City Of Akron Water Reclamation Facility

1. INTRODUCTION

The City of Akron Water Reclamation Facility (WRF) is the cornerstone of wastewater infrastructure for the Greater Akron metropolitan area and a pivotal environmental safeguard for the Cuyahoga River watershed. As one of the largest treatment facilities in Ohio, the plant treats an average of 65–75 million gallons daily (MGD) with a hydraulic design capacity to handle wet weather flows peaking significantly higher due to the region’s combined sewer system.

Originally commissioned in 1928, the facility has transitioned from basic primary treatment to a sophisticated tertiary treatment complex. It is the central component of the “Akron Waterways Renewed!” program—a $1.4 billion comprehensive initiative driven by a federal Consent Decree to eliminate Combined Sewer Overflows (CSOs). Today, the Akron WRF is distinguished not only by its volume but by its innovation in energy sustainability; the on-site Akron BioEnergy Center generates renewable electricity from anaerobic digestion, positioning the facility as a leader in the waste-to-energy sector.

2. FACILITY OVERVIEW

A. Service Area & Coverage

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The Akron WRF serves a 96-square-mile area covering the City of Akron and neighboring jurisdictions, including Fairlawn, Cuyahoga Falls, Stow, Springfield Township, and Bath Township. The collection system is a hybrid of separate sanitary sewers and legacy combined sewers. The combined portion, serving the older urban core, historically contributed to significant CSO events, necessitating the massive infrastructure overhauls seen over the last decade, including the construction of the Ohio Canal Interceptor Tunnel (OCIT) which feeds directly to the plant.

B. Operational Capacity

The facility operates with a design average flow of 90 MGD. However, the plant’s hydraulics are engineered for extreme variability. During dry weather, flows average between 60 and 70 MGD. During storm events, the facility activates wet-weather protocols capable of processing peak secondary flows up to 220 MGD, with total hydraulic throughput capacity (including chemically enhanced primary treatment) reaching even higher levels to mitigate CSO discharges.

C. Discharge & Compliance

Treated effluent is discharged into the Cuyahoga River. The plant’s performance is critical to the river’s ongoing recovery—a waterway famous for its historical pollution but now a designated American Heritage River. The facility operates under a strict National Pollutant Discharge Elimination System (NPDES) permit issued by the Ohio EPA, requiring rigorous removal of biological oxygen demand (BOD), total suspended solids (TSS), ammonia, and seasonal disinfection for bacteria.

3. TREATMENT PROCESS

The Akron WRF utilizes a conventional activated sludge process modified for step-feed operations during high flows, complemented by advanced anaerobic digestion for solids processing.

A. PRELIMINARY TREATMENT

Raw wastewater enters the headworks via gravity interceptors. The process begins with **Coarse Screening** utilizing mechanically cleaned bar screens to remove large debris (rags, wood, plastics) that could damage downstream pumps. This is followed by **Grit Removal**, where aerated grit chambers reduce the velocity of the flow, allowing heavy inorganic materials like sand, gravel, and eggshells to settle out. The removed grit is washed and dewatered for landfill disposal.

B. PRIMARY TREATMENT

Flow proceeds to rectangular **Primary Settling Tanks**. Here, hydraulic velocity is minimized to allow settleable organic solids to drop to the bottom as primary sludge, while oils and greases float to the surface for skimming.
Performance: Typically removes 50-60% of TSS and 30-40% of BOD. During wet weather events, ferric chloride and anionic polymer can be added to these tanks to enhance settling rates (Chemically Enhanced Primary Treatment – CEPT), allowing the units to handle hydraulic surges while maintaining removal efficiencies.

C. SECONDARY TREATMENT (Activated Sludge)

The biological heart of the plant consists of **Aeration Basins** employing an Activated Sludge process.
Configuration: The system is designed with **Step Feed** capability. During normal flows, it operates as a conventional plug-flow system. During peak wet weather, influent is introduced at multiple points along the aeration train. This strategy prevents the washout of Mixed Liquor Suspended Solids (MLSS) to the secondary clarifiers, protecting the biomass inventory while treating high volumes.
Clarification: The mixed liquor flows to **Secondary Clarifiers**, where the biological floc settles. A portion of the settled solids is returned to the aeration tanks as Return Activated Sludge (RAS), while the excess is removed as Waste Activated Sludge (WAS) for processing.

D. TERTIARY / WET WEATHER TREATMENT

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To manage excess wet weather flows that exceed the biological capacity, the facility utilizes **Retention Basins** and an **Enhanced High Rate Treatment (EHRT)** system. The EHRT unit employs ballasted flocculation (or similar high-rate settling technologies) to provide rapid solids separation and disinfection for storm flows, ensuring that even bypass water receives treatment before blending or discharge.

E. DISINFECTION

The clarified effluent undergoes **Chlorination** for disinfection to eliminate pathogenic organisms. Liquid sodium hypochlorite is the primary agent. Before discharge to the Cuyahoga River, the water is **Dechlorinated** using sodium bisulfite to prevent toxicity to aquatic life. Disinfection is typically required during the recreation season (May through October) per Ohio EPA standards.

F. SOLIDS HANDLING (Akron BioEnergy Center)

Akron has revolutionized its solids handling through the **Akron BioEnergy Center**.
Thickening: Primary sludge and WAS are thickened (gravity belts/centrifuges) before digestion.
Anaerobic Digestion: The facility utilizes a Temperature-Phased Anaerobic Digestion (TPAD) or similar high-efficiency configuration. This process stabilizes the sludge, reduces pathogen counts, and generates significant quantities of methane-rich biogas.
Dewatering: Digested biosolids are dewatered using high-solids centrifuges.
Disposal: The Class A/B biosolids are land-applied as soil amendment or disposed of via landfill if necessary.

4. INFRASTRUCTURE & FACILITIES

A. Physical Plant

Situated on a sprawling campus in the Cuyahoga Valley, the site includes administrative offices, a fully certified environmental laboratory, maintenance shops, and the massive treatment tankage. The topography requires significant pumping capacity to lift influent from the deep tunnel systems into the treatment train.

B. Energy Systems & The BioEnergy Center

The Akron BioEnergy Center is a defining feature of the facility.
Cogeneration: The facility captures biogas produced during anaerobic digestion and burns it in Combined Heat and Power (CHP) engine generators.
Electricity Generation: The system is capable of generating over 1.2 MW of renewable electricity, offsetting a significant percentage (often 30-50% or more) of the plant’s electrical demand.
Net-Zero Initiatives: The plant also accepts high-strength organic waste (FOG – fats, oils, grease) from external sources to boost gas production, generating revenue and further increasing energy output.

C. Odor Control

Given its location near the Cuyahoga Valley National Park and residential zones, odor control is paramount. The facility utilizes chemical scrubbers (wet scrubbers) and biofilters at the headworks and sludge processing areas to capture and treat hydrogen sulfide and other odorous compounds.

5. RECENT UPGRADES & MAJOR PROJECTS

Under the “Akron Waterways Renewed!” program, the facility has seen over $300 million in direct and related improvements over the last decade.

6. REGULATORY COMPLIANCE & ENVIRONMENTAL PERFORMANCE

A. Permit Requirements

The facility operates under NPDES Permit No. 3PF00000*ND. Key limits typically include:

• CBOD5: Weekly averages typically capped around 15-20 mg/L (seasonal variance).
• TSS: Weekly averages approx. 20-25 mg/L.
• Ammonia-Nitrogen: Strict limits (often < 2.0 mg/L in summer) to prevent toxicity.
• E. coli: < 126 CFU/100mL (Monthly Average) during recreation season.

B. Consent Decree Status

The City of Akron entered into a Consent Decree with the U.S. EPA and Ohio EPA (lodged 2009, entered 2014) to address CSOs. The WRF upgrades are a direct result of this legal mandate. The goal is zero untreated overflows in a typical rainfall year. The facility has successfully met milestones regarding secondary bypass elimination and increased wet weather treatment capacity.

7. OPERATIONAL EXCELLENCE

A. Staffing & Safety

The Sewer Bureau employs a specialized team of state-certified wastewater operators (Class I through IV), maintenance mechanics, electricians, and laboratory technicians. The plant emphasizes rigorous safety training, particularly regarding confined space entry and hydrogen sulfide exposure.

B. Technology & Innovation

Akron WRF utilizes a robust SCADA (Supervisory Control and Data Acquisition) system for real-time monitoring of all unit processes. The integration of the BioEnergy Center places the facility at the forefront of the “Utility of the Future” concept, moving beyond simple treatment to resource recovery (energy and biosolids).

8. CHALLENGES & FUTURE PLANNING

A. Current Challenges

• Financial Burden: The cost of the mandated improvements has led to significant sewer rate increases for residents. Balancing affordability with compliance remains a primary administrative challenge.
• Aging Infrastructure: While major systems have been upgraded, the underlying structure dates to 1928, requiring constant maintenance of concrete tanks and conveyance galleries.

B. Future Planning

Future focus areas include:

• Nutrient Removal Optimization: Anticipating stricter future limits on Total Phosphorus and Total Nitrogen to address algal blooms in the Lake Erie watershed.
• BioEnergy Optimization: Seeking additional high-strength waste streams to maximize generator uptime and revenue.
• Integrated Planning: Utilizing “Integrated Planning” frameworks to prioritize stormwater projects that offer the highest environmental return on investment.

9. COMMUNITY & REGIONAL IMPACT

The Akron WRF is a driver of the environmental renaissance of the Cuyahoga Valley. By virtually eliminating raw sewage discharges, the facility has allowed the Cuyahoga River to rebound, supporting kayaking, fishing, and the return of sensitive species like river otters and bald eagles. Economically, the plant provides stable, high-skilled employment and supports regional development by ensuring sewer capacity availability.

10. TECHNICAL SPECIFICATIONS SUMMARY

11. FAQ SECTION

Technical Questions

Q: What is the hydraulic retention time (HRT) of the system?
A: At average flows, HRT is standard for activated sludge (6-8 hours in aeration). During peak wet weather step-feed operation, HRT drops significantly, necessitating the use of the EHRT systems for excess flow.

Q: How much energy does the Akron BioEnergy Center produce?
A: The facility can generate approximately 1.2 to 2.0 MW of electricity depending on feedstock availability and biogas production rates, aiming for net-zero electrical consumption.

Q: Is the facility under a Consent Decree?
A: Yes, a federal Consent Decree was entered in 2014 requiring the City to implement the “Akron Waterways Renewed!” Long Term Control Plan to address Combined Sewer Overflows.

Public Interest Questions

Q: Does the plant smell?
A: While wastewater treatment naturally produces odors, Akron WRF employs advanced scrubbers and biofilters to neutralize odors before they leave the property line. Occasional odors may occur during maintenance or extreme weather.

Q: Where does the water go after treatment?
A: The treated, clean water (effluent) is discharged into the Cuyahoga River, which eventually flows north into Lake Erie.

Q: Can I tour the facility?
A: The City of Akron occasionally offers tours for educational groups and during specific open house events. Interested parties should contact the City of Akron Sewer Bureau directly for availability.