آب و فاضلاب (Mar 2021)
Investigation of the Sediment Formation Factors in Drinking Water Distribution Network of the City of Sough and its Relationship to Water Properties
Abstract
Given the increasing consumption of potable water in the world, efforts to adopt new solutions for the obtainment of the right amount of desirable water is essential. One of the chief issues facing the majority of industries including water industry is corrosion and sedimentation. The present study was conducted to address the corrosion and sedimentation of drinking water supply and distribution reservoirs in the city of Sough, Kohgiloye-Boyer-Ahmad province. Through descriptive analysis, the Langelier, Raisner, Pokorius, and aggressive indices to determine the corrosion and sedimentation potential of the water supply network were used. This study was aimed measure chemical and physicochemical information of 84 water samples from wells, water reservoirs and allocated water supply network of the area. The samples were collected and analyzed from 2007 to 2016 by the provincial Water and Wastewater Company. The results indicated that the mean indices were -0.589±0.63 (low to moderate corrosion), 8.470±0.797, (low to moderate corrosion), 7.472±0.228 (low to moderate corrosion), respectively and 12.015±0.227 (mild aggressive or very corrosive) respectively. The water supply sources under investigation had low to moderate corrosion and little tendency to develop eggshell sedimentation. The water supply sources of the study area had low to moderate corrosion and had a slight tendency for eggshell sedimentation. Drinking water allocated to Sough water supply network in the direction of joint drinking water transmission of Dehdasht and Sough within 17 km of joint water supply from Sepah Tapeh reservoir (Dehdasht and Sough joint) is separated and directed, within 15 km by the transfer line and pump station, to Sough city. The average values of corrosion and sedimentation indices of the city of Sough water supply and distribution network (Lanzeley, Reisner, Pokoris and aggressive) were 0.63, 6.8, 7.28 and 12.8, respectively which indicate tendency toward sedimentation, relative tendency toward CaCO3, and non-aggressiveness. Despite the fact that the average pH of the joint water resources of both cities was 7.78. In summer, the water pH of Sough allocated water network increased to 8.5. Values and mean values of corrosion and sedimentation indices of Sough water supply network during hot seasons of the year show that the water of this network tends to precipitate. The findings also suggest that the average water temperature of the allocated water supply network in these 15 kilometers of transition which includes the transmission line and surfaced metal reservoirs had an increase in temperature around 10 °C. This temperature rise was due to the environment temperature (above 48 °C), the hot water in metal reservoirs and the surfaced steel transmission line in water supply network components. This physical change of water temperature is the main factor behind sedimentation.
Keywords
