An Intensified Hybrid Constructed Wetland for Polluted Channel Water Treatment

A hybrid system integrated by anaerobic filter-baffled subsurface horizontal constructed wetland (AFwet) was studied for treating polluted channel water, varying the hydraulic retention time (HRT) from 8 to 2 days. A conventional wetland (CW) and baffled conventional wetland (bCW) were used as control systems. The higher COD and ammonium nitrogen removal efficiencies were achieved at HRT of 8 days, of which the AFwet system was the best. At HRT of 2 days, COD removals for CW, bCW, and AFwet system were 54.22%, 72.96%, and 80.68%, respectively, whereas the ammonium removals were 34.16%, 50.07%, and 95.97%, correspondingly. The experimental results showed that the anaerobic filter intensified the ammonium removal, achieving removal efficiencies above 90%. The smallest footprint of 2.2 m(2)/PE (population equivalent) was obtained at hydraulic loading rate (HLR) of 0.14 m(2)/m(3) day and organic loading rate (OLR) of 36.2 g COD/m(2) day. Nowadays, footprint and pollutant removal are significant indicators for the choice of constructed wetland.

Automated summary

This study investigated the performance of a hybrid system, consisting of anaerobic filter-baffled subsurface horizontal constructed wetland (AFwet), for treating polluted channel water. The results showed that the AFwet system achieved the highest COD and ammonium nitrogen removal efficiencies at a hydraulic retention time (HRT) of 8 days. The anaerobic filter in the system intensified ammonium removal, achieving removal efficiencies above 90%. Additionally, the system had the smallest footprint at specific hydraulic loading rate and organic loading rate conditions.