Comparison of the performance of horizontal and vertical flow constructed wetland planted with Rhynchospora corymbosa

Abstract

Treatment performance of horizontal flow (HF) and vertical flow (VF) constructed wetland planted with Rhynchospora corymbosa were compared. The average porosity of the CW beds were 0.55, hydraulic retention time (HRT) of 3 days, hydraulic loading rate (HLR) and Organic Loading rate were 0.058 m/day and 3.96 (g·BOD/m²·day), respectively with a volumetric flow rate of 0.14 m³/day. The pollutant concentration of graywater before and after its introduction to the CWs was measured using standard sampling and analyses methods. The mean removal efficiencies (RE) for HF and VF CWs were BOD, 35% and 35.4%; COD, 61.9% and 56.7%; TN, 87% and 92%; TP, 95% and 65%; TSS, 86% and 59.6%; pH, 8.8% and 12.8%, respectively. The graywater was highly contaminated in terms of nutrient and organic load. The mean values of the parameters tested for different CWs were significantly different (P ≤ 0.05). This comparative study favored HF over VF Constructed wetland with HF found to be a viable alternative for graywater treatment for organics, nutrients and suspended solids removal. The result provided insight into the performance of CWs planted with R. corymbosa.

Keywords:

• Constructed wetlands
• graywater
• phytoremediation
• pollutant removal efficiency
• Rhynchospora corymbosa

Acknowledgments

We thank the management of Landmark University for the provision of adequate laboratory equipment and the commitment of the laboratory staff and assistants. We gratefully acknowledge the critical comments and corrections of respected reviewers whose comments and corrections improved this work considerably.

Disclosure statement

The authors declared that there is no any conflict of interests.