[USCC] Re: Waste grease and fat

William (Bill) Carter compost@compostingcouncil.org
Tue Apr 2 10:08:00 2002


There are 2 different food-service oil/grease wastes that are often =

PB was asking about "grease trap waste" from restaurant grease traps. =
These traps are in the wastewater plumbing downstream of the restaurant =
sinks to capture grease and food solids and prevent them from overloading =
wastewater treatment plants. This material is high-90's% water ("flowable =
liquid") and NASTY. Composting it where possible is about the highest-end =
use it has currently.  Otherwise it is a major pain for disposal.

The other "grease" is primarily recovered cooking oil with cooking =
residues, largely from restaurant frying. It has traditionally been =
collected for rendering, primarily to recover clarified oil for use in =
animal feed and sometimes for other commercial applications of vegetable =
oil/animal fat.

This latter waste would presumably be a potential feedstock for refinement =
into fuels, but that use would have to be weighed against the relatively =
high-end rendering products. (Incidentally, I've been told cooking oil, =
even home bacon drippings, was collected and processed to recover =
glycerine for the making of nitroglycerine in World War II.) The former =
(grease trap waste) would seem to have far too much water (not to mention =
impurities) to be a cost-effective fuel resource.

Please correct me if I've misinterpreted.

      - Bill

Bill Carter
Watershed Management Team    MC 147
Texas Natural Resource Conservation Commission
P.O. Box 13087
Austin, TX  78711-3087
Phone:  512-239-6771
Fax:  512-239-4410

>>> CAVM@aol.com 03/31/02 04:32PM >>>
In a message dated 3/31/2002 12:01:19 PM Central Standard Time,=20
compost-request@compostingcouncil.org writes:

>  CARLBSEEDSINC@aol.com 03/30/02 12:38PM >>>
> If restaurant grease trap waste (flowable liquid) were applied to wood
> chip-yard waste piles and turned regularly would the results be =
> or
> not? =20

Not to sound anti-composting but oil and grease have other uses in some=20
cases.  For example, there is a move to make biodiesel from what is =
WVO, waste vegetable oil.  Animal fats have the same potential.  But =
material also has very high BTU when used as an additive to boiler =
fuel.  It would likely have about 95% of the BTU diesel fuel.  We are=20
exploring the use of fat and grease as boiler fuel for a client in =
now.  He will soon decide if he prefers biodiesel or bunker fuel.

The volume of the material, reliable supply and the local situation have =
lot to do with your options.  Composting may not be much of an option in =
areas either.  I guess that some local authorities would prefer to =
a problem away than deal with it.

Neal Van Milligen
Kentucky Enrichment Inc.