Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5117348 | Journal of Environmental Management | 2017 | 7 Pages |
â¢Data summary of Bacillus spore decontamination from drinking water infrastructure.â¢Flushing was ineffective at removing spores adhered to iron and cement-mortar.â¢Chlorine dioxide (25 mg/L) was the most effective decontaminating agent.â¢Data will help responsible authorities make decontamination decisions.
Decontamination of Bacillus spores adhered to common drinking water infrastructure surfaces was evaluated using a variety of disinfectants. Corroded iron and cement-mortar lined iron represented the infrastructure surfaces, and were conditioned in a 23 m long, 15 cm diameter (75 ft long, 6 in diameter) pilot-scale drinking water distribution pipe system. Decontamination was evaluated using increased water velocity (flushing) alone at 0.5 m sâ1 (1.7 ft sâ1), as well as free chlorine (5 and 25 mg Lâ1), monochloramine (25 mg Lâ1), chlorine dioxide (5 and 25 mg Lâ1), ozone (2.0 mg Lâ1), peracetic acid 25 mg Lâ1) and acidified nitrite (0.1 mol Lâ1 at pH 2 and 3), all followed by flushing at 0.3 m sâ1 (1 ft sâ1). Flushing alone reduced the adhered spores by 0.5 and 2.0 log10 from iron and cement-mortar, respectively. Log10 reduction on corroded iron pipe wall coupons ranged from 1.0 to 2.9 at respective chlorine dioxide concentrations of 5 and 25 mg Lâ1, although spores were undetectable on the iron surface during disinfection at 25 mg Lâ1. Acidified nitrite (pH 2, 0.1 mol Lâ1) yielded no detectable spores on the iron surface during the flushing phase after disinfection. Chlorine dioxide was the best performing disinfectant with >3.0 log10 removal from cement-mortar at 5 and 25 mg Lâ1. The data show that free chlorine, monochloramine, ozone and chlorine dioxide followed by flushing can reduce adhered spores by > 3.0 log10 on cement-mortar.