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

Table 1-10: Flow and Load Peaking Factors
Loading
Condition
Flow Peaking
Factors
TSS Load
Peaking Factors
CBOD Load
Peaking Factors
TKN Load
Peaking Factors
Minimum Week 0.81 0.72 0.72 0.72
Minimum Month 0.83 0.79 0.83 0.83
Annual Average 1.00 1.00 1.00 1.00
Maximum Month 1.22 1.23 1.28 1.28
Maximum Week 1.50 1.53 1.53 1.53
Maximum Day 2.00 1.78 1.78 1.78
Peak Hour 2.00 2.00 2.00 2.00
These peaking factors were applied to the 2045 projected loads to determine peak loading
conditions. The peaking factors were applied to the projected 2045 flows and loads to create the
influent flows and loads assumptions shown in Table 1-11 and are as follows:
Table 1-11: Basis of Design Influent Flow and Load
Average
Peak Hour
Flow (mgd) 39.2 78.4
TSS (lb/d) 54,700 109,400
CBOD (lb/d) 39,900 79,800
TKN (lb/d) 8,700 17,400
Of concern is that the current CBOD load at the Red Hook WPCP (39,800 pounds per day on an
annual average basis) is slightly greater than the BEPA CBOD projected load for 2045 (39,000
pounds) despite this service area being a likely area of population and employment growth.
1.3.3 North River
Existing and future flows and loads were evaluated and used as a basis of design for the North
River WPCP.
1.3.3.1 Existing Flows and Loads
An evaluation of existing flows and loads was performed to develop peaking factors that may be
used for future flow and load projections. Plant Data from 2003 to 2005 was evaluated to
determine average and peak (monthly, weekly and daily) loadings to the facilities. Peaking
factors (monthly, weekly and daily) were developed for flows and loads and were determined
based on 2 times the standard deviation plus the average to ensure designs are not based on
anomalies that would result in excessive costs. Plant data is shown in Appendix A of the North
River Report. Table 1-12 shows the flow and load conditions at the plant and Table 1-13 shows
the peaking factors that will be used to evaluate future conditions.