Constructed wetlands in the production of crimson fountain grass flower stems

Abstract

The advantages of using constructed wetlands (CWs) for the decentralized treatment of wastewater include the operational simplicity, low cost, high-purification potential, and generation of plant biomass. Different plant configurations and species have been evaluated in CWs to increase the efficiency and the commercial and landscaping interest of plants grown in these units. Owing to its characteristics such as tolerance to different water levels, ease of acquisition, and associated economic value, crimson fountain grass (Cenchrus setaceus) is a potential plant to grow in CWs. The objective of this study was to evaluate the production of crimson fountain grass flower stems grown in horizontal-subsurface-flow (HSSF) CWs with different baffle arrangements. The three 1.0-m2 HSSF CWs cultivated with 10 crimson fountain grass seedlings differed in the presence of partitions inside the units, as follows: no internal partitions; horizontal baffles; vertical baffles. The cultivated grass was analyzed for clump fresh weight (g), flower stem length (cm), panicle length (cm), panicle diameter (mm), and panicle dry weight (g). The experimental design was completely randomized with a split-plot in time, with three treatments, 10 replicates, and nine collection periods. The results obtained in the CWs during 9 months of monitoring indicated that the grass grown in the CWs with vertical baffles had higher clump fresh weight, longer stem length, and greater panicle size and dry weight. Given the high water and nutrient availability, the cultivation of ornamental plants in CWs can be considered a profitable option that allows high production of plant structures in a small physical space.