Jefferson County Valley Creek Wastewater Treatment Plant Bessemer

1. INTRODUCTION

The Valley Creek Wastewater Treatment Plant (WWTP) stands as a cornerstone of environmental protection in central Alabama, operating as the largest facility within the Jefferson County Environmental Services Department (JCESD) network. Located in Bessemer, Alabama, this facility is engineered to treat an average daily flow of 75 million gallons per day (MGD), serving a substantial portion of the Birmingham metropolitan area, including heavy industrial zones and dense residential corridors.

Commissioned to protect the Black Warrior River basin, the plant has played a central role in the region’s recovery from historical sewer overflows. Following decades of intensive capital improvements driven by one of the nation’s most comprehensive EPA Consent Decrees, Valley Creek has evolved into a modernized facility capable of handling extreme wet-weather peaks exceeding 300 MGD. Today, the plant utilizes conventional activated sludge processes coupled with advanced solids handling to ensure stringent compliance with NPDES standards, representing a critical asset in the economic and environmental health of Jefferson County.

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2. FACILITY OVERVIEW

A. Service Area & Coverage

The Valley Creek WWTP services the “Valley Creek System,” which is the largest distinct drainage basin in the Jefferson County sewer network. The service area encompasses approximately 100 square miles, covering the western and central portions of the Birmingham metropolitan area. Municipalities served include the City of Bessemer, Hueytown, Fairfield, Midfield, Brighton, and portions of the City of Birmingham. The influent profile is a complex matrix of domestic wastewater mixed with significant industrial discharges, necessitating robust pretreatment monitoring and resilient biological processes.

B. Operational Capacity

While the facility maintains a permitted design capacity of 75 MGD for average flows, its engineering significance lies in its hydraulic peaking capabilities. Due to the age of the collection system and significant Inflow and Infiltration (I/I) challenges in the geological basin, the plant is designed to manage peak instantaneous flows approaching 350 MGD. Historical data indicates average dry weather flows fluctuate between 35 and 50 MGD, utilizing approximately 60% of the base design capacity, allowing for substantial buffering during storm events.

C. Discharge & Compliance

Treated effluent is discharged into Valley Creek, a water body that has historically suffered from industrial degradation but has seen marked ecological improvement in recent decades due to enhanced treatment standards. The discharge point is regulated under NPDES Permit AL0022713, administered by the Alabama Department of Environmental Management (ADEM). The facility operates under strict limits for Carbonaceous Biochemical Oxygen Demand (CBOD), Total Suspended Solids (TSS), Ammonia-Nitrogen, and E. coli, ensuring the protection of downstream water quality in the Black Warrior River ecosystem.

3. TREATMENT PROCESS

A. PRELIMINARY TREATMENT

The headworks at Valley Creek are designed for high-velocity removal of inorganic debris to protect downstream mechanical equipment. The system utilizes mechanically cleaned coarse bar screens to remove large rags and debris. Following screening, flow enters aerated grit chambers where velocity is reduced, allowing sand, gravel, and coffee grounds to settle while keeping organic material in suspension. The extracted grit is washed and dewatered before being hauled to a sanitary landfill. Given the high I/I during wet weather, the headworks includes hydraulic bypass channels to prevent flooding of the preliminary structures during peak flow events.

B. PRIMARY TREATMENT

Wastewater flows by gravity into primary clarifiers. These large circular tanks reduce the velocity of the water to allow settleable organic solids to drop to the bottom as primary sludge, while grease and oils float to the surface for skimming. The primary clarifiers at Valley Creek are essential for reducing the organic loading (BOD) on the secondary aeration basins by approximately 30-35% and TSS by up to 60%. Primary sludge is pumped directly to the solids handling train for anaerobic digestion.

C. SECONDARY TREATMENT

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The biological heart of the plant utilizes a Conventional Activated Sludge process. The facility employs multiple parallel aeration basins equipped with fine-bubble diffused aeration systems to maximize oxygen transfer efficiency. In these basins, a mixed liquor of microorganisms consumes the remaining dissolved organic matter and ammonia.

A critical operational strategy at Valley Creek is the ability to operate in “Step Feed” mode during high-flow events. This configuration prevents the washout of biological solids (biomass) during heavy rains by distributing influent flow at multiple points along the aeration basin, preserving the Mean Cell Residence Time (MCRT) necessary for treatment. Following aeration, the mixed liquor enters secondary clarifiers where the biomass settles out. A portion is returned to the head of the aeration basins as Return Activated Sludge (RAS), while excess growth is removed as Waste Activated Sludge (WAS).

D. DISINFECTION

Historically reliant on gaseous chlorine, the facility has undergone upgrades to modernize its disinfection approach. Currently, the plant utilizes Ultraviolet (UV) disinfection as the primary method for pathogen reduction during normal operations. The UV system channels effluent through banks of UV lamps, scrambling the DNA of bacteria and viruses to prevent reproduction. This shift reduces the formation of disinfection byproducts (DBPs) and eliminates the safety hazards associated with storing large volumes of chlorine gas. Chlorination/dechlorination backup systems remain available or are used for peak wet weather flows that exceed UV transmissibility limits.

E. SOLIDS HANDLING

Valley Creek operates a robust solids handling facility. Primary sludge and WAS are thickened—typically using gravity thickeners for primary and dissolved air flotation (DAF) or gravity belt thickeners for WAS—before being blended and fed into anaerobic digesters. The plant utilizes mesophilic anaerobic digestion to stabilize the sludge, reducing volatile solids and pathogen content.

The digestion process produces biogas (primarily methane), which is captured. The digested sludge (biosolids) is then dewatered using mechanical belt filter presses to achieve a cake solid concentration suitable for transport. The final Class B biosolids are typically hauled off-site for beneficial reuse through land application or disposal in permitted landfills.

4. INFRASTRUCTURE & FACILITIES

A. Physical Plant

The Valley Creek site spans over 50 acres in Bessemer. The campus includes the main operations building, a fully equipped compliance laboratory, maintenance shops, and the extensive tankage required for the 75 MGD process. The architecture is industrial, with recent additions focusing on functional resilience against flooding, as the plant sits at a low elevation relative to the receiving stream.

B. Energy Systems & Odor Control

Energy management is a priority given the facility’s scale. The aeration blowers represent the largest electrical load. JCESD has investigated and implemented various energy recovery strategies over the years, including the beneficial use of digester gas to heat the digesters, reducing natural gas dependency.

Odor control is a sensitive operational parameter due to the plant’s proximity to residential areas and the historic Bessmer downtown. The facility utilizes chemical scrubbers (wet scrubbers) and activated carbon filters at high-generation points such as the headworks and sludge dewatering buildings to mitigate hydrogen sulfide and mercaptan emissions.

5. RECENT UPGRADES & MAJOR PROJECTS

Valley Creek Peak Flow Management & Reliability (2010s-Present)

Project Context: The defining driver for capital projects at Valley Creek has been the 1996 Consent Decree. While the decree was terminated in late 2023 regarding certain obligations, it necessitated decades of investment.

Scope & Improvements:

• Blower Replacement Project: Replacement of aging centrifugal blowers with high-efficiency turbo blowers to improve aeration control and reduce energy consumption by up to 30%.
• UV Disinfection Retrofit: Installation of a high-intensity UV system to replace primary reliance on chlorination, improving effluent quality and operator safety.
• Collection System Rehabilitation: While technically outside the fence line, JCESD invested over $1 billion system-wide (with a heavy focus on the Valley Creek basin) in cured-in-place pipe (CIPP) lining and pipe replacement to reduce the massive I/I loads that hydraulically stress the plant.

Digester Gas & Energy Projects

JCESD has engaged in projects to rehabilitate the anaerobic digester covers and mixing systems. Upgrades typically involve replacing floating covers and installing linear motion mixers to enhance volatile solids reduction and gas production efficiency.

Upcoming Planning (2025-2030):

With the consent decree era concluding, the focus is shifting toward asset management and lifecycle replacement. Future projects are expected to focus on tertiary filtration feasibility to meet potential future nutrient limits (nitrogen and phosphorus) and further automation of the SCADA system for remote monitoring.

6. REGULATORY COMPLIANCE & ENVIRONMENTAL PERFORMANCE

A. Permit Requirements

Operating under NPDES Permit AL0022713, Valley Creek is subject to stringent discharge limitations. The permit generally dictates:

• CBOD5: Monthly average limits typically around 10-15 mg/L.
• TSS: Monthly average limits typically around 30 mg/L.
• Dissolved Oxygen: Minimum 5.0 mg/L to support aquatic life.
• E. Coli: Seasonal limits (geometric mean) to ensure swimmable/fishable status.

B. Compliance History

Historically, the facility faced challenges related to Sanitary Sewer Overflows (SSOs) within the collection system rather than plant-specific treatment failures. However, following the extensive capital improvements, the plant consistently meets its effluent discharge parameters. The termination of the Consent Decree serves as a regulatory testament to the improved operational stability and capacity management achieved by Jefferson County.

7. OPERATIONAL EXCELLENCE

A. Staffing

The facility is staffed 24 hours a day, 365 days a year. It requires a hierarchy of ADEM-certified wastewater operators, with shift supervisors typically holding Grade IV certifications, the highest level in Alabama. The team is supported by a dedicated maintenance staff comprising industrial electricians, mechanics, and instrumentation technicians.

B. Performance Metrics

Valley Creek typically achieves removal efficiencies exceeding 95% for both TSS and BOD during dry weather flows. The facility utilizes a robust SCADA (Supervisory Control and Data Acquisition) system that provides real-time data on flows, dissolved oxygen levels, tank levels, and equipment status, allowing for immediate process adjustments.

8. CHALLENGES & FUTURE PLANNING

A. Inflow and Infiltration (I/I)

The primary engineering challenge remains the wet-weather response. Despite massive rehabilitation, the geology and age of the Bessemer-area collection system allow significant groundwater and stormwater intrusion. The plant must constantly balance the biology of the activated sludge system against hydraulic washouts during severe storms.

B. Nutrient Regulation

Like many facilities in the Southeast, Valley Creek faces the prospect of future numeric nutrient criteria for Nitrogen and Phosphorus. The current infrastructure is designed primarily for Carbon removal and Nitrification (Ammonia removal). Future permits may require the construction of denitrification zones or chemical phosphorus removal facilities, necessitating significant capital expenditure.

C. Financial Sustainability

Following Jefferson County’s historic bankruptcy (triggered largely by sewer debt), the department operates under a strict rate structure and asset management plan. Balancing the need for continued infrastructure renewal with ratepayer affordability remains the strategic priority for JCESD leadership.

9. COMMUNITY & REGIONAL IMPACT

The Valley Creek WWTP is an economic enabler for western Jefferson County. By providing reliable wastewater capacity, it supports major industrial operations and commercial developments along the I-20/59 corridor. Furthermore, the improved water quality in Valley Creek has contributed to the revitalization of the watershed, turning what was once an industrial drainage ditch into a recovering ecosystem that flows into the recreational waters of the Black Warrior River.

10. TECHNICAL SPECIFICATIONS SUMMARY

11. RELATED FACILITIES

The Valley Creek WWTP is part of a larger network operated by Jefferson County. Engineers and operators may also be interested in:

• Village Creek WWTP: The other major large-scale facility serving the northern Birmingham area.
• Five Mile Creek WWTP: Serving the northern county communities.
• Cahaba River WWTP: A highly advanced facility discharging into the environmentally sensitive Cahaba River.

12. FAQ SECTION

Technical Questions

Q: What is the peak flow capacity of Valley Creek WWTP?
A: The facility is hydraulically rated to handle peak flows of approximately 350 MGD to manage wet weather surges.

Q: Does Valley Creek perform biological nutrient removal (BNR)?
A: Currently, the plant is designed for BOD removal and nitrification (ammonia removal). It does not have a dedicated BNR process for Total Nitrogen or Total Phosphorus at this time.

Q: How are biosolids handled?
A: Sludge is stabilized via anaerobic digestion, dewatered using belt filter presses, and the resulting Class B biosolids are typically land-applied or landfilled.

Q: Is the plant currently under a Consent Decree?
A: The 1996 Consent Decree, which drove massive upgrades, was largely terminated in late 2023, marking a return to standard regulatory oversight under ADEM.

Public Interest Questions

Q: Does the plant smell?
A: While wastewater treatment naturally generates odors, Valley Creek employs chemical scrubbers and carbon filters to minimize odors. Occasional odors may occur during maintenance or extreme weather events.

Q: Where does the water go after treatment?
A: The treated, disinfected water is discharged into Valley Creek, which flows into the Black Warrior River.

Q: Who do I contact for a tour?
A: Tours are typically arranged through the Jefferson County Environmental Services Department Public Education office.