Lake Region Water Treatment Plant, BELLE GLADE, FL
Complete professional installation of a new water treatment facility; implementation of leading-edge water treatment technology; economical expansion options; expert handling of delicate and costly membrane elements; professional upgrade of critical electrical and other systems; dependable back-up emergency power; extensive performance testing to ensure proper operation; efficient shift to fast-track installation to help client handle an unexpected drought combined with unusually low water levels; greater safety for plant operators and the surrounding community.
To provide clean water that tastes, smells, and looks better than their previous water, and is from a more reliable source.
SCOPE OF SERVICES
The Lake Region Water Treatment Plant (WTP) provides water to the cities of Belle Glade, Pahokee, and South Bay in western Palm Beach County. Prior to implementation of this project, these communities relied on the surface water supply drawn from Lake Okeechobee. This source suffered from taste and odor problems due to turbidity, variations in quality, and algae blooms in the lake and surface runoff. Reliability was also an issue because of droughts and conflicts with the South Florida Water Management District's (SFWMD) efforts to manage the lake's water levels.
The PBCWUD awarded Poole & Kent the contract for construction of a new 10-million- gallons-per-day (mgd) capacity low-pressure reverse osmosis (LPRO) water treatment plant. Poole & Kent's scope of work included scheduling, coordinating, procuring, and installing all reverse osmosis (RO) process equipment, finished water storage, and high-service pumping. The company also received, stored, and loaded the membrane elements for the LPRO process, and oversaw coordination and completion of a 30-day membrane system performance test. All membrane process equipment and pumps are housed in a new building. In addition, the company installed the plant's disinfection system, which uses new on-site sodium hypochlorite generation- and-feed technology. This avoids the risks to water treatment plant operators and the surrounding community posed by the storage and handling of the large quantities of chlorine gas typically associated with conventional gas chlorination systems. Equipment installed and the processes it supports include:
- For the well pumps, Pool & Kent used stainless steel submersible turbine pumps to bring raw water for the reverse osmosis (RO) process from the brackish Upper Floridian Aquifer, which is approximately 1,300 feet deep.
- The process design included a 0.5-milliongallons- per-day (mgd) raw water blend. This maintains desirable levels of certain dissolved minerals in the finished water.
- Chemical pretreatment systems for the RO process include bulk storage tanks, chemical metering pumps, and chemical piping for 93-percent sulfuric acid. The acid reduces feedwater pH to help control carbonate scaling; an antiscalant helps control membrane fouling.
- A 5-micron filtration system with stainless steel cartridge filters pre-treats membrane feedwater.
- The RO process consists of four two-stage membrane units, each with a permeate capacity of 2.375 mgd. Each unit is equipped with a dedicated stainless steel vertical turbine membrane feed pump. The RO system operates at a recovery rate of 80 percent, with the 20 percent reject concentrate disposed of in a deep injection well.
- The membrane permeate is routed to a degasification system for removal of dissolved hydrogen sulfide and carbon dioxide gas. This system consists of two packed-tower, forceddraft- type degasifiers and blowers, and two odor-control scrubbers to remove the hydrogen sulfide from the degasifier off-gas.
- Following degasification, the treated water is collected in the newly constructed clearwell for chemical post-treatment. Posttreatment chemical systems include bulk storage and feed systems that deliver sodium hydroxide to adjust pH, sodium hypochlorite and ammonia for disinfection, and fluoride for oral hygiene.
Following post-treatment and disinfection, the finished water is pumped from the clearwell to a 3.0-million gallon (MG) pre-stressed concrete storage tank with a new high-service transfer pumping system. The water is then ready for distribution. Back-up emergency power for the plant is provided by a diesel-powered generator and distribution system. The diesel fuel is stored on site. In addition, Poole & Kent oversaw a variety of associated improvements, including miscellaneous site work, as well as paving, grading, and drainage. The company also put in ductile iron, PVC, and stainless steel yard piping, and upgraded the electrical, instrumentation, and controls systems.
During the height of construction activities, the South Florida area experienced a record drought that stretched into mid-2008. The drought and extremely low water levels in Lake Okeechobee, the source of the client's water at that time, created water quality problems with the municipalities' existing water supply. This prompted aggressive project acceleration. As a result, the Poole & Kent team, in cooperation with the owner, the SFWMD, and other concerned governing authorities, brought the plant on line by March 31, 2008, approximately three months ahead of schedule.
The PBCWUD owns and operates five water treatment plants that provide potable water to customers in the cities of Belle Glade, Pahokee, and South Bay in western Palm Beach County.