The current article presents a simple new route of cost-effective and straight forward synthesis of the anatase structure of Titanium dioxide (TiO2) nanoparticles (NPs). The solvent Hydrothermal Phase Transformed (HPT) method adopted for the conversion of bulk precursor of TiO2 powder at Nano scale to get contaminated free photoactive TiO2 NPs. The morphology, crystal phase and surface area characterization of NPs completed through scanning electron microscopy (SEM). The composition of elements in NPs determined through Energy Dispersive X-Ray Spectroscopy (EDS or EDX). The Fourier-transform infrared spectroscopy (FTIR) employed for molecular components and structures. Synthesized NPs showed 3D hexagonal pure anatase phase with size of 68 to 97 nm. The toxicity of TiO2 NPs discovered on the water chemistry using two microbes like Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli.) and Acridine Orange (AO) by the dose-dependent manner followed by higher antimicrobial activities and degradation properties at shallow concentration in water respectively. The higher antimicrobial activities of 3D crystal structure related to its highest photo catalytic properties leading to membrane damage of microbes and mineralization of the dye. The recycled photo catalyst TiO2 after 4 cycles retained the degradation efficiency of 75% against AO, subsequently concluded that the method of preparation was effective.