Hampton Roads Sanitation District Virginia Initiative Plant Norfolk

FACILITY BASIC INFORMATION

1. INTRODUCTION

The Virginia Initiative Plant (VIP) is a cornerstone of the Hampton Roads Sanitation District’s (HRSD) regional wastewater infrastructure. Located on the banks of the Elizabeth River in Norfolk, Virginia, this 40-MGD facility is globally recognized in the environmental engineering community for two distinct achievements: it is the namesake of the “VIP Process,” a high-rate biological nutrient removal configuration adopted worldwide, and it currently serves as the testing ground for the Sustainable Water Initiative for Tomorrow (SWIFT).

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Commissioned to address stringent Chesapeake Bay preservation standards, the plant serves a dense urban corridor including the City of Norfolk and strategic military installations. Beyond conventional treatment, the facility represents a paradigm shift in water resource management. With the integration of the SWIFT Research Center, VIP not only treats wastewater to meet National Pollutant Discharge Elimination System (NPDES) limits but also purifies effluent to drinking water standards for aquifer recharge, combating land subsidence and saltwater intrusion in the Potomac Aquifer.

2. FACILITY OVERVIEW

A. Service Area & Coverage

The VIP service area encompasses the majority of the City of Norfolk, extending into northern sections of Chesapeake and western Virginia Beach. This catchment area is characterized by a mix of high-density residential zones, commercial districts, and significant industrial and military contributors. The collection system feeding VIP is complex, relying on a network of regional interceptors and pump stations to transport flow through the flat, tidally influenced topography of the Hampton Roads region.

B. Operational Capacity

The plant is rated for a design average flow of 40 MGD with a peak hydraulic capacity of 80 MGD. Historically, the plant operates near 28-32 MGD on average, providing a capacity buffer for wet weather events. However, the aging collection system in the older parts of Norfolk is subject to Inflow and Infiltration (I&I), which can cause rapid flow spikes during storm events, necessitating robust hydraulic control strategies at the headworks.

C. Discharge & Compliance

Treated effluent is discharged into the Elizabeth River. As a tributary to the Chesapeake Bay, this water body is subject to some of the strictest Total Maximum Daily Load (TMDL) requirements in the United States, particularly regarding Total Nitrogen (TN) and Total Phosphorus (TP). The facility consistently operates in compliance with its VPDES permit, achieving nutrient removal levels that significantly exceed secondary treatment standards.

3. TREATMENT PROCESS

The Virginia Initiative Plant utilizes a sophisticated treatment train known as the VIP Process, a modification of the A2O (Anaerobic-Anoxic-Aerobic) process designed specifically to maximize biological phosphorus removal and denitrification while maintaining high-rate treatment capability.

A. PRELIMINARY TREATMENT

Raw influent enters the headworks where it passes through mechanical bar screens to remove large debris, rags, and plastics. Following screening, flow enters aerated grit chambers. These chambers reduce the velocity of the water, allowing heavier inorganic materials (sand, gravel, coffee grounds) to settle while keeping lighter organic matter in suspension. The removed grit is washed and dewatered for landfill disposal. Odor control at the headworks is critical due to the plant’s proximity to the residential neighborhoods of Larchmont and Edgewater; multistage chemical scrubbers are utilized to treat foul air.

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B. PRIMARY TREATMENT

Wastewater flows into rectangular primary clarifiers. These tanks reduce the velocity of the flow, allowing settleable solids to drop to the bottom as primary sludge and floatable grease/scum to rise to the surface. Chain-and-flight mechanisms scrape the bottom sludge to hoppers and skim the surface. The primary treatment stage typically removes 50-60% of Total Suspended Solids (TSS) and 30-40% of Biochemical Oxygen Demand (BOD), reducing the organic load on the subsequent biological stage.

C. SECONDARY TREATMENT (The VIP Process)

This is the technological heart of the facility. The VIP Process is a high-rate BNR configuration that differs from standard A2O by staging the recycle streams to protect the anaerobic zone from nitrate intrusion.

• Configuration: The biological reactors are divided into three specific zones: Anaerobic, Anoxic, and Aerobic.
• Anaerobic Zone: Promotes the growth of Phosphate Accumulating Organisms (PAOs), which release stored phosphorus in this stage to uptake volatile fatty acids (VFAs).
• Anoxic Zone: Mixed liquor is recycled here. Nitrate produced in the aerobic zone is converted to nitrogen gas (denitrification) by bacteria using the organic carbon present in the wastewater.
• Aerobic Zone: Fine bubble diffusion provides oxygen for nitrification (ammonia to nitrate conversion) and BOD oxidation. PAOs take up luxury amounts of phosphorus here.
• Clarification: The mixed liquor flows to secondary clarifiers where the biomass settles. A portion is returned as Return Activated Sludge (RAS) to the head of the reactor, while the excess is removed as Waste Activated Sludge (WAS).

D. SWIFT ADVANCED TREATMENT (Partial Stream)

A portion of the secondary effluent is diverted to the SWIFT Research Center (1 MGD capacity) for advanced purification. This train includes:

• Flocculation & Sedimentation: Enhanced removal of particles.
• Ozonation: Breaks down trace organics, pharmaceuticals, and pathogens.
• Biofiltration (BAC): Biologically Active Carbon filters remove oxidation byproducts and remaining organics.
• Granular Activated Carbon (GAC): Polishing step for adsorption of contaminants.
• UV Disinfection: High-intensity UV light for final pathogen inactivation before aquifer recharge.

E. DISINFECTION (Main Plant)

For the main plant flow discharging to the Elizabeth River, chlorination is used for disinfection. A dedicated contact tank ensures sufficient detention time for pathogen kill. Following chlorination, the effluent undergoes dechlorination using sodium bisulfite to prevent toxicity to aquatic life in the receiving waters.

F. SOLIDS HANDLING

VIP utilizes a robust solids management system suitable for an urban footprint:

• Thickening: Primary sludge is gravity thickened; WAS is thickened using Dissolved Air Flotation (DAF) or rotary drum thickeners.
• Anaerobic Digestion: Thickened sludge is blended and fed to anaerobic digesters. These tanks operate at mesophilic temperatures, reducing volatile solids and producing methane gas.
• Energy Recovery: The biogas produced is captured and used to fire boilers that heat the digesters and facility buildings.
• Dewatering & Disposal: Digested sludge is dewatered using high-solids centrifuges. The resulting cake is incinerated on-site in fluid bed or multiple hearth incinerators, reducing the volume to ash, which is hauled to a landfill.

4. INFRASTRUCTURE & FACILITIES

A. Physical Plant

The VIP facility occupies a constrained site adjacent to the Old Dominion University campus and the Port of Virginia. The architecture utilizes brick facades to blend with the surrounding institutional and residential aesthetics. The site includes the main process tanks, the solids handling building, an administration/laboratory complex, and the prominent SWIFT Research Center.

B. Energy Systems

Energy management is a priority given the energy-intensive nature of aeration and pumping. The plant utilizes Variable Frequency Drives (VFDs) on major pumps and blowers. The anaerobic digestion process allows for cogeneration potential, offsetting natural gas requirements for heating. The SWIFT facility serves as a pilot for energy-efficient advanced treatment, testing protocols that minimize the carbon footprint of water reuse.

C. Odor Control

Located near high-value real estate, VIP employs one of the most extensive odor control systems in the HRSD network. Primary sources (headworks, primary clarifiers, and solids handling) are covered and ventilated to chemical scrubbers and biotrickling filters. The system is continuously monitored to ensure zero-nuisance conditions at the fence line.

5. RECENT UPGRADES & MAJOR PROJECTS

SWIFT Research Center (2016-2018)

• Project Scope: Construction of a 1.0 MGD advanced water treatment demonstration facility and visitor education center.
• Budget: Approx. $25 Million.
• Drivers: Address depleting groundwater levels in the Potomac Aquifer, prevent saltwater intrusion, and reduce nutrient discharge to the Chesapeake Bay.
• Technology: Integrated an 8-step carbon-based advanced treatment train (ozone, BAC, GAC) rather than the standard membrane-based (RO) approach, retaining beneficial minerals in the water and eliminating brine disposal issues.
• Results: Successfully recharges the Potomac Aquifer with water exceeding drinking water standards. The data gathered here is guiding the design of full-scale SWIFT implementation across HRSD.

Nutrient Removal Optimization & Control System Upgrades (2019-2023)

• Scope: Replacement of aging aeration control systems, installation of new sensors (ammonia/nitrate probes), and upgrades to the SCADA network.
• Technical Highlights: Implementation of Ammonia-Based Aeration Control (ABAC) strategies to optimize blower output based on real-time biological demand, reducing energy usage while ensuring permit compliance.
• Outcome: Enhanced stability of the nitrification/denitrification process and reduction in energy costs per million gallons treated.

Upcoming: Full-Scale SWIFT Implementation

Status: Planning/Design Phase (2024-2027)
HRSD plans to expand the SWIFT capabilities at VIP and other facilities to eventually treat a significant percentage of the region’s wastewater for aquifer recharge. This involves major capital expenditure to scale up the advanced treatment train piloted at the Research Center.

6. REGULATORY COMPLIANCE & ENVIRONMENTAL PERFORMANCE

A. Permit Requirements

The facility operates under a Virginia Pollutant Discharge Elimination System (VPDES) permit administered by the Virginia DEQ. Key limits focus on:

• Total Nitrogen (TN): Annual average limits consistent with the Chesapeake Bay Watershed Implementation Plan (typically < 5-8 mg/L).
• Total Phosphorus (TP): Strictly limited (typically < 1.0 mg/L).
• Bacteria: Enterococci limits for protection of recreational waters.

B. Environmental Stewardship

VIP has consistently received Platinum Awards from the National Association of Clean Water Agencies (NACWA) for consecutive years of perfect permit compliance. The transition toward SWIFT represents a shift from “compliance” to “restoration,” as the facility actively replenishes the groundwater resource rather than simply discharging to surface waters.

7. TECHNICAL SPECIFICATIONS SUMMARY

8. CHALLENGES & FUTURE PLANNING

A. Climate Resilience

Situated in Norfolk, a city facing significant sea-level rise and recurrent flooding, VIP must manage hydraulic challenges. HRSD ensures the facility’s critical assets are hardened against storm surge. The SWIFT program itself is a resilience strategy, as injecting water into the aquifer generates positive pore pressure that can slow the rate of land subsidence in the region.

B. Aging Infrastructure

Commissioned in the early 1990s, mechanical and electrical components at VIP are reaching the end of their useful life. The Capital Improvement Plan (CIP) prioritizes the rehabilitation of concrete tanks, replacement of centrifuges, and modernization of the incineration complex to meet new Clean Air Act standards (SSI rules).

9. FAQ

Technical Questions

Q: What is the “VIP Process”?
A: It is a biological nutrient removal configuration developed at this facility. It involves a specific arrangement of anaerobic, anoxic, and aerobic zones with staged recycling of mixed liquor to maximize phosphorus removal and denitrification efficiency.

Q: Does the plant use Reverse Osmosis (RO) for SWIFT?
A: No. The SWIFT Research Center utilizes a carbon-based treatment train (Ozone-BAC-GAC). This avoids the creation of a brine concentrate waste stream and preserves the chemical compatibility of the treated water with the existing groundwater profile.

Q: How is waste activated sludge (WAS) handled?
A: WAS is thickened via DAF, anaerobically digested to reduce volume and pathogens, dewatered via centrifuges, and incinerated on-site.

Public Interest Questions

Q: Can the public tour the facility?
A: Yes, specifically the SWIFT Research Center. HRSD offers regular educational tours to the public, schools, and professional groups to demonstrate the advanced water purification process.

Q: Does the plant smell?
A: The plant is located near residential areas, so extensive odor control measures (scrubbers and covered tanks) are in place. Under normal operations, odors are contained within the site boundary.