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The Jelutong Sewage Treatment plant on Penang Island caters to an ultimate capacity of 1.2 million population equivalent. The facility serves as a centralized sewage treatment plant and includes 12 nos. of Sequential Batch Reactor tanks and associated Process Tanks.
The soils are primarily soft marine clay deposits up to 10m depth. A third of the site was covered by an old domestic landfill. The original foundation design was piled foundation but this was later found to present a few undesirable construction limitations like noise pollution during pile driving; pre-boring and removal of landfill material; and transportation and storage of pre-cast piles on a congested site.
Keller introduced optimised foundation systems to support major process tanks and other infrastructure facilities using ground improvement techniques. Vibro Concrete Columns were constructed in the landfill area, forming concrete pile-like elements (with working loads up to 50Tons) by displacing the rubbish rather than requiring removal. Likewise, Deep Soil Mixing columns were constructed in the marine clay outside the landfill area which increased strength of marine clay by more than 40 times. For other lighter tank structures, Vibro Stone Columns were utilized similarly. In total, more than 20,000 columns were built with these methods, reaching a maximum depth of 15m.
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