City Manager's Bi-Weekly Report Volume 2 | Issue 14 | September 14, 2018 | Page 16

Utility Systems Cont’d Why Free Chlorinate? Free chlorination of our vast water distribution system is currently underway. We are temporarily modifying the disinfection process between August 31 and September 28. Port St. Lucie Utility Systems has not conducted a free chlorination operation since May 2008, which is a testament to our ability to maintain our outstanding water quality. Martin County Utilities, West Palm Beach Public Utilities, City of Fort Lauderdale, and Miami-Dade Water Department are just a few of our many neighboring utilities who conduct free chlorination annually or as they deem necessary. The Florida Department of Environmental Protection (FDEP) cites in their Disinfection Byproducts Requirements the following, "The definition of 'normal operating conditions' include any routine maintenance practices. An event such as a chlorine burn, a switch from chloramine to chlorine, is considered to be part of normal operations of a system for periodic maintenance. A water line break or other disruptive event which is outside the control of the facility is considered non-normal operation condition. The length of chlorine burns should be kept to a maximum of 21 days. Whenever possible, systems should try to optimize processes using guidance such as AWWA manual 'A Guide to the Implementation and Use of Chloramines'." The American Water Works Association (AWWA) states, “chloramines are widely used to maintain a disinfectant residual in water distribution systems. However, chloraminated distribution systems can promote the growth of nitrifying bacteria, an undesirable condition known as nitrification. Many chloraminated systems minimize the potential for nitrification by converting from chloramines to free chlorine on a periodic basis. The concept behind this switch is that free chlorine will oxidize any ammonia present in the distribution system, thus removing the food source for nitrifying bacteria, and will reduce the number of nitrifying bacteria.” Our Promise Port St. Lucie Utility Systems will continue to work closely with FDEP and our other regulatory agencies to maintain and provide a safe and clean water supply for our customers through the use of preventative maintenance and industry- wide best practices. Water is essential for life and it is essential for this utility to continue to provide clean, safe, great-tasting drinking water our customers can trust. References: 1. Florida Department of Environmental Protection Memorandum: Clarification of Rile 62-550.822 Disinfection Byproducts (DBP) Requirements 2. American Chemistry Council https://chlorine.americanchemistry.com/Chlorine/ DrinkingWaterFAQ/ 2. American Water Works Association https://www.awwa.org/store/productdetail.aspx? productid=7989 3. Centers for Disease Control and Prevention https://www.cdc.gov/healthywater/drinking/public/chlorine -disinfection.html 4. Port St. Lucie Utility Systems 2017 Water Quality Report Hydrant flushing schedule Watch Positively Port St. Lucie for an in-depth discussion with Utility Systems Laboratory, Cross Connection, and Environmental Compliance Manager Joe Presti and Cross Connections Supervisor Glen Cockrell. 16