Yasushi Matsufuji* and Ayako Tachifuji*
*Faculty of Engineering, Fukuoka University
+ Correspondence should be addressed to Ayako Tachifuji:
(8-19-1, Nanakuma, Jonan-ku, Fukuoka, 814-80 Japan)
Abstract
Recently much attention has been focused on the problems of global warming due to greenhouse gases, notably carbon dioxide and methane. Because these gases cause serious problems to the global environment, their generation from landfill sites containing solid wastes has drawn considerable attention and their environmental impact has caused major concern.
At present there is no basic data available concerning gases generated by the biodegradation of solid wastes in landfills. Specifically, no assessment has been made concerning greenhouse gases from different landfill types. The purpose of this study was to develop a prediction formula for estimating the gasification rate by different landfill types. The formula is based on the measurement data for a long-term aerobic and anaerobic material balance, obtained from two large-scale lysimeters. This paper will also give the semiaerobic type conversion effect on the reduction of gas generation using the Sheldon Arleta equation. From these results, we proposed countermeasure for their reduction.
The main results obtained was as follows; 1) Prediction formulas for gas generation from each landfill type can expressed by a regression cumulative gasification rate curve, related to easily degradable organic matter; 2) Based on the formulas, the amount of greenhouse gases generated from the semiaerobic type of landfill is 54% less than that from the anaerobic one; 3) The conversion of landfill type from anaerobic to semiaerobic type can reduce the amount of greenhouse gases generated from the landfill; 4) As obtained by the Sheldon Arleta equation, the total amount of landfill methane generation in Japan is 0.32 Mt%C/year, corresponding to 21.8%-34.4% of Japan's total methane generation.
Key words: global warming, greenhouse gases, solid waste, landfill type, semiaerobic type