3. Biogenic nitric acid The biogenic ammonia present in water environments stimulate the concrete corrosion caused by the biogenic nitric acid. The ammonization bacteria (urobacteria) decompose urea and cause the ammonia formation. Bacteria belonging to Nitrosomonas, Nitrosococcus, Nitrosospira and Nitrosolobus genera oxidize the ammonia to nitrous acid subsequently oxidized to nitric acid by Nitrobacter and Nitrococcusbacteria. This acid reacts with calcium compounds in the hardened cement paste to form the water-soluble calcium nitrate, easily rinsed from the concrete structure[17]. It has been shown that the biogenic nitric acid produced by the nitrifying bacteria causes severe corrosion of the mineral building materials. High cells numbers of the nitrifying bacteria were present on both historical sandstone buildings as well as on modern concrete buildings [8, 9].
We know we have Nitrification going on in the pipeline. Looks like we're generating nitric acid which is why we're getting high levels of concrete degradation.
Is there a way to determine this in the concrete samples of the pipe with the petrographic analysis? Can he test for calcium nitrate?
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