음식폐기물바이오차의 염분 제거 및 농업적 활용

Abstract

Food waste (FW) emissions in South Korea amounted to 4.77 million tons in 2021, and continue to increase. Various technologies have been developed to treat FW, with recent research focusing on biochar production through pyrolysis to reduce FW. However, the agricul tural application of food waste-biochar (FWBC) is lim ited by the salt accumulated during pyrolysis. This study investigated salt removal from and the kinetic characteristics of FWBC, and subsequently evaluated its agricultural applications. FW was pyrolyzed at 350°C for 4 h, and subsequently washed for 0.1, 0.25, 0.5, 0.75, 1, 5, 15, and 30 min to remove salt. FWBC had a salt concentration of 5.75%, which was effectively removed through washing. The salt concentration de creased rapidly at the beginning (1 min) and then slowly decreased, unlike in FW, in which the salt decreased continuously and slowly. The salt removal speed con stant (K) was 1.5586 (Stage 1, FWBC) > 0.0445 (Stage 2, FWBC) > 0.0026 (FW). In a lettuce cultivation ex periment, higher biomass was achieved using washed FWBC than when using unwashed FWBC and FW, and soil properties were improved. Overall, these findings suggest that although FW reduction using pyrolysis causes a salt accumulation problem, the salt can be ef fectively removed through washing. The use of washed FWBC can enhance plant growth and soil properties.