AWWA JAW60540

Bench-scale experiments determined the inactivation rates of adenovirus serotype 2 with low-pressure, high-output ultraviolet (UV) light, chlorine (Cl₂), and preformed chloramines. Studies with sequential chloramines were also done to mimic water treatment practices. Sequential experiments with adenovirus serotype 2 suspended in laboratory-grade water and natural waters containing ammonia were exposed to either UV light followed by Cl₂/chloramines or the reverse sequence. Adenovirus log reductions were quantified through cell culture techniques. A free Cl2 C × T (concentration × time) of 1.22 mg-min/L resulted in a 3.72-log reduction, a preformed chloramine C × T of 264.5 mg-min/L resulted in a 1.2-log reduction, a sequential chloramine C × T of 40.5 mg-min/L resulted in a 1-log reduction, and a UV dose of 40 mJ/cm₂ resulted in a 1-log reduction. Up to 4-log reductions were achieved with a UV dose of 40 mJ/cm₂ followed by a sequential chloramine C × T of 27.2 mg-min/L. This suggests that sequential disinfection may be the best option for dealing with UV-resistant organisms such as adenoviruses. Includes 39 references, figures.