Proposing a constructed wetland within the branch drains network to treat degraded drainage water in Tina Plain, North Sinai, Egypt

Abstract

ABSTRACT To treat degraded agricultural wastewater due to non-point pollution source in cultivated area (Tina Plain), Egypt, a wetland system within branch drain network was proposed and designed, which consists of a sedimentation pond followed by four vegetated bed cells of reed (Phragmites australis), and an open water disinfection zone. The relaxed tank in series model was used to design the wetland. The model input data were influent flow 600 m3 d−1, winter temperature 18 °C, hydraulic retention time 5.8 d, influent pollutant concentrations 500, 300, 480, and 20 mg L−1 for TSS, BOD, COD, and TN, respectively, and 100,000 MPN 100 mL−1 for FC. Results show a wetland system area of 0.078, 0.24, and 0.3 ha for sedimentation pond, vegetated reed bed cells, and disinfection zone, respectively. The expected removal efficiencies for TSS, BOD, COD, TN, and FC were 96.4%, 96.2%, 95%, 75%, and 97%, respectively. The wetland hydrology was computed using local climate data and FAO-CROPWAT 8 model. The proposed wetland area was compared with literature to show its feasibility for wetland operation conditions. The proposed system met the allowable limits of Egyptian environmental regulations, simple construction, operation, and has a low construction cost of one UDS m−2