The Effectiveness of Pseudomonas aeruginosa in Degrading Biochemical Oxygen Demand and Chemical Oxygen Demand in Small Island Domestic Wastewater

The high organic content of domestic wastewater on small islands increases the risk of environmental pollution and disease spread. Limited resources and infrastructure exacerbate waste management challenges in these regions. This study aimed to identify local bacteria from domestic wastewater and test the effectiveness of Pseudomonas aeruginosa in degrading BOD and COD. This study was conducted in the Spermonde Islands of Makassar City. Wastewater samples were collected from six locations and analyzed using MALDI-TOF MS. Effectiveness tests were carried out in a simple 5 L ex situ bioreactor using a completely randomized design (CRD) with two factors: bacterial inoculum concentration (0%, 5%, 10%, and 15%) and incubation time (2, 4, 6, and 8 days). Pseudomonas aeruginosa effectively reduced BOD and COD by 64–77% and 63–77%, respectively. Variations in inoculum concentration did not significantly affect BOD and COD reduction (p > 0.05), whereas incubation time had a significant effect (p < 0.05). The highest removal efficiency was observed on day 6. These findings suggest that optimizing the incubation time is more critical than increasing the inoculum concentration for successful bioremediation. Pseudomonas aeruginosa is a practical and economical option for supporting sustainable wastewater management on small islands and can be integrated into household-scale communal wastewater treatment plants (WWTPs) to improve treatment effectiveness.