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.
Highlights
Water eutrophication results primarily from the massive introduction of nutritive salts, ammonium and nitrate [1]
Three common plant species were collected from the Shuxi River in Taian for use in the experiment: Scirpus validus, Phragmites australis, and Acorus calamus
This study found that three species of emergent plants have a significant effect on nitrate removal, and the nitrate removal percentage varies with the plant species and the initial concentration
Summary
Water eutrophication results primarily from the massive introduction of nutritive salts, ammonium and nitrate [1]. High levels of nitrogen fertilizer and an increasing intensity of human activities (animal husbandry, atmospheric deposition and industrial waste water discharge) have caused considerable nitrate enrichment of surface waters [2]. This enrichment has led to several environment problems, such as an increase in the concentration of nitrate-nitrogen in underground and surface water [3] and possessed a serious threat to human health and water security. China’s environmental bulletin (2014) reported that the average groundwater nitrate content was 10.9 mg/L, and even drinking water in some places had levels greater than 50 mg/L [5]. Meaningful nitrate removal from water must be a priority
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
