In situ treatment technologies for pit latrines to mitigate groundwater contamination by fecal pathogens: a review of recent technical advances

Abstract

On-site sanitation systems such as pit latrines are extensively used around the world, while there is a growing number of evidence documenting the impact of pit latrines on groundwater quality that may affect human health. Hence, this paper summarizes the various safe-sanitation technologies by broadly categorizing them into fecal pathogen disinfection methods (anaerobic digestion, chemical disinfection, biological additives, solar pasteurization and vermicomposting) and capturing methods (pit lining and permeable reactive barriers, the latter of which simultaneously capture and sanitize fecal sludge in pit latrines). While some of the reviewed technologies have been widely practiced for mitigating microbial contamination of the groundwater, others are still in the early stage of commercialization and field validation. Though there are challenges to the selection and adoption of the most appropriate technology, this paper discusses the readiness of each technology as a stand-alone fecal sludge management solution. HIGHLIGHTS Pit latrines impact groundwater quality that may affect human health.; Low-cost treatment techniques are discussed to capture and treat pathogens in pit latrines.; Pit liners such as peat, clay, hydrophobic membranes and permeable reactive barriers help capture pathogens.; When compared with other methods, the chemical disinfection method with chlorine, lime, Ikati and Soda ranked best with the highest score.;

Keywords

• fecal pathogen
• groundwater contamination
• pit latrine
• pit lining
• sludge treatment