Silver and Zinc Oxide Nanoparticles for Effective Aquaculture Wastewater Treatment

This study explores the use of silver nanoparticles (Ag NPs) and zinc oxide nanoparticles (ZnO NPs), either singly or in combination, for the nanoremediation of aquaculture wastewater. Aquaculture wastewater was treated with varying doses of Ag NPs and ZnO NPs across the following six groups: Group 1 (0.05 mg Ag NPs/L), Group 2 (1 mg ZnO NPs/L), Group 3 (0.05 mg Ag NPs/L + 1 mg ZnO NPs/L), Group 4 (0.025 Ag NPs/L + 0.5 mg ZnO NPs/L), Group 5 (0.1 mg Ag NPs/L + 2 mg ZnO NPs/L), and a control group. Water quality, microbial loads and nanomaterial concentrations were assessed over ten days. Transmission electron microscopy (TEM) showed average particle sizes of 102.5 nm for Ag NPs and 110.27 nm for ZnO NPs. The removal efficiencies of NH₄-N were over 98% across treatment groups. In addition, COD removal efficiencies were 33.33%, 68.82%, 49.59%, 61.49%, and 37.65%. The log-reductions in aerobic plate counts for the nanoparticle-treated wastewater were 1.191, 1.947, 1.133, 1.071, and 0.087, compared to a reduction of 0.911 in untreated wastewater. Silver concentrations ranged from 0.0079 to 0.0192 mg/L, while zinc concentrations ranged from 0.3040 to 0.9740 mg/L, indicating that ZnO-NPs represent a sustainable treatment method for aquaculture wastewater.