Study of the Effectiveness of Domestic Wastewater Treatment in the City of Brazzaville Using Vertical-Flow Artificial Marshes Planted with Cyperaceae (Cyperus alternifolius L.)

Abstract

Domestic wastewater can cause environmental pollution if it is discharged into the environment without prior treatment, particularly because of its high organic load. In this study, the experimental pilot consisted of two basins: the first was planted with Cyperus alternifolius L., and the second was unplanted and used as a control to monitor the effectiveness of phytoremediation. The system was regularly supplied with municipal wastewater from Brazzaville at a frequency of once every seven (7) days. Thirteen (13) physicochemical parameters were measured before and after treatment. The assessment of removal performance showed that the system achieved a marked decrease in the mean concentrations of several measured parameters from the feedwater, including TSS (372.2, 8.16 and 16.70 mg/L), turbidity (85, 6.5 and 11.41 NTU), and COD (291.37, 92.97 and 69.94 mg/L). \(NO_3^-\) (124.7, 26.01 and 20.32 mg/L), \(PO_4^3-\) (74, 17.41 and 12.06 mg/L), nickel (6.3, 0.71 and 0.16 mg/L), and copper (3.35, 0.10 and 0.13 mg/L) were measured in the feedwater, control filter and Cyperus alternifolius L. planted filter, respectively. Multivariate analysis of means and standard deviations revealed a statistically significant difference in more than twelve (12) parameters in the filtrates from the two filters, with p-value < 0.001. The Cyperus alternifolius L. planted filter contributed to the assimilation of pollutants present in wastewater, resulting in improved treatment performance under the experimental conditions.