Floating Wetlands for Sustainable Drainage Wastewater Treatment

• Published in: Sustainability Vol. 14; no. 10; p. 6101
• Main Authors: Gabr, Mohamed Elsayed, Salem, Madleen, Mahanna, Hani, Mossad, Mohamed
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.05.2022
• Subjects: Agricultural production; Agriculture; Aquatic plants; Artificial wetlands; Biochemical oxygen demand; Canals; Chemical oxygen demand; Dissolved solids; Drainage; Drainage systems; Effluents; Eichhornia; Electrical conductivity; Electrical resistivity; Impaired water use; Irrigation; Irrigation practices; Irrigation systems; Nymphaea lotus; Performance evaluation; Phosphorus; Pistia stratiotes; Plant species; Pollutant removal; Pollutants; Precipitation; Semi arid areas; Solid suspensions; Surface water; Total dissolved solids; Total suspended solids; Variance analysis; Vegetation; Wastewater irrigation; Wastewater pollution; Wastewater reuse; Wastewater treatment; Water quality; Water resources; Water treatment; Wetlands; Suez Canal; Egypt
• ISSN: 2071-1050; 2071-1050
• DOI: 10.3390/su14106101

The preservation of water resources in modern urbanized society is a major concern. In this study, a floating constructed wetland (FWT) pilot plant was designed and constructed for the treatment of a polluted wastewater drain. A series of experiments were run continuously for a year in pilot-scale FWTs in a semi-arid area located in Egypt’s Delta. Four aquatic plant species (Eichhornia, Ceratophyllum, Pistia stratiotes, and Nymphaea lotus) were used to assess the performance of FWTs for pollutant removals, such as biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), total nitrogen (TN), total phosphorus (TP), electrical conductivity (EC), and total dissolved solids (TDS), from drainage wastewater to reuse the treated effluent in irrigation practices. The FWT systems were fed drainage tainted water on a weekly basis, and the concentrations and removal efficiency were assessed in the experiments. The average reduction in BOD, COD, TSS, TDS, TN, EC, and TP were 76–86%, 61–80%, 87–95%, 36.6–44.1%, 70–97%, 37–44%, and 83–96%, respectively. ANOVA with Post-HOC t-tests show that the Eichhornia, Pistia stratiotes, and Nymphaea lotus have the highest BOD and COD removal performance, whereas Pistia stratiotes and Nymphaea lotus have the highest TN and TP removal performance. In all cases, the Nymphaea lotus performed well in terms of pollutant removal. In addition, a design procedure for a FWT systems is presented. For wastewater treatment, FWT systems have proven to be a low-cost, long-term option.