Scale-up and design of a multi-phase multitubular photoreactor for wastewater treatment

The influences of the backmixing degree in photocatalytic reactors and the decay of radiant energy on the enlarged design of the photoreactor were studied. The results show that the distance between the lamp and the interface irradiated by UV light is required to be less than 10 cm since the radiant energy decreases remarkably with the distance in the inverse ratio of 1.56. Compared with annular reactors, the degradation efficiency of the organic compounds in water in multitubular photocatalytic reactors is higher owing to the smaller backmixing degree. The multi-phase water-treatment equipment composed of three multitubular photocatalytic reactors was designed to dispose the dying wastewater, and the chemical oxygen demand (COD) value can be reduced from 150-180 mg/L to less than 50 mg/L. The outlet water after treated is superior in quality to the first-grade norm of the national standard.