Ecological Risk Assessment of Using Swine Wastewater for Agriculture

Abstract

The environmental consequences of swine farming are of increasing public concern particularly from waste and waste water. Environmental risk assessment is a key tool to deal with concerns from wastewater reuse by land application.The aims of this study were to evaluate: (i) the diffuse pollution from swine farm, in terms of water quality parameters in effluent and copper contamination due to the application of swine waste water in different Thai soil series; and (ii) the impact of copper in swine wastewater on soil biota activity (soil respiration and earthworm avoidance behavior). The results found that wastewater effluent had average BOD, COD,TDS, Total N, pH and EC at 467, 320, 3950, 0.048 mg/L, 7.8 and 4.5 dS/m, respectively, and average copper concentration of 0.05-0.28 mg/L. Copper contamination was analyzed in two Thai soil series (Roi et (Re) and Namphong (Ng) soil series) after application of the swine wastewater. The results showed that copper level in the Roi et soil series was higher than for Namphong soil series but the copper concentration in leachate from two soil series was the opposite. Soil microbial activity in soil receiving application of swine wastewater was greater than found for the control plot (without applying swine wastewater). The 50% avoidance behavior of earthworm on copper (EC₅₀) in the Namphong (Ng) and Roi et (Re) soil series were 153and 61 mg/kg soil at 7 days. In conclusion, the land application of swine waste water effluence should consider the ecological risks and impact on soil ecosystem from different soil ecosystems as a basis for land management.