Controls on nitrogen export to an ephemeral stream network of St. Croix, US Virgin Islands.

Ephemeral streams are important pollutant conduits, but the mechanisms that control nutrient transport to these systems remain unclear. In the US Virgin Islands (USVI), where most streams flow ephemerally, a lack of continuous hydrologic and water quality data limits our understanding of streamflow behavior and its influence on water quality. We therefore assessed the impact of soil moisture and hydrometeorological conditions on nitrogen (N) concentrations within an ephemeral stream on St.

Greenhouse gas emissions from advanced nitrogen-removal onsite wastewater treatment systems.

Advanced onsite wastewater treatment systems (OWTS) designed to remove nitrogen from residential wastewater play an important role in protecting environmental and public health. Nevertheless, the microbial processes involved in treatment produce greenhouse gases (GHGs) that contribute to global climate change, including CO, CH, NO. We measured GHG emissions from 27 advanced N-removal OWTS in the towns of Jamestown and Charlestown, Rhode Island, USA, and assessed differences in flux based on OWTS technology, home occupancy (year-round vs.

Comparison of N2O Emissions and Gene Abundances between Wastewater Nitrogen Removal Systems.

Biological nitrogen removal (BNR) systems are increasingly used in the United States in both centralized wastewater treatment plants (WWTPs) and decentralized advanced onsite wastewater treatment systems (OWTS) to reduce N discharged in wastewater effluent. However, the potential for BNR systems to be sources of nitrous oxide (NO), a potent greenhouse gas, needs to be evaluated to assess their environmental impact. We quantified and compared NO emissions from BNR systems at a WWTP (Field's Point, Providence, RI) and three types of advanced OWTS (Orenco Advantex AX 20, SeptiTech Series D, and Bio-Microbics MicroFAST) in nine Rhode Island residences ( = 3 per type) using cavity ring-down spectroscopy.