Removing pollutants and recovering resources in treatment wetlands cultivated with ora-pro-nobis and citronella
摘要
Treatment wetlands (TW) have been used as an attractive alternative for sewage post-treatment, being efficient in organics and solids removal. This study investigated pollutants removal and resources recovery in TW cultivated with Cymbopogon winterianus (CN) and Pereskia aculeata (OPN). The TW were evaluated operating at a flow rates of 300 and 450 L day−1. The TWs efficiency was determined by laboratory analysis, while the productivity of the plants was evaluated in terms of fresh matter, dry matter and productivity per hectare. In addition, the macronutrients in the leaf tissue of the plants were analysed, as well as the amount of nutrients extracted by each species. The TW effluents had an average COD of 79.5 and 81 mg L−1, TSS of 21 and 19 mg L−1, and TAN of 58 and 46 mg L−1 for CN and OPN units, respectively. Both TW proved to be compliant with legislation, even under organic loading rates of 492 and 659 kg ha−1 day−1 COD. However, they showed limitations on nutrient removal at higher loads. Both plant species adapted well to the flooded conditions and high loading rates, which resulted in a biomass production of 24.97 t ha−1 yr−1 for CN and 9.65 t ha−1 yr−1 for OPN. This performance highlights these species which stand out as viable options for the sewage post-treatment in TW. The plants have also shown the potential for additional production, such as fragrances and proteins. The findings suggest a promising way forward for the circular economy and sustainable development.