Constructed wetlands for mariculture wastewater treatment: From systematic review to improvement measures and insights

Mariculture wastewater typically contained high salinity and various pollutants, posing challenges for bioremediation technologies. Constructed wetlands (CWs) had been successfully used to treat a variety of wastewaters, being environmentally friendly and cost-effective. After nearly 20 years of development, they have provided a potential alternative technology for treating wastewater from mariculture. This review elucidated the state-of-the-art knowledge regarding the use of CWs for mariculture wastewater treatment, systematically summarizing and evaluating the research progress in the optimization of design strategies, operational strategies, and environmental parameters, as well as proposing corresponding improvement measures and insights. It was recommended that the efficiency of CWs in treating mariculture wastewater could be increased through the enhancement of design strategies (e.g., plants, microorganisms, and substrates), the improvement of operational patterns (e.g., water flow regime and mode, hydraulic retention time, hydraulic loading rate, and water table depth), and the adjustment of environmental parameters (e.g., pH, temperature, humidity, salinity, and nutrient levels). Furthermore, future research should focus on the removal of different types of target pollutants from mariculture wastewater. Strategies to enhance purification processes should be developed to overcome the scale-up challenges and promote the commercialization of this technology, enabling large-scale implementation under practical conditions. This review provided theoretical guidance and practical support for the future scientific construction of CW purification systems and their application in the treatment of saline wastewaters such as those from mariculture.