City Of Savannah Presidents Street Wastewater Treatment Plant

The President Street Water Reclamation Center (WRC) stands as the cornerstone of wastewater infrastructure for the City of Savannah, Georgia. As the largest facility operated by the City’s Water Resources Department, it is permitted to treat a design flow of 27 million gallons per day (MGD). Located just east of the historic downtown district, the facility serves the core population of Savannah, handling flows from the city’s extensive collection system.

Originally constructed in the 1970s utilizing a cryogenic pure-oxygen process, the plant has undergone significant transformation in the last decade. Following a massive capital improvement program completed circa 2016, the facility was converted to a modern, energy-efficient conventional activated sludge process. Today, the President Street WRC represents a critical line of defense for the water quality of the Savannah River, supporting both the regional ecosystem and the thriving port economy.

FACILITY OVERVIEW

A. Service Area & Coverage

The President Street WRC serves the central and northern portions of Chatham County, including the historic downtown Savannah area, residential neighborhoods, and significant commercial corridors. The collection system is vast and complex, characterized by:

• Service Population: Approximately 140,000+ residents (city core and surrounding areas).
• Collection Infrastructure: A network of gravity sewers and force mains feeding into master lift stations that convey flow to the President Street headworks.
• Industrial Inputs: The facility accepts flow from light industrial and commercial sectors, necessitating robust influent monitoring programs.

B. Operational Capacity

The facility is engineered to handle substantial hydraulic variations, particularly given Savannah’s coastal climate and older combined/inflow-susceptible piping infrastructure.

• Design Capacity: 27 MGD (Annual Average Daily Flow).
• Current Average Daily Flow: Approximately 18.5 – 21 MGD.
• Peak Hydraulic Capacity: Capable of handling sustained peak flows exceeding 60 MGD during wet weather events.
• Capacity Utilization: Currently operating at approximately 70-75% of design capacity, allowing room for projected regional growth.

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C. Discharge & Compliance

Treated effluent is discharged into the Savannah River, a major tidal water body. The discharge is regulated under the National Pollutant Discharge Elimination System (NPDES) administered by the Georgia Environmental Protection Division (GA EPD).

• NPDES Permit Number: GA0020133
• Receiving Water Classification: Coastal/Estuarine (Tidal).
• Critical Parameters: Due to the Savannah River’s dissolved oxygen (DO) TMDL (Total Maximum Daily Load), the plant must strictly control Ammonia-Nitrogen and BOD/CBOD to prevent oxygen sag in the river.

TREATMENT PROCESS

The President Street WRC utilizes a customized secondary treatment train designed to transition from preliminary screening to high-level biological treatment and disinfection. The specific process flow is detailed below:

A. Preliminary Treatment (Headworks)

Raw wastewater enters the facility through large diameter force mains. The headworks facility is enclosed to manage odors and protect equipment from the elements.

• Screening: Mechanical bar screens remove large debris, rags, and plastics (ragging is a significant issue in urban systems).
• Grit Removal: Vortex grit chambers are utilized to remove heavy inorganic solids (sand, gravel) using centrifugal force. This protects downstream pumps and clarifiers from abrasion.
• Odor Control: The headworks is equipped with chemical scrubbers (wet scrubbers) and/or biotrickling filters to treat hydrogen sulfide (H₂S) before air is exhausted.

B. Primary Treatment

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Flow proceeds to primary clarifiers where gravity settling occurs.

• Configuration: Multiple circular primary clarifiers.
• Mechanism: Center-feed wells with skimmer arms to remove fats, oils, and grease (FOG) and bottom scrapers to collect primary sludge.
• Performance: Typically removes 30-35% of BOD and 50-60% of Total Suspended Solids (TSS) prior to the biological stage.

C. Secondary Treatment (Activated Sludge)

This stage represents the most significant engineering upgrade at the facility. The plant previously used a covered, high-purity oxygen system (UNOX style), which was energy-intensive and difficult to maintain. It has been converted to an open-air Conventional Activated Sludge (CAS) system.

• Aeration Basins: The retrofitted basins utilize fine-bubble diffused aeration. This technology maximizes oxygen transfer efficiency (OTE) compared to coarse bubble or mechanical surface aeration.
• Blowers: High-efficiency turbo or hybrid blowers provide air to the grid, controlled by Dissolved Oxygen (DO) probes to optimize energy consumption.
• Biological Process: The microbial biomass consumes organic matter and converts ammonia to nitrate (nitrification), which is critical for meeting the Savannah River DO standards.
• Secondary Clarifiers: Mixed liquor flows to secondary clarifiers where biological floc settles. Return Activated Sludge (RAS) is pumped back to the aeration basins, while Waste Activated Sludge (WAS) is sent to solids handling.

D. Disinfection

Following secondary clarification, the effluent undergoes disinfection to neutralize pathogens.

• Technology: Ultraviolet (UV) Disinfection.
• Configuration: In-channel UV banks.
• Benefits: The switch to UV eliminated the need for bulk chlorine gas storage and sulfur dioxide (for dechlorination), significantly improving site safety and eliminating the risk of chlorination byproducts (trihalomethanes) in the effluent.

F. Solids Handling & Biosolids

President Street is a regional hub for solids processing.

• Thickening: Primary sludge and WAS are thickened (using gravity belts or rotary drums) to reduce hydraulic volume.
• Digestion: Anaerobic digestion stabilizes the sludge, reducing volatile solids and pathogen counts.
• Dewatering: Digested sludge is dewatered using high-solids centrifuges.
• Biosolids Drying: The facility features a thermal drying system. This process converts dewatered cake into Class A EQ (Exceptional Quality) pelletized fertilizer. These pellets are marketed and sold/distributed for agricultural use or soil amendment, diverting waste from landfills.

INFRASTRUCTURE & FACILITIES

A. Physical Plant

The site occupies a large industrial footprint off President Street. The layout includes the Administration Building, Maintenance Shop, Operations Control Center, and the extensive tankage of the treatment train. Recent architectural improvements to the admin buildings have modernized the workspace for city engineers and operators.

B. Energy Systems

Wastewater treatment is energy-intensive. The conversion to fine-bubble aeration was primarily an energy-efficiency driver.

• Power: The plant operates on a dual-feed electrical supply for redundancy.
• Backup Generation: massive diesel generators ensure the plant maintains hydraulic control and treatment capability during grid outages, which is vital during hurricane season.

C. Odor Control

Given the plant’s proximity to the Eastern Wharf development and historic district, odor control is paramount. The facility utilizes a multi-stage approach including covering primary sources (headworks), chemical scrubbing, and biofiltration units to treat foul air streams before release.

RECENT UPGRADES & MAJOR PROJECTS

President Street Plant Conversion (2013-2016)

This was the defining project for the modern facility.

• Project Scope: Demolition of the cryogenic oxygen plant; retrofitting existing basins for fine bubble aeration; installation of new high-efficiency blowers; construction of new electrical distribution systems; upgrade to UV disinfection.
• Budget: Approximately $70 Million.
• Funding: Financed largely through Georgia Environmental Finance Authority (GEFA) loans and Clean Water State Revolving Funds (CWSRF).
• Contractors: Design by Thomas & Hutton / Jacobs (CH2M); Construction by Crowder Construction Company.
• Results: The project reduced energy costs, improved effluent consistency, and eliminated hazardous chlorine gas from the site.

Biosolids Dryer Facility

• Scope: Installation of a thermal drying facility to process dewatered sludge into Class A pellets.
• Driver: Reduce landfill tipping fees and create a beneficial reuse product.
• Outcome: Sustainable solids management complying with 40 CFR Part 503 regulations.

REGULATORY COMPLIANCE

A. Permit Requirements

The facility operates under a stringent NPDES permit. Key limitations typically include:

• TSS (Total Suspended Solids): Monthly average limits ~30 mg/L.
• BOD/CBOD: Strictly regulated to protect river oxygen levels.
• Ammonia (NH3-N): Seasonal limits usually apply, often tighter in summer months.
• Fecal Coliform: Must meet recreational water quality standards.
• Dissolved Oxygen (DO): Minimum effluent DO requirement (often > 5.0 mg/L).

B. Compliance History

The President Street WRC has maintained a strong record of compliance following its modernization. The conversion to activated sludge provided operators with greater process control, reducing the risk of permit excursions during flow variances.

OPERATIONAL EXCELLENCE

A. Staffing

The plant is staffed 24/7/365. It requires highly skilled personnel, including:

• Operations: Georgia Class I and Class II Wastewater Operators.
• Maintenance: Industrial electricians, millwrights, and instrumentation technicians.
• Laboratory: The facility houses a certified laboratory for process control and compliance reporting.

B. Technology

The plant utilizes a robust SCADA (Supervisory Control and Data Acquisition) system. This network of PLCs and HMIs allows operators to monitor dissolved oxygen levels, pump status, and flow rates in real-time from the control room, enabling rapid response to changing influent conditions.

CHALLENGES & FUTURE PLANNING

A. Infiltration and Inflow (I/I)

Like many historic cities, Savannah battles I/I. During heavy rains, stormwater enters the sanitary sewer system, causing flow spikes at the plant. The City has an ongoing aggressive pipe rehabilitation program to line sewers and seal manholes to reduce this hydraulic load.

B. Climate Resilience

Located in a coastal low-country zone, the plant is vulnerable to storm surge and sea-level rise. Future planning involves hardening critical electrical infrastructure and raising key assets above projected flood elevations to ensure continuity of service during hurricane events.

C. Nutrient Removal

While currently compliant, future regulatory trends usually point toward stricter nutrient limits (Total Nitrogen and Total Phosphorus). The facility’s layout and process selection were designed with flexibility to accommodate further nutrient removal upgrades if mandated by future NPDES cycles.

TECHNICAL SPECIFICATIONS SUMMARY

RELATED FACILITIES

The City of Savannah operates a network of treatment facilities to manage regional growth. While President Street is the largest, it works in concert with:

• Crossroads WRC: Serving the airport and rapidly growing industrial/logistics corridors.
• Georgetown WRC: Serving the southern residential communities.
• Wilshire WRC: Serving the southside residential and commercial areas.

FAQ

Technical Questions

1. What is the specific aeration method used at President Street?
The facility utilizes fine-bubble diffused aeration powered by high-efficiency turbo/hybrid blowers. This replaced the legacy high-purity oxygen (cryogenic) system.

2. Does the plant produce Class A or Class B biosolids?
The plant produces Class A biosolids through a thermal drying process, resulting in pathogen-free fertilizer pellets.

3. What is the NPDES limit for TSS?
While limits vary by season and permit cycle, typical monthly averages for facilities of this class in Georgia are around 30 mg/L.

4. Is the facility equipped for biological nutrient removal (BNR)?
The current activated sludge configuration supports nitrification (ammonia removal). Full denitrification and phosphorus removal may require chemical addition or process adjustments depending on future permit limits.

Public Interest Questions

5. Does the plant smell?
The City utilizes advanced odor control scrubbers and biofilters, particularly at the headworks and solids handling buildings, to minimize odors reaching the nearby downtown and riverfront areas.

6. Where does the water go after treatment?
The highly treated effluent is discharged into the Savannah River, where it rejoins the natural water cycle.

7. How does the plant handle hurricanes?
The facility has massive backup power generators and emergency response protocols to maintain operations during grid failures caused by tropical storms.

8. Who runs the facility?
The facility is owned and operated by the City of Savannah Water Resources Department and staffed by state-licensed wastewater professionals.