Background:
The biosolids treatment system at the Sawgrass Wastewater Treatment Plant (WWTP) utilizes a Dissolved Air Flotation Thickener (DAFT) process. This process thickens Waste Activated Sludge (WAS), with separated water returned to secondary treatment for further processing. The thickened WAS (TWAS) is then pumped from the sludge holding tanks to the City’s biosolids building, where it undergoes dewatering via centrifuges.
The existing DAFT facility is experiencing significant mechanical deterioration and has reached the end of its useful life. The two DAFT units, installed in 1987 and 1996, include flotation tanks, skimmers, pumps, polymer systems, air compressors, and a canopy structure which show substantial wear and require replacement to maintain reliable operations and permit compliance.
On August 10, 2021, the City Commission approved Project Agreement 21-009-HS with Hazen and Sawyer P.C. (Hazen) for the Sawgrass Wastewater Water Treatment Plant DAF Thickening Process Improvements project. Services included within the Project Agreement include engineering design, permitting, and bidding services.
The DAF improvements were originally intended to be completed as a single project and coordinated with the new Blower/Electrical Building under the Sawgrass WWTP Train A Secondary Treatment project, as portions of the work rely on new equipment to be housed in that facility. The new blower building is under construction but has an extended schedule for completion. In the interim, the DAF system has continued to experience operational failures, particularly with the east unit’s upper skimmer system. To avoid further delaying critical rehabilitation work, City Staff and Hazen identified portions of the project that could be constructed independently. As a result, the City amended the project agreement to divide the improvements into two phases, with Phase 1 addressing the most urgent equipment and structural needs. Included within the Phase 1 scope of work will be the replacement of instrumentation and control devices, new drive units with variable-speed motors, replacement of longitudinal upper skimmers, structural repairs to both DAF tanks, interior and exterior tank coatings, replacement of process piping and appurtenances, new canopy over the DAF tanks, along with associated electrical, instrumentation, and control work.
The DAF Phase 2 Improvements project is expected to be advertised in the near future and will include the pressurization tanks, polymer systems, air compressor systems, pumps, motors, and associated equipment that depend on the Blower/Electrical Building currently under construction under a separate construction contract (Sawgrass WWTP Train A Secondary Treatment project).
On August 29, 2025, Bid No. 25-56-04-CM was issued for the DAF Phase 1 project. Following the evaluation conducted by the Purchasing Office, Utilities Department, and Hazen and Sawyer, and under a separate Agenda Item Request, it is being recommended that the contract be awarded to the lowest responsive and responsible bidder, RF Environmental Services, Inc.
To support successful project execution, City staff developed Project Agreement 26-008-HS with Hazen, to provide Construction Management Services for engineering services during construction. These services will ensure all work complies with the bid documents and will support certification by permitting agencies.
Staff negotiated a fee for these professional services with Hazen, that is considered fair and reasonable for the scope and complexity of the work. This project is included within the City’s Five-year Capital Improvement Program and is listed in item number 26 in Exhibit ‘A’ Scope of Services of the Continuing Services Agreement with Hazen and Sawyer P.C.