Deciphering acyl-homoserine lactones-mediated quorum sensing on geotextile bio-clogging in municipal solid waste and bottom ash co-disposal landfills

Abstract

Bottom ash co-disposed in landfills accelerates geotextile clogging and decreases landfill stability. As the main contributor to clogging, bio-clogging may be associated with quorum sensing (QS) in microbial communities. This study investigated the potential roles of acyl-homoserine lactones (AHLs)-mediated QS in geotextile bio-clogging under different landfill conditions, including municipal solid waste landfill and bottom ash co-disposal landfill. The unit area of geotextile bio-clogging mass in the municipal solid waste landfill (MSW_G) ranged from 5.2 × 10-3 to 8.2 × 10-3 g/cm2, while it was in the range of 8.4 × 10-3 to 1.2 × 10-2 g/cm2 in the bottom ash co-disposal landfill (BA_G). Two types of AHLs were detected and the total AHLs content in the MSW_G (1,616.9 ± 103.8 ng/g VSS) was half of that in the BA_G (3,233.0 ± 646.8 ng/g VSS). High contents of the AHLs could increase bio-clogging. The bio-clogging was also attributed to QS genes and extracellular polymeric substances (EPS). EPS aggregation was stimulated due to the higher Ca2+ and Mg2+ in the BA_G. These results suggested that the co-disposal of bottom ash could increase the AHLs content, resulting in accelerated bio-clogging.