The effects of purifying livestock wastewater by different aquatic plants

Large amounts of nitrogen and phosphorus and other pollutants in livestock wastewater caused serious water pollution. Using aquatic plants can be effective for removal and purification livestock wastewater. In this paper, the purifying efficiency of livestock wastewater with three aquatic plant species, Potamogeton pectinatu, Elodea nuttallii, and Duckweed were investigated by Aquatic plant purification tank simulating experiment. The results showed that the aquatic plants had significant removal efficiency. The removal efficiency of Turbidity attained 80.6%, 82.6%, 90.8% respectively and dissolved oxygen, respectively, increased to 83%, 89.3%, 94.8%. Removal rate of COD in Duckweed tank accounted for 43.83%, which was significantly higher than those in Potamogeton pectinatu, and Elodea nuttallii tanks. Three aquatic plants had high removal rate of total phosphorus (TP), which reached 84.4%, 90.5%, 95.95% respectively. Removal rate of total nitrogen (TN) which attained 76.4% in Elodea nuttallii tank was evidently higer than those in Potamogeton pectinatu, and Duckweed tanks. Moreover, removal rate of ammonia nitrogen (NH₄⁺-N) in three aquatic plants tank had reached more than 95%. Over all, the pollutant removal efficiency showed a sequence of Duckweed > Elodea nuttallii > Potamogeton pectinatu.