Evaluating clogging effect in vertical flow constructed wetlands with different HLRs.

Abstract

Vertical Flow Constructed Wetlands (VFCW) are renowned for low cost and eco-friendly processes in wastewater (WW) treatment. This study methodically explored the impact of varying hydraulic loading rates (HLR) on VSSF CW performance, utilizing three laboratory-scale experimental units planted with Umbrella palm (Cyperus alternifolius). The study reveals that HLR is a critical factor determining performance of VFCW and the clogging effect. Conversely, lower HLRs lead to underutilization of the wetland’s capacity, resulting in subpar pollutant removal and resource inefficiency. This research enhances the relationship between HLR and pollutant removal in VSSF operated at 20 cm/d, 35 cm/d and 50 cm/d HLRs, respectively. Results showed that the wetland system operated at 20 cm/d HLR had the highest overall removal efficiency as BOD5 (Biological oxygen demand) - 74%), COD (Chemical oxygen demand) - 69%, NH4 + (Ammonium) - 60%, NO3 – (Nitrate - 56%, PO4 3 – (Phosphate) - 50%, TSS (Total suspended solids) - 77%, FC (Faecal coliform) - 79% and lowest clogging. However, considering cost efficiency HLR can further optimize between 20 cm/d and 35 cm/d.