Do a web search of "grease" and the first two pages are concerning a 1970's vintage movie starring John Travolta. Try "fog" and you will get pages of information on low clouds and water vapor, and a poem, "Fog" by Carl Sandburg. Now type in fats, oils and grease or "F.O.G.'s", and you will pick up a vast array of technical data on a major problem for sewer systems, actually a $25 billion per year problem for U.S. taxpayers. The problem is so serious it has made the front page of the Wall Street Journal! They reported 75% of the nation's sewers work at half capacity because of grease clogs. The Journal and most other articles use the word "grease" as an all encompassing term for what is actually fats, oils and grease or F.O.G. Oils and grease come in two forms: polar and non-polar. Polar is associated with food and non-polar is related to petrochemical hydrocarbons. For the sake of this article, we will be discussing polar F.O.G.'s as related to restaurants and food processors.
Why is this problem gaining so much attention in recent years? A lot has to do with the growth of take-out restaurants and double-digit restaurant sales growth. Restaurants create F.O.G.'s, especially fast food and many ethnic restaurants. Globally, F.O.G. output has tripled since the 1960's to over 100 million tons per year. It is estimated that U.S. restaurants dump over three billion pounds of F.O.G.'s per year, which results in F.O.G.'s being the No. 1 cause of sewer overflow - an estimated 40,000 illegal overflows per year. Cities are implementing fines of up to $1,000 per day and 60 days in jail for willful violations of F.O.G. discharges.
Grease traps, three-part separators or oil water separators, also sometimes called interceptors, have been around since the 1940's. There are an estimated one million grease traps in the United States. Basically, a grease trap operates on the principal that F.O.G.'s have a lower specific gravity than water. As such, they rise and float on the surface of water. This is under ideal conditions. 
What happens in a kitchen and drain is the F.O.G.'s are emulsified with detergents and hot water. Also, they mix with solids, such as dirt and food particles, etc. In addition, turbulence mixes them up. In time, the hot water will cool and the detergents will release the emulsified F.O.G.'s from suspension. The F.O.G.'s will rise and congeal on the surface, often as a solid mass, and then must be physically removed or they will block the grease trap or sewer lines and create an overflow. Overflows are a health hazard and a legal or sometimes criminal liability.
Many managers do not realize that you're supposed to pump them out. The grease trap faces an "out of sight, out of mind" situation. 21,000 restaurants have over 5,000 F.O.G. based back ups per year. New York City uncovered a 73% rate of grease trap abuse. The city now has a $1,000 per day fine.

Grease traps must be sized properly to work right. A typical Chinese restaurant could need a 5,000-gallon grease trap. The size is important due to the required dwell time so the F.O.G.'s can be released from suspension. Temperature, detergents and the amount of solids, as well as turbulence all contribute to the release and coalescing (joining of F.O.G. particles together), and their subsequent rise to the surface.
The problem is further exasperated by the local sewer authorities who do not want to receive F.O.G.'s from the pump out trucks. These grease trap pump out services must have a place to discharge the F.O.G. waste. Increasingly, Landfills will not take it, and many sewer treatment works will not take it as the concentrated F.O.G. mixture upsets the balance of the plant and creates odors. F.O.G. wastewater must have a concentrated pre-treatment to break down the F.O.G.'s before they enter the plant. These pre-treatment systems are expensive and are not widely available.
How can we safely, effectively and economically solve the grease problem? A number of technologies have been proven to have varying degrees of success in breaking down F.O.G.'s. The breakdown methods are performed by three major categories: physically, chemically and biologically. First is physically or mechanically. These methods include: 

Macerator Pumps - Similar to a kitchen garbage disposal, these grinding type pumps break F.O.G. down to a slurry.

Oil Wheels - These discs are slow moving wheels that dip into the top of a grease trap. As the F.O.G.'s stick to the wheel, they are scraped off by a scraper and flow into a waste reservoir.

Aeration - High volume of air is bubbled into the grease trap, which mechanically breaks the solidified grease down to slurry. Aeration can be applied by using a fluidized media bed to enhance the breakdown.

DAF or Dissolved Air Flotation - Large volume of compressed air is injected into water. This air saturated water is then realeased into an open top vessel, where the air then comes out of solution, thereby breaking emulsions and aiding the F.O.G.'s to rise and congeal.

Biological Bacteria - Aerobic Sewer Treatment System utilizing various medias and bacteria to literally digest the F.O.G.'s into water and carbon dioxide.

Chemically Ozone - O3 is an oxygen molecule with a loosely held extra atom that is very aggressive. Ozone will oxidize and break down grease. As it does so, the O3 turns to O2 or oxygen! Ozone and other advanced oxidation gas also eliminate sewer and F.O.G. odors and airborne bacteria.

Saponification/Base Hydrolysis Reactions - The use of caustics to alter the pH, thereby turning the F.O.G.'s into soap, similar to the cowboys who used lye and fat to make soap! RGF Environmental has taken ten proven technologies and combined them into a compact unit. By combining technologies, you provide redundancy. The system utilizes aeration in a fluidized bed reactor to physically break down the F.O.G.'s. In addition, rather than just using air, RGF uses advanced oxidation gases, including ozone, hydro peroxides, and super oxide ions. These advanced oxidation gases also reduce sewer odors and airborne bacteria. As the ozone breaks down F.O.G.'s, it then converts to oxygen, which in turn promotes aerobic bacteria growth.  F.O.G specific bacteria are then continuously dripped into the oxygen enriched chamber to automatically break down the remaining F.O.G.'s. This is all done in a five-chamber Bio Ox Reactor. A periodic oxidation purge provides a saponification flush of the system. A compact unit has been designed for hotels with indoor lift stations. The two-foot square footprint makes installation simple. A Bio Reactor can be used, or the existing sump can be used as the Reactor Vessel. This system will break the F.O.G.'s down to short chain molecules, which are readily digestible by a treatment plant.                   RGF Bio Ox Mod              RGF Bio Ox in ground                                                Typical Layout     Authors Ronald G. Fink President, RGF Environmental Group. BSME, Numerous patents, including patents pending on PhotohydroionizationTM , authored over 50 published technical papers. Mr. Fink has a 30 year background in nuclear power, air and water treatment. Walter B. Ellis Vice President Research & Development, RGF Environmental Group. BS Degree in Biology & Marine Biology. Mr. Ellis is a specialist in Advanced Oxidation. He has authored several published technical papers and has numerous patents.

RGF Bio Ox Lift Station Unit   Bio Ox Lift Station Unit Existing sump

                                                            
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