RESUMO
Coastal wetlands and estuaries are impacted by nutrient loads from a variety of sources including infrequently occupied hunting and fishing camps. The marshland upwelling system (MUS) was designed to treat wastewater in the coastal environment where traditional septic systems or centralized wastewater collection and treatment are not viable. A laboratory macrocosm study was designed to simulate field conditions in which domestic wastewater is treated via injection into a marsh subsurface. Treatment of wastewater nitrogen (N) utilizing the MUS was examined under high (â¼20â ppt) and low (â¼2â ppt) salinity conditions. Two N wastewater solutions were used, one treatment consisted of 100â mg NH4-Nâ L-1, while a second treatment consisted of 80â mg NH4-Nâ L-1/20â mg NO3-Nâ L-1. The 20â ppt salinity treatment was found to have a negative impact on NH4-N sorption. The potentially mineralizable N rate was higher in the low salinity treatment, which could potentially be offset by the higher sorption capacity at lower salinities. The background salinity of the local groundwater should be considered as the salinity will play a role in the longevity of the system.