Effect of sodium alginate on UVC inactivation of coliphage MS2

Organic micro-pollutants in drinking water treatment, including soluble microbial products (SMP) can affect the disinfection process of pathogens. This work studied the effect of sodium alginate (SA), a natural polysaccharide and model SMP, on UV inactivation of coliphage MS2 as an entric virus surrogate. SA could enhance UV inactivation, and the effect might be related to reactive oxygen species (ROS) generated from the SA solution. Calculated by UV dose requirement for a 4 log MS2 inactivation, 50 mg L-1 SA increased the inactivation efficiency by approximately 50%. Scavengers of possible reactive species were applied, and t-BuOH and NaN3 reduced the enhancing effect, indicating the production and contribution of hydroxyl radical and singlet oxygen, respectively. The former was not produced in the absence of SA, while the latter was generated by both the test medium and SA. The overall mechanism of virus disinfection by UV in the presence of SA was proposed to include direct UV damage, singlet oxygen produced from the test medium and SA, and hydroxyl radical from SA.