm/y). The SRB inoculated cell treated with GLT reduced the corrosion rate from 6.73 x 10-3 mm/y to 3.68 x 10-3 mm/y. It was hypothesized that a biocide-surfactant combination would enhance a biocide’s activity, lowering corrosion in a semi-continuous biocorrosion cell. The biocide and surfactant were GLT (30 ppm) and Tween 80 (TW80; 100 ppm). MIC increased in the presence of a non-inhibitory concentration of GLT (23.4 x 10-3 mm/y), compared to the untreated +SRB condition (8.29 x 10-3 mm/y). The non-ionic surfactant alone reduced MIC (4.57 x 10-3 mm/y) and even more in combination with GLT (3.69 x 10-3 mm/y). Approximately half of the 16S rDNA sequences in the biofilm on the test surface were identified as belonging to the genera Desulfovibrio and Desulfomicrobium. The utility of a semi-continuous system for MIC studies and biocide testing was demonstrated. The concept of regular partial medium replacement is applicable to different corrosion cell
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and corrosion coupon geometries. Biocide-surfactant combinations may have the potential to reduce the concentration of biocide used in the field. Additionally, Acid- Producing Bacteria (APB) are important across many industries ranging from food microbiology to the oil and gas industry. In oil and gas fields, APB are cultured using a standard phenol red medium outlined by the American Petroleum Institute and NACE. In this study, enumerating APB from oilfield produced water was non-optimal using the medium outlined in the literature. To address this issue, a semi-defined medium for enumerating APB was developed, resulting in higher recoveries compared to a standard phenol red medium (e.g., 1.1 x 104 APB/cm2 vs < 0.4 APB/cm2). | en_US |
