Repurposing spent biomass of vetiver grass used for stormwater treatment to generate biochar and ethanol

Viravid Na Nagara; Dibyendu Sarkar; Sameer Neve; Hadeer Saleh; Michel Boufadel; Subhasis Giri; Rupali Datta

doi:10.1016/j.chemosphere.2024.142196

Repurposing spent biomass of vetiver grass used for stormwater treatment to generate biochar and ethanol

Chemosphere. 2024 Apr 29:358:142196. doi: 10.1016/j.chemosphere.2024.142196. Online ahead of print.

Authors

Viravid Na Nagara¹, Dibyendu Sarkar², Sameer Neve¹, Hadeer Saleh¹, Michel Boufadel³, Subhasis Giri⁴, Rupali Datta⁵

Affiliations

¹ Department of Civil, Environmental, and Ocean Engineering, Stevens Institute of Technology, Hoboken, NJ, 07030, USA.
² Department of Civil, Environmental, and Ocean Engineering, Stevens Institute of Technology, Hoboken, NJ, 07030, USA. Electronic address: dsarkar@stevens.edu.
³ Center for Natural Resources, Department of Civil and Environmental Engineering, New Jersey Institute of Technology, Newark, NJ, 07102, USA.
⁴ Department of Ecology, Evolution, and Natural Resources, Rutgers, The State University of New Jersey, New Brunswick, NJ, 08901, USA.
⁵ Department of Biological Sciences, Michigan Technological University, Houghton, MI, 49931, USA.

PMID: 38692362
DOI: 10.1016/j.chemosphere.2024.142196

Abstract

Stormwater pollution is a key factor contributing to water quality degradation, posing substantial environmental and human health risks. Although stormwater retention ponds, also referred to as wet ponds, are commonly implemented to alleviate stormwater challenges by reducing peak flow and removing suspended solids, their effectiveness in removing heavy metals and nutrients is limited. This study evaluated the performance of floating treatment platforms (FTPs) featuring vetiver grass (Chrysopogon zizanioides), a non-invasive, nutrient- and metal-accumulating perennial grass, in removing heavy metals (Cu, Pb, and Zn) and nutrients (P and N) in stormwater retention ponds. Furthermore, the potential for utilizing the spent vetiver biomass for generating biochar and bioethanol was investigated. The study was conducted in a greenhouse setup under simulated wet and dry weather conditions using pond water collected from a retention pond in Stafford Township, New Jersey, USA. Two FTPs with vetiver (vegetated FTPs) were compared with two FTPs without vetiver (non-vegetated FTPs), which served as controls. Results showed that the removal of heavy metals and nutrients by the FTPs with vetiver was significantly higher (p < 0.05) than the FTPs without vetiver. Notably, vetiver showed resilience to stormwater pollutants and hydroponic conditions, displaying no visible stress symptoms. The biochar and bioethanol generated from the spent vetiver exhibited desirable yield and quality, without raising concerns regarding pollutant leaching, indicated by very low TCLP and SPLP concentrations. This study provides compelling evidence that the implementation of vetiver-based FTPs offers a cost-effective and environment-friendly solution for mitigating stormwater pollution in retention ponds. Furthermore, the utilization of vetiver biomass for biofuel and biochar production supports clean production and fostering circular economy efforts.

Keywords: Biochar; Bioethanol; Floating treatment platform; Metals; Nutrients; Vetiver grass.