NYCDEPCostAnalys isReport-0607 .pdf - New York-New Jersey ...

two options are defined for process modeling purposes, as New York City WPCPs currently
exceed base secondary treatment standards. These levels do enter our costing analysis.
• Base Case – The base case is developed using the design dry weather flow rate (DDWF) and
the projected 2045 wastewater characteristics. A TN removal of 35 percent and an effluent
CBOD of 25 mg/L and TSS of 30 mg/L are assumed. Removals of 85 percent for CBOD
and TSS were applied when this condition proven to be stricter. These characteristics are
consistent with SPDES permit requirements.
• Existing Conditions – Based on the plant flow and effluent quality for Fiscal Years 2003 to
2005, this level assumes the current plant performance observed will continue.
• Existing Conditions with Solids Filtration – Equivalent to the previous level of technology
plus filtration. The Filtration design level utilizes deep bed filters provided at the end of the
secondary process train to reduce the particulate fraction of the secondary effluent discharged
under the existing conditions. This technology preserves the existing secondary treatment
infrastructure, but designs the additional unit process based on the plant-specific 2045 flows
and loads. (carbon only)
• Existing Conditions with Microfiltration/Ultrafiltration – The
Microfiltration/Ultrafiltration design level further reduces the particulate fraction of the
secondary effluent from the existing conditions through the implementation of membrane
technology. This technology preserves the existing secondary treatment infrastructure, but
designs the additional unit process based on the plant-specific 2045 flows and loads. (carbon
only)
• Advanced Basic BNR – Based on the original AWT design guidance, the Advanced Basic
BNR design will provide enhancements to the current step feed operation for increased BNR
performance at the facilities. This level of treatment is currently under construction at the
Bowery Bay, Wards Island, and Tallman Island WPCPs to meet Long Island Sound Total
Nitrogen goals. (nitrogen only)
• Full Step BNR – This treatment level provides the Advanced Basic BNR level with
additional flexibility, and incorporates supplemental carbon addition to enhance
denitrification. This level of treatment is currently under construction at the Hunts Point
WPCP to meet Long Island Sound Total Nitrogen goals. (nitrogen only)
• Full Step BNR with Solids Filtration – Equivalent to the previous level of technology, the
Filtration design level would utilize deep bed filters at the end of the process train to reduce
the particulate fraction of the secondary effluent discharge. (carbon and nitrogen)
• Full Step BNR with Microfiltration/Ultrafiltration – The Microfiltration/Ultrafiltration
design level further reduces the particulate fraction of the secondary effluent through the
implementation of membrane technology. (carbon and nitrogen)
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