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Cincinnati, OH, United States

Clark R.M.,9627 Lansford Dr. | Yang Y.J.,U.S. Environmental Protection Agency | Impellitteri C.A.,U.S. Environmental Protection Agency | Haught R.C.,U.S. Environmental Protection Agency | And 3 more authors.
Journal - American Water Works Association | Year: 2010

It has been hypothesized that internal corrosion of metal pipes can result in the deterioration of water quality, including the loss of chlorine residuals. Pipe-wall demand for free chlorine has been attributed to a number of factors such as pipe age and material, pipe diameter, temperature, and pipe roughness. Recent studies have demonstrated that in older unlined metal pipes, chlorine wall demand increases with flow rate. DiGiano and Zhang (2005) observed, in their experiments, that cast-iron pipes exhibited zero-order pipe wall reactions, which increased with velocity because of mass transfer considerations. They found that steel pipes exhibited first-order reactions. Al-Jasser (2007) demonstrated that service age in both steel and cast-iron pipes can increase wall demand. © 2010 American Water Works Association. Source


Clark R.M.,9627 Lansford Dr. | Carson J.,9627 Lansford Dr. | Thurnau R.C.,9627 Lansford Dr. | Krishnan R.,9627 Lansford Dr. | Panguluri S.,9627 Lansford Dr.
Journal / American Water Works Association | Year: 2010

A CPHM with shared frailty for metallic and PVC pipe has been developed. The model was developed with data from a water supply utility whose pipe composition, age, and break frequency can be classed as a typical US distribution system. The pipe run model was developed to make decisions regarding repair and replacement for various types of material. However, utilities are increasingly taking a more analytical approach and using their maintenance and cost histories to get a better perspective on their asset management activities. These types of models can also be useful in making decisions regarding the management of distribution system components. Water utilities are increasingly concerned with applying asset management techniques to their distribution systems. Data from other water systems would also allow estimation of model parameters for other piping materials. Modeling a larger variety of piping materials would be extremely useful. Source

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