EUROCORR: Effects of surface roughness on anaerobic marine biofilm formation and microbiologically-influenced corrosion of UNS G10180 carbon steel

The challenge in understanding and predicting microbiologically influenced corrosion (MIC) is the lack of robust and reproducible model biofilm systems that reflect realworld operating conditions. Furthermore, there are no internationally recognised standards or test methods with which to evaluate control strategies effective against MIC. Current industrial standards provide insightful guidance when it comes to the detection, testing and evaluation of MIC; however, less than 25% of risk-based inspections analyse sessile biofilm samples when investigating corrosion. This work aims to develop and validate a model biofilm system to investigate the role of biofilm communities within MIC. The effect of surface roughness on MIC and biofilm formation between As Received (Ra Control = 2.2360 ± 0.3450 μm & Ra Test 2.4971 ± 0.6720 μm), and 25 μm polished (Ra Control = 1.3938 ± 0.0897 μm & Ra Test 1.6781 ± 0.1133 μm) carbon steel coupons (UNS G10180) will be investigated. The objective is to run two CDC biofilm reactors, one control and one test reactor inoculated with an anaerobic marine sediment sample. Both reactors will be run with an electrochemical
cell setup and H2S microsensor, whilst maintaining anaerobic conditions.
Corrosion rates will be monitored daily via linear polarization resistance and
electrochemical impedance spectroscopy measurements, with potentiodynamic
polarization performed at the end. Similarly, changes in H2S concentration will be
monitored daily (will reflect the activity of sulphate-reducing prokaryotes). Once the experiment is complete, biofilm viability through LIVE/DEAD imaging and monitoring of ATP activity will be assessed alongside any changes in prevalence and activity of different species within the biofilm using molecular microbial methods (qPCR and 16S rRNA amplicon sequencing). Gravimetric analysis alongside surface profilometry will be performed to assess the extent of the corrosion degradation. In combination these methods will provide a holistic understanding, providing novel insights into the effect of surface roughness on MIC.
We hypothesise that carbon steel coupons with greater surface roughness will
facilitate biofilm attachment and growth, and thus exhibit higher corrosion rates.