Fine Bubble Plasma (FBP) for Sustainable Aquaculture Wastewater Management: Enhanced Pollutant Removal, Agricultural Reusability, and Life-Cycle Sustainability

The growth of intensive aquaculture has led to the generation of wastewater with a high content of organic matter, nutrients, and persistent micropollutants (e.g., antibiotics and steroidal hormones). Conventional biological treatment processes are often insufficient for such complex effluents. This study presents a fine bubble plasma (FBP) system for the treatment and reuse of aquaculture wastewater. The removal efficiency of FBP for COD, MT (17α-methyltestosterone), and TCN (tetracycline) was 2.6, 2.0, and 1.4× that of Plasma, respectively. Meanwhile, FBP exhibits significantly lower EE/O (electrical energy per order, kWh/m3·order–1) than Plasma. The EE/O for COD, MT, and TCN in the FBP group was 38.9%, 56.2%, and 75.9% that of Plasma group. More importantly, FBP-treated wastewater safely promoted seed germination and crop growth. Molecular (Gene Ontology/Kyoto Encyclopedia of Genes and Genomes) analyses indicate that FBP may stimulate the generation of endogenous reactive oxygen species inside plants to promote nutrition uptake. The life cycle assessment gave an average of 0.24 and 0.21 USD/L life-cycle cost (LCC) for aquaculture wastewater treatment in the FBP and Plasma groups. Despite an ∼15% higher LCC, FBP delivers substantial advantages in “double pollutant removal efficiency, significantly lower energy consumption, and promotion of agricultural yield”, making it a sustainable solution for aquaculture wastewater management.