Soil Accumulation of N, P, C, and Solids In Marsh-Pond-Marsh Constructed Wetlands Treated with Anaerobic Lagoon Swine Wastewater.

Traditionally swine wastewater is flushed from swine houses into an anaerobic lagoon and sprayed on fields and causing P accumulation in soils. Constructed wetlands treated with anaerobic lagoon swine wastewater have proved to reduce the concentration of nutrients and there by use of less land for wastewater application. However, the sustainability and efficiency of constructed wetlands depends on age of the wetlands, accumulation of solids, detritus, and nutrients. Therefore, constructed wetlands (marsh-pond-marsh) treated with anaerobic lagoon swine wastewater for the past eight years have been investigated for accumulation of C, detritus, solids, N, and P in soils. The amount of TKN, NH4, NO3, P, total P, PO4, and total C were higher in 0-2 cm and decreased with depth. The efficiency of wetlands decreased over years in removal of P. The removal of N is a function of nitrification and denitrification and was slightly affected by the N loads applied to the wetlands. Constructed wetlands proved to be good sinks to treat wastewater.