Louisville Metropolitan Sewer District Morris Forman Water Quality Treatment Center

1. INTRODUCTION

The Morris Forman Water Quality Treatment Center (WQTC) is the largest and oldest wastewater treatment facility in Kentucky, serving as the backbone of the Louisville and Jefferson County Metropolitan Sewer District (MSD) infrastructure. Treating an average of 105 million gallons daily (MGD) and serving nearly 75% of Jefferson County’s population, this facility is critical to the environmental health of the Ohio River.

Originally commissioned in 1958 and formerly known as the West County Treatment Plant, the facility has evolved into a highly complex operation capable of handling massive hydraulic swings inherent to Louisville’s combined sewer system (CSS). The plant recently completed a landmark Biosolids Processing Solution project, making it one of the few facilities in North America to utilize Thermal Hydrolysis Process (THP) technology to produce Class A biosolids. As Louisville MSD executes its extensive consent decree obligations to mitigate Combined Sewer Overflows (CSOs), the Morris Forman WQTC remains the central node for regional water quality compliance and technological innovation.

2. FACILITY OVERVIEW

A. Service Area & Coverage

The facility serves the core of Metro Louisville, encompassing the historic city limits and western Jefferson County. This service area is unique due to the presence of a legacy Combined Sewer System (CSS), where stormwater and sanitary sewage share conveyance infrastructure. The plant serves a dense urban mix of residential, commercial, and heavy industrial users, including the Rubbertown industrial complex, which necessitates robust influent monitoring. The collection system feeding Morris Forman includes the massive Ohio River Interceptor (ORI), which conveys flow from across the city to the plant’s headworks.

B. Operational Capacity

Morris Forman is designed with significant hydraulic flexibility to manage wet weather events:

• Design Average Flow: 120 MGD
• Peak Secondary Treatment Capacity: 120 MGD
• Peak Wet Weather Treatment Capacity: 350 MGD (via primary treatment and disinfection)
• Hydraulic Capacity: The plant can hydraulically pass significantly higher flows during extreme events to prevent upstream basement backups, though treatment effectiveness varies above the 350 MGD threshold.

Historical flow trends show extreme variability; during dry summers, flow may drop to 80 MGD, while wet weather events can sustain flows at maximum capacity for days, requiring aggressive wet weather operating protocols.

C. Discharge & Compliance

Treated effluent is discharged into the Ohio River via a submerged multi-port diffuser system. The facility operates under NPDES Permit KY0022411, administered by the Kentucky Division of Water (KDOW). Due to the size of the receiving water body, the plant relies on secondary treatment standards with limits on Carbonaceous Biochemical Oxygen Demand (CBOD), Total Suspended Solids (TSS), and Ammonia-Nitrogen. The facility is also a focal point of MSD’s Integrated Overflow Abatement Plan (IOAP) to address federal consent decree requirements regarding CSOs.

3. TREATMENT PROCESS

A. PRELIMINARY TREATMENT

The headworks facility is designed to handle high-velocity influent from the deep tunnel and interceptor systems.

• Screening: Four mechanically cleaned coarse bar screens remove large debris, logs, and rags common in combined systems.
• Pumping: The raw wastewater pump station lifts influent from the interceptor depth to the surface level for gravity flow through the plant.
• Grit Removal: Aerated grit chambers decrease the velocity of the wastewater, allowing heavy inorganic materials like sand and gravel to settle while keeping organic matter in suspension.

B. PRIMARY TREATMENT

Following grit removal, flow enters the primary clarification stage. The plant utilizes rectangular primary sedimentation basins equipped with chain-and-flight sludge collectors.

• Configuration: Multiple parallel rectangular basins.
• Mechanism: Settleable solids drop to the bottom as primary sludge, while grease and oils are skimmed from the surface.
• Wet Weather Operations: During peak wet weather events (flows > 120 MGD), flow exceeding the secondary capacity receives primary treatment and disinfection before blending with secondary effluent or discharging, a permitted practice under the CSO Long-Term Control Plan.

C. SECONDARY TREATMENT (High Purity Oxygen)

The core biological treatment at Morris Forman utilizes a High Purity Oxygen (HPO) activated sludge process, specifically the UNOX system. This technology was selected during the 1970s expansion for its ability to treat high-strength waste in a smaller footprint than conventional aeration.

• Oxygen Generation: On-site cryogenic oxygen generation plant (Cryo) separates nitrogen from air to produce >90% pure oxygen.
• Reactor Basins: The oxygen is fed into covered, multi-stage aeration basins. The covered design maximizes oxygen transfer efficiency and helps contain odors.
• Clarification: Mixed liquor flows to circular secondary clarifiers where biological floc settles. Return Activated Sludge (RAS) is recycled to the HPO basins, while Waste Activated Sludge (WAS) is sent to solids processing.

D. DISINFECTION

The facility employs chemical disinfection to manage pathogen levels before discharge.

• Chlorination: Sodium hypochlorite is applied to the secondary effluent (and primary effluent during wet weather bypass).
• Dechlorination: Sodium bisulfite is added prior to the outfall to neutralize residual chlorine, protecting aquatic life in the Ohio River.
• Contact Basins: Dedicated chlorine contact channels ensure sufficient dwell time for pathogen inactivation.

E. SOLIDS HANDLING (Advanced)

Morris Forman operates one of the most advanced solids handling facilities in the region, centered on the “Biosolids Processing Solution” (BPS).

• Thickening: Gravity belt thickeners concentrate WAS and primary sludge.
• Thermal Hydrolysis Process (THP): The plant utilizes the Cambi THP system. Sludge is boiled under high pressure and then rapidly decompressed (steam explosion). This sterilizes the sludge (Class A) and ruptures cell walls to improve digestion.
• Anaerobic Digestion: The pre-treated sludge enters anaerobic digesters. Because of THP, the digesters operate at higher loading rates and produce significantly more biogas.
• Dewatering: Digested sludge is dewatered using high-solids centrifuges.
• Heat Drying: The dewatered cake is dried in thermal dryers to produce a pelletized product.
• Beneficial Reuse: The final product is marketed as “Louisville Green,” a Class A EQ (Exceptional Quality) fertilizer used widely in local agriculture and land application.

4. INFRASTRUCTURE & FACILITIES

A. Physical Plant

The site covers approximately 55 acres along the Ohio River. Notable structures include the distinctive cryogenic oxygen plant towers and the massive new solids handling complex. The site also houses a state-of-the-art laboratory that performs compliance testing for Morris Forman and other MSD facilities.

B. Energy Systems & Biogas

The facility is a significant energy consumer but has made strides in recovery. The THP and anaerobic digestion process generates substantial volumes of biogas.

• Biogas Utilization: Biogas is utilized in boilers to generate steam required for the Thermal Hydrolysis Process, creating a semi-closed energy loop.
• Flood Protection: The plant includes a dedicated flood pumping station capable of pumping treated effluent into the river even when the Ohio River is at flood stage, protecting the plant from hydraulic backup.

C. Odor Control

Given its proximity to the Chickasaw and Park Duvalle neighborhoods, odor control is paramount. The HPO basins are covered, capturing process air. The new solids handling facility features extensive foul air capture systems routed to chemical scrubbers and biofilters to neutralize sulfides and ammonia before release.

5. RECENT UPGRADES & MAJOR PROJECTS

Morris Forman Biosolids Processing Solution (BPS) – $200+ Million (2015-2022)

• Project Scope: Complete replacement of the obsolete Zimpro wet air oxidation system with a modern Thermal Hydrolysis Process (THP).
• Technology: Installation of CambiTHP B6-4 system, new anaerobic digesters, centrifuges, and thermal dryers.
• Drivers: The previous solids system was energy-intensive, maintenance-heavy, and prone to failures. The new system aimed for Class A biosolids and energy recovery.
• Results:
  • Production of “Louisville Green” Class A EQ biosolids.
  • Significant increase in biogas production for process heating.
  • Reduction in volume of solids requiring transport/disposal by 50%.

Sedimentation Basin Rehabilitation – $22 Million (2018-2020)

• Scope: Rehabilitation of primary and secondary clarifier mechanical components, concrete repair, and replacement of chain-and-flight mechanisms.
• Impact: Restored reliability to the physical separation processes, ensuring consistent TSS removal and permit compliance.

Upcoming: Waterway Protection Tunnel Connection

• Scope: While technically a collection system project, the 4-mile Waterway Protection Tunnel will store combined sewage during storms.
• Plant Impact: The tunnel will pump stored flow to Morris Forman for treatment once storm peaks subside, maximizing the plant’s utilization and reducing untreated overflows into the Ohio River.

6. REGULATORY COMPLIANCE & ENVIRONMENTAL PERFORMANCE

A. Permit Requirements

Under KPDES Permit KY0022411, the facility adheres to secondary treatment standards. Key limits include:

• CBOD5: 25 mg/L (Monthly Average)
• TSS: 30 mg/L (Monthly Average)
• Ammonia-Nitrogen: Seasonally variable limits to protect aquatic life.
• E. Coli: 130 colonies/100ml (Recreation Season).

B. Compliance History

Morris Forman has maintained a strong compliance record regarding effluent chemistry. The primary regulatory challenge remains the management of wet weather flows. The facility operates under a Federal Consent Decree (entered in 2005, amended subsequently) requiring MSD to eliminate sanitary sewer overflows and significantly reduce combined sewer overflows. Morris Forman is the treatment terminus for these captured flows.

7. OPERATIONAL EXCELLENCE

MSD employs a highly skilled workforce at Morris Forman, including Class IV certified wastewater operators (the highest level in Kentucky), industrial electricians, and millwrights. The facility utilizes a robust SCADA system for real-time monitoring of the HPO process and solids handling train. The laboratory is NELAP-accredited, ensuring data integrity for regulatory reporting.

8. CHALLENGES & FUTURE PLANNING

A. Wet Weather Management

The defining challenge for Morris Forman is the “yoyo” effect of hydraulic loading. Managing the transition from 60 MGD dry weather flow to 350 MGD wet weather flow requires precise operator intervention to prevent biomass washout in the secondary clarifiers.

B. Aging Infrastructure

While the solids train is brand new, much of the liquid train infrastructure dates to the 1970s. Concrete degradation in the headworks and primary basins is an ongoing maintenance priority.

C. Emerging Contaminants

Like all major utilities, MSD is monitoring regulatory developments regarding PFAS. Because Morris Forman receives industrial wastewater, source control and potential future treatment modifications for “forever chemicals” are part of long-term strategic planning.

10. TECHNICAL SPECIFICATIONS SUMMARY

11. RELATED FACILITIES

Morris Forman relies on a network of major lift stations and interceptors. The Ohio River Interceptor is the primary artery feeding the plant. The facility works in conjunction with the Waterway Protection Tunnel, a deep-rock storage tunnel designed to capture CSOs and release them gradually to Morris Forman for treatment. MSD also operates other regional facilities, including the Derek R. Guthrie WQTC, which serves the separater sanitary sewer areas of the county.

12. FAQ SECTION

Technical Questions

1. What is the peak hydraulic capacity of Morris Forman WQTC?
The plant can treat up to 350 MGD during wet weather events. Flows beyond this may bypass secondary treatment but still receive primary treatment and disinfection in accordance with the CSO Long Term Control Plan.

2. Does Morris Forman use biological nutrient removal (BNR)?
Currently, the plant focuses on ammonia-nitrogen removal through its activated sludge process but does not have a specific configuration for total nitrogen or biological phosphorus removal, as the Ohio River discharge limits do not currently mandate limit-of-technology nutrient removal.

3. How does the High Purity Oxygen (HPO) system benefit the plant?
The HPO system allows for a higher concentration of mixed liquor suspended solids (MLSS) and a smaller physical footprint compared to conventional aeration, which is critical given the land-constrained site surrounded by urban development.

Public Interest Questions

4. What is “Louisville Green”?
Louisville Green is the brand name for the fertilizer pellets produced at Morris Forman. It is a biosolid product rich in nitrogen and phosphorus, safe for general fertilizer use due to the high-temperature sterilization process.

5. Does the plant smell?
Wastewater treatment inherently generates odors, but Morris Forman uses covered process basins and high-tech chemical scrubbers to scrub air before it is released. The move to anaerobic digestion and thermal drying has further contained odors compared to previous technologies.

6. Is the plant protected from Ohio River floods?
Yes. A massive flood wall and a dedicated flood pumping station protect the facility, allowing it to continue treating wastewater and pumping effluent into the river even when the river level is significantly higher than the plant’s discharge pipes.