Journal of Animal Environmental Science ISSN:1226-0274(Print) 축산시설환경학회지

Bio-gas production offers the dual benefit of livestock manure treatment and energy extraction. However, anaerobic digestate containing residual nutrients like nitrogen and phosphorus lacks defined legal standards posing potential environmental risks if improperly managed. Understanding its physical and chemical characteristics is crucial to prevent soil, water, and air pollution.This study assessed the quality of anaerobic digestates and liquid fertilizers from domestic biogas facilities. Anaerobic digestate had average values of pH 8.21, EC 48.68 mS/cm, NaCl 0.28%, moisture 96.99%, CODCr 20,973 mg/L, SCODCr 8,016 mg/L, T-N 0.53%, P₂O₅ 0.13%, K₂O 0.30%, and total NPK content of 0.95%. NH₄-N was 3911 mg/L, NO₃–N 228 mg/L. Trace elements As, Cd, and Hg were below detection limits; Pb 0.49 mg/kg, Cr 0.89 mg/kg, Cu 13.90 mg/kg, Ni 0.47 mg/kg, Zn 58.21 mg/kg, CaO 1,219.41 mg/kg, MgO 429.11 mg/kg, B₂O₃ 56.76 mg/kg, MnO 11.18 mg/kg, Fe 255.41 mg/kg, Mo 8.56 mg/kg. Liquid fertilizer by anaerobic digestate had pH 8.69, EC 29.74 mS/cm, NaCl 0.23%, moisture 97.46%, COD_Cr 14,022 mg/L, SCOD_Cr 5,710 mg/L, T-N 0.30%, P₂O₅ 0.08%, K₂O 0.27%, total NPK content 0.65%. NH₄-N was 1923 mg/L, NO₃–N 334 mg/L. Trace elements As, Cd, Hg, and Cr were below detection limits; Pb 0.23 mg/kg, Cr 0.76 mg/kg, Cu 9.79 mg/kg, Ni 0.41 mg/kg, Zn 51.78 mg/kg, CaO 693.73 mg/kg, MgO 268.18 mg/kg, B₂O₃ 50.56 mg/kg, MnO 6.63 mg/kg, Fe 190.70 mg/kg, Mo 7.30 mg/kg. Maturity assessment using mechanical disruption indicated "immature or semi-mature" status for most samples. The germination index yielded a value of "0" for all samples.