Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8420313 | Journal of Microbiological Methods | 2018 | 6 Pages |
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 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 50â¯ppm glutaraldehyde (GLT), a common oil field biocide, in an abiotic cell was 3.6 times more corrosive (24.5â¯Ãâ¯10â3â¯mm/y) than a biocorrosion cell inoculated with a sulfate-reducing bacteria (SRB) enrichment (6.73â¯Ãâ¯10â3â¯mm/y). The SRB inoculated cell treated with GLT (50â¯ppm) reduced the corrosion rate from 6.73â¯Ãâ¯10â3â¯mm/y to 3.68â¯Ãâ¯10â3â¯mm/y. It was hypothesized that a biocide-surfactant combination would enhance biocide activity, thereby lowering corrosion in a semi-continuous biocorrosion cell. The biocide and surfactant were GLT (30â¯ppm) and Tween 80 (TW80; 100â¯ppm). MIC of SRB increased in the presence of a non-inhibitory concentration of GLT (23.4â¯Ãâ¯10â3â¯mm/y), compared to the untreated +SRB condition (8.29â¯Ãâ¯10â3â¯mm/y). The non-ionic surfactant alone reduced MIC (4.57â¯Ãâ¯10â3â¯mm/y) and even more so in combination with GLT (3.69â¯Ãâ¯10â3â¯mm/y). Over 50% of 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 and corrosion coupon geometries. Biocide-surfactant combinations may have the potential to reduce the concentration of biocides used in the field. In addition, a semi-defined medium for enumerating Acid-Producing Bacteria (APB) was developed, resulting in higher recoveries compared to a standard phenol red medium (e.g., 1.1â¯Ãâ¯104 APB/cm2 vsâ¯<â¯4â¯Ãâ¯10â1 APB/cm2).
Keywords
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Authors
Mary M. Eid, Kathleen E. Duncan, Ralph S. Tanner,