LAUSR

ABSTRACT This research aimed to study the effectiveness of heat transfer in soil using the underground release of hot water with a hydraulic head. Pressure heads of 1.0, 1.5 and 2.0 m were utilized for underground release with a nozzle to investigate heat transfer in soil necessary to inhibit microbial growth through underground hot water release using a pressure head of liquid. The nozzle was made of stainless steel pipe (SUS304). The proposed system was designed to inhibit microbes of Ralstonia solanacearum with a hot water volume flow of 300, 400 and 500 ml min−1, while temperature was kept constant at 70 ºC. The hot water released underground provided higher soil temperature with shorter working time. The research found that the number of layers and diameter of drilled holes had a significant effect on soil temperature distributed at various depth levels (y-plan), resulting in enhanced performance (100%) for the inhibition of microbes in an x-plan radius of 15 cm for a shorter time of 20–30 min with one nozzle.