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### History of Waste Management - Kagawa Prefecture - April 2007 to the 2020s #### 2007: Technology Development and Introduction In 2007, Ikeda Construction Industry Co., Ltd. in Kagawa Prefecture developed a technology to solidify and improve dredged sediment generated at construction sites. This technology enabled the reuse of approximately 10,000 tons of dredged sediment annually as construction materials like roadbed fill, reducing costs by about 30% compared to conventional disposal methods. It also succeeded in reducing carbon dioxide emissions, drawing attention as a model case for recycling construction waste generated within Kagawa Prefecture. The technology was rolled out across the region, receiving high praise from local governments and the construction industry.

#### 2010s: Expanding Application Scope During the 2010s, the application scope of this technology expanded throughout Kagawa Prefecture. Ikeda Construction Industries collaborated with local municipalities to promote its use at port and river dredging sites. Furthermore, improvements to the gypsum-based soil improvement solidifying agent enhanced processing efficiency. During this period, approximately 12,000 tons of dredged sediment were reused annually within Kagawa Prefecture, widely utilized in both public and private construction projects. Additionally, the stabilization of the improved soil's quality facilitated its use in diverse applications, such as road construction and embankment reinforcement projects.

#### 2020s: Technological Evolution and Expansion In the 2020s, Ikeda Construction Industries introduced new high-concentration thin-layer dredgers and pump vessels, achieving greater efficiency in dredging operations. The use of gypsum-based soil improvement solidifiers enabled homogeneous modification of dredged sediment, allowing for immediate removal and early reuse. This technology recycles over 10,000 tons of sediment annually, simultaneously reducing processing costs and environmental impact. Furthermore, Kagawa Prefecture established the "Kagawa Prefecture Construction Waste Recycling Guidelines," promoting Ikeda Construction Industry's technology throughout the prefecture.

#### Future Outlook Kagawa Prefecture anticipates further technological innovation and expanded local recycling. Ikeda Construction Industries plans to develop new construction materials utilizing the improved soil and aims to increase annual processing capacity to 15,000 tons. This initiative will continue to draw nationwide attention as an advanced model case for realizing a sustainable society.