An innovative approach to reproduce the biodeterioration of industrial cementitious products in a sewer environment. Part I: Test design

A test method to evaluate biogenic resistance of cementitious pipe products intended for sewer networks is presented. It consisted in inoculating pipes with a highly diverse microbial consortium (urban wastewater treatment plant), and trickling a feeding solution containing a safe and soluble reduced sulfur source, thiosulfate, over the inoculated surface in order to select a sulfur-oxidizing activity. Thiosulfate was used in the form of an aqueous solution, which facilitated the monitoring of (i) the bacterial activity by sulfur mass balances in the liquid phase, and thus quantification of acid production, and of (ii) the leaching of cementitious ions. Cement-based linings made of (i) blast furnace slag cement and (ii) calcium aluminates cement were tested. Results showed the selection of sulfur-oxidizing bacteria and the production of biogenic acid. Differences were shown between the linings in terms of Ca and Al dissolution. Biomass characterization highlighted the influence of the lining composition on colonization.