Takayuki Shimaoka*, Mineki Suematsu**, Sangchul Park*** and Masataka Hanashima*

* Department of Civil Engineering, Faculty of Engineering, Fukuoka University
** Designing Department, Technical Center, OYO Corporation
*** Department of Civil Engineering, Faculty of Engineering, Kyushu University

+ Correspondence should be addressed to Takayuki Shimaoka:
(8-19-1 Nanakuma, Johnan-ku, Fukuoka 814-80 Japan)

Abstract

In order to elucidate the mechanism of self-purification in solid waste layers under recirculatory semi-aerobic landfill conditions, experiments were performed with lysimeters simulating, semi-aerobic landfills with or without recycling leachate, and the numerical simulations for the behavior of leachate organic carbon and nitrogenous components in solid waste layers under recirculatory semi-aerobic landfill conditions were carried out. Data from the experiments indicated that, in a solid waste layer, the depths where the biodegradation of nitrogenous components by nitrification and denitrification occurred, were very different among the semi-aerobic landfill type and the recirculatory semi-aerobic landfill type. The observed concentrations of organic carbon and nitrogen in the leachate were simulated with comparatively good coincidence by two Liquid Regions Models dividing the liquid phase in a solid waste layer into the stream region and stagnant one.

Key words: recirculatory semi-aerobic landfill, pollutants, denitrification, self-purification, numerical simulation