Innovative Solutions for the Most Challenging Lift Station in Sarasota County: Rehabilitation of the Wendell Kent Regional Pump Station

Excessive repairs and maintenance have plagued the Wendell Kent Regional Pump Station (Sarasota County, Fla.) since operation began in 2007. The station conveys flow from more than two dozen upstream lift stations and approximately one-third of the influent to the County's largest water reclamation facility. Chronic issues included severe FOG accumulation (weekly ~12-inch mats), extreme H₂S vapor concentrations (>1,000 ppm), recurring odors, pumping reliability risks, and premature corrosion, culminating in an emergency replacement of the ductile iron influent force main in 2021, less than 15 years from going in service. Concurrent development around the site increased expectations for quieter, low-profile, and visually unobtrusive odor control. This abstract presents the multidimensional rehabilitation of Wendell Kent RPS, including CFD-guided hydraulic mixing, adjustable baffle modifications, odor-control modeling and validation, corrosion-resistant materials and coatings, and stringent bypass pumping and construction phasing within a 12 MGD envelope. Weekly FOG accumulation required intensive manual removal. Wet well geometry and influent distribution promoted stratification, dead zones, and limited shear, allowing scum and floatables to coalesce. Upstream interventions lacked durable effectiveness at the RPS scale, necessitating hydraulic solutions within the wet well. Measured H₂S concentrations exceeding 1,000 ppm indicated aggressive biogenic corrosion conditions, resulting in widespread metal degradation and premature asset failure. Proximity to newer development heightened odor, noise, and visual constraints, while operational risk tolerance remained low due to ~24 upstream stations feeding the basin and an RPS capacity of 12 MGD (ADF ~4 MGD). The rehabilitation therefore required improved reliability, redundant pumping and sensing, and a robust bypass strategy to maintain service during construction. [b]Objectives[/b] 1. Suppress FOG through hydraulic optimization to improve influent distribution, shear, and transport. 2. Reduce H₂S emissions and stabilize wet well off-gas through appropriate conditioning and odor control. 3. Eliminate corrosion pathways using corrosion-resistant materials and verified coating systems. 4. Increase reliability through redundancy, instrument differentiation, and resilient emergency pumping arrangements. 5. Improve community-facing profile and acoustics with a quieter, low-profile odor control solution. [b]Methods & Design Approach[/b] Field assessments supported phased design and construction planning. CFD compared baffle and hydraulic jet configurations to minimize dead zones, increase surface shear, and limit air entrainment. External pumped jet mixing was selected over aeration, submersible mixers, and chemical approaches to deliver targeted, maintainable shear with low noise. Stop-log baffles provided commissioning adjustability for seasonal/diurnal variability. Odor control was sized using wet well volume (~3,600 ft³) and ventilation targets (~1,500 cfm; ~25 ACH) and validated through field testing to confirm emissions, blower sizing, and acoustics. Corrosion mitigation used HDPE influent piping with fused fittings, lined valves, and certified coatings installed under strict QA/QC. Reliability upgrades included redundant level instrumentation, diesel emergency pumping provisions, and fail-safe control logic. A 12 MGD bypass plan maintained service during demolition, installation, and coating work. [b]Alternatives & Selection Rationale[/b] Aeration/large-bubble mixing were rejected for energy, noise, and aerosolization risk; submersible mixers for corrosive-environment maintenance burden; and hot water spray/chemicals as symptomatic rather than hydrodynamic fixes. Metallic influent piping was excluded due to high-H₂S failure history. Odor control options were screened for performance, low profile, and low noise, with final selection supported by modeling and field validation. [b]Early Outcomes[/b] Initial observations indicate reduced frequency and thickness of FOG accumulation, improved odor-control performance, mitigated corrosion risk through material separation and coatings, and increased operational resilience during construction through redundancy and bypasses. [b]Discussion & Lessons Learned[/b] Durable FOG control requires reshaping hydraulics, not surface treatments. CFD proved effective as a decision-support tool when paired with operational insight. Material selection is a primary lifecycle risk control in high-H₂S environments, and coating performance depends on rigorous QA/QC. Reliability must extend beyond steady-state operation to construction and abnormal events. Community interface considerations can be met without compromising process performance. [b]Conclusion[/b] Rehabilitating the Wendell Kent RPS required addressing root causes through hydraulic redesign, corrosion-resistant materials, validated odor control, and reliability-focused infrastructure. Early performance suggests meaningful reductions in FOG and odors, improved asset protection, and enhanced operational resilience. The approach provides a transferable framework for utilities facing similar wet well, corrosion, and community interface challenges.