An experiment was conducted to study how well different types of constructed wetlands can remove nitrogen, phosphorus, and N2O emissions from sewage. Wetlands with slag, zeolite, and paddy soil substrates were tested, each with different plants. The results showed that all three wetlands effectively removed nitrogen and phosphorus, with plants playing a key role in nutrient assimilation. Lolium mutliflorum was the most effective at removing nitrogen and phosphorus. N2O emissions from the wetlands were low and had minimal impact on nitrogen removal. Overall, constructed wetlands with various substrates and plants can efficiently treat sewage by removing nitrogen, phosphorus, and N2O emissions.