Current AffiliationRavi Shankar Kadambala Graduate Student, Solid Waste Research Group Department of Environmental Engineering Sciences University of Florida Gainesville, Florida ravi22k@ufl.edu Back To >> Students's page PhD DissertationDesign, construction, operation and monitoring of a hybrid vertical well leachate recirculation system for a MSW bioreactor.Abstract :A bioreactor landfill operates to rapidly transform and degrade organic waste (US EPA 2007). The increase in waste degradation and stabilization is accomplished through the addition of liquid and air to enhance microbial processes. An effective moisture addition system is a key element in the operation of a bioreactor. Full scale application of bioreactor has been hindered due to the lack of ability to inject liquid uniformly in the waste (Pradeep et al 2005). This most common ways for recirculation of leachate is either by using the vertical or horizontal wells. Verticals wells have a limited liquid distribution and have a potential for flooding the wells resulting in the formation of seeps at the surface of the landfills. Horizontal wells are costly and have to be installed during active disposal of garbage on the landfill cell. Differential settlement can modify the slope of trenches and drains. The first objective of my research is to examine the impact of leachate recirculation into vertical wells on the pore water pressure in the waste in the surrounding area of the landfill. Thus an experiment is proposed to bury pore water pressure transducers at locations surrounding several vertical wells in a landfill, adding leachate to those wells, and measuring the resulting pore water pressures in the surrounding waste. This experiment will enable us to determine the flow pattern of the leachate surrounding the vertical wells and how well the actual landfill data compare to numerical modeling results. The second objective of my proposal is to build a leachate recirculation system that can reduce some of the disadvantages of the vertical well leachate recirculation system, by building a hybrid vertical well leachate recirculation system. In this system, a cluster of vertical wells would be connected to a lateral leachate recirculation line through which the leachate would be injected. More waste will then be placed on top of this hybrid vertical well system. This type of hybrid vertical well system has a number of potential advantages over the conventional vertical wells. This system will allow us to inject leachate under pressure. This would increase the quantity of leachate injected in these vertical wells cluster. This system will not allow seeps to form on top of the landfill due to over flow of leachate through the vertical wells. Less number of pipes would come of the side slope of the landfill. The third objective in my research is to enhance the rate of decomposition using both aerobic and anaerobic methods in this hybrid vertical well leachate recirculation system. All though aerobic decomposition is much faster than anaerobic decomposition it is really difficult to add enough air uniformly to the entire waste to cook aerobically. So it is proposed to only add air into the waste mass initially for an extended period of time. The readily biodegradable materials such as food waste would degrade rapidly due to aerobic decomposition. Aerobic decomposition would decrease when a readily biodegradable material such as food waste is decomposed and air is no longer able to penetrate further through the biodegradable waste mass. Air injection would then be stopped. Leachate would then be injected into the waste. This would stop aerobic decomposition as there would be no oxygen left for the aerobic microorganism to survive. Anaerobic decomposition would then take over resulting in decomposition of the remaining biodegradable waste mass. |
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