Kazuhiro Takamizawa, Osamu Yamamoto, Isao Fukunaga, Zensuke Inoue and Atsuhiro Honda

Abstract

Design considerations for leachate treatment process at a sea-based solid waste disposal site are introduced. They include prediction of leachate quality and quantity, establishment of design alternatives and their selection. Leachate is variable in quantity and quality as waste dumping progresses, and also has characteristics of sea water. Leachate quality prediction was performed by an experiential method. Leachate quantity was predicted considering rainwater balance at an existing sea-based solid waste disposal site. Design alternatives were based on the characteristic situation of a sea-based solid waste disposal site and were chosen by design criteria. Finally, a combined process of a facultative pretreatment pond and an aerated lagoon, followed by chemical coagulation, was selected and constructed. Capacities of the facultative pretreatment pond and aerated lagoon are 73,900m3 and 369,000m3, respectively. The aerated lagoon has six floating aerators of 3,600kg O2/day each. Capacities of the chemical coagulation tank using polymerized ferric sulfate and settling tank are 41m3 and 308m3, respectively.

Key words: leachate treatment, sea-based solid waste disposal site, design alternatives, facultative pre-treatment pond, aerated lagoon