Coupled effect of microbiologically induced calcium carbonate and biofilms in leachate

Abstract

Fouling and clogging are persistent challenges to the collection and treatment of leachate. The main components of fouling and clogging are calcium carbonate (CaCO₃) and biofilms. However, the relationships between CaCO₃ and biofilms remain to be clarified. In this study, the interaction between microbially induced CaCO₃ precipitation (MICP) and biofilms was investigated using Luria-Bertani (LB) or urea media. Results showed that the bacteria promoted the precipitation of CaCO₃ and the formation of a complex mixture of biofilms. The amount of formed CaCO₃ in the urea medium was 12.9 times of that in the LB medium. The high MICP potential in the urea medium was associated with increased pH and alkalinity. In addition, the clogging materials exhibited a layered structure and uneven distribution over the clogging width and depth profile. These results indicated the presence of nucleation sites of CaCO₃ on the surface of and inside the bacteria. This research provides insights into the regulation of MICP and biofilms through dynamic control of clogging and fouling.

Keywords: Alkalinity; Biofilm; Calcium carbonate; Fouling; Leachate.