TiO₂Photocatalytic Disinfection Test In Reclaimed Water

This paper investigated the applicability of the TiO2photocatalytic technology as the process of reclaimed water disinfection taking the water of advanced treatment as the research object. The type of catalyst, catalyst concentration, illumination time, illumination intensity, pH, aeration rate, organic matter content, turbidity and other factors were tested to investigate the impact on the photocatalytic effect and determined the parameters of photocatalytic reaction,taking the rate of pathogenic microorganisms inactivation as the control indicator;Investigated the effect of inactivation of photocatalytic reaction to removal pathogenic microorganism such as staphylococcus aureus, streptococcus faecalis, fecal coliform and bacteria;Also investigated the photocatalytic reaction removal efficiency of ammonia nitrogen, COD, UV254and other pollution indicators. The results show that:(1) The best result of inactivation appears at:selected P25catalyst, catalyst concentration of0.5g/L, the illumination time of30min, the illumination intensity of14.33mW/cm2, the amount of aeration of0.18L/h.y Organic compounds and the turbidity in water is inversely proportional to the photocatalytic inactivation effect. In the same degree of acid-base In the case of pH>7, the inactivation rate is better than that of pH<7.(2) The photocatalytic inactivation of staphylococcus aureus, streptococcus faecalis, fecal coliform, bacteria shows that UV+TiO2only needs10min to inactivate staphylococcus aureus completely, much better than that of UV (neeeds60min); For the inactivation of fecal coliform,UV+TiO2can inactivate fecal coliform completely in10min, longer than UV. For the inactivation of streptococcus faecalis, UV+TiO2and UV can both reach the inavtivation rate of99%in lmin under illumination. For the inactivation of the total number of bacteria, the efficiency of UV is higher than that of UV+TiO2in5min; while after5min,the inactivation efficiency of UV+TiO2continued to be higher than that of UV. Within30min UV+TiO2inactivation, bacteria will appear to be photoreactivation and dark reactivation.(3) When UV irradiation intensity is14.33mW/cm2, TiO2concentration is0.5g/L, the ammonia nitrogen, COD, UV254removal rate is37%,31%,35%on60min photocatalytic reaction, respectively. The ammonia nitrogen, COD, UV254removal rate is61%,67%,48% on180min photocatalytic reaction, respectively.(4) Photocatalytic inactivation of pathogenic microorganisms confirm the Chick order of reaction efficiency model:r=-kN. In this study, self-developed photocatalytic membrane reactor combines the photocatalytic technology and membrane treatment process, catalyst recovery rate reached94%, which can recover the catalyst effectively and contribute to the improvement of effluent quality:when the ultraviolet light strength is57.32mW/cm2, after60min photocatalyst membrane treatment process, the COD removal efficiency increased from43.5%to63%,UV254removal rate from40.7%to47.8%, ammonia removal efficiency increased from40.7%to47.8%, turbidity removal rate increased from23.0%to60.0%.