In this study, the characteristics of a small-scale piggery wastewater were investigated, and experiments were performed for the treatability of the waste by using a septic tank soil trench system. Results of the research showed that the average BOD, SS, TKN and TP concentrations of a piggery wastewater were 1,530, 1,236, 562 and 85㎎/ℓ, respectively. The average BOD removal efficiency of the septic tank was determined to be 55% and it was noticed the efficiency was greatly influenced by temperature. It was also found that the average BOD removal efficiencies were 68% for type I soil trench and 78% for type B.