Wards Island Water Pollution Control Plant

Location: Wards Island, NY

Wards IslandWards IslandThe Wards Island Water Pollution Control Plant (WPCP) is a secondary wastewater treatment plant currently permitted to treat 275 million gallons per day (MGD) average dry weather flow (ADWF) and 550 MGD wet weather flow (WWF).

The plant has been in operation since 1937 and serves a population of over 1 million in Manhattan and the Bronx. The plant’s service area consists of over 12,000 acres in northeastern Manhattan, western Bronx, Randalls Island, and Wards Island. The plant is located on an 84-acre site on Wards Island, which is in the East River at the intersection of Manhattan, Queens and the Bronx.

The IPE construction project had increased the plant’s capacity from 250 to 275 MGD ADWF and from 500 to 550 MGD WWF. The IPU Phase 1 project had implemented improvements to the plant’s effluent disinfection system and installed a polymer addition system to improve final sedimentation of the Aeration Tanks (ATs) mixed liquor. Improvements to the plant’s off-site headwork facilities, the Bronx and Manhattan Grit Chambers, are currently under construction under the IPU Phase 2 project.

Nitrogen Control

Nitrogen discharged to the Western Long Island Sound has been identified as the most significant contributor to hypoxia, which results in adverse ecological effects. Extensive water quality testing and modeling have been conducted by the New York City Department of Environmental Protection (NYCDEP) and the Long Island Sound Study (LISS).  Based on a determination by the LISS of the required Total Nitrogen (TN) discharge load reduction (using 1990 levels as a baseline) to meet water quality standards in the Western Long Island Sound, the New York State Department of Environmental Conservation (NYSDEC) modified the State Pollutant Discharge Elimination System (SPDES) permit for New York City WPCPs to reduce their allowable nitrogen discharge.

The NYCDEP negotiated a Judicial Decree with the NYSDEC for a program that would implement Biological Nitrogen Removal (BNR) treatment capabilities at the four Upper East River (UER) WPCPs (Bowery Bay, Hunts Point, Tallman Island, and Wards Island) and at the 26th Ward WPCP to meet the nitrogen discharge loads in Long Island Sound and Jamaica Bay. Under this Judicial Decree, the NYCDEP agreed to implement BNR treatment capabilities at the Wards Island WPCP by December 31, 2010.

In addressing the Judicial Decree, guidelines for the implementation of BNR were developed by the Advanced Wastewater Treatment Program Management Team (AWT). These guidelines were based on the implementation of advanced basic step-feed BNR treatment at the UER WPCPs and the 26th Ward WPCP to meet nitrogen reduction goals while maximizing the use of existing facilities and with a defined implementation cost. The AWT issued a technical memorandum entitled “Revised Nitrogen Management Plan, Program Guidance Document”; dated April 2003 (referred to as the April 2003 Revised Guidance Document). This document included guidelines and recommendations for the design and operation of basic step-feed BNR treatment at the UER WPCPs and the 26th Ward WPCP. The Total Maximum Daily Load (TMDL) for nitrogen discharge included in this document was based on a 10-year goal with design year conditions of 2012.

Plant Stabilization 2

The nutrient removal work for the implementation of advanced basic step-feed BNR, as defined by the April 2005 Revised Guidance Document, at the Wards Island WPCP is included in Plant Stabilization 2, Contract WI-79 BNR Treatment and Miscellaneous Improvements. Plant Stabilization 2 provides for modifications to existing facilities and systems to extend operations and includes improvements to implement advanced basic step-feed BNR at the Wards Island WPCP.

During construction, CCJM reviewed shop drawings, answered Requests for Information (RFI), provided construction inspection, evaluated and negotiated proposed change orders, developed Operation Maintenance Manuals, and conducted operators training.