An Overview of the Water Production Process From the PW/Utilities Connection Newsletter
The following story ran in the August issue of PW/Utilities Connection newsletter. Stories like this one and others from the City’s Public Works & Utilities Department are published monthly in the PW/Utilities Connection newsletter. If you'd like a free subscription to the newsletter, please send an e-mail to firstname.lastname@example.org.
City of Melbourne Water Production Process Explained
At a recent water quality town hall meeting, the audience seemed attuned and appreciative of the description given by Water Production Superintendent David Phares on the Melbourne water production process. It seems worth a recap for those who were not able to attend the meeting or would like a chance to read the details.
The City of Melbourne supplies drinking water to a residential and commercial population of approximately 182,000. In addition to Melbourne, the water service area that covers 100 square miles includes Melbourne Beach, Indialantic, Indian Harbour Beach, Satellite Beach, Palm Shores, Melbourne Village and some parts of unincorporated Brevard County. Melbourne also supplies water on a wholesale basis to West Melbourne. The average water demand is approximately 17 million gallons per day (MGD).
There are two raw water sources used in the water production process that includes Lake Washington and the Floridan Aquifer. Each source is treated using a different treatment method.
Surface Water Treatment
Surface water is treated at the John A. Buckley Surface Water Treatment Plant using an Actiflo process to treat approximately 12.5 MGD. This is a high-rate water treatment process that uses fine sand and polymer to remove color and solids from lake water. Following this, the treated water goes through an ozonation process for greater control of taste and odor. Then the water is filtered through granulated activated carbon filters.
According to Phares, “There are very few water treatment facilities in the U.S. that have a process this complicated or use a raw water source that is as challenging to treat every day.”
Brackish groundwater is pumped from four production wells. It is then treated at the Joe Mullins Reverse Osmosis (RO) Water Treatment Plant. The RO process is used to remove a large majority of contaminants from water by pushing the water under pressure through semi-permeable membranes. The RO treatment process includes two treatment trains, each designed to produce 2.5 million gallons per day of product water for a total capacity of 5.0 MGD.
Blending and Distribution
After treatment, the water from both plants is blended and pumped to the distribution system to meet demands. Chloramine, which is formed from the combination of free chlorine and ammonia, is used for disinfection. Chloramine booster stations help maintain disinfection residuals at the extremities of the system.
Water storage tanks improve system pressure and storage capacity. Regular flushing at fire hydrants helps keep the water fresh while aging pipes are changed out under an ongoing, aggressive pipe replacement program.
In-house lab technicians run about 30,000 chemical analysis tests per year, along with approximately 2,500 bacteriological tests annually. The lab is crucial to ensuring water quality standards are met. They also collect other samples to send to contractors for further testing. Compliance testing monitors the quality of the raw lake water, water produced at the plant and throughout the distribution system. Testing is also done to monitor the stages of water treatment.
Currently, Lake Washington supplies approximately two-thirds of the water necessary to meet the total demand while groundwater provides the remaining one-third. Plans call for the City to double the RO capacity and install six additional wells in 2022 through 2024.
Melbourne’s water is highly regulated by the Florida Department of Environmental Protection. Detailed monthly reports are submitted and an annual water quality report (also known as a consumer confidence report) is sent to all customers every summer, as required by the U.S. Environmental Protection Agency. Much of the language in the report is mandatory for all public water systems and includes a chart of the testing results from the previous year, covering primary and secondary contaminants. Strict rules are in place to alert customers if any testing or testing procedures are in violation. In addition, precautionary boil water notices are required to be issued if pressure drops below 20 psi, which can happen due to water main breaks or other events.
Aerial view of the water production plants at Lake Washington.