University of Illinois at Chicago, Ph.D.
EREF Scholar 2018
Numerical Modeling of Temperature Effects on Geosynthetic Interfaces in Landfill Liners
Heat generation and elevated temperatures in municipal solid waste landfills, resulting from biodegradation and other inorganic reactions within the waste, are currently a huge concern for landfill owners as it poses serious challenges for safe and effective management of landfills. Temperatures within the waste affect several aspects of landfill management such as the gas generation quality and quantity, leachate quality, waste’s mechanical properties, landfill slope stability and waste settlement. In addition, the long-term stability and integrity of the landfill lining systems, which is often dictated by the interface shear strength of geosynthetic components (e.g. geomembrane, geotextile) is jeopardized by waste temperatures, since the interface shear strength characteristics (e.g. strength, stiffness, friction angle) of the geosynthetic components are temperature sensitive. Now, with the advent of leachate recirculating landfills (also known as bioreactor landfills) the heat generation and temperatures within the landfills may be further exacerbated due to rapid and enhanced waste decomposition rates. In this regard, there is a need for a numerical model that can realistically simulate the evolution and distribution of heat and temperature within the landfill and consequently aid in evaluating the influence of waste temperatures on the interface shear behavior of geosynthetic components in a liner system. Over the years, several researchers have published numerical models to simulate coupled interactions (e.g. fluid flow, mechanics, biochemical reaction kinetics) within the waste. However, these coupled models neglected the effect of heat generation and temperature distribution on waste decomposition and also did not account for the interaction of the waste with the geosynthetic interfaces in the liner system as it degrades.
Girish is working with his academic advisor Prof. Krishna Reddy at UIC on a NSF- funded project to develop a practical and reliable coupled thermo-hydro-bio-mechanical model that can enable safe design and operation of stable, effective and sustainable engineered landfills, thereby minimizing immediate as well as long-term risks to the environment and public health. One of the major objectives of his research is to expand the application of the experimental findings on the performance of geosynthetic liner interfaces till date and realistically analyze the complex interaction between the waste and the geosynthetic interfaces by incorporating the effects of heat generation and waste temperature in the conventional and bioreactor landfills, using the developed coupled numerical model. The results from this study will enable the landfill design professionals and landfill owners to analyze the impacts that the temperature has on the long-term performance of the liner system thus providing insights into design considerations for lining systems with potential exposure to high waste temperatures.
Girish Kumar was born and brought-up in India. He graduated with a Bachelor of Technology Degree in Civil Engineering in May 2015 from the National Institute of Technology Karnataka (NITK) in India, where he enjoyed building sand castles along the university owned private beach. He then joined the University of Illinois at Chicago (UIC) as a doctoral student with a Civil Engineering major in January 2016 and is currently a 3rd year Ph.D. student in the Department of Civil and Materials Engineering at UIC. His research at UIC is primarily focused on a NSF-project dealing with fundamental characterization and numerical modeling of the coupled processes in bioreactor landfills. He anticipates to bid goodbye to his fellow lab colleagues in December 2020.
Girish also assists his lab colleagues working on another NSF funded project that involves mitigating landfill gas emissions using steel slag amended biocover systems. The project proposes an innovative, low-cost and practical biogeochemical cover system that utilizes biochar to oxidize landfill methane emissions into carbon dioxide and subsequently sequester carbon dioxide via mineral carbonation using steel slag, thus rendering zero emissions through landfill covers. As the President of the Sustainable Remediation Forum student chapter at UIC, Girish is constantly engaged beyond the walls of the laboratory by organizing expert lectures and seminars from academicians and industry professionals to keep himself aware of the technical know-how of different fields.
Girish is a foodie, enjoys traveling/trekking to explore new places and make new friends.