Linking human health, climate change, and food security through ecological-based sanitation systems

Abstract:

Ensuring access to clean, safe sanitation for the world’s population remains a challenging, yet critical, global sustainability goal. Ecological-based sanitation (EcoSan) technology is a promising strategy for improving sanitation, particularly in areas where financial resources and infrastructure are limiting. The composting of human waste and its use as an agricultural soil amendment can tackle three important challenges in developing countries – providing improved sanitation for vulnerable communities, reducing the spread of intestinal-born pathogens, and returning nutrients and organic matter to degraded agricultural soils. The extent of these benefits and potential tradeoffs are not well known, but have important implications for the widespread adoption of this strategy to promote healthy communities and enhance food security.

We quantified the effects of EcoSan on the climate and human health in partnership with Sustainable Organic Integrated Livelihoods (SOIL) in Haiti. We measured greenhouse gas emissions (nitrous oxide, methane, and carbon dioxide) from compost piles that ranged in age from 0 to 14 months (i.e. finished) from two compost facilities managed with or without cement lining. We also measured emissions from a government-operated waste treatment pond and a grass field where waste has been illegally dumped. The highest methane emissions were observed from the anaerobic waste pond, whereas the dump site and compost piles had higher nitrous oxide emissions. Net greenhouse gases (CO₂-equivalents) from unlined compost piles were 8x lower than lined compost piles and 20 and 30x lower than the dump and waste pond, respectively. We screened finished compost for fecal pathogens using bacterial 16S sequencing. Bacterial pathogens were eliminated regardless of the type of composting process. Pilot trials indicate that the application of compost to crops has a large potential for increasing food production. This research suggests that EcoSan systems are effective at achieving multiple sustainability goals including the provision of sanitation, mitigating climate change, and increasing food security.