Learning how to curtail phosphorus
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A pilot project pointed the way for full-scale treatment of phosphorus at Metro.
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The Metropolitan Syracuse Wastewater Treatment Plant (Metro) is considered a major source of the
phosphorus that reaches Onondaga Lake. Phosphorus removal
with conventional technologies is expensive. The Onondaga County Department of Water Environment Protection (WEP)
implemented a $1.9 million pilot projectcompleted 6
years ahead of scheduleto evaluate six different
phosphorus treatment technologies.
This pilot project concluded that high-rate
flocculated settling (HRFS) could reduce phosphorus in
Metro's discharge to extraordinarily low levels (0.12
mg/L as a 12-month rolling average). On the basis of
this work, WEP can use HRFS to meet New York State effluent
requirements.
The pilot project also provided a basis of design for
the full-scale phosphorus treatment facility that WEP
is now building.
It appears today that the HRFS technology may be able
to achieve lower limits than Onondaga County currently must
meet. Moreover, because of the high efficiency of the
HRFS system, WEP has projected significant savings
over more traditional filter technologies.
By 2012 Onondaga County must reduce the phosphorus
discharges to 0.02 mg/L, the most restrictive in the
U.S. and perhaps in the world. To meet such a low
limit, the County is again testing technologies.
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