PROBLEM TO BE SOLVED: To provide a soil aggregate which is suitable for improving bottom sediment of various water areas including seaweed bed.SOLUTION: An improver system 3 containing a double-shaft stirring blade 5 is held at the tip of a ladder 2 extending from a workboat 1. The improver system 3 is sunk to water bottom, and an aqueous solution containing an aggregating agent and an adsorption carrier carrying a hydroxy metal ion is supplied to the improver system 3 from a first mixer 11 mounted on the workboat 1 and mixed with bottom mud S of the bottom sediment to promote aggregation of the bottom mud S. After the aggregation has moderately progressed, an aqueous solution containing a solidifier is supplied to the improver system 3 from a second mixer 12 mounted on the workboat 1 to promote further aggregation and solidification and replace the bottom sediment with the water-resistant soil aggregate.COPYRIGHT: (C)2006,JPO&NCIPI【課題】藻場はもちろん、各種水域の底質の改良に向けて好適な団粒土を提供する。【解決手段】作業船1から延ばしたラダー2の先端に、2軸の撹拌翼5を内装した改良装置3を持たせ、この改良装置3を水底に降ろした状態で、作業船1上に設置した第1混合機11から団粒化剤とヒドロキシ金属イオンを担持した吸着担体とを含む水溶液を前記改良装置3内に供給して、底質の底泥Sと混合し、底泥Sの団粒化を促進する。そして、適当に団粒化が進んだ段階で、作業船1上に設置した第2混合機12から固化剤を含む水溶液を改良装置3内に供給して、団粒化をより一層促進させると共に固化を進め、底質を耐水性を有する団粒土で置換する。【選択図】図1
