Constructed Wetland Enhancement via Chemical Coagulation using variable Hydraulic Retention Times for wastewater Treatment

Document Type : Original Article


1 Water Pollution Control Dep., National Research Centre, Dokki, Cairo, Egypt

2 Housing and Building Research Center (HBRC), Sanitary and Environmental Engineering Institute

3 Chemistry Department, Faculty of Science, Cairo University, Giza, Egypt. 5 Centre of Hazard Mitigation, Environmental Studies and Research (CHMESR), Cairo University, Giza, Egypt.

4 Chemistry Department, Faculty of Science, Cairo University, Giza, Egypt


Countries with arid and semi-arid climates suffer from scarcity of drinking water sources. Therefore, treated sewage water is an unconventional source of water. The separation of sewage into grey and black water reduces the pollution water. Grey water becomes simpler to treat. The treated effluent can be reused to irrigate many crops. The aim of this work was to apply the sedimentation process enhanced by chemical coagulants (FeCl3/lime), followed by a hybrid constructed wetland to treat grey water. The Horizontal constructed wetland was subsurface flow (SSF-CW) and followed by vertical flow constructed wetland (VF-CW). The hydraulic loading rate (HLR) of 170, 85, and 56.6 corresponding to organic loading rates (OLR) of 717.4, 358.70, and 239.13 kg BOD5 at (1, 2, and 3 days), respectively was applied. The COD, BOD5, and TSS were reduced by 90.42, 90.65, and 91.4% at hydraulic residence time (HRT) of 3 days while at HRT of 2 days the removal rates were 90.83, 89.82, and 91.1%, respectively. The treatment efficiency at two and three days was in accordance with the laws of discharging the treated wastewater into the sewerage networks, as well as the Egyptian code for treated effluent reuse.


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