Urban renewal projects generate substantial volumes of solid waste, making effective resource utilization critical for sustainable development. This study addresses a significant gap in circular economy research by quantifying both the economic and carbon-sequestration benefits of synergistic, multi-type solid waste utilization (SWU) within a renewal context. Using the Hefei Garden Expo Park renewal project as a case study, this research applies circular economy theory, cost‒benefit analysis, and the market value method to assess the economic value of in situ solid waste utilization and the carbon sequestration potential of the resulting green space. The results demonstrate that synergistic utilization of soil, construction, and plant waste generates substantial cost savings compared with conventional disposal, with soil waste contributing the largest share due to its volumetric dominance. The created green space provides an additional carbon sink value, although the latter is considerably smaller in scale than the direct economic benefits from waste utilization. This study provides empirical evidence on resource recycling and carbon sequestration in urban renewal projects, serving as an important reference for promoting sustainable urban development.