This study reports the incidental collection and exploratory analysis of a biofilm sample obtained from a water distribution pipeline in the Central Province of Sri Lanka, which had been in continuous service for approximately 50 years. Access to the pipe interior was achieved during a repair operation, providing a rare opportunity to directly sample an aged pipeline under the typical operating conditions of a tropical, developing country. An exploratory research design was adopted to examine the bacterial community composition and was explicitly framed as hypothesis-generating rather than testing predefined hypotheses. Bacterial community composition was analyzed using high-throughput MiSeq sequencing. At the genus level, the community was strongly enriched with Clostridium sensu stricto lineages, notably type 1 (relative abundance of 9.19%), type 12 (8.58%), and type 9 (3.09%). Several other genera, Nitrospira (4.94%), Bacillus (4.60%), Methyloligobacillus (3.75%), Hyphomicrobium (2.14%), and Haliangium (1.82%), occurred at moderate abundances, raising their potential consequences on biological and chemical water quality issues. Given the exploratory nature of the study, these findings represent site-specific biofilm characteristics in an aging drinking water distribution line in Sri Lanka. Although limited to a single biofilm sample, this study provides empirical observations from a rarely accessible environment and identifies knowledge gaps to guide future comprehensive investigations into biofilm dynamics, microbial ecology, and infrastructure management in tropical water distribution systems.
Gunawardana et al. (Wed,) studied this question.