View article

The addition of external carbon sources is crucial for effective biological treatment of nutrient-rich but carbon-depleted hydroponic wastewater using constructed wetlands. In this study, we examined the effects of applying three types of carbon substrates, namely sucrose, hydroponic kale residues, and common reed litter, on the nutrient removal efficiency and greenhouse gas emission rate of vertical flow constructed wetlands. The addition of sucrose and common reed litter was shown to perform equally well in enhancing the removal of total nitrogen (84.9–93.5%), nitrate (98.3–99.8%) and phosphate (53.8–55.2%) as compared to the control. Moreover, the application of common reed litter led to significantly lower mean CH₄ and N₂O emissions than that of kale residues. These findings suggested that Phragmites reed litter, which is easily found in wetlands worldwide, could be an effective, low-cost and climate …