Horizontal Subsurface Flow Wetland with Phragmites australis for Reducing COD, pH, and Temperature in the Anchac-Huasi Wastewater Treatment Plant

Reyes Kelly Raquel T.; Cazorla Claudia Sundely P. · Proceedings of the LACCEI international Multi-conference for Engineering, Education and Technology (2025) · DOI: 10.18687/laccei2025.1.1.733

Resumen

This study evaluated the efficiency of a horizontal subsurface flow constructed wetland (HSSF-CW), vegetated with Phragmites australis, in reducing physicochemical parameters such as Chemical Oxygen Demand (COD), pH, and temperature in the domestic effluent treated by the Anchac-Huasi Wastewater Treatment Plant (WWTP), located in the highlands of Ayacucho, Peru. A pilot-scale experiment was conducted using six treatment cells: three vegetated and three without plant cover (control), operated under hydraulic retention times (HRT) of 4 and 6 days. The characterization of the influent revealed a neutral condition (pH 7.03), an average temperature of 14.4 °C, and a significant organic load (COD 440 mg/L). The results showed that the vegetated cells achieved an average COD removal of up to 94.77 %, while the control units did not exceed 67.27 %. One-way ANOVA confirmed that both the presence of Phragmites australis and the increase in HRT significantly influenced the improvement in effluent quality. Vegetation contributed to pH stabilization and provided more consistent thermal regulation across cells, demonstrating its positive role in the system’s performance. Moreover, longer HRTs enabled greater efficiency in the degradation of organic matter. This study supports the use of nature-based technologies as a viable and sustainable solution for wastewater treatment in rural communities.

Instituciones: Universidad Peruana de Ciencias Aplicadas