Advanced Wastewater Treatment Facility
Carmel Sewer District No. 2
Carmel, NY

The Town of Carmel's requirements for a WWTP upgrade coincided with New York City's requirement for upgraded treatment standards for watershed discharges. The current plant, located within the Croton Watershed, was discharging 0.350 mgd to a tributary of one of NYC's water supply reservoirs. NYC's limitation for total phosphorous was set at 0.2 mg/l—one of the most stringent in New York State.

JRFA was retained at the conceptual phase. DEIS and FEIS work included significant intermittent stream waste assimilation capacity studies. The issued 1.1 mgd SPDES permit was written based on these standards.

Stringent phosphorus removal requirements necessitated a broad investigation of technologies capable of meeting a 0.2 mg/l discharge parameter. Extensive flocculation and sedimentation tests were run with a variety of available polymers. Claroflocculators, with adjustable alum and polymer feed , were selected for inclusion in the second and third stages of settling. To augment the flocculation/sedimentation process, a 3-month pilot filter study was conducted. Selected polymers were included in the process and a deep bed multimedia filter was designed that met the 0.2 mg/l requirement.

Currently, this is one of the few wastewater treatment plants in New York State that meets this requirement.