BASIC LANDFILL BIOREACTOR KINETIC MODEL

摘要

During the past few years, the concept of the "landfill as a bioreactor" has received considerable attention both in academic circles as well as from private and public landfill owners. Among other things, it is suggested that operating a landfill as a "bioreactor" has the potential to 1) reduce leachate treatment. needs; 2) increase landfill gas (LFG) production; 3) increase waste density, resulting in more air space; and 4) potentially decrease long term monitoring requirements. Concurrently, the recirculation of leachate and possible nutrient addition presents certain issues and problems that need to be addressed, which are a result of "bioreactor" operation. These potential problems include odor control, waste stability issues, side slope leachate breakouts, differential settlement and other issues. The common thread of both the positive and negative aspects of "bioreactors" is that they are the result or product of an attempt to: 1. Accelerate the biological decomposition process. 2. Which involves changing the reactor kinetics and creating more landfill gas. 3. The more landfill gas created and removed, the less mass remains in the landfill. 4. This results in higher waste density and more air space, and 5. Lower risk of groundwater pollution. This paper considers the practical implications of the basic bio-chemical processes, concepts and kinetics that are taking place in a landfill, and places them in context with the goals espoused for accelerating these processes in a "bioreactor". The basic components of the biological process are set into motion by bringing the organic fraction of the waste as a carbon source, into contact with water and possibly nutrients, in the presence of biological organisms. Reactions occur which subsequently release carbon dioxide and methane (landfill gas), which, when extracted, represents a large tonnage of converted waste material leaving the reactor.