Microbiome analysis of landfill leachate samples sourced from Powerstown landfill Co. Carlow

Abstract

Little is known about the microbial ecology of closed landfill, or how the diversity of these communities changes over time. This study focuses on the bacterial community diversity analysis of landfill leachate (LFL) sourced from Powerstown landfill Co. Carlow, Ireland. The LFL samples used in this study came from both closed and active landfill, and represent different phases of the landfill. HiSeq sequencing systems based 16S rRNA gene sequence analysis was used to investigate the bacterial communities of a total of six LFL samples; four samples from landfill cells (two from closed landfill cells and two from active landfill cells), and two samples sourced from a leachate tank (LT) collected over an interval of 2.5 years. Members of the phylum Proteobacteria (Pseudomonadota) were dominant in all landfill samples investigated (56 to 71%), followed by Bacteroidetes (Bacteroidota) (7 to 21%). The operating status of landfills (i.e. active / closed) and the age of landfill were found to affect the bacterial composition of LFL. Members of the class Epsilonproteobacteria and genus Sulfurimonas were dominant in LFL from active landfill, while the class Betaproteobacteria and genus Pusillimonas were dominant in closed landfill. Furthermore, it was observed that the composition of the microbial community in active landfill showed fluctuation by the progressing landfill age, while the bacterial composition of closed landfill tends to be stable as the year the landfill is closed.