Abstract

The thermal conductivity of soil is a crucial parameter for designing energy geo-structures, as it determines the rate at which heat can be transferred through a material. This paper explores the influence of the presence of bacteria on soil thermal conductivity. To investigate this, soil samples were collected from four different regions in Gujarat, including Surat, Bhadbhut, Navsari, and Bhuj. A laboratory-scale experimental setup was developed based on the guarded hot plate method to measure the thermal conductivity of soil samples. The microorganisms were isolated from the soil samples using a serial dilution and spread plate method and two types of microorganisms were selected from each soil sample. The isolated microorganisms were introduced into the soil samples and the thermal conductivity was measured after a week of incubation. The thermal conductivity of soil samples was measured for curing periods of 7 days, and the results of thermal conductivity were compared before and after treatment. The results demonstrated that E. coli decreases the thermal conductivity values of sandy soil and S. aureus gives good results for sandy soil compared to clayey soil. The microorganisms isolated from soil were all of the Bacillus family.

Keywords: Thermal conductivity; Micro-organisms; Temperature; Guarded hot plate method; Bacillus