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RE: [GreenYes] restaurant oil and grease
An interesting issue, looking at the balancing and minimization of total impacts.
In the Madison, WI area, the issue is neither the hydraulic capacity nor the grease itself at the wastewater treatment plant; the plant has both the volume capacity and can handle the grease, fats and oils just fine, even producing energy from the methane generated from digestion of the grease, oils and fats. However, the staff at the treatment plant said that the oils, greases and fats can be a problem in the collector sewers and lift stations within these sewers and that the local municipalities often require the restaurants to install grease traps/interceptors, which are then pumped out on a regular basis.
It was noted that other wastewater treatment plants may have different designs, and that greases, oils and fats may be a problem for them, but it was more likely that the limitation is in the sewers, not in the treatment plant.
It was also noted that the issue of garbage disposal units -- especially home units -- is more of a hydraulic and nutrient loading issue, vs a grease, oil and fat issue.
For the landfill, our studies (including for our own site) suggest that the decomposition of the disposables will produce methane that will have limited capture by the landfill gas recovery system. The greases, oils, and fats will tend degrade quickly, in the newer layers of the landfill, above the levels of the slotted portion of the gas extraction system. This gas will then tend to escape to the atmosphere, where it is a powerful global climate change gas. Unfortunately, hard numbers for this situation are not available.
John Reindl, Recycling Manager
Dane County, Wisconsin Dept of Public Works
-----Original Message-----
From: Gary Liss []
Sent: Thursday, October 03, 2002 12:41 PM
Subject: Re: [GreenYes] restaurant oil and grease


There are 3 groups that I know of that have looked at related issues in some depth: Seattle/King County Area, Half Moon Bay, and San Diego County.

Key seems to be whether there is sufficient wastewater treatment capacity or not.  In Half Moon Bay, in the 1990s they banned commercial garbage disposal units while they had restricted capacity on their treatment plant.  I believe that treatment plant has now been expanded, and don't know if they lifted the commercial ban.

In San Diego County, Rick Anthony did extensive analysis of these issues, in preparation for developing new sewer rates, charging by the concentration of loading on the sewer system.

In King County/Seattle, they have plenty of wastewater treatment capacity.  They did extensive studies in the 1990s on this issue and decided it was OK for people to use garbage disposal units there.

Rick Anthony: 858-272-2905
Half Moon Bay: George Irving, Montara Sanitary District could get you the right person.  George is at 650-728-3545 or <>
Seattle: Jenny Bagby or Henry Friedman at (206) 733-9147 could get you the right person in King County; <> or


At 07:59 AM 10/03/2002 -0700, wrote:

The Long Beach Water Department has produced a brochure for restaurant owners about BMPs for keeping fats, oils, and grease out of the sewers.  Unfortunately, one of their recommendations is that restaurants use disposable paper products instead of washable dishware.  I would like to recommend a change to their brochure, but wonder if this issue of "waste water vs. solid waste" has been addressed somewhere else.  It seems that most agencies are either waste water or solid waste, and very few deal with both.  I tried contacting the Sanitation Districts of Los Angeles County (who do handle both solid waste and waste water) and the gentleman with whom I spoke didn't seem to understand why recommending disposables would be a problem.  His attitude seemed to be that since there was landfill space, better to send stuff to the landfill than put it into the sewer.  The gentleman e-mailed me factsheets that th! e Sanitation Districts send out, and they go even further with disposables.  The Sanitation Districts recommend the use of paper towels so that grease doesn't get into the sewers from washing machine wastewater!  It doesn't require much imagination to take this to its logical conclusion -- single-use everything (clothing, equipment, cars, buildings...), throw it all away.  Come to think of it, that's not a far stretch for what we already have :-(.

My instinct is to recommend that the Water Dept. just  remove any reference to disposables.  It seems to me that following the other oil and grease BMPs would keep grease out of the sewer without adding to the solid waste stream.  Have other agencies addressed restaurant oil/grease while also incorporating an understanding of solid waste reduction?  I would like to be able to put my recommendation(s) in terms to which the Water Department will be receptive.

Thanks in advance for your help.

Sharon Gates
Recycling Specialist
City of Long Beach, California

Gary Liss
Fax: 916-652-0485

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