Development of state of art test setup to measure thermal conductivity of soils infused with treated and un‐treated natural microorganisms

Abstract

Soil is a natural heterogeneous material and from its formation process, heat transfer capacity (thermal conductivity) of soil is playing vital role in many engineering applications. The aim of this research study is to enhance thermal conductivity using natural and treated bacteria from soil samples procured from four different regions namely Dholera, Navsari, Sabarmati River, and Madhavpur of Gujarat, India. To fulfill this objective, thermal conductivity test set‐up was indigenously developed based on guarded hot plate method and is calibrated up to 150°C temperature. The colonies of microorganisms available in soil were studied by serial dilution and spread plate technique. Further, influence of microorganisms on soil structure aggregation pre and post treatment was analyzed by microscope. Four types of microorganisms were introduced in the soil and the thermal conductivity of sample is measured for curing period of 7, 14, 21, and 28 days. The results indicate increment in k value for thermal conductivity in clayey soil up to 26.67% and decrement in sandy soil is up to 45.45%, while most optimum results were observed for 7 days curing period. Present research demonstrates use of microbes available in various soils to enhance heat transfer mechanism through proper identification and treatment.