Phosphorus attenuation and mobilization in sand filters treating onsite wastewater.

The effectiveness of phosphorus (P) removal by sand filters is limited during septic tank effluent (STE) treatment. The elevated effluent P concentrations pose threats to drinking water quality and contribute to eutrophication. The concern of P leaching from sand filters is further exacerbated by the increased frequency of flooding and natural precipitation due to climate change.

Potential release of legacy nitrogen from soil surrounding onsite wastewater leaching pools.

This study examined whether the accumulation of nitrogen (legacy nitrogen) within and surrounding leaching pools for onsite wastewater treatment may act as a source of nitrogen contamination to groundwater upon changes to the quantity and/or composition of the influent to the pool. In this study, one concrete leaching pool with neutral pH (A, pH 6.9) and one leaching pool after acid washing (B, pH 3.