Helicobacter pylori Removal through Gravel Filtration in a Water Treatment System of the Municipality of Popayán, Cauca

Abstract

Multi-stage filtration technology (MSFT) is an alternative that reduces the risk of fecal contamination, allowing for reliable water purification in rural water supplies. MSFT is composed of two gravel filtration (GF) stages: one including dynamic gravel filters (DyGF) and up-flow gravel filters (UGF), and a final stage with slow sand filters (SSFs). However, with the purpose of reducing construction costs, this technology is partially implemented, leaving SSFs for a later construction stage and limiting its treatment potential. To evaluate the removal capabilities regarding fecal contamination (especially that by the pathogen H. pylori) of a two-stage GF system, the quality of raw and treated water and the hydraulic parameters of Los Llanos treatment system (municipality of Popayán, Cauca) were monitored for 15 weeks. This system is operated and maintained by the community. The results showed the removal efficiency regarding turbidity to be 16% (p=0,045) and 34% (p=0,030) for the DyGF and the UGF, respectively. The color removed by the DyGF reached 19% (p=0,033), and the UGF reported a value of 30% (p=0,041). The reduction of total coliforms was limited by the system’s operation and maintenance, exhibiting a tendency towards increased concentrations at the outlet. The presence or absence of H. pylori was determined via the PCR molecular technique. A greater presence was evidenced in treated water than in raw one, which may be associated with a limited operation and a low maintenance frequency of the system. The implementation of MSFT, without the complement of SSFs, is not reliable in ensuring quality of water, particularly from a perspective of microbiological control and H. pylori control.