Affiliations: School of Municipal and Environmental Engineering,
Harbin Institute of Technology, Harbin 150090, China | School of Environmental Science and Engineering, Ocean
University of China, Qingdao 266003, China | Shenzhen Water (Group) Co., LTD., Shenzhen 518031,
China
Abstract: The concentration of suspended solids of effluent often varies in a
wide range, therefore the dose of ultraviolet light (UV) in disinfection
process needs to be adjusted to meet the disinfection criterion at a high
frequency, and the desired disinfection effect is difficult to be ensured. The
particles size and particle-associated fecal coliform (F.C.) contribution, and
their influence on UV disinfection were investigated when
ClO_2 and UV combined disinfection process was used. The
results showed that suspended solids content had a major impact on UV
disinfection efficiency, especially the large particle size fraction. Particles
(D>10μm) associated F.C. were difficult to be disinfected and were the
main part of the tailings of F.C. inactivation curve.
Pre-ClO_2 oxidation could reduce the number of particles in
effluent, and make large particles decrease to small ones. Therefore, the
influence of particles on UV disinfection could be reduced after
pre-ClO_2 oxidation, and the resistance ability to particle
loadings of combined process was enhanced. Moreover, the combined process has a
lot of advantages, such as low toxicity, low operational/maintenance costs; it
is also convenient to be established in the existing wastewater plant or the
new planned one.
