ZnO photocatalyst particles were immobilized onto waste polystyrene (PS) using thermal attachment method at low temperature for the removal of textile dye and pathogen microorganisms from water. The as-prepared photocatalyst (ZnO-PS) was characterized by X-ray diffraction, scanning electron microscopy combined with energy dispersive X-ray spectroscopy, and thermogravimetric analysis. X-ray diffraction studies of the ZnO-PS catalyst proved that formation of the hexagonal wurtzite phase on the PS surface has occurred. The study was aimed making a "green chemistry" approach and exploring the photocatalytic property of metal oxide immobilized polymer (ZnO-PS) for removal of methylene blue (MB) dye solution. Beside this applicability of ZnO-PS as photocatalyst for its bactericidal property against Gram negative Escherichia coli and fungicidal property against Aspergillus niger was also assessed. The material exhibited good photocatalytic activity for removal of MB under UVA (lambda = 365 nm) at ambient temperature and pressure. An effective antimicrobial activity for E. coli and A. niger with 100 and 40% with ZnO-PS, respectively, proved that it is an efficient, reliable and non-hazardous catalyst. This simple and economical preparation strategy of metal oxide immobilized polymer may be an improved and good choice for the new catalyst systems utilizing polymer or other waste as support material.