Guangdong nongye kexue (May 2023)
Study on the Purification Effect of Woody Plants on Mariculture Wastewater with Different Salinity
Abstract
【Objective】To study the removal effect of different woody plants on pollutants in mariculture wastewater, and to provide reference for the purification of mariculture wastewater by plants.【Method】Terminalia neotaliala Capuron and Buxus sinica were selected for hydroponic pot experiment to study the effects of different salinity (0 ‰, 2.5 ‰, 5 ‰, 7.5 ‰, 10 ‰, 15 ‰, 20 ‰) on the purification of mariculture wastewater.【Result】(1) The removal rates of TN and TP by T. neotaliala Capuron and B. sinica decreased with the increase of salinity, and the removal rate of COD fluctuated with the increase of salinity. The removal efficiency of TN and TP by T. neotaliala Capuron was higher than that of B. sinica. (2) Under different salinity conditions, the two plants had different absorption and removal effects on nitrogen and phosphorus. The accumulation of nitrogen showed the rule of underground > aboveground. The accumulation of phosphorus in T. neotaliala Capuron showed underground > aboveground at low salinity, while the accumulation of phosphorus in B. sinica fluctuated with the increase of salinity. The accumulation of nitrogen and phosphorus in T. neotaliala Capuron was higher than that in B. sinica. When the salinity was 0‰, 2.5‰, 5‰, 7.5‰, 10‰, 15‰, 20‰, the amount of nitrogen and phosphorus taken away by T. neotaliala Capuron absorption was 1.83 mg/g, 2.01 mg/g, 1.78 mg/g, 1.91 mg/g, 1.95 mg/g, 1.35 mg/g and 1.68 mg/ g, respectively. With the increase of salinity, the accumulation of K+ in T. neotaliala Capuron and B. sinica fluctuated greatly, while the accumulation of Na+ showed an increasing trend. When salinity > 2.5 ‰, the accumulation of Na+ showed the rule of aboveground > underground, and the increase of Na+ accumulation reduced the ability of plants to remove nitrogen and phosphorus. (3) pH, ORP, DO and other environmental factors have a certain influence on the removal of pollutants from sewage and the absorption of nitrogen, phosphorus, K+ and Na+ by plants.【Conclusion】The two plants have a certain removal effect on the pollutants of mariculture wastewater, and the purification effect is better than CK. The purification effect of T. neotaliala Capuron on mariculture wastewater is better than that of B. sinica. T. neotaliala Capuron can be preferentially selected for the treatment of mariculture wastewater.
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