Clogging in subsurface flow constructed wetlands: Mechanisms, influencing factors, measurements, modelling, and remediation

Clogging has garnered growing interest as a significant operational and maintenance concern that affects the sustainable development and implementation of sub-surface flow (SSF) wetlands in wastewater treatment. The existing literature on clogging has been found to have limitations, as none of the studies have provided a comprehensive overview of the entire clogging process, starting from its initiation to remediation. In addition, very few works have addressed the models that were utilized to forecast the occurrence of system clogging. This study primarily focuses on the process of clogging, in widely used SSF wetland systems due to its negative impact on the lifespan of these systems. The article seeks to evaluate different forms of clogging and their developmental mechanisms, as well as the influencing factors. The work thoroughly examines the several techniques used to measure and evaluate clogging. The current review also encompasses the examination of several mathematical models used to predict the clogging of the system. Lastly, it also emphasizes the remediation methods required to resolve clogs. The main objective of this review is to bring all pertinent information on the clogging of SSF wetlands to the attention of prolific researchers with the goal of mitigating system clogging and establishing CW technology as a viable and sustainable alternative for wastewater treatment in the near future.