Design of Multi-Story Sewage Treatment Facilities

Abstract

In Osaka City, due to rises in land prices and the rapid advances of urbanization, it is difficult to enlarge sites for sewage treatment facilities. To enhance efficient land utilization, construction of multi-story facilities has been promoted. This effort commenced with the building of a two-story primary settling tank, followed by two-story final settling tanks, aeration tanks vertically combined with final settling tanks and three-story final settling tanks. Together with the introduction of these multi-story facilities, efforts have also been made to further deepen the aeration tanks. One of the features of the city's multi-story sewage treatment facilities is the use of outlet pipes for purified wastewater in the final settling tanks. This has helped promote introduction of multi-story facilities. These multi-story facilities in Osaka City have already been in operation for ten to twenty years under satisfactory treatment conditions. The area occupied by a multi-story structure is only 46% that of conventional single-story structures. Construction cost for single- and multi-story structures is almost equal.