Location
Leeds, West Yorkshire, LS2 9JT, United Kingdom
Event Website
https://engineering.leeds.ac.uk/icdcs2018
Keywords
artificial sewage; biofilm; concrete; microbial corrosion; pore structure; strength
Abstract
In this study, the artificially intensified sewage with different levels of chemical oxygen demand (COD) were prepared, and the changes in weight and strength, as well as the micro morphology, mineral compositions and pore structure of concrete specimens immersed in the artificially intensified sewage and water were investigated in comparison. In parallel, the COD, pH, H2S and O2 values, as well as the microbial species and contents of sewage were monitored in the corrosion process. Furthermore, the microbial structure and activities within biofilm developed on concrete surface were also analyzed. The results indicated that the increase of COD concentration of sewage from 300 to 9000 mg/L led to the decline of sewage pH from 6.4 to 2.3 and increase of biofilm thickness from 300 to 800 μm, as well as the substantial growth of dominant microorganisms (Bacteroidete, Proteobacteria, etc.). The drop of pH level and O2 concentration within biofilm also indicated the high activities of sulfate-reducing and sulfur-oxidizing reaction. Correspondingly, after 150 days of immersion both the mass loss and strength decline rate of concrete increased from 0.32% to 1.78% and from 10.6% to 31.7%, respectively. Furthermore, the microstructure of the specimens in sewage became loose and porous. The CH content of specimens in sewage was significant lower than that of specimens in water, and both the cumulative mercury quantity and harmful macropore proportion of specimens in intensified sewage were significantly larger than that of specimens in water, which indicated the chemical reaction between CH and some acid substance. Overall, the sewage concentration increased by 30 times can triple the corrosion rate of concrete. The results obtained are expected to explore a fast and realistic method to simulate the concrete corrosion in full flow sewer pipes.
Included in
Study on accelerated microbial corrosion of concrete by artificially intensified sewage
Leeds, West Yorkshire, LS2 9JT, United Kingdom
In this study, the artificially intensified sewage with different levels of chemical oxygen demand (COD) were prepared, and the changes in weight and strength, as well as the micro morphology, mineral compositions and pore structure of concrete specimens immersed in the artificially intensified sewage and water were investigated in comparison. In parallel, the COD, pH, H2S and O2 values, as well as the microbial species and contents of sewage were monitored in the corrosion process. Furthermore, the microbial structure and activities within biofilm developed on concrete surface were also analyzed. The results indicated that the increase of COD concentration of sewage from 300 to 9000 mg/L led to the decline of sewage pH from 6.4 to 2.3 and increase of biofilm thickness from 300 to 800 μm, as well as the substantial growth of dominant microorganisms (Bacteroidete, Proteobacteria, etc.). The drop of pH level and O2 concentration within biofilm also indicated the high activities of sulfate-reducing and sulfur-oxidizing reaction. Correspondingly, after 150 days of immersion both the mass loss and strength decline rate of concrete increased from 0.32% to 1.78% and from 10.6% to 31.7%, respectively. Furthermore, the microstructure of the specimens in sewage became loose and porous. The CH content of specimens in sewage was significant lower than that of specimens in water, and both the cumulative mercury quantity and harmful macropore proportion of specimens in intensified sewage were significantly larger than that of specimens in water, which indicated the chemical reaction between CH and some acid substance. Overall, the sewage concentration increased by 30 times can triple the corrosion rate of concrete. The results obtained are expected to explore a fast and realistic method to simulate the concrete corrosion in full flow sewer pipes.
https://docs.lib.purdue.edu/icdcs/2018/pse/13
