In developing countries, waterborne diseases caused by the pathogenic bacteria are afflicting people who lack access to clean drinking water and live in poor sanitary conditions. User-friendly and low-cost point-of-use (POU) disinfection systems have become the key solution for providing safe drinking water. Herein, a biomass-based renewable film filter with good mechanical strength, porous network structure, and robustly immobilized silver nanoparticles was facilely fabricated via Fe(III) cross-linking-induced collagen fibers (CFs) and gallic acid-protected silver nanoparticle (GA@AgNP) self-assembly. Scanning electron microscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, and X-ray diffraction were employed to characterize the GA@AgNPs-Fe-CF composite film. This film exhibited both excellent bacterial anti-adhesive and bactericidal activities, which effectively prevented biofouling during the filtration process because of the anionic GA@AgNPs. As the bactericidal filter is driven by gravity, 1 L of the natural water sample was treated by the GA@AgNPs-Fe-CF film for 20 min, and the water quality was in full compliance with the drinking water guidelines of the World Health Organization (WHO), demonstrating the potential application of the proposed filter in POU water disinfection.