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RE: Total Petroleum Hydrocarbon


Your numbers of 1 to 4 ppm sound very low and I suspect they are based on
the use of lots of water or it may have been a cold water wash. A study by
the City of Los Angeles showed average levels of 160 ppm in the wash water
from street cleaning.

Typically, anything less than 10 ppm is likely to be dissolved. I recall
reading somewhere that the presence of a visible sheen equates to 10 ppm
dissolved phase. The actual levels however will depend on the composition of
the waste. You also have to be very careful because the use of cleaners and
detergents will emulsify the oil and grease. Emulsification can also occur
during steam cleaning.


-----Original Message-----
From: Peter Kallin [mailto:p.kallin@omnienvironmental.com]
Sent: Friday, June 09, 2000 4:56 AM
To: Multiple recipients of list
Subject: Total Petroleum Hydrocarbon

Dear Fellow NPSers-
Does anyone have a feel (preferably with a reference) for what percentage of
total petroleum hydrocarbon in runoff from street/parking lot is
typically "free oil" floating on top of the water as opposed to
dissolved or sorbed to suspended solids?  I am looking at a site where I
anticipate the flow weighted concentrations to be on the order of 1-4
ppm and wondering how much I can retain in a bioretention system using a
3 inch baffle in the outflow structure to prevent the surface water
>(with floating oil) from flowing out under high flow conditions.  I have
seen studies by
manufacturers such as Stormceptor that claim 80-95% reduction of "free
oil" with this kind of separation but don't have a feel for how much of
the total load is really "free oil" floating on top. Any ideas?
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Dr. Peter L. Kallin                            |
Omni Environmental Corporation                 |
Research Park                                  |
321 Wall St.                                   |
Princeton, N.J. 08540-8831                     |
(609) 924-8821 (Ext. 26)   Fax:(609) 924-8831  |
pkallin@omnienvironmental.com                  |
<http://www.omnienvironmental.com>             |
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