Rockaway Wastewater Treatment Plant Queens

FACILITY BASIC INFORMATION

• Official Name: Rockaway Water Resource Recovery Facility (WRRF)
• Location: 106-21 Beach Channel Drive, Rockaway Park, Queens, NY 11694
• Operating Authority: New York City Department of Environmental Protection (NYC DEP)
• Design Capacity: 45 MGD (Dry Weather Flow)
• Peak Wet Weather Capacity: 90 MGD
• Current Average Flow: ~19-22 MGD
• Population Served: ~90,000 (Seasonal fluctuations up to 120,000)
• Service Area: Rockaway Peninsula and Broad Channel (approx. 6,026 acres)
• Receiving Water Body: Jamaica Bay
• SPDES Permit Number: NY0026221
• Year Commissioned: 1952 (Major expansions in 1978 and 2010s)

1. INTRODUCTION

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The Rockaway Water Resource Recovery Facility (WRRF) serves as a vital infrastructure asset for the New York City Department of Environmental Protection (NYC DEP), managing wastewater for the entire Rockaway Peninsula and the island community of Broad Channel. Commissioned in 1952 and substantially upgraded in subsequent decades, this 45-MGD facility holds a unique position within the NYC DEP portfolio due to its geographic isolation on a barrier peninsula and its discharge into the ecologically sensitive Jamaica Bay.

The facility has become a case study in modern infrastructure resilience following Hurricane Sandy in 2012, which caused catastrophic flooding and operational failure at the site. Following a massive capital investment exceeding $400 million in resiliency and biological upgrades, the Rockaway WRRF now features state-of-the-art flood protection systems and advanced biological nutrient removal (BNR) capabilities. It stands today not only as a guardian of public health but as a critical protector of the Jamaica Bay estuarine ecosystem.

2. FACILITY OVERVIEW

A. Service Area & Coverage

The Rockaway WRRF serves a drainage area of approximately 6,026 acres. The service area is distinct within New York City; it covers the long, narrow Rockaway Peninsula and the island of Broad Channel. The collection system is largely a separate sanitary sewer system, unlike the combined sewer systems (CSS) prevalent in Manhattan and older parts of the city, although infiltration and inflow (I/I) remain significant operational variables during storm events. The service population is approximately 90,000 year-round residents, but this figure spikes significantly during summer months due to tourism at Rockaway Beach and Jacob Riis Park.

B. Operational Capacity

The plant is designed for a dry weather flow of 45 million gallons per day (MGD) and can handle a peak wet weather flow of 90 MGD. Historically, the plant operates at approximately 50% of its hydraulic design capacity, with average daily flows ranging between 19 and 22 MGD. This excess hydraulic capacity provides operational flexibility but requires careful process control to maintain biological density in aeration tanks during low-flow periods.

C. Discharge & Compliance

Treated effluent is discharged into Jamaica Bay via an outfall located near the facility. Jamaica Bay is a nutrient-sensitive estuary and a critical wildlife habitat within the Gateway National Recreation Area. Consequently, the facility operates under strict State Pollutant Discharge Elimination System (SPDES) permit limits, particularly regarding nitrogen loading. The NYC DEP has entered into consent orders with the New York State Department of Environmental Conservation (NYSDEC) to aggressively reduce Total Nitrogen (TN) discharges into the bay to prevent hypoxia and algal blooms.

3. TREATMENT PROCESS

A. PRELIMINARY TREATMENT

Raw sewage enters the plant through the main interceptor, where it undergoes preliminary treatment to protect downstream mechanical equipment. The headworks facility includes:

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• Mechanically Cleaned Bar Screens: These remove large debris (rags, plastics, wood). The facility utilizes heavy-duty climbing rake screens designed to handle heavy loadings during storm events.
• Grit Removal: Following screening, flow enters aerated grit chambers where velocity is controlled to allow inorganic sands and gravel to settle while keeping organic solids in suspension.
• Odor Control: The headworks area is enclosed and ventilated through activated carbon adsorption vessels to mitigate odors, a critical requirement given the plant’s proximity to residential neighborhoods.

B. PRIMARY TREATMENT

Effluent from the grit chambers flows to the primary sedimentation tanks. The facility utilizes rectangular primary settling tanks equipped with chain-and-flight sludge collectors. These mechanisms scrape settled primary sludge to hoppers at the inlet end and skim floating grease and scum to troughs at the outlet end. The primary treatment stage targets the removal of 50-60% of Total Suspended Solids (TSS) and 30-35% of Biochemical Oxygen Demand (BOD).

C. SECONDARY TREATMENT (Step-Feed BNR)

The core of the Rockaway WRRF is its secondary treatment system, which uses the activated sludge process. To meet stringent nitrogen limits for Jamaica Bay, the plant has been retrofitted for Biological Nutrient Removal (BNR).

• Configuration: The aeration tanks operate in a step-feed configuration. This splits the influent flow into multiple distinct passes within the aeration tank.
• Process Biology: By feeding carbon-rich primary effluent into anoxic zones within the aeration tank, the facility promotes denitrification. Bacteria utilize the nitrate produced in the aerobic zones as an oxygen source, converting it to nitrogen gas which is released into the atmosphere.
• Carbon Augmentation: To maximize nitrogen removal, the facility has provisions for supplemental carbon addition (such as glycerol or methanol) to drive the denitrification process during periods of low influent carbon.
• Final Settling: Mixed liquor flows to rectangular final settling tanks (secondary clarifiers) where the biological floc settles. Return Activated Sludge (RAS) is pumped back to the aeration tanks, while Waste Activated Sludge (WAS) is removed for processing.

D. DISINFECTION

The clarified effluent undergoes disinfection using sodium hypochlorite (liquid chlorine) in contact tanks. The dosing is flow-paced and monitored via residual chlorine analyzers. Following sufficient contact time to ensure pathogen inactivation (specifically targeting Fecal Coliform), the effluent is dechlorinated (if required by seasonal permit limits) or discharged directly to the outfall in Jamaica Bay.

E. SOLIDS HANDLING

The Rockaway WRRF processes solids generated from both primary and secondary treatment:

• Thickening: Primary sludge is typically gravity thickened, while waste activated sludge (WAS) is thickened using dissolved air flotation (DAF) or mechanical thickeners to reduce volume.
• Anaerobic Digestion: Thickened sludge is pumped to anaerobic digesters. These enclosed tanks operate at mesophilic temperatures (~98°F), reducing volatile solids and producing methane gas (biogas).
• Biogas Utilization: The biogas produced is utilized on-site to fuel boilers that heat the digesters and facility buildings, contributing to energy neutrality.
• Dewatering: Unlike some NYC facilities that dewater on-site, Rockaway historically functions as a thickening facility, with digested sludge pumped or barged to regional dewatering hubs (like the 26th Ward or Wards Island facilities) for final processing into biosolids cake.

4. INFRASTRUCTURE & FACILITIES

A. Physical Plant

The site spans several acres on the bay side of the Rockaway Peninsula. The architecture is utilitarian, typical of mid-20th-century municipal industrial design, but recent additions feature modern resilient design elements. The site includes the main pump building, aeration tanks, settling tanks, digestion complex, and an administrative/laboratory building.

B. Energy & Resiliency Systems

Energy management is a dual priority alongside resilience.

• Cogeneration: The facility utilizes waste heat from operations and biogas for heating.
• Emergency Power: Post-Sandy upgrades included the installation of massive emergency generators housed in elevated structures well above the FEMA 500-year flood elevation.
• Electrical Distribution: All critical electrical substations and switchgear have been elevated or hardened to preventing outages during storm surges.

C. Odor Control

Given the density of the surrounding Rockaway Park residential community, odor control is paramount. The facility utilizes a combination of chemical scrubbers and activated carbon filters at the headworks and sludge processing areas. Real-time perimeter monitoring helps operations staff adjust ventilation rates and chemical dosing to prevent off-site migration.

5. RECENT UPGRADES & MAJOR PROJECTS

The Rockaway WRRF has been the subject of intense capital improvement, driven primarily by the devastation of Hurricane Sandy (2012) and the Jamaica Bay Eutrophication restrictions.

MAJOR PROJECT: Rockaway WRRF Resiliency Upgrade

• Timeline: 2015 – 2021 (Phased)
• Budget: ~$450 Million (Combined projects)
• Funding: NYC DEP Capital Funds, FEMA Hazard Mitigation Grants, NYS Environmental Facilities Corporation (SRF).
• Project Drivers: In 2012, Hurricane Sandy’s storm surge inundated the plant, knocking it offline for days and requiring emergency bypasses. The plant required a complete overhaul to withstand future climate change impacts.
• Scope & Technical Highlights:
  • Construction of a reinforced flood wall around critical infrastructure.
  • Elevation of main electrical substations and switchgear ~16 feet above sea level.
  • Installation of submersible pumps capable of operating even if the dry well floods.
  • Hardening of the Main Sewage Pump Station.
  • Installation of new watertight doors and flood gates.
  • Replacement of damaged cabling and instrumentation with corrosion-resistant, submersible alternatives.

MAJOR PROJECT: Nitrogen Removal & Process Upgrades

• Timeline: Ongoing (Part of the Jamaica Bay Improvement Plan)
• Scope: Implementation of automated process controls for Step-Feed BNR and carbon addition.
• Objective: To meet the aggregate nitrogen discharge limits for Jamaica Bay, protecting the marshlands from degradation caused by excessive nutrients.
• Technology: Installation of ammonium and nitrate probes for real-time aeration control (ABAC – Ammonia-Based Aeration Control) to optimize nitrification/denitrification efficiency while reducing energy consumption.

6. REGULATORY COMPLIANCE & ENVIRONMENTAL PERFORMANCE

A. Permit Requirements

The facility operates under SPDES Permit NY0026221. Key parameters include:

• CBOD5: 25 mg/L (Monthly Average)
• TSS: 30 mg/L (Monthly Average)
• Total Nitrogen: Subject to an aggregate load limit for all Jamaica Bay plants (typically aimed at net reductions to protect the estuary).
• Settleable Solids: 0.1 mL/L
• pH: 6.0 – 9.0

B. Compliance History

The Rockaway WRRF generally maintains a strong compliance record. Since the operational stabilization following the post-Sandy reconstruction, the facility has consistently met secondary treatment standards. The primary regulatory focus remains on the “Jamaica Bay Watershed Protection Plan,” which mandates continuous reductions in nitrogen loading. The facility has successfully reduced nitrogen output significantly compared to 1990s baselines.

7. OPERATIONAL EXCELLENCE

A. Staffing

The plant is staffed 24/7/365 by NYC DEP personnel, including Senior Sewage Treatment Workers, Oilers, and Electricians. Operators hold NYSDEC certifications ranging from Grade 1 to Grade 4A (highest level). The facility also houses maintenance crews responsible for the predictive and corrective maintenance of rotating equipment.

B. Technology & Monitoring

The facility utilizes a sophisticated SCADA (Supervisory Control and Data Acquisition) system that was completely modernized post-Sandy. This system allows for centralized monitoring of all unit processes, tank levels, dissolved oxygen profiles, and energy usage. Remote telemetry connects the plant to the NYC DEP central command, ensuring coordinated wet-weather responses across the city’s network.

8. CHALLENGES & FUTURE PLANNING

A. Climate Change & Sea Level Rise

Located on a barrier peninsula, the Rockaway WRRF is on the front lines of climate change. While recent upgrades have hardened the facility against storm surges, long-term sea-level rise poses a threat to hydraulic grade lines and gravity discharge capabilities. Future planning involves assessing the need for effluent pumping stations to combat rising tide levels in Jamaica Bay.

B. Energy Neutrality Goals

NYC DEP has aggressive goals to achieve energy neutrality by 2050. The Rockaway facility is targeting increased biogas capture and process optimization (reducing aeration blower energy consumption) to lower its carbon footprint.

C. Changing Influent Characteristics

As water conservation measures (low-flow fixtures) proliferate across NYC, the influent wastewater is becoming more concentrated (higher strength). This requires adjustments in the biological treatment process to handle higher loading rates per gallon of flow.

9. COMMUNITY & REGIONAL IMPACT

The Rockaway WRRF allows for the habitation and tourism economy of the Rockaway Peninsula. Without this facility, the density of Rockaway Park and the clean beaches that attract millions of New Yorkers annually would be impossible. The NYC DEP actively coordinates with the local Community Board and environmental groups (such as the Jamaica Bay Ecowatchers) to ensure plant operations support the recreational and ecological goals of the region.

10. TECHNICAL SPECIFICATIONS SUMMARY

11. RELATED FACILITIES

• 26th Ward WRRF: Another major NYC DEP facility discharging to Jamaica Bay, often working in tandem with Rockaway under the Jamaica Bay Watershed Protection Plan.
• Jamaica WRRF: Located further inland, also discharging to the bay.
• Coney Island WRRF: Serves the adjacent region to the west (Brooklyn).

12. FAQ

Technical Questions

1. What is the hydraulic retention time (HRT) of the aeration tanks?
The HRT varies based on flow, but typically ranges from 4 to 6 hours in step-feed mode to ensure adequate nitrification/denitrification.

2. Does Rockaway WRRF have Combined Sewer Overflow (CSO) outfalls?
While most of NYC has combined sewers, the Rockaway peninsula is primarily served by separate sanitary sewers. However, infiltration during storms can still cause high flows.

3. How is the facility powered during grid outages?
Post-Sandy upgrades installed elevated emergency generators capable of powering the entire facility indefinitely during grid failures.

4. Does the facility dewater sludge on-site?
Generally, no. Rockaway digests sludge but typically transports processed biosolids to other NYC DEP facilities or private contractors for final dewatering and disposal.

Public Interest Questions

5. Does the plant smell?
Odor control is a high priority. The plant uses carbon filtration and chemical scrubbers. While occasional odors may occur during maintenance, systems are in place to capture 99% of odorous compounds.

6. Is the water released into Jamaica Bay safe?
Yes. The effluent meets strict state and federal standards for bacteria and pollutants, making it safe for the marine environment.

7. How was the plant affected by Hurricane Sandy?
The plant was severely flooded and knocked offline. Since then, over $400 million has been invested to raise equipment and build flood walls, making it one of the most resilient plants in the region.