Pengaruh Nitrat terhadap Biokorosi Logam oleh Konsorsium Bakteri Pereduksi Sulfat dari PLTA Saguling

The Influence of Nitrate in Metal Biocorrosion caused by Sulfate Reducing Bacteria from Saguling Hydropower. The corrosion facilitated and accelerated by the activities of microorganism is called biocorrosion. Sulfate reducing bacteria (SRB) is known as the bacteria that cause biocorrosion in anaerobic condition by using sulfate as the final electron acceptor. Biocorrosion reduces equipment lifetime and increases maintenance cost in industry. In the cooling system in Saguling hydropower, corrosion was commonly caused by utilization of contaminated water due to anorganic and organic waste, especially sulfate. In this research, sulfate reducing bacteria was isolated from biofilms in the cooling system of Saguling Hydropower. Molecular analysis using PCR-DGGE method with dsrB gene (350 bp) as molecular markers showed that SRB consortium contained 12 bands and assumed as different species of SRB. SRB consortium was tested to determine its biocorrosion activity over metal material of ST37 (carbon steel) and SUS304 (stainless steel). The consortium then treated with 7 different nitrate concentrations to determine its effect against the sulfate reducing bacteria activity. SRB consortium caused higher corrosion to ST37 than SUS304L, with the corrosion rate of 0.07660 mm/year and 0.00265 mm/year, respectively. Concentration of 10 mM nitrate effectively inhibited corrosion rate on ST37 and caused the changes in sulfate reducing bacteria communities, indicated by the disappearance of 6 bands in DGGE profile