Constructed wetlands for water management and reuse in agriculture

Global warming mainly induced by anthropogenic causes has already restricted the increase in agricultural productivity along with aggravating the conflict between water supply and demand. In this context, constructed wetlands (CWs) can be one of nature-based solutions for the treatment and reuse of unconventional wastewater sources. The aim of this research was to evaluate the performance of CWs in wastewater treatment (i.e., agricultural drainage water and domestic wastewater) and to explore the potential of their effluents for agricultural reuse. In order to achieve this goal, the work based on literature review and experimental approach was carried out. The findings showed that CWs can be an effective option for treating both agricultural drainage water (ADW) and domestic wastewater. It was also found that systems treating ADW can be effective even after a long period of operation. The treatment performance of CW systems is affected by the design and operational factors. For instance, the application of simple hydraulic structures and vegetation establishment can improve the pollutant removal efficiencies by increasing hydraulic retention time. Moreover, the addition of other technologies (e.g., UV treatment, anaerobic reactors) could further improve the quality of wastewater treated by single-stage CWs. In particular, it is strongly recommended to add special disinfection technologies to CW treatment systems to meet agricultural reuse standards since it was shown that the microbial loads often exceed the limits (e.g., E. coli).