The NYCDEP Rockaway Algal Turf Scrubber® (ATS) pilot was implemented in New York City to evaluate the use of attached-algae treatment for nitrogen and phosphorus load reduction within the Jamaica Bay watershed. The pilot was located adjacent to Jamaica Bay at the Rockaway Water Pollution Control Plant, where wastewater treatment plant flow was pumped through two parallel ATS pilot floways.
NYCDEP Rockaway ATS pilot floway installed adjacent to the Rockaway Water Pollution Control Plant in Queens, New York. The pilot evaluated attached-algae treatment under high hydraulic loading rates using municipal wastewater treatment plant flow.
The Rockaway pilot provided important site-specific performance data for applying ATS technology to municipal wastewater effluent in a northern coastal climate. The project also supported evaluation of ATS design assumptions, hydraulic loading, algal productivity, nutrient recovery, dissolved oxygen response, and the potential application of larger-scale ATS systems for wastewater and watershed nutrient management.
Facility Summary
Facility: NYCDEP Rockaway Algal Turf Scrubber® Pilot
Location: Rockaway Water Pollution Control Plant, Queens, New York
Technology: Algal Turf Scrubber® / attached-algae floway
Scale: 56,000 GPD; two 350-foot-long by 1-foot-wide pilot floways
Status: Pilot testing completed
Operating Period: 2010–2011
Source Water: Rockaway Water Pollution Control Plant flow
Operating Context: Municipal wastewater treatment plant; Jamaica Bay watershed; combined sewer overflow and nutrient-management planning
Application: Nitrogen and phosphorus load reduction, algal biomass recovery, hydraulic loading evaluation, and full-scale performance projection
Owner / Sponsor: New York City Department of Environmental Protection
HydroMentia Role: ATS technology consultation, performance evaluation, data review, and project reporting
Operating Context
The Rockaway ATS pilot was implemented for the New York City Department of Environmental Protection as part of a broader effort to evaluate ecological and best management practice approaches for improving water quality in the Jamaica Bay watershed. The project was located at the Rockaway Water Pollution Control Plant, which discharges to Jamaica Bay.
The Rockaway pilot differed from many earlier ATS projects because it evaluated municipal wastewater treatment plant flow in a dense urban setting with limited available land and a northern coastal climate. These conditions made the project challenging from the outset. Rather than representing a conservative full-scale design approach, the pilot was intended to test ATS performance under aggressive hydraulic loading conditions and to help define the practical limits of the technology for this application.
Historically, early ATS systems were commonly operated at much lower linear hydraulic loading rates. Subsequent HydroMentia work, including testing at the S-154 ATS facility, showed that higher hydraulic loading could improve treatment performance under appropriate conditions. The Rockaway pilot extended that line of investigation by operating two parallel floways at substantially higher loading rates, with one floway operated at approximately 20 gpm per linear foot and the other at approximately 40 gpm per linear foot.
Operational Significance
The Rockaway pilot is significant because it tested ATS technology under unusually demanding wastewater and hydraulic conditions. NYCDEP was managing very large wastewater flows to Jamaica Bay, while the land area available for ecological treatment was limited. The pilot therefore provided a practical opportunity to evaluate whether high-rate attached-algae treatment could contribute meaningfully to nutrient management in a highly urbanized wastewater setting.
The project also provided important lessons about the limits of applying ATS to municipal wastewater in northern climates. Seasonal temperature variation, winter conditions, high nutrient loading, repeated flow interruptions, and dry-out events affected algal establishment and system performance. These constraints are important to understanding the results and should be considered in any interpretation of the pilot data.
From a technology-development perspective, Rockaway helped define the upper range of hydraulic loading that could be explored for ATS wastewater applications. The test did not demonstrate that high-rate ATS systems could replace conventional wastewater nutrient-removal processes where land availability is severely constrained. However, it did provide valuable information regarding hydraulic loading, algal productivity, nutrient recovery, oxygenation, operational sensitivity, and the design limitations of attached-algae treatment in dense urban wastewater applications.
Photographs
NYCDEP Rockaway ATS algal growth 100′ down the floway operating at a linear hydraulic loading rate of 40 gpm/lf.
Lower Manhattan from Rockaway ATS pilot.
View NYCDEP Rockaway ATS photo gallery
Additional facility photographs are available in HydroMentia’s Facebook photo archive. Facebook may require visitors to sign in to view the full gallery.
Reports and Publications
The Rockaway pilot is documented in HydroMentia’s final performance report for the New York City Algal Turf Scrubber® Pilot Program.
Technical report: NYC Rockaway Algal Turf Scrubber® Pilot Program Performance Report — September 16, 2010 through December 13, 2011
Related Facilities
Related HydroMentia ATS facilities and demonstrations include Falls Lake ATS, Maryland Port Administration Algal Flow-Way, Osprey Marsh ATS, Egret Marsh ATS, S-154 ATS, and other full-scale and pilot-scale attached-algae treatment systems.