This paper describes a twofold approach to computer modeling of lead and copper corrosion and the transport of the metals through the water distribution system.  The soluble lead and copper transport through a distribution system is modeled based upon the maximum solubility of these metals over the temperature and pH range likely to be encountered from the water source, through the high end of the expected temperature range in hot water heaters and dishwashers.  The impact of mixing water sources on solubility can also be modeled.  An expanded version of methods developed by Dr. Shock of the US Environmental Protection Agency is used for the models for the solubility calculations.  The ion association model calculations include the impact of phosphates and polyphosphate treatments on lead and copper solubility.  Similar methods are used to determine the maximum soluble inhibitor concentrations in industrial and municipal systems.  Corrosion rate models are developed and used for the prediction of lead, copper and mild steel corrosion rates.  Generalized models are discussed as well as the development of models for a specific water source or blend based upon field and/or laboratory testing.

17-06: Modelling Lead and Copper Corrosion and Solubility