Comparison of different surface disinfection treatments of drinking water facilities from a corrosion and environmental perspective

Surface disinfection of water facilities such as water wells requires measures that can remove pathogens from the walls to ensure a high drinking water quality, but many of these measures might increase corrosion of the contact surfaces (often highly pure steel) and affect the environment negatively due to disinfectant-contaminated waste sludge and wastewater. Today, most treatments worldwide are based on hypochlorites. We investigated the extent of corrosion during treatments of steel at relevant conditions of ozone, sodium, and calcium hypochlorite for drinking water preparation, utilizing weight loss, electrochemical, solution analytical, and surface analytical methods. The ozone treatment caused significantly less corrosion as compared with sodium or calcium hypochlorite with 150–250 mg/L active chlorine. Hypochlorite or other chlorine-containing compounds were trapped in corrosion products after the surface disinfection treatment with hypochlorite, and this risked influencing subsequent corrosion after the surface disinfection treatment. A life cycle impact assessment suggested ozone treatment to have the lowest negative effects on human health, ecosystems, and resources. Calcium hypochlorite showed the highest negative environmental impact due to its production phase. Our study suggests that ozone surface disinfection treatments are preferable as compared with hypochlorite treatments from corrosion, economic, and environmental perspectives. Funding details: Ministry of Science and Higher Education of the Russian Federation, К2-2019-007; Funding text 1: Visby Scholarship Offer 02149_2017 from Swedish Institute. Ministry of Science and Higher Education of the Russian Federation in the framework of Increase Competitiveness Program of NUST «MISiS» (№ К2-2019-007), implemented by a governmental decree dated 16th of March 2013, N 211.; Funding text 2: Open access funding provided by Royal Institute of Technology. Valentin Romanovski is grateful for a scholarship from the Swedish Institute within the Visby program and for the financial support of the Ministry of Science and Higher Education of the Russian Federation in the framework of Increase Competitiveness Program of NUST «MISiS» (№ К2-2019-007), implemented by a governmental decree dated 16th of March 2013, N 211. The authors thank Jonas Hedberg for some useful references and for help with operating the Raman Spectrometer. The authors thank Peter May for valuable discussions and help regarding the JESS software for chemical speciation modeling.