Work

Field Testing of Storm-Resilient Floating Mat Systems for Grass Cultivation and Biochar Generation

Year: 2026

Type: preprint

Abstract: Storm events pose significant challenges to the stability and performance of a floating treatment wetland designed to cultivate aquatic plants. This study examines the resilience and ecological performance of a floating foam mat that harbors aquatic plants, serving multiple purposes: nutrient removal (e.g., nitrate and phosphate), carbon sequestration from the atmosphere, heavy metal removal, and biochar production. Plant growth trials were conducted in a watershed using 10 modular floating mats containing two aquatic macrophytes, common rush ( Juncus effusus ) and switchgrass ( Panicum virgatum ), from mid-June to December 2025 (6 months) to assess vegetation growth, biomass composition, and pyrolysis product yields. Biomass monitoring showed that common rush had a root length of 64 cm (2′1") and a stem length of 67 cm (2′2"), while switchgrass had the highest root length of 97.5 cm (3′2") and a stem length of 128 cm (4′2") over a five-month period. The plant survival rate for each mat ranged from 90% to 92% by the end of harvesting. The CHNS analysis revealed that switchgrass roots had the highest concentrations of nitrogen (2.2%) and sulfur (0.3%). The common rush stem had higher concentrations of carbon (~ 45%) and hydrogen (~ 6%), like switchgrass. Elemental concentrations showed high potassium (K) levels (> 10,000 ppm) in both biomasses. Furthermore, pyrolyzed biomass produced the highest biochar yield at CR-PR (0.48 g/g) and SG-WR (0.42 g/g), and the lowest at CR-WC (0.35 g/g) and SG-WS (0.39 g/g). These variations in pyrolysis product amount and elemental compositions highlight differences in biomass chemical composition across plant parts. This study offers practical insights into creating storm-resilient systems that support ecological restoration and biomass valorization into pyrolysis products, such as biochar and biooil, which can be used as soil amendments and biofuels, respectively.

Source: Research Square

DOI: 10.21203/rs.3.rs-10022989/v1