A long-term assessment of the effectiveness of a semi-artificial wetland in removing organic materials and nutrients from agricultural drainage water

Agricultural drainage water from sugarcane fields typically contains a high level of nutrients and organic substances. During different seasons of the year, this study examined the effectiveness of constructed wetlands in improving agricultural drainage water from sugarcane fields to Naseri Wetland in southwest Khuzestan province by removing organic materials and nutrients. Over a long period (2020-2021) of time, a semi-artificial wetland in Khuzestan province of Iran was tested for its efficacy in removing nutrients and organic matter from sugarcane field drainage water. The wetlands were divided into three sections (3.5 km in length, 1.2 km in width, and 0.5 m in depth) and the beginning of each segment was considered a sampling station and was referred to as ST1, ST2, and ST3. In all four seasons, the removal efficiency (RE) of the studied parameters was significant irrespective of seasonal temperature. In addition, the retention time had a significant effect on RE as distance from ST0 increased. The maximum REs of NO3, NH4, TN, PO4, TP, BOD, and COD were achieved at ST3 by 65, 65, 65, 93, 94, 75, and 64 %, respectively. By using this system, the quality of agricultural drainage water can be raised to the desired standard for discharge into the environment and for agricultural use. In light of the large amount of agricultural drainage water, wetlands are an environmental friendly method for treating excess water, which not only prevents pollution of limited freshwater resources, but also adds secondary resources to production cycle. With careful design and implementation, constructed wetlands could offer a practical solution to reclaiming agricultural drainage water in Khuzestan and other regions with similar climates.

Automated summary

This study examined the effectiveness of constructed wetlands in improving agricultural drainage water by removing organic materials and nutrients, and found that wetlands are an environmental friendly method for treating excess water and can raise the quality of agricultural drainage water to desired standards. The maximum removal efficiency of various parameters was achieved at a certain sampling station, and wetlands can be a practical solution for reclaiming agricultural drainage water in Khuzestan and similar regions.