Orange County Eastern Water Reclamation Facility

1. Introduction

The Eastern Water Reclamation Facility (EWRF) serves as a cornerstone of water resource management for the rapidly expanding eastern sector of Orange County, Florida. Operated by Orange County Utilities (OCU), this facility is a prime example of modern “One Water” philosophy, converting wastewater into a valuable community resource through high-level disinfection and nutrient removal. Currently rated at 24 million gallons per day (MGD), the EWRF supports a diverse service area that includes the University of Central Florida (UCF), the Central Florida Research Park, and dense residential corridors.

Unlike traditional wastewater treatment plants that discharge into surface waters, the EWRF is designed as a zero-discharge facility under normal operating conditions. It directs 100% of its effluent toward public access reuse (PAR) for irrigation and wetlands augmentation. Following the completion of the Phase V expansion, the facility features state-of-the-art biological nutrient removal (BNR) systems, ensuring compliance with Florida’s rigorous groundwater protection standards and supporting the region’s long-term sustainability goals.

2. Facility Overview

A. Service Area & Demographics

The EWRF services the eastern portion of the Orange County Utilities service area, a region characterized by mixed-use development, high-tech industry, and significant institutional presence. The service area encompasses approximately 80 square miles, serving an estimated population equivalent of over 200,000 residents. The collection system funnels flow through a network of regional master pump stations, accommodating the high diurnal peaks associated with the university and residential populations.

B. Operational Capacity

The facility has undergone sequential expansions to keep pace with regional growth. The most recent major upgrade (Phase V) brought the permitted capacity to 24.0 MGD.

• Annual Average Daily Flow (AADF): ~17-19 MGD
• Design Capacity: 24.0 MGD
• Peak Hydraulic Capacity: ~60 MGD (Peak 2-hour flow)

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Current planning indicates the facility will require expansion to 30+ MGD (Phase VI) within the next decade to accommodate projected growth in the Innovation Way corridor.

C. Discharge & Reuse Strategy

The EWRF operates under a Florida Department of Environmental Protection (FDEP) permit that emphasizes water reclamation. The facility produces reclaimed water that meets “public access” standards. The effluent management system is comprised of:

• Public Access Reuse (PAR): Distribution to residential neighborhoods, golf courses, and commercial properties for irrigation via a purple pipe network.
• Rapid Infiltration Basins (RIBs): Groundwater recharge via percolation ponds located on-site and at regional RIB sites.
• Wetlands Augmentation: Highly treated effluent is used to maintain hydroperiods in constructed and natural wetlands, enhancing local ecology.

3. Treatment Process

The EWRF utilizes a sophisticated treatment train designed to achieve Advanced Wastewater Treatment (AWT) standards, specifically targeting low nutrient concentrations (5-5-3-1 standards for CBOD, TSS, TN, TP). The process is divided into two primary plants (Plant 1 and Plant 2) running in parallel.

A. Preliminary Treatment

Raw wastewater enters the headworks where it undergoes physical separation. The facility utilizes mechanical coarse and fine bar screens to remove large debris and rags. Following screening, flow enters vortex grit removal systems where inorganic solids (sand, gravel) are settled out by centrifugal force. The headworks is enclosed and ventilated to chemical scrubbers for odor control, utilizing a multi-stage process (often acid/bleach or biological) to neutralize hydrogen sulfide.

B. Secondary Treatment (Biological Nutrient Removal)

The core of the EWRF is its Biological Nutrient Removal (BNR) system. The facility utilizes a modified 5-stage Bardenpho process (or similar Carrousel oxidation ditch configurations in older trains) to achieve nitrification, denitrification, and biological phosphorus removal.

• Anaerobic Zone: Promotes the growth of Phosphorus Accumulating Organisms (PAOs) for biological phosphorus removal.

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• Anoxic Zones: Facilitate denitrification, converting nitrates into nitrogen gas.
• Aerobic Zones: Provide oxygen via fine-bubble diffused aeration (smart aeration control) for nitrification (ammonia to nitrate conversion) and BOD oxidation.
• Internal Recycle (IR): High-volume internal recirculation pumps move nitrate-rich mixed liquor from aerobic to anoxic zones.

Secondary clarification is achieved via circular center-feed clarifiers with suction-header sludge removal mechanisms. Return Activated Sludge (RAS) is pumped back to the anaerobic zone, while Waste Activated Sludge (WAS) is diverted to solids handling.

C. Tertiary Treatment

To meet public access reuse standards, secondary effluent undergoes tertiary filtration. The facility utilizes Deep Bed Sand Filters and/or cloth media disc filters (depending on the specific train/phase). This stage physically removes remaining suspended solids and particulate phosphorus, polishing the water to near-drinking water clarity. Alum or polymer may be added upstream of filters to aid in coagulation and flocculation of phosphorus.

D. Disinfection

The EWRF utilizes High-Level Disinfection (HLD) using chlorine (sodium hypochlorite). While UV is common in many modern plants, chlorine is preferred here to maintain a residual disinfectant concentration in the extensive reclaimed water distribution network, preventing biological regrowth in the pipes. The system includes chlorine contact chambers (CCC) designed to provide the required contact time (CT) at peak flows.

E. Solids Handling

Solids processing is consolidated on-site. The process flow includes:

1. Thickening: WAS is thickened using Rotary Drum Thickeners (RDTs) or Gravity Belt Thickeners (GBTs) to reduce water volume.
2. Digestion: Thickened sludge is stabilized in Aerobic Digesters. Air is supplied to reduce volatile solids and vector attraction.
3. Dewatering: High-solids centrifuges dewater the digested sludge, producing a cake of approximately 18-22% solids.
4. Disposal: The resulting Class B biosolids are hauled off-site for land application (agricultural use) or composting at regional facilities.

4. Infrastructure & Energy

Physical Plant

The site spans several hundred acres, incorporating not just the hardscape treatment units but also extensive buffer zones and rapid infiltration basins. The campus includes a dedicated Operations Control Center (OCC), a certified water quality laboratory, and heavy maintenance bays.

Energy Efficiency & Reliability

Wastewater treatment is energy-intensive. EWRF has implemented Variable Frequency Drives (VFDs) on all major prime movers (blowers, RAS pumps) to match energy consumption with biological demand. The facility is backed by a tier-4 diesel generation complex capable of running the entire plant during grid outages—critical for hurricane resilience.

Odor Control

Given the proximity to residential zones like Waterford Lakes, odor control is paramount. The facility utilizes a combination of bio-trickling filters and chemical scrubbers at the headworks and solids handling buildings. Negative pressure is maintained in these buildings to prevent fugitive emissions.

5. Recent Upgrades & Major Projects

Phase V Expansion (2014-2018)

Project Value: ~$45 Million
Scope: The most significant recent undertaking was the Phase V expansion, designed to increase capacity from 19.0 MGD to 24.0 MGD.

• Key Improvements: Construction of a new BNR train, new secondary clarifiers, and expansion of the tertiary filtration system.
• Technology: Installation of high-efficiency turbo blowers to replace aging centrifugal blowers, significantly reducing the energy footprint per gallon treated.
• Drivers: Population growth in the UCF/Research Park corridor and stringent nutrient load limits imposed by the St. Johns River Water Management District.

Reclaimed Water Storage & Pumping Improvements (2020-2023)

To manage diurnal demand for irrigation water, OCU invested in expanded ground storage tanks and high-service pump stations. This allows the facility to store effluent during low-demand periods (night) and deliver it at high pressure during peak irrigation windows.

Upcoming: Phase VI Expansion (Planning Phase)

Orange County Utilities is currently in the preliminary design and master planning stages for Phase VI, which will likely push the facility capacity beyond 30 MGD. This project will also address aging infrastructure in the original “Plant 1” trains and potentially introduce membrane technologies if future regulatory limits tighten regarding emerging contaminants.

6. Regulatory Compliance & Environmental Performance

The EWRF operates under a rigorous FDEP Domestic Wastewater Facility Permit. As a facility discharging to reuse systems that may interact with groundwater, it adheres to strict AWT limits.

Typical Permit Limits (Annual Average):

• CBOD5: 5.0 mg/L
• TSS: 5.0 mg/L
• Total Nitrogen (TN): 3.0 mg/L
• Total Phosphorus (TP): 1.0 mg/L
• Fecal Coliform: Non-detect (High-level disinfection)

The facility consistently operates well below these limits, often achieving TN levels below 2.0 mg/L through optimized denitrification. This performance is critical for the “Eastern Service Area,” which is subject to Basin Management Action Plans (BMAPs) aimed at protecting the Econlockhatchee River and St. Johns River watersheds.

7. Operational Excellence

The EWRF is staffed 24/7 by state-certified wastewater operators. The facility leverages a comprehensive SCADA (Supervisory Control and Data Acquisition) system that provides real-time monitoring of Dissolved Oxygen (DO), Oxidation-Reduction Potential (ORP), and nutrient analyzers. This data integration allows for “feed-forward” control strategies, adjusting aeration and chemical dosing based on incoming ammonia loads.

Recognition: The facility has received multiple Earle B. Phelps Awards and operational excellence awards from the Florida Water Environment Association (FWEA), recognizing it as one of the top-performing advanced treatment facilities in the state.

8. Challenges & Future Planning

Nutrient Loading: As regulators tighten limits on nutrient loading to the Wekiva and St. Johns basins, EWRF must continuously optimize biological processes to reduce nitrogen without excessive chemical costs.

Biosolids Disposal: With Florida legislation (SB 712) placing stricter regulations on land application of biosolids to prevent nutrient runoff, OCU is evaluating long-term solids strategies, potentially including advanced thermal drying or regional collaboration for Class A biosolid production.

Growth Management: The linear growth of the UCF area requires constant capital improvement planning (CIP). Balancing active construction of Phase VI while maintaining permit compliance at near-capacity flows will be the primary engineering challenge of the coming decade.

10. Technical Specifications Summary

11. Related Facilities

The EWRF is part of a tri-facility network operated by Orange County Utilities, which also includes:

• South Water Reclamation Facility (SWRF): Serves the tourism corridor and southern residential areas (approx. 43 MGD capacity).
• Northwest Water Reclamation Facility (NWRF): Serves the Apopka and northwest county areas.

These facilities are interconnected via a complex force main and reclaimed water network, providing system redundancy and regional flexibility.

12. Frequently Asked Questions

Technical Questions

Q: What is the TN target for EWRF?
A: The permit generally requires an annual average of 3.0 mg/L Total Nitrogen, though operational targets are often lower (around 2.0-2.5 mg/L) to ensure a margin of safety.

Q: Does EWRF generate energy from biogas?
A: No. Because the facility utilizes aerobic digestion (which does not produce methane) rather than anaerobic digestion, there is no biogas cogeneration on site.

Q: How is the reuse water pressurized?
A: The facility utilizes high-service vertical turbine pumps to pressurize the reclaimed water distribution network, maintaining system pressure for irrigation customers miles away.

Public Interest Questions

Q: Is the water leaving the plant safe to touch?
A: Yes. The reclaimed water meets “public access” standards, meaning it is safe for incidental contact (like sprinklers hitting a passerby), though it is not potable (drinking) water.

Q: Can I tour the facility?
A: Orange County Utilities occasionally hosts tours for educational groups, universities (UCF), and professional organizations. Public tours should be requested directly through the OCU public outreach department.

Q: What causes odors near the plant?
A: While the plant has extensive odor control, occasional odors can occur during maintenance of scrubbers or extreme weather changes. OCU maintains a 24-hour hotline for odor complaints to adjust chemical dosing immediately.