Evaluation of water corrosion, scaling extent and heterotrophic plate count bacteria in asbestos and polyethylene pipes in drinking water distribution system

ABSTRACT

Corrosion and scaling is one of the most important factors influencing drinking water quality that cause health disorders and economic problems. The aim of this study was to evaluate these phenomena in two sources of surface (Makou city) and ground water (Khoy city) in water networks. Corrosion and scaling potential was surveyed by Langelier, Ryzener, aggressiveness, Larson and Puckorius Indices and with measuring water physical, chemical, and microbial parameters. Statistical paired samples t-test displayed significant difference in means value of Langelier, Ryzener, Puckorius indices between cold and warm seasons of the year in Khoy samples and significant difference in means value of Ryzener, Puckorius and aggressiveness indices between cold and warm seasons of the year in Makou samples (p-value <0.001). Heterotrophic plate count water samples investigated in two cold and hot seasons in Khoy were respectively 14 ± 16 cfu ml⁻¹ and 41 ± 26 cfu ml⁻¹ and in the town of Makou were 11 ± 7 cfu ml⁻¹ and 61 ± 29 cfu ml⁻¹, respectively. In terms of health impacts, corrosion in different mains is important, then providing proper measures for balancing water quality before entering to the network and substituting of mains to prevent economic and health problems are necessary.

KEYWORDS:

• corrosion index
• health impacts
• water
• Langelier
• Ryzener