Productive Reuse of Industrial Wastewater for the Cultivation of a Biofuel Feedstock Using <i>Salicornia</i>

Highlights Salicornia can be grown in constructed wetlands with cooling tower blowdown water if additional nutrients are added. Flue gas desulfurization wastewater can be used to cultivate Salicornia in lower concentrations (=20%). Salicornia had low glucan and lignin content while the extractives content remained undefined. Non-uniform seeds with low germination rates limit the adoption of Salicornia into constructed wetlands. ABSTRACT. Integrating water treatment into a circular bioeconomy improves sustainability by minimizing environmental pollution and maximizing resource utilization. Salicornia, a salt-tolerant oilseed crop, was explored for its cultivation in a constructed wetland designed for industrial wastewater. Salicornia’s oil seed properties were also explored for its use as a cellulosic ethanol feedstock, providing a secondary revenue stream. The goal of this study was to determine how the composition of two sources of industrial wastewater, flue gas desulfurization wastewater (FGDW) and cooling tower blowdown water (CTBW), affects the germination, survivability, early seedling growth, and lignocellulosic composition of Salicornia. The results indicated that full-strength CTBW could be used to cultivate Salicornia if nutrients were added. Treatment water containing 20% FGDW observed increased seedling height and survival compared to 60% and 100% FGDW treatments, demonstrating that Salicornia can be used in systems treating FGDW after dilution. Low glucan and lignin content showed that Salicornia may not be a good lignocellulosic biofuel feedstock; however, a large percentage of the extractives content was unidentified and could have additional monetary value (e.g., feed, cosmetics, pharmaceuticals). Before exploring its use in commercial products, research is needed to quantify the potential contaminant accumulation in the biomass from treating various industrial wastewater sources. However, the use of Salicornia in large-scale systems is limited until a source of uniform seed with higher germination rates and survivability is found. Keywords: Biomass composition, Constructed wetland, Cooling tower blowdown water, Flue gas desulfurization wastewater, Phytoremediation.