City Of Toledo Water Reclamation Facility

TARGET AUDIENCE

• Municipal consulting engineers evaluating wet weather treatment strategies (CSO control)
• Wastewater treatment plant operators and managers
• Environmental regulators focused on Lake Erie nutrient reduction
• Engineering firms pursuing hydraulic capacity upgrades
• University researchers studying Great Lakes water quality and algal blooms

1. INTRODUCTION

The Bay View Water Reclamation Plant (WRP) serves as the environmental fortress for Northwest Ohio, processing wastewater for the metropolitan Toledo area before discharging into the Maumee River, the largest tributary to Lake Erie. As the largest wastewater treatment facility in the region, Bay View plays a pivotal role in protecting the Great Lakes watershed from nutrient pollution and harmful algal blooms (HABs).

Operated by the City of Toledo, the facility is distinguished by its massive wet weather treatment capabilities. Following the completion of the 18-year, $527 million Toledo Waterways Initiative (TWI) in 2020, the plant now boasts a peak hydraulic capacity of 400 million gallons per day (MGD). This capacity is achieved through a hybrid system combining conventional activated sludge with high-rate ballasted flocculation, allowing the facility to virtually eliminate untreated Combined Sewer Overflows (CSOs) from the plant headworks, setting a regional benchmark for wet weather management in older industrial cities.

2. FACILITY OVERVIEW

A. Service Area & Coverage

The Bay View WRP services a diverse metropolitan area covering approximately 100 square miles. The service area includes the City of Toledo and contractual service districts in Lucas County, including the City of Rossford, Village of Walbridge, City of Northwood, Village of Ottawa Hills, and several townships. The collection system is a hybrid of separated sanitary sewers and aging combined sewers (stormwater and sanitary), necessitating the facility’s robust wet weather management protocols.

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B. Operational Capacity

The plant operates with a base design average flow of 100 MGD, with typical dry weather flows averaging between 60 and 65 MGD. However, the defining characteristic of Bay View is its elasticity. During significant precipitation events, the facility activates its High Rate Treatment (HRT) train. Historical trends indicate that while average dry weather flows have stabilized due to water conservation and population shifts, peak flow management remains the primary operational focus due to the region’s increasing storm intensity.

C. Discharge & Compliance

Treated effluent is discharged via Outfall 001 into the Maumee River, near the river’s mouth at Maumee Bay (Lake Erie). Given Lake Erie’s sensitivity to eutrophication, the plant operates under strict NPDES limitations regarding phosphorus and nitrogen. The facility has consistently met compliance standards following the TWI upgrades, specifically targeting Total Phosphorus limits to combat the recurrence of cyanobacterial blooms in the Western Basin of Lake Erie.

3. TREATMENT PROCESS

The Bay View WRP utilizes a split-stream treatment approach during wet weather events to maximize hydraulic throughput while maintaining permit compliance. The process train is described below:

A. PRELIMINARY TREATMENT

Influent wastewater enters the headworks where it passes through mechanical bar screens (typically 1/2 to 3/4 inch spacing) to remove large debris. Following screening, flow enters aerated grit chambers where velocity is reduced to allow inorganic sands and gravel to settle. The grit is removed, washed, and disposed of in landfills. The headworks is equipped with chemical scrubbers for odor control, critical due to the plant’s proximity to residential areas and the Maumee River waterfront.

B. PRIMARY TREATMENT

Flow is distributed to primary settling tanks. These rectangular clarifiers reduce flow velocity, allowing settleable solids to drop to the bottom as primary sludge and greases/oils to float to the surface for skimming. Ferric chloride is often added at this stage or prior to it to precipitate phosphorus and enhance sedimentation, achieving significant BOD and TSS reduction before biological treatment.

C. SECONDARY TREATMENT (Conventional Train)

The main biological treatment utilizes a Step Feed Activated Sludge process. This configuration allows operators to introduce primary effluent at multiple points along the aeration basin, which provides flexibility in managing solids loading and oxygen demand—vital for a plant handling variable CSO loads.

• Aeration: The basins utilize fine bubble diffusion to maximize oxygen transfer efficiency.
• Clarification: Mixed liquor flows to circular secondary clarifiers where biological floc settles.
• RAS/WAS: Return Activated Sludge is pumped back to the aeration basins, while Waste Activated Sludge is sent to the solids handling train.

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D. WET WEATHER TREATMENT (High Rate Treatment)

To handle flows exceeding the secondary treatment capacity (typically above 200 MGD), the plant utilizes a Ballasted Flocculation system (Actiflo® type technology).

• Process: Microsand and polymer are injected into the excess flow. The sand provides a heavy surface area for floc to attach to, drastically increasing settling velocity.
• Performance: This system allows for rapid clarification with a small physical footprint, treating the “peak” flow that bypasses the biological aeration tanks.
• Blending: The high-rate treated effluent is blended with the secondary effluent prior to disinfection, ensuring the combined discharge meets permit limits.

E. DISINFECTION

The facility utilizes chlorination (sodium hypochlorite) for disinfection to eliminate pathogenic organisms. Following the contact period in chlorine contact tanks, the effluent is dechlorinated using sodium bisulfite to protect aquatic life in the Maumee River. Disinfection is typically required during the recreation season (May through October).

F. SOLIDS HANDLING (Biosolids)

Toledo employs an advanced solids processing facility:

• Thickening: Waste activated sludge is thickened using gravity belt thickeners or dissolved air flotation (DAF).
• Digestion: Primary and thickened waste sludge undergo anaerobic digestion. This process stabilizes the solids, reduces volume, and generates methane gas.
• Dewatering: Digested sludge is dewatered using high-solids centrifuges.
• Beneficial Reuse: The final product is a Class A EQ (Exceptional Quality) biosolid marketed as “Nu-Earth.” It is widely used for agricultural land application and soil blending due to its nutrient content.

4. INFRASTRUCTURE & FACILITIES

A. Physical Plant

The site spans extensive acreage along the Maumee River. Architectural features range from historic 1920s brick structures to modern concrete basins constructed during the TWI era. The site includes a fully equipped NELAP-accredited laboratory responsible for compliance testing and process control analysis.

B. Energy Systems

The Bay View WRP is a significant energy consumer but employs recovery strategies. The anaerobic digesters produce biogas (methane), which is captured and utilized in Cogeneration (Combined Heat and Power – CHP) units. These engines generate electricity to offset grid consumption and produce heat required to maintain optimal temperatures in the digesters, exemplifying a circular energy model.

5. RECENT UPGRADES & MAJOR PROJECTS

The defining engineering achievement for the City of Toledo has been the Toledo Waterways Initiative (TWI).

Upcoming Projects (2024-2027)

With the major consent decree work completed, focus has shifted to asset management and nutrient optimization. Upcoming projects include:

• Aeration System Upgrades: Replacement of diffusers and blower optimization for energy efficiency.
• Electrical Distribution Improvements: Modernization of switchgear and substations to ensure reliability during grid fluctuations.
• Phosphorus Removal Optimization: Enhanced chemical dosing controls to meet tightening Total Phosphorus limits for Lake Erie protection.

6. REGULATORY COMPLIANCE & ENVIRONMENTAL PERFORMANCE

A. Permit Requirements

The facility operates under Ohio EPA NPDES Permit 2PF00000. Critical effluent limits include:

• CBOD5: Weekly/Monthly averages (typically < 15-25 mg/L).
• TSS: Weekly/Monthly averages (typically < 20-30 mg/L).
• Total Phosphorus: Strict limits (often < 1.0 mg/L monthly avg) to combat eutrophication.
• E. coli: Seasonal limits for recreational contact.

B. Compliance History

Since the completion of TWI, Bay View has maintained a strong record of compliance. The implementation of the wet weather high-rate train has successfully mitigated the bypass events that historically plagued the facility during heavy storms.

7. OPERATIONAL EXCELLENCE

A. Staffing

The facility is staffed 24/7/365 by a team of approximately 80-100 employees, including Ohio EPA certified wastewater operators (Class I through Class IV), maintenance mechanics, electricians, chemists, and administrative support. The Division of Water Reclamation emphasizes continuous education to maintain licensure.

B. Technology & Innovation

Toledo utilizes a robust SCADA system for real-time monitoring of all plant processes and remote pump stations. The integration of the Wet Weather Facility logic into the main plant control allows for automated diversion of flows based on hydraulic setpoints, minimizing operator reaction time during flash flood events.

8. CHALLENGES & FUTURE PLANNING

A. Current Challenges

• Nutrient Management: The algal bloom crisis in Lake Erie puts constant political and regulatory pressure on the plant to achieve lower phosphorus limits, potentially requiring future tertiary filtration.
• Aging Infrastructure: While TWI addressed capacity, much of the base infrastructure (concrete tanks, piping galleries) dates back decades and requires rehabilitation.
• Rate Affordability: Balancing the debt service from the $527M TWI program with affordable rates for Toledo residents remains a fiscal challenge.

B. Future Planning

The City maintains a long-term Capital Improvement Plan (CIP) focused on “State of Good Repair.” Future planning involves assessing the feasibility of biological nutrient removal (BNR) to reduce chemical costs and sludge production associated with ferric chloride addition.

9. COMMUNITY & REGIONAL IMPACT

The Bay View WRP is integral to the regional economy. By protecting the water quality of the Maumee River and Lake Erie, the facility supports the region’s multi-billion dollar fishing, boating, and tourism industries. The “Nu-Earth” biosolids program also supports the local agricultural community by providing a low-cost, nutrient-rich soil amendment, closing the loop on waste.

10. TECHNICAL SPECIFICATIONS SUMMARY

11. RELATED FACILITIES

Toledo CSO Basin Network: The plant is supported by a network of CSO storage basins located throughout the city, including the massive Downtown Storage Basin. These facilities capture first-flush stormwater and store it until the Bay View WRP has capacity to treat it.
Pump Stations: Over 30 lift stations convey wastewater to the plant, with major influent pumping located on-site.

12. FAQ SECTION

Technical/Professional Questions

1. What is the peak hydraulic capacity of the Bay View WRP?
The plant has a total peak wet weather capacity of 400 MGD, achieved by combining the secondary treatment capacity with the high-rate wet weather auxiliary train.

2. Does the facility use Biological Nutrient Removal (BNR)?
Currently, the plant primarily relies on chemical precipitation (ferric chloride) for phosphorus removal rather than a dedicated anaerobic/anoxic biological selector zone, though this may be evaluated in future master plans.

3. How is the “Nu-Earth” product classified?
Nu-Earth is a Class A Exceptional Quality (EQ) biosolid, meaning it meets strict pathogen and metal limits, allowing for unrestricted land application.

4. Was the Toledo Waterways Initiative a Consent Decree project?
Yes. The TWI was the result of a settlement with the U.S. EPA to address longstanding issues with Combined Sewer Overflows (CSOs) discharging raw sewage into local waterways.

Public Interest Questions

5. Does the plant cause the algae in Lake Erie?
No. In fact, the plant is a primary defense against algae. While wastewater treatment plants contribute a small percentage of total phosphorus to the lake, agricultural runoff is cited by researchers as the primary driver. Bay View strictly adheres to phosphorus limits to minimize its impact.

6. Can the public tour the Bay View facility?
Yes, the City of Toledo Department of Public Utilities typically offers tours for educational groups and during open house events. Interested parties should contact the Division of Water Reclamation directly.

7. How does the plant control odors?
The plant utilizes chemical scrubbers and biofilters at the headworks and solids handling buildings—the two primary sources of odor—to scrub air before it is released.