Optimization of organics and nitrogen removal in intermittently aerated vertical flow constructed wetlands: Effects of aeration time and aeration rate

• Optimization of organics and nitrogen removal in aerated VFCWs was evaluated.
• The optimal aeration time and aeration rate were 4 h d−1 and 1.0 L min−1.
• Greater removal of COD (97%), NH4+-N (98%) and TN (90%) was achieved simultaneously.

In this study, to optimize aeration for the enhancement of organics and nitrogen removal in intermittently aerated vertical flow constructed wetlands (VF CWs) for treating domestic wastewater, the experimental VF CWs were operated at different aeration time (1 h d−1, 2 h d−1, 4 h d−1, 6 h d−1, 8 h d−1 and 10 h d−1) and aeration rate (0.1 L min−1, 0.2 L min−1, 0.5 L min−1, 1.0 L min−1 and 2.0 L min−1) to investigate the effect of artificial aeration on the removal efficiency of organics and nitrogen. The results showed that the optimal aeration time and aeration rate were 4 h d−1 and 1.0 L min−1, which could create the appropriate aerobic and anoxic regions in CWs with the greater removal of COD (97.2%), NH4+-N (98.4%) and TN (90.6%) achieved simultaneously during the experiment. The results demonstrate that the optimized intermittent aeration is reliable option to enhance the treatment performance of organics and nitrogen at a lower operating cost.

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