Quantitative Evaluation Methods for Surface Processing Technology Using Microbial Biofilm: Microbial Biofilm on Iron and Steel Slag, and the Effects of Slag Attached Biofilm on pH Buffering Action
Toshiyuki Takahashi, Hotaka Kai, Nobumitsu Hirai
Iron and steel slags are being used, on a trial basis, as environmental remediation agents for marine sediments in rocky coastal waters. In addition to chemical risk such as component leakage of slag into the environment, formation of biofilms is inevitable due to the adhesion of environmental microorganisms to slag surfaces. The transformation of free-living microorganisms into biofilm forms not only alters microbial behavior and various physicochemical tolerances, but also changes the properties of the material. However, the impact and effects of biofilms on materials remain unclear due to the challenges of performing detailed analyses of biofilms on materials such as chemically active slag. Therefore, in this study, slags coated with biofilms were prepared and their chemical effects were investigated to determine whether microbes improve slag function. Furthermore, prior to determining the effects of the slag coated with biofilm, quantitative evaluation techniques for assessing slag biofilms were developed. The review is specifically focused on accurate quantitative evaluation methods for assessing biofilms on slag. Additionally, changes in the chemical properties of slag-coated biofilms are summarized. This technique for modifying slags using microbial biofilm can be applied to the development of novel materials, not only for slag but also for other materials, as material processing and surface treatment technology.