MULTISOLUTION APPROACH TO AN ELECTRONIC FIRMS
COMPLEX WASTEWATER DISCHARGE PROBLEMS
Ronald B. Friedman, Consulting Engineer
Wappingers Falls, New York 12590
Richard Arnesen, Facilities Engineer
Fairchdd Camera and Instrument Corporation
Wappingers Falls, New York 12590
A. A. Friedman, Associate Professor
Department of Civil Engineering
Syracuse University
Syracuse, NY 13210
Fairchdd Camera and Instrument Corporation's Wappingers Falls, NY facdity manufactures MOS chips resulting in an acidic waste stream high in fluorides and ammonia. The
treated wastes discharge to an intermittent stream and must meet New York SPDES effluent
limitations of 2.4 mg/1 F and 2 mg/1 NH3-N. The need to plan for production expansion
requirements for a renewal SPDES Permit coupled with a history of periodically discharging
up to 100 mg/1 F and 20 mg/1 NH3-N dictated the need for substantial changes in the wastewater treatment system. This paper describes the steps taken to evaluate and utilize existing
facdities to economically meet the stringent effluent limitations for fluoride and NH3-N.
WASTEWATER SOURCES
Four major waste streams contributed to two point discharges as indicated in Figure 1.
Non-contact cooling water (NCCW) and excess deionized process water (DI) with a combined flow of about 200 gpm were discharged to a storm drain system that also receives roof
drainage along with surface drainage from a small portion of a parking lot. This NCCW
stream does not require treatment and is discharged directly to an intermittent stream.
Sanitary wastes (about 7000 gpd) are first treated by a septic tank-subsurface and filter
system. Effluent from the sand filter is collected and receives further treatment along with
other wastes in aerated lagoons. A fluoride acid waste stream (about 5000 gpd) is collected
and discharges to two 10,000 gallon holding/neutralization tanks. The fluoride acid waste
stream, designated as FW in Figure 1, usually has a pH around 1 and typically contains about
2000 mg/1 F and about 1000 mg/1 NH3-N. The balance of the waste waters, designated as
IW on Figure 1, consist of about 1 10,000 gpd of various quench and rinse waters and waste
acids such as H2 SO« that are discharged to a 20,000 gallon aerated neutralization tank.
Lime and/or caustic soda were added to the FW wastes in the 10,000 gallon tanks as an
uncontrolled batch neutralization process, the pH adjusted supernatant was then pumped to
the inlet of the neutralization tank where it co-mingled with the IW stream. A pH probe in
the 20,000 gallon neutralization tank activated a caustic soda feed pump on demand. The
neutralization tank effluent and treated sanitary wastes are mixed at a manhole and then
discharged to an aerated lagoon system consisting of four 250,000 gallon cells in series.
An end wick filter, consisting of a submerged perforated pipe surrounded by graded gravel
and filter sand in each of the last two cells provided the final treatment step prior to disinfection and discharge. Lime and calcium sludge from the HF acid holding/treatment tanks
and sanitary septic tank sludge were removed on a routine basis by approved scavengers.
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