Cyperus giganteus pruning residues from constructed wetlands: Potential for energy production

Abstract

The objective of this study was the full characterization of pruning residue from macrophyte Cyperus giganteus from tertiary wastewater treatment plant (WTP), Ponte dos Leites, located in Araruama, RJ, Brazil. Analyses aimed to systematically assess the feasibility of using the pruning residues as an energy resource. To do so, macrophytes were submitted to experimental analyses of their physical properties (real density: 0.44–0.77 g cm−3, bulk density: 0.08–0.09 g cm−3, among other characteristics), chemical and proximate analyses, and thermal analysis. Results of thermal behavior characterized the biomass as a viable energy source (high heat value, 14–16 MJ kg−1). C. giganteus different samples fractions analyses confirmed that molecular structures of the macrophyte (lignin: 17.3–26.8 wt %, cellulose: 27.8–32.6 wt %, hemicellulose: 30.1–31.5 wt %; depending on the plant part) affect thermal decomposition behavior. Maximum mass losses ranged from 83.43 to 75.91%. Energy production potential from biomass pruning residues generated at Ponte dos Leites was estimated to be around 92,400 MJ mês−1. This shows the effectiveness of using pruning residues biomass from macrophyte Cyperus giganteus for energy production, highlighting its energy potential, and support its use as inputs in thermal conversion processes.