new chief operator, spent many hours reviewing historical data and current operational strategies. With the help of staff, he was able to make numerous changes over the course of a year, and within that time, reduced the average effluent nitrogen from 15 mg/L to 6 mg/L. The initial operational changes included reducing and optimizing the internal nitrate recycle and relocating the dissolved oxygen (DO) sensors in the aeration basins to provide more consistent and representative DO readings. Then, the staff focused its attention on the current DO control strategy by reviewing the existing control logic associated with the blowers, DO setpoint, proportionalintegral-derivative (PID) control, and mostopen-valve (MOV) strategies. The previous strategy utilized only a PI control method in the programmable logic controller (PLC) and had issues maintaining the DO setpoint within the basins.
After looking at historical DO and air flow trends, the staff started utilizing the D function of the PID control loop by creating a new strategy looking at the rate of change of the actual DO measurements to come up with an additional parameter to adjust the proportional gain. The results of the new strategy, developed in-house, achieved DO measurements in the basins much tighter to the actual DO setpoint, which in turn saved energy on the blower usage and improved the TN removal process. After these changes, the WRF saw an improvement in pH and a remarkable reduction in effluent TN from an average of 15 mg/L to 6 mg/L. Matthew and his team have also taken on major, in-house projects, such as rebuilding electrical panels, completely rehabilitating the sodium hypochlorite storage tanks and pumps, and numerous updated and optimized control schemes on supervisory control and data acquisition (SCADA), including in-house PID
tuning. They created a cascade and PID control loop after installing a free chlorine analyzer on the influent side of the CCC to automate the sodium hypochlorite dosing for the CCC. Since this improvement, the WRF has saved over 300 gallons of sodium hypochlorite per day and found the new strategy to be much easier to operate versus the original scheme. The dedication and hard work of the entire maintenance, electrical, and operational staff resulted in the Southwest WRF consistently producing exceptional effluent quality, exceeding all regulatory requirements, in addition to reduced chemical usage and energy demands. Matt Tebow, P.E., is a water/wastewater engineer with Kimley-Horn in West Palm Beach. S
NEWS BEAT The Florida Department of Environmental Protection (FDEP), in partnership with the Fish & Wildlife Foundation of Florida, has purchased a 578acre parcel in Gulf County within the St. Joe Timberland Florida Forever project. The property lies within the Apalachicola River and Bay watershed and expands upon the state’s recent 20,168-acre addition to the Lake Wimico tract. Through this acquisition, the public will have access to large expanses of natural areas throughout north Florida. These tracts include examples of almost all the natural communities of north and central Florida, including scrub, swamps, and springs. “This land is one of the most undeveloped, diverse, productive, and economically important natural systems in the southeastern United States,” said Noah Valenstein, FDEP secretary. “This acquisition will protect drinking water supplies, preserve the vitality and connectivity of wildlife habitats, and expand public lands access. This success is the result of cross-sector partnerships and dedicated coordination.” “The permanent protection of Lake Wimico is a great example of Florida Forever dollars being used to protect numerous aspects of Florida’s resources,” said Callie DeHaven, director of FDEP division of state lands. “We’re proud that we were able to work with our partners to complete this important acquisition and we look forward to continuing to build
these types of partnerships to acquire additional lands for conservation and recreation.” Said Andrew Walker, Fish & Wildlife Foundation of Florida president and chief executive officer, “We’re thrilled to partner with FDEP to add to the Apalachicola River wildlife and environmental area, ensuring that future generations can experience its natural beauty. The public is also part of this effort by purchasing the Wildlife Foundation of Florida license plate. Twenty-five dollars from each purchase supports protection and management of public lands.” “The public will benefit from this partnership as it provides more access to enjoy natural Florida,” said Kipp Frohlich, director of Florida Fish & Wildlife Commission (FWC) division of habitat and species conservation. “This project aligns perfectly with our mission to manage fish and wildlife resources and provide recreational opportunities—now and for future generations.” Florida Forever is the state’s conservation and recreation lands acquisition program, a blueprint for conserving the state’s natural resources and renewing its commitment to conserve its natural and cultural heritage. The FDEP division of state lands is Florida’s lead agency for environmental management and stewardship.
R
The South Florida Water Management District (SFWMD) governing board has
unanimously approved full funding for the Everglades Agricultural Area (EAA) Reservoir Project’s Stormwater Treatment Area (STA). “This vote will fully fund the Stormwater Treatment Area, the state’s portion of the EAA Reservoir Project, and help us continue to expedite this critical project,” said Chauncey Goss, SFWMD governing board chair. “Under the leadership of the governor, we are already turning dirt ahead of schedule to make this project a reality even sooner. The EAA Reservoir Project is critical to reducing damaging discharges, sending more water south, and storing excess rainfall.” The $64 million transfer from the Florida Department of Environmental Protection (FDEP) will provide SFWMD all the funds it needs to complete the 6,500-acre STA that will clean water stored in the 240,000 acre-foot EAA Reservoir and allow it to be moved south to the Everglades. The SFWMD expects to complete the STA portion of the project by 2023. When used in conjunction with other critical Everglades restoration projects that will be completed over the next several years, the EAA Reservoir Project will reduce environmentally damaging discharges from Lake Okeechobee to the northern estuaries. The project will also increase the flow of clean water south to Everglades National Park. The reservoir and STA are a combined Everglades restoration effort being completed by SFWMD and the U.S. Army Corps of Continued on page 48
Florida Water Resources Journal • January 2021
47
