Phosphate Treatment by Five Onsite Wastewater Systems in a Nutrient Sensitive Watershed

Excess phosphate (P) loading to surface waters increases productivity sometimes causing an imbalance leading eutrophication and water quality degradation. Wastewater contains elevated concentrations of P other contaminants that pose threats environmental health. Onsite wastewater systems (OWS) are used in many rural areas, but most not monitored for removal effectiveness. The goal this research was gain a better understanding the treatment efficiency OWS nutrient-sensitive watershed. Groundwater monitoring infrastructure, including networks wells piezometers, installed at five sites with coastal North Carolina. samples from piezometers septic tanks were collected analyzed physicochemical parameters. Results suggest significant reductions (79.7 99.1%) occurring soil immediately beneath drainfield trenches, groundwater near more than 35 downgradient alike significantly relative background concentrations. areas sandy soils such as Hoods Creek watershed may be sources water. Nutrient management policies watersheds should include provisions assessing reducing contributions waters.