AWWA ACE93153

During the first round of monitoring for the Lead and Copper Rule, the City of Martinez was surprised by high lead levels. The rule permits water utilities to consider how measures to control corrosion will affect other regulated water quality parameters. All of the corrosion control options called for modified chemical addition following filtration; thus, none would interfere with the primary disinfection process. But, because all the options require altering the finished water's pH, residual disinfection could be affected; this would need to be monitored. Phosphate inhibitor feed would also require a flushing program to remove existing corrosion byproducts in the distribution system. Addition of a zinc orthophosphate could cause problems for wastewater treatment facilities: one uses wetland treatment and the other uses a furnace. Phosphate corrosion inhibitors would cause taste problems during the transition period, especially for customers in older homes with galvanized pipes. Operational reliability would not be a concern for the pH adjustment option, which would require only a small increase in the existing sodium hydroxide feed levels. Of all the options, pH adjustment seems to cause the least problems and also be the least expensive.