N-doped TiO2 nano particles for ultra violet photocatalytic degradation of coliform and fecal coliform from hospital wastewater effluent

Abstract

The photocatalytic process as an advanced oxidation process (AOP) has attracted worldwide attention in water and wastewater industry. The photocatalytic process can be used for water and wastewater disinfection. The purpose of this study was to remove coliform and fecal coliform from real hospital wastewater using UV and UV/ N-doped TiO2 photocatalytic process. A secondary effluent samples were taken from Ali-ebne Abitaleb Hospital in Zahedan. The real samples of effluent containing N-doped TiO2 nanoparticles were exposed to UV light in a reactor. Multi-tube fermentation method (MPN/100ml) was used for counting of coliform and fecal coliform bacteria and evaluation of process efficiency. The results showed that the mechanism of inactivation of coliform and fecal coliform by N-doped TiO2 nanoparticles and UV follows the first-order equation and simultaneous application of N-doped TiO2 nanoparticles and UV (N-doped TiO2/UV) increase the efficiency of photocatalytic process and deactivate completely the coliform and fecal coliform in 10 minutes. The results of this study also showed that with increasing the contact time, the removal efficiency of coliform and fecal coliform increase in the presence of UV light. The highest efficiency of the nanoparticles in bacterial inactivation was achieved in dose 120 mg/l the presence of light UV and it was 100%. Nano-photocatalytic process can be used an efficient method for removal of coliform and fecal coliform from hospital real effluent, and N-doped TiO2/UV process is a reliable antibacterial method for water and wastewater disinfection.