New Performance-Based Passive Septic Tank Underground Drainfield for Nutrient and Pathogen Removal Using Sorption Media

Abstract Removal of nutrients and pathogens in wastewater effluents is very important for the sustainability of the aquatic ecosystem and environment. On-site sewage treatment and disposal systems commonly referred as septic systems are one of the major sources of nutrients and pathogens in groundwater systems. Drainfields in septic tank systems are normally located in permeable, unsaturated natural soil or imported fill material so that wastewater can infiltrate and percolate through the underlying soil to the groundwater for final disposal. In the past, removal of nutrients in these conventional drainfields was too low to meet the water quality requirements. This article presents a new passive underground drainfield of innovative design with soil amendments (sorption media) for nutrient and pathogen removal in a field-scaled septic tank system. This new system, which is filled with green sorption media consisting of recycled materials mixed with naturally occurring materials, was fully tested in both Ph...