Citywide integrated planning and water quality assessment

New York City Department Environmental Protection (DEP) owns and operates 14 wastewater treatment plants that process 1.2 billion gallons per day of dry weather flow within the five boroughs of New York City. Over the last 10 years, DEP has been engaged in multiple programs to improve water quality in NY Harbor and the region as well as maintain facilities in a state-of-good-repair with a capital expenditure of about $10 billion over past ten years; some of the major existing regulatory programs included the Biological Nitrogen Removal Program and the Combined Sewer Overflow Program. In addition to these existing programs, there are some emerging unfunded requirements such as the Municipal Separate Storm Sewer System Program along with new water quality based effluent limits being included in the next round of the State Pollutant Discharge Elimination System permits that will include ammonia limits, total residual chlorine limits, free cyanide limits, and likely in the future the pathogen indicator will be changed from fecal coliform to enterococcus to coincide with the Environmental Protect ion Agency Recreation Water Quality Criteria that the New York State Department of Environmental Conservation will be adopting into future regulations. Many of these new regulatory mandates are intertwined and it's difficult if not impossible to address one parameter without evaluating the impacts it will have on other parameters. As a result, DEP is undertaking a an integrated management plan to address newly proposed water quality based effluent limits holistically in conjunction with the ongoing BNR upgrades since all these new parameters influence one another. DEP will be implementing a phased integrated planning approach that will re-evaluate how these limits were derived including performing updated dye dilution studies, plume modeling, and water effect ratios in conjunction with conducting bench, pilot, and full scale studies.