Greywater Treatment for Safe Recycling Via Hybrid Constructed Wetlands and Sludge Evaluation

Arid and semi-arid areas suffer from scarcity of water resources. Nile River is the primary source of drinking water in Egypt. It supplies about 85% of the country need of water. In the meantime, 86% of the total source of Egypt goes for agriculture purpose. Therefore, adequate treated sewage water could be considered unconventional source of water. The separation of sewage water into grey and black wastewater is new trend that could be implemented in the remote areas as an economical and feasible solution for reuse purposes. The present study is concerning with grey wastewater treatment using hybrid constructed wetlands (HCW) enhanced by sedimentation process as pre-treatment. The HCW was subsurface flow (SSF-CW) followed by vertical flow (VF-CW). The hydraulic loading rate (HLR) was 56.6 m(3) ha(-1).day(-1) and the corresponding organic loading rates (OLR) was 239.13 kg BOD5 ha(-1).day(-1) at 3 days retention time. The COD, BOD5, and TSS in the final treated effluent were reduced by 90.42, 90.65, and 91.4% respectively. The treatment efficiency proved to be in accordance with the Egyptian laws of discharging the treated wastewater into the sewerage networks, as well as the Egyptian code concerning the reuse of the treated effluent. The study was extended to investigate the quality of the produced sludge. The obtained results indicated that the sludge characteristics comply with the limits of Law (93/1962) for safe reuse as soil conditioner.