A considerable amount of construction and demolition wood waste (CDWW) is generated, mostly landfilled, contributing to severe environmental effects. The management of CDWW is a significant challenge as it is a hazardous contaminated waste. In this context, the circular economy (CE) concept is a solution as it comprises waste minimisation and efficient recovery of resources. Although much research is found in the literature on CDWW end-of-life management, research on CE implementation considering every life cycle stage is still scarce. In this review, we endeavour to integrate CE in CDWW to identify the waste management strategies involved in the life cycle phases. The databases were searched from 2009 to 2020 and were analysed using CiteSpace version 5.7.R1 software. Forty-nine articles were identified, and the six life cycle stages were explored. The analysis shows that CE for wood waste is essential and has greater growth potential. While the LCA studies are limited to environmental viewpoints, combining economic and social perspectives is necessary for sustainable development. Overall, based on the research findings, a theoretical framework was proposed. This study, as a consequence, promotes the application of recycled wood into multiple valuable products and thus encourages waste management to boost CE and sustainability.
26 February 2024 in Science of The Total Environment
The deterioration of concrete sewer structures due to bio-corrosion presents critical and escalating challenges from structural, economic and environmental perspectives. Despite decades of research, this issue remains inadequately addressed, resulting in billions of dollars in maintenance costs and a shortened service life for sewer infrastructure worldwide. This challenge is exacerbated by the absence of standardized test methods and universally accepted mitigation strategies, leaving industries and stakeholders confronting an increasingly pressing problem. This paper aims to bridge this knowledge gap by providing a comprehensive review of the complex mechanisms of bio-corrosion, focusing on the formation and accumulation of hydrogen sulfide, its conversion into sulfuric acid and the subsequent deterioration of concrete materials. The paper also explores various factors affecting bio-corrosion rates, including environmental conditions, concrete properties and wastewater characteristics. The paper further highlights existing corrosion test strategies, such as chemical tests, in-situ tests and microbial simulations tests along with their general analytical parameters. The conversion of hydrogen sulfide into sulfuric acid is a primary cause of concrete decay and its progression is influenced by environmental conditions, inherent concrete characteristics, and the composition of wastewater. Through illustrative case studies, the paper assesses the practical implications and efficacy of prevailing mitigation techniques. Coating materials provide a protective barrier against corrosive agents among the discussed techniques, while optimised concrete mix designs enhance the inherent resistance and durability of the concrete matrix. Finally, this review also outlines the future prospects and challenges in bio-corrosion research with an aim to promote the creation of more resilient and cost-efficient materials for sewer systems.