Evaluation of Overland Flow Treatment for Swine Lagoon Effluent

Overland flow, on slopes of 5 and 11%, was used as a means of treating wastewater effluent from the second cell of a swine waste anaerobic lagoon system. Wastewater samples from both surface runoff and soil percolate (depths of 0.3, 0.9, and 1.5 m) were collected and analyzed for TKN-N, NH4-N, ON-N, NO3-N, pH, COD, K, EC, and TP-P. Using these data, along with the hydraulic loading rates and quantitative runoff collection, mass balances on the above parameters were calculated to determine the surface treatment of the lagoon effluent. These mass balances suggest that overland flow is an excellent treatment system for liquid lagoon effluents with mass reductions of greater than 60% for all parameters on both slopes, except NO3-N, which had an approximate increase of 1.7 times on the 11% slope. Samples collected from the three lysimeter depths (soil percolate) suggest that NO3-N leaching from the plots may be a concern over an extended period of use. The runoff from overland flow systems of this type will require further treatment.