The wastewater generated during the plastic recycling is an aspect that is often overlooked in the process. This wastewater contains pollutants that can affect the environment and human health. To address this problem, a study was conducted to design and evaluate the performance of an anoxic-oxic (AO) system and an anoxic-oxic-oxic (AO2) system in treating plastic recycling wastewater. Additionally, the study collected wastewater from a plastic recycling company and activated sludge from a sewage treatment plant to test the viability of biological treatment for treating plastic recycling wastewater. The results showed that both systems were effective at reducing chemical oxygen demand (COD), with the AO system having a higher percent COD removal (98.13%) than the AO2 system (85.33%). Also, there were 18 unique colonies isolated from the wastewater and activated sludge. Overall, the study concludes that biological treatment can be used to treat plastic recycling wastewater, and the design of upscaled system is crucial to fully solve the wastewater problem.