Aerodynamic noise generated by industrial fans and blowers remains a significant challenge in ventilation and cooling systems. Inspired by the silent-flight capability of owls, this study proposes and experimentally evaluates a novel non-uniform serrated blade modification for aeroacoustic noise reduction in a five-bladed blower. Unlike previous investigations that primarily employed uniform serration geometries, the present design adopts a physics-based biomimetic approach in which the serration dimensions vary along the blade span according to the distribution of vortex intensity identified in previous aerodynamic studies. This strategy aims to target dominant noise-generating regions and improve the effectiveness of passive flow control. The proposed zigzag attachments were installed separately on the leading and trailing edges of the blower blades, and acoustic measurements were conducted in an anechoic chamber in accordance with ISO 3745. The results showed that the leading-edge serration reduced the overall sound pressure level (OASPL) by 1.61 dB, with a maximum local reduction of 14 dB at 2 kHz. The trailing-edge configuration achieved a larger OASPL reduction of 2.58 dB and a maximum attenuation of 15 dB at 150 Hz. These improvements are attributed to the suppression of dominant vortex structures and the reduction of turbulent pressure fluctuations responsible for aeroacoustic noise generation. The findings demonstrate that combining biomimetic inspiration with flow-physics-based design provides an effective, low-cost, and industrially applicable solution for noise mitigation in rotating machinery, offering a promising pathway toward the development of next-generation low-noise aerodynamic systems.