City Of Grand Rapids Water Resource Recovery Facility

FACILITY BASIC INFORMATION

Plant Name: Grand Rapids Water Resource Recovery Facility (formerly Wastewater Treatment Plant)

Location: 1300 Market Avenue SW, Grand Rapids, Kent County, Michigan

Operating Authority: City of Grand Rapids Environmental Services Department

Design Capacity: 61.1 MGD

Current Average Flow: ~38-40 MGD

Population Served: ~275,000 (Regional Service Area)

Service Area: Grand Rapids plus 10 customer communities in Kent and Ottawa Counties

Receiving Water Body: Grand River (Lake Michigan Watershed)

NPDES Permit Number: MI0024252

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Year Commissioned: Original site established 1930; Major expansion/modernization continuous

1. INTRODUCTION

The City of Grand Rapids Water Resource Recovery Facility (WRRF) serves as the cornerstone of wastewater infrastructure for West Michigan’s largest metropolitan area. Treating an average of 40 million gallons daily (MGD) with a hydraulic design capacity of 61.1 MGD, the facility provides critical sanitation services for approximately 275,000 residents across Grand Rapids and ten surrounding partner communities. Operated by the City’s Environmental Services Department, the facility has transitioned from a traditional treatment mindset to a “resource recovery” model, emphasized by its 2020 renaming from “Wastewater Treatment Plant” to WRRF.

The facility is distinguished by its successful execution of the Combined Sewer Overflow (CSO) elimination project—a decades-long effort completed in 2015—and its recent transition to anaerobic digestion with energy recovery. Following an $80 million investment in biodigestion technology completed in roughly 2023, the plant now recovers energy from high-strength waste, including loads from the city’s robust brewing industry (“Beer City USA”), aiming for partial energy independence while protecting the water quality of the Grand River and downstream Lake Michigan.

2. FACILITY OVERVIEW

A. Service Area & Coverage

The WRRF operates as a regional utility hub. While owned by the City of Grand Rapids, it functions under long-term service agreements with a broad metropolitan service area covering approximately 130 square miles. Customer communities include:

• Cities: Grand Rapids, East Grand Rapids, Kentwood, Walker, Wyoming (partial)
• Townships: Ada, Cascade, Gaines, Grand Rapids Charter, Tallmadge

The collection system is extensive, comprising over 1,100 miles of sanitary sewer mains. Notably, the City completed the separation of its historic combined sewer system, significantly reducing the frequency and volume of overflow events, though the plant must still manage significant inflow and infiltration (I/I) during wet weather events typical of the Great Lakes region.

B. Operational Capacity

The facility maintains a design average flow of 61.1 MGD. However, hydraulic capacity is engineered to handle significantly higher peak flows associated with wet weather events, capable of processing peak hourly flows exceeding 90 MGD through secondary treatment. Historically, the plant processes an average daily flow (ADF) ranging between 36 and 42 MGD depending on annual precipitation levels. The facility utilizes approximately 65-70% of its rated hydraulic capacity on average, leaving adequate room for regional growth and industrial expansion.

C. Discharge & Compliance

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Treated effluent is discharged into the Grand River, the longest river in Michigan, which flows west to discharge into Lake Michigan at Grand Haven. The facility operates under National Pollutant Discharge Elimination System (NPDES) permit No. MI0024252, administered by the Michigan Department of Environment, Great Lakes, and Energy (EGLE). The WRRF consistently achieves high compliance rates, particularly regarding phosphorus removal—a critical parameter for the health of the Great Lakes watershed—and E. coli reduction via ultraviolet disinfection.

3. TREATMENT PROCESS

The Grand Rapids WRRF employs a conventional activated sludge process augmented by advanced preliminary treatment and tertiary-level disinfection. The treatment train is designed to handle variable hydraulic loads and high-strength industrial waste characteristic of the local food and beverage manufacturing sector.

A. PRELIMINARY TREATMENT

Influent enters the facility via the Market Avenue pump station and gravity interceptors. Preliminary treatment includes:

• Coarse Screening: Automated mechanically cleaned bar screens remove large debris, rags, and plastics to protect downstream pumps.
• Grit Removal: Aerated grit chambers decrease the velocity of the wastewater, allowing heavy inorganic materials (sand, gravel, coffee grounds) to settle while keeping organic matter in suspension.
• Flow Equalization: While the plant does not have massive external equalization basins, the hydraulic profile allows for flow pacing through the headworks to manage diurnal peaks.

B. PRIMARY TREATMENT

Flow proceeds to rectangular primary clarifiers. In this stage, approximately 60-70% of suspended solids and 30-40% of BOD are removed via gravity settling.

• Configuration: Multiple parallel rectangular tanks equipped with chain-and-flight sludge collectors.
• Scum Removal: Surface skimmers remove grease, oils, and floating debris, which is critical given the high FOG (Fats, Oils, and Grease) potential from the service area.
• Chemical Enhancement: Ferric chloride is added prior to primary clarification to precipitate phosphorus and enhance settling, crucial for meeting the strict 1.0 mg/L (and often lower) monthly average phosphorus limits.

C. SECONDARY TREATMENT

The biological engine of the plant is the Activated Sludge process.

• Aeration Basins: The plant utilizes a plug-flow aeration configuration. Air is supplied via fine-bubble diffusers, which replaced older coarse bubble systems to improve oxygen transfer efficiency (OTE) and reduce energy costs.
• Biological Process: Microorganisms consume dissolved organic matter. The system is operated to achieve nitrification (conversion of ammonia to nitrate) during warmer months to meet seasonal ammonia limits.
• Secondary Clarifiers: Mixed liquor flows to circular secondary clarifiers where biological floc settles. Return Activated Sludge (RAS) is pumped back to the aeration basins, while Waste Activated Sludge (WAS) is thickened and sent to solids handling.

D. DISINFECTION

In 2015, the facility completed a major conversion from chlorination to Ultraviolet (UV) disinfection.

• Technology: High-intensity, low-pressure UV lamp banks located in effluent channels.
• Mechanism: UV light disrupts the DNA of pathogens (E. coli, fecal coliform), rendering them unable to reproduce.
• Benefit: This eliminates the need for hazardous chlorine gas storage and the subsequent dechlorination step (sulfur dioxide), removing residual chemicals from the discharge to the Grand River.

E. SOLIDS HANDLING & RESOURCE RECOVERY

This is the most technologically advanced section of the facility, following recent major upgrades.

• Thickening: Primary sludge and WAS are thickened (using gravity belt thickeners or rotary drum thickeners) before digestion.
• Anaerobic Digestion: The facility operates three large anaerobic digesters (constructed circa 2020-2022). These tanks operate at mesophilic temperatures (~98°F).
• Co-Digestion: The system is designed to accept high-strength organic waste (HSW) from local industries (e.g., brewery waste, dairy processing), increasing biogas production.
• Dewatering: Digested sludge is dewatered using high-performance centrifuges to produce a drier cake.
• Biosolids Disposal: The resulting Class A or high-quality Class B biosolids are utilized for land application as fertilizer, completing the nutrient cycle.

4. INFRASTRUCTURE & FACILITIES

A. Physical Plant

The site occupies a significant industrial footprint along the Grand River at 1300 Market Avenue SW. The facility includes distinct zones for headworks, primary treatment, secondary treatment, and the new solids handling complex. The administration building houses a state-certified laboratory capable of performing compliance testing for BOD, TSS, pH, Ammonia, and Phosphorus.

B. Energy Systems & Cogeneration

The WRRF is a leader in energy recovery.

• Combined Heat and Power (CHP): The anaerobic digesters produce methane-rich biogas. This gas is conditioned and fed into a CHP cogeneration engine.
• Energy Generation: The CHP system generates electricity to power plant operations, offsetting approximately 40-60% of the facility’s grid energy consumption.
• Heat Recovery: Waste heat from the engines is captured to heat the digesters and facility buildings, maximizing thermal efficiency.

C. Odor Control

Given the facility’s proximity to developing commercial areas and the Oxford Trail, odor control is a priority. The recent biodigester project included the installation of high-capacity biofilters and activated carbon scrubbers specifically dedicated to the headworks and sludge processing areas to capture hydrogen sulfide and other odorous compounds.

5. RECENT UPGRADES & MAJOR PROJECTS

Bio-Digestion and Combined Heat & Power (CHP) Project – (2019-2023)

• Project Scope: Construction of three anaerobic digesters, a biogas conditioning system, a CHP cogeneration facility, and a septage/high-strength waste receiving station. This replaced the facility’s aging sewage sludge incinerators.
• Project Budget: ~$82 Million (Phase I and II combined)
• Funding Sources:
  • Municipal Revenue Bonds
  • State Revolving Fund (SRF) loans managed by EGLE

• Project Drivers: The primary driver was the end-of-life status of existing incinerators, tightening air quality regulations, and the city’s goal to achieve 100% renewable energy for municipal operations.
• Technical Highlights: The co-digestion capability allows the plant to monetize the treatment of industrial high-strength waste while boosting gas production for energy generation.
• Results: Elimination of incineration ash; significant reduction in grid energy purchase; generation of Class A/B biosolids for beneficial reuse.

UV Disinfection Upgrade – (2013-2015)

• Project Scope: Demolition of chlorine contact tanks and installation of a channelized UV disinfection system.
• Budget: ~$15 Million
• Results: Improved safety by removing chlorine gas; compliance with lower total residual chlorine limits; reduced toxicity to the Grand River ecosystem.

Current/Upcoming Projects (2024-2027)

The facility maintains a robust Capital Improvement Plan (CIP). Upcoming focus areas include:

• Retention Basin Improvements: Rehabilitation of wet-weather retention structures to ensure managing peak flows during extreme climate events.
• Pump Station Reliability: Upgrades to the Market Avenue Pump Station (MAPS) electrical and mechanical systems.
• PFAS Remediation Strategy: While primarily a source-control effort, the plant continues to invest in monitoring infrastructure for Per- and Polyfluoroalkyl Substances.

6. REGULATORY COMPLIANCE & ENVIRONMENTAL PERFORMANCE

A. Permit Requirements

The WRRF operates under a stringent NPDES permit that regulates discharge into the Grand River. Key parameters include:

• Phosphorus: 1.0 mg/L monthly average (often achieving < 0.5 mg/L).
• Ammonia Nitrogen (NH3-N): Seasonally variable limits to prevent toxicity to aquatic life.
• E. coli: Limits effective May through October (recreational season).
• TSS & BOD5: Standard secondary treatment limits (typically 30 mg/L monthly average).

B. Environmental Stewardship

The Grand Rapids WRRF has received recognition for its Industrial Pretreatment Program (IPP). This program monitors and regulates discharges from over 70 significant industrial users (SIUs), including metal finishers and food processors. This is critical for preventing pass-through of pollutants like PFAS and heavy metals.

7. OPERATIONAL EXCELLENCE

A. Staffing

The facility is staffed by approximately 40-50 full-time employees, including operations, maintenance, laboratory, and administrative personnel. Michigan Class A Wastewater Certification is required for superintendents and shift supervisors, ensuring high-level technical competency.

B. Technology & Innovation

The WRRF utilizes a modern SCADA (Supervisory Control and Data Acquisition) system for real-time monitoring of all unit processes. The transition to anaerobic digestion has positioned Grand Rapids as a regional leader in the “Water Resource Recovery” paradigm, shifting focus from waste treatment to energy and nutrient harvesting.

8. CHALLENGES & FUTURE PLANNING

A. Emerging Contaminants (PFAS)

Like many Michigan utilities, Grand Rapids faces challenges regarding PFAS. The facility has been proactive in source tracking, identifying plating and finishing industries contributing to PFOS/PFOA loads, and requiring upstream treatment before discharge to the sewer.

B. Climate Resilience

The Grand River is subject to flooding. The facility’s location in the floodplain requires constant vigilance regarding flood protection levels. Future planning accounts for higher intensity storm events that could challenge hydraulic throughput, despite the separated sewer system.

C. Aging Infrastructure

While the digesters are new, portions of the interceptor system and primary treatment structures date back decades. Asset management plans prioritize the rehabilitation of concrete structures and the replacement of electrical switchgear to maintain reliability.

9. COMMUNITY & REGIONAL IMPACT

The WRRF is vital to the economic health of West Michigan. By providing reliable high-strength waste treatment, it directly supports the region’s booming food and beverage processing sector. The facility’s move toward energy neutrality aligns with the City of Grand Rapids’ broader sustainability goals. Furthermore, the Environmental Services Department engages the public through the “Grand Rapids Water” initiative, offering educational tours and transparency regarding water quality data.

10. TECHNICAL SPECIFICATIONS SUMMARY

11. RELATED FACILITIES

The WRRF relies on a network of critical infrastructure:

• Market Avenue Pump Station: The primary lift station delivering flow to the headworks.
• Retention Basins: While the CSO project is complete, retention structures remain to manage extreme wet weather flows and prevent untreated discharge.
• Rainscaping Infrastructure: The City maintains extensive green infrastructure (bioswales, porous pavement) throughout the service area to reduce stormwater inflow to the collection system.

12. FAQ SECTION

Technical/Professional Questions

1. What is the hydraulic retention time (HRT) of the Grand Rapids WRRF?
While specific operational HRT varies by flow, the facility is designed with standard activated sludge parameters, typically offering 4-6 hours in aeration basins during average flow conditions.

2. Does the facility accept high-strength external waste?
Yes. The recent biodigester upgrade included a receiving station specifically for high-strength organic waste (HSW) and septage to boost biogas production.

3. How does the facility handle phosphorus limits?
Phosphorus is removed primarily through chemical precipitation using Ferric Chloride added prior to primary clarification, ensuring compliance with the 1.0 mg/L limit.

4. Is the Grand Rapids WRRF a Combined Sewer system?
Grand Rapids successfully completed a long-term CSO separation project in 2015. The collection system is now largely separated, though I/I influences still cause flow peaking during storms.

5. What is the energy output of the CHP system?
The cogeneration system is designed to offset approximately 40-60% of the plant’s electrical demand, depending on biogas production rates and seasonal heating needs.

Public Interest Questions

6. Does the plant smell?
The facility utilizes advanced biofilters and carbon scrubbers, particularly around the new solids handling buildings, to minimize odors. However, occasional odors may be detectable in the immediate industrial vicinity.

7. Where does the water go after treatment?
The treated, disinfected water is discharged into the Grand River, which eventually flows into Lake Michigan.

8. Why was the name changed to “Water Resource Recovery Facility”?
The name change reflects a shift in philosophy. The plant no longer just “treats waste”; it recovers valuable resources like clean water, energy (biogas), and nutrients (fertilizer).