Abstract Passive wastewater treatment systems are widely used in the Arctic, but studies addressing the vadose zone dynamics that influence the operation and performance of subsurface or soil‐based infiltration systems, such as rapid infiltration basins, are rare. In Fort Good Hope, a community of 628 inhabitants situated on the banks of the Mackenzie River, Northwest Territories, Canada, wastewater is collected by trucks and discharged into a trench where it quickly infiltrates into the ground. A comprehensive year‐round study was conducted to assess the system operation and treatment performance, including soil and water sampling and analysis for physical, chemical, and microbial indicators, and continuous monitoring of soil moisture and temperature at multiple locations and depths in the vadose zone. The site is characterized by deep permafrost, highly permeable soil, and a thick unsaturated zone. These conditions result in satisfactory system performance under harsh operating conditions. Freeze‐thaw processes may help enhance or partially restore soil hydraulic conductivity, and cold‐adapted bacteria genera involved in non‐traditional nitrification‐denitrification pathways were found. Among the contaminants of interest, the accumulation of nitrate in groundwater is the most prominent concern. The research findings provide novel insights into vadose zone dynamics and the key processes and concerns involved in the operation and performance of soil‐based wastewater treatment systems in the Arctic.
Boratto et al. (Sun,) studied this question.