Phytoremediation Potential of Three Species of Macrophytes for Nitrate in Contaminated Water

Abstract

Three species of aquatic plants (Scirpus validus, Phragmites australis and Acorus calamus) were used as experimental materials to study their capacity to purify contaminated water and their effects on water pH and dissolved oxygen (DO). The water was contaminated with different concentrations of nitrate (5 mg/L, 15 mg/L and 25 mg/L). The results indicated that the concentration of nitrate, species of aquatic plant and their interaction significantly impacted denitrification (P = 0.00). Under the same concentrations, the three species of aquatic plants provided varying degrees of purification. Acorus calamus provided effective purification under all three concentrations of nitrate wastewater, with removal percentages of 87.73%, 83.80% and 86.72% for nitrate concentrations of 5 mg/L, 15 mg/L and 25 mg/L, respectively. In terms of the purification ability by unit fresh weight, Acorus calamus exhibited the worst purification capacity, whereas the capacities of Scirpus validus and Phragmites australis were higher. The purification capacity of Scirpus validus for the three concentrations was as follows: 0.08 mg/(L•g FW), 0.29 mg/(L•g FW), and 0.51 mg/(L•g FW). The capacity of Phragmites australis was 0.07 mg/(L•g FW), 0.25 mg/(L•g FW), and 0.53 mg/(L•g FW). The capacity of Acorus calamus was 0.04 mg/(L•g FW), 0.12 mg/(L•g FW), and 0.21 mg/(L•g FW). Under increased concentrations of nitrate, the three species of aquatic plants exhibited various degrees of increased purification capacity. Under the different concentrations of nitrate, the three species exhibited the same trends with respect to water pH and DO, increasing first and then falling. The pH remained at approximately 7.5, and the DO fell to 4.0 mg/L. A comprehensive analysis reveals that Acorus calamus provides excellent nitrate purification, although by unit fresh weight, both Scirpus validus and Phragmites australis provide superior purification capacity.

Phytoremediation potential of macrophytes against heavy metals, nitrates and phosphates: A review

“…In terms of nitrate removal percentage, there was a highly significant difference between the three species of aquatic plants (Table 3, P < 0.01). The nitrate removal percentage of Acoruscalamus was the highest, at 86.16 percent, and the nitrate removal percentage of Phragmitesaustralis was much lower, at only 62.34 percent, than the other two species (Li et al, 2016). Phytoremediation potential of aquatic macrophytes against phosphates: The ability of Eichhornia crassipes and Pistia stratiotes to sequester phosphorus was calculated.…”