Coney Island Wastewater Treatment Plant Brooklyn

Introduction

The Coney Island Wastewater Resource Recovery Facility (WRRF) serves as a cornerstone of sanitation infrastructure for South Brooklyn, treating an average of 110 million gallons daily (MGD) of wastewater for approximately 600,000 residents. Originally commissioned in 1935 and operated by the New York City Department of Environmental Protection (NYC DEP), this facility was one of the first three modern sewage treatment plants constructed in New York City.

Situated adjacent to Shell Bank Creek and Rockaway Inlet, the facility plays a pivotal role in protecting the water quality of Jamaica Bay and the local recreational beaches. Following the devastation of Superstorm Sandy in 2012, the Coney Island WRRF became a focal point for municipal resiliency engineering, undergoing extensive retrofits to withstand climate change-induced sea-level rise and storm surges. Today, it operates as a sophisticated Level 4 treatment facility, balancing historical infrastructure with modern biological nutrient removal (BNR) capabilities.

Facility Overview

A. Service Area & Coverage

The Coney Island WRRF services a drainage basin covering approximately 15,087 acres (23.6 square miles) of South Brooklyn. The service area is predominantly residential but includes significant commercial zones and recreational areas. The specific neighborhoods served include:

• Coney Island and Brighton Beach
• Sheepshead Bay and Gravesend
• Homecrest and Madison
• Manhattan Beach
• Portions of Midwood and Canarsie

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The collection system is a combined sewer system (CSS), meaning it conveys both sanitary sewage and stormwater runoff. This configuration presents significant hydraulic challenges during precipitation events, requiring robust wet-weather operating protocols.

B. Operational Capacity

The facility is designed to handle substantial flow variations characteristic of combined sewer systems:

• Design Dry Weather Flow: 110 MGD
• Design Wet Weather Flow: 220 MGD (2x DDWF)
• Current Average Daily Flow: ~70–80 MGD

During heavy rainfall, flows exceeding the plant’s secondary treatment capacity are managed through the system’s regulators and combined sewer overflow (CSO) outfalls, though recent “Grey Infrastructure” projects aim to maximize flow capture and treatment.

C. Discharge & Compliance

The treated effluent is discharged into Rockaway Inlet, which connects Jamaica Bay to the Atlantic Ocean. The outfall is located approximately 7,500 feet from the facility. The plant operates under a State Pollutant Discharge Elimination System (SPDES) permit issued by the New York State Department of Environmental Conservation (NYSDEC). Due to the ecological sensitivity of Jamaica Bay, the facility is subject to strict nitrogen loading limits to prevent eutrophication.

Treatment Process

The Coney Island WRRF utilizes a Step Aeration Activated Sludge process, modified over the decades to enhance nutrient removal and wet weather handling. The treatment train follows a conventional gravity flow path.

A. Preliminary Treatment

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Raw influent enters the plant through the Main Sewage Pumps. Preliminary treatment is critical for protecting downstream mechanical equipment:

• Screening: Heavy-duty mechanical bar screens remove large debris (rags, wood, plastics). Screenings are compacted and hauled to landfills.
• Grit Removal: The facility utilizes aerated grit chambers where velocity is reduced, allowing inorganic solids (sand, gravel, coffee grounds) to settle while organic matter remains suspended.

B. Primary Treatment

Flow proceeds to primary sedimentation tanks. These rectangular tanks reduce the velocity of the wastewater to allow settleable solids to drop to the bottom as primary sludge, while grease and oils float to the surface for skimming.

• Configuration: Rectangular tanks with chain-and-flight mechanisms.
• Removal Efficiency: Typically removes 60-65% of Total Suspended Solids (TSS) and 30-35% of Biochemical Oxygen Demand (BOD).

C. Secondary Treatment (Biological)

The biological engine of the plant is the Step Aeration Activated Sludge process. This configuration introduces primary effluent at multiple points along the aeration tank, rather than just at the head. This allows for better distribution of oxygen demand and provides solids loading flexibility.

• Aeration Tanks: Four major batteries of aeration tanks. Air is supplied via centrifugal blowers through fine-bubble diffusers to maximize oxygen transfer efficiency.
• Biological Process: Microorganisms (activated sludge) consume dissolved organic matter. To meet Jamaica Bay water quality standards, the plant utilizes BNR (Biological Nutrient Removal) strategies to reduce nitrogen levels.
• Secondary Clarifiers: The mixed liquor flows to final settling tanks where the biomass settles out. A portion is returned to the aeration tanks as Return Activated Sludge (RAS), and the excess is removed as Waste Activated Sludge (WAS).

D. Disinfection

The clarified effluent undergoes disinfection to eliminate pathogenic organisms before discharge.

• Method: Chlorination using Sodium Hypochlorite (NaClO).
• Contact Tanks: Dedicated chlorine contact tanks ensure sufficient contact time (typically 15-30 minutes at peak flow) for effective kill rates of fecal coliform.
• Residual Control: Effluent is monitored to ensure Total Residual Chlorine (TRC) remains within permit limits to protect aquatic life in Rockaway Inlet.

E. Solids Handling

Solids processing is a major operational component at Coney Island WRRF:

• Thickening: Primary sludge and WAS are thickened (typically via gravity thickeners) to reduce volume.
• Anaerobic Digestion: Thickened sludge is pumped to anaerobic digesters. The facility utilizes mesophilic digestion (approx. 95°F) to stabilize volatile solids and reduce pathogens. This process generates methane gas (biogas).
• Dewatering: Digested sludge is chemically conditioned and dewatered using centrifuges.
• Disposal: The resulting “sludge cake” is hauled off-site for beneficial reuse (land application) or landfill disposal, depending on current city contracts.

Infrastructure & Facilities

A. Physical Plant

The site occupies roughly 25 acres in a dense urban environment. The architectural style of the original 1930s structures reflects the Art Deco influence of the WPA era, though much is obscured by modern industrial retrofits. The site includes the Main Building (pump room and screens), Generator Building, Sludge Degritting Building, and administrative offices.

B. Energy Systems & Cogeneration

The Coney Island WRRF is a significant energy consumer but also an energy producer. The facility captures biogas produced during anaerobic digestion.

• Cogeneration: The plant utilizes onsite engines/generators designed to run on digester gas. This cogeneration system provides electricity for plant operations and heat for the digestion process, reducing reliance on the Con Edison grid and lowering the facility’s carbon footprint.
• Waste Heat Recovery: Heat recovered from the engine jackets is used to maintain digester temperatures.

C. Odor Control

Given its proximity to residential neighborhoods like Sheepshead Bay, odor control is paramount. The facility utilizes dual-stage odor control systems, primarily focusing on the headworks and sludge processing areas. Technologies include misting towers and activated carbon adsorption units to treat foul air before release.

Recent Upgrades & Major Projects

NYC DEP Resiliency Program (Post-Sandy) – $100M+ (2014-2020)

Context: During Superstorm Sandy (2012), the Coney Island WRRF was inundated by storm surge, damaging electrical distribution systems, motors, and controls. The plant operated on emergency bypass for a period following the storm.

Project Scope:

• Flood Protection: Installation of flood barriers and raising of critical equipment above the new FEMA 100-year flood elevation plus freeboard.
• Pumping Systems: Replacement of dry-pit pumps with submersible pumps capable of operating even if the pump room floods.
• Electrical Hardening: Elevation of substations, switchgear, and emergency generators.
• Seal Water Systems: Installation of independent seal water systems to protect pumps during surge events.

Main Sewage Pump (MSP) Upgrade

Scope: Replacement of the original main sewage pumps and prime movers. This project modernized the influent pumping capacity to ensure reliability during peak wet weather events. It involved installing Variable Frequency Drives (VFDs) to allow for precise flow matching and energy efficiency.

Biological Nutrient Removal (BNR) Retrofits

Scope: Structural and process modifications to the aeration tanks to create anoxic zones. This allows for denitrification (conversion of nitrate to nitrogen gas), essential for meeting the Nitrogen Total Maximum Daily Load (TMDL) requirements for Jamaica Bay.

Regulatory Compliance & Environmental Performance

A. Permit Requirements

The facility operates under SPDES Permit NY0026182. Key compliance parameters generally include:

• BOD5 & TSS: 30 mg/L (monthly average) with required 85% removal efficiency.
• pH: 6.0 to 9.0 standard units.
• Fecal Coliform: 200 MPN/100 mL (30-day geometric mean).
• Total Nitrogen: Aggregate load limits apply to the Jamaica Bay watershed plants (Coney Island, 26th Ward, Jamaica, Rockaway).
• Settleable Solids: 0.1 mL/L daily maximum.

B. Compliance History

The Coney Island WRRF has maintained a strong compliance record in recent years. Occasional exceedances are typically associated with extreme wet weather events where hydraulic capacity is stressed, leading to bypass or reduced settling efficiency. The facility is part of the NYC DEP’s Long Term Control Plan (LTCP) to address Combined Sewer Overflows into Coney Island Creek and Jamaica Bay.

Operational Excellence

Staffing: The facility is staffed 24/7/365. The workforce consists of Sewage Treatment Workers (STWs), Senior STWs, Oilers, Stationary Engineers (Electric), and maintenance staff, overseen by a Plant Superintendent and Deputy Superintendents. All operators must adhere to NYSDEC certification requirements.

SCADA & Automation: The plant utilizes a distributed control system (DCS) for real-time monitoring of flows, tank levels, dissolved oxygen (DO) profiles, and pump status. This automation allows for “feed-forward” control strategies to manage storm flows effectively.

Challenges & Future Planning

A. Climate Change & Sea Level Rise

As a coastal facility, the primary long-term challenge is sea-level rise. While the Post-Sandy upgrades provided immediate hardening, long-term planning (looking toward 2050 and 2080) involves assessing the hydraulic profile of the outfall. Higher tides reduce the hydraulic head available for gravity discharge, potentially requiring effluent pumping in the future.

B. Aging Infrastructure

While mechanical systems have been upgraded, the underlying civil structures (concrete tanks, channels) date back to 1935. Concrete rehabilitation and structural reinforcement are ongoing maintenance priorities to prevent rebar corrosion and spalling.

C. Energy Neutrality Goals

In line with OneNYC 2050 goals, the DEP is exploring ways to make WRRFs energy neutral. Future projects at Coney Island may focus on enhancing biogas production (via co-digestion of food waste) and improving the efficiency of the cogeneration engines.

Technical Specifications Summary

Related Facilities

The Coney Island WRRF operates within the larger Jamaica Bay watershed ecosystem managed by NYC DEP. Engineers and operators may also be interested in:

• 26th Ward WRRF: Located in East New York, discharging into the northern part of Jamaica Bay.
• Rockaway WRRF: Located on the Rockaway Peninsula.
• Jamaica WRRF: Located near JFK Airport.

These four plants are often managed collectively regarding Nitrogen aggregate limits for the bay.

Frequently Asked Questions

Technical Questions

1. Does the Coney Island WRRF have tertiary filtration?
No, the facility currently utilizes advanced secondary treatment with BNR capabilities but does not employ tertiary media filtration or membrane systems.

2. How is grit handled at the facility?
Grit is removed via aerated grit chambers, washed/classified to remove organics, and hauled to landfills. It is not reintroduced into the biosolids stream.

3. Is the facility equipped for co-digestion?
While NYC DEP has piloted food waste co-digestion at the Newtown Creek facility, Coney Island primarily digests indigenous sewage sludge. However, strategic plans often review the capacity for co-digestion at other plants.

Public Interest Questions

4. Does the plant affect swimming at Coney Island Beach?
The plant discharges into Rockaway Inlet, away from the Atlantic Ocean beaches of Coney Island. The effluent is disinfected to meet strict health standards. Beach closures are generally related to untreated CSOs during heavy rain, not the treatment plant effluent.

5. Can the public tour the facility?
NYC DEP occasionally offers tours for educational groups and during special events (like Open House New York), but it is not open to the public on a walk-in basis due to security and safety regulations.