Definition of the Criteria to Evaluate the Viability of Post-Use Options for Excavated Concrete Sewer Pipes in Rotterdam

Abstract

This study aimed to define and evaluate the viability of post-use options for excavated concrete sewer pipes. The research was conducted with a combination of literature review and expert interviews with professionals from the Municipality of Rotterdam. The process involved several key steps. The goal was to create a conceptual framework that can evaluate the viability of post-use options for excavated concrete sewer pipes. Initially, the study identified two existing circular economy theories from which four circular strategies were adopted. The potential post-use options for the excavated sewer pipes, were developed based on those strategies such as reuse, repurpose, refurbish, and recycle. The potential post-use options were identified through literature review. Following this, viability criteria were developed from academic literature and expert interviews. These criteria were categorized into general criteria, which must be met by all post-use options, and specific criteria specified to each circular strategy.A conceptual framework was established using the identified viability criteria, designed to evaluate the practical feasibility of post-use options for concrete sewer pipes. This framework was then applied to a test case involving excavated concrete sewer pipes in Rotterdam, serving as a prototype application to test its practical applicability. Seven potential post-use options were evaluated using the framework. From those seven, only two options were considered viable for the test case of Rotterdam. These were, repurposing the pipes for breakwater construction and recycling them using a conservative breaking installation. Other options were rejected due to factors such as insufficient remaining lifetime, lack of structural integrity, and inefficiency. The study concluded by demonstrating the practical application of leading criteria to evaluate post-use options. It also provided insights into the limitations of the study and suggested areas for future research, particularly in improving data accuracy and expanding the applicability of the criteria. However, the study faced some limitations. Some academic criteria were too generalized and not directly applicable to the specific context of concrete sewer pipes. The study heavily relied on expert opinions from the Municipality of Rotterdam, which may introduce bias or limit the perspective to that specific locality