Pelayaran memiliki peran vital dalam sejarah, ekonomi, dan lingkungan, khususnya di negara kepulauan seperti Indonesia. Salah satu aspek penting dalam pengoperasian kapal modern adalah pengolahan limbah melalui Sewage Treatment Plant (STP), di mana aeration blower berfungsi menyediakan oksigen bagi bakteri aerob yang menguraikan limbah. Penelitian ini menganalisis ketidakoptimalan kinerja aeration blower pada STP tipe SBT-40 di kapal MV. Muhasyir. Penurunan tekanan udara dari 0,02 MPa menjadi 0,008 MPa menyebabkan bau tidak sedap dan gangguan proses biodegradasi. Metode penelitian meliputi observasi, wawancara, studi dokumentasi, dan tinjauan pustaka. Hasil menunjukkan kerusakan pada rotor dan bearing blower akibat kurangnya perawatan berkala dan pelaksanaan Planned Maintenance System (PMS) yang tidak konsisten. Faktor penyebab dianalisis menggunakan diagram fishbone, mencakup aspek manusia, mesin, metode, material, lingkungan, dan pengukuran. Solusi yang diusulkan meliputi pelatihan teknis, inspeksi rutin, penggantian komponen aus, serta pemasangan sensor tekanan dan getaran. Penelitian ini menekankan pentingnya perawatan preventif dan sistem monitoring untuk menjaga efektivitas STP dalam mendukung pelayaran ramah lingkungan. Shipping has a vital role in history, economy, and the environment, especially in an archipelagic country like Indonesia. One of the important aspects of modern ship operation is the treatment of waste through the Sewage Treatment Plant (STP), where the aeration blower functions to provide oxygen for aerobic bacteria that decompose waste. This study analyzes the non-optimal performance of aeration blower in SBT-40 type STP on MV ships. Muhasyir. A decrease in air pressure from 0.02 MPa to 0.008 MPa causes unpleasant odors and disruption of the biodegradation process. The research methods include observation, interviews, documentation studies, and literature reviews. The results showed damage to the rotor and blower bearings due to lack of periodic maintenance and inconsistent implementation of the Planned Maintenance System (PMS). The causative factors were analyzed using fishbone diagrams, including human, machine, method, material, environmental, and measurement aspects. The proposed solution includes technical training, regular inspections, replacement of wear components, and installation of pressure and vibration sensors. This study emphasizes the importance of preventive maintenance and monitoring systems to maintain the effectiveness of STPs in supporting environmentally friendly shipping.