What Should You Do With Your
Biodiesel Waste /By-Products?

Biodiesel production produces three major biodiesel waste products: glycerin, methanol, and (sometimes) water... and then there's that occasional failed batch as well! Below are some options for what to do with each.

The Glycerin By-Product:

For every 10 parts of biodiesel produced, there is 1 part glycerin formed. Glycerin is becoming so abundant with increased biodiesel production that the demand for it has dropped, causing some people to have to pay to dispose of it. Here are some options for what to do with the glycerin (most ideas are to convert it into something more valuable to be sold):

• Many home-brewers are making soap from the biodiesel waste glycerin .

• Glycerin can be converted into ethanol through fermentation with a strain of E. coli. This method of producing ethanol actually has higher yields than the traditional way of producing ethanol!

• Researchers have found that when glycerin is combined with a harmless strain of E.coli, succinate is formed. Succinate is used to flavor food and drinks, is an ingredient in perfumes and dyes, and in nontoxic plastic solvents. Succinate has a large market in the US.

• Formate can be produced from glycerin and E-coli strains. It is a common preservative in animal feed, and is also used as an antibacterial agent.

• PureVision has made a form of lignin that can be used in to manufacture glue, detergent, and sealants. It has an estimated worth of $300 a ton.

• Professor Lin is trying to turn the resulting glycerin from the catalyst he developed into 1,3 propanediol (1,3-PDO). This is used as a base material for a substance used when making clothing, upholstery and fabrics.

• Glycerin can be used to produce a hydrogen rich gas for use in fertilizers, food production and chemical plants.

• It can also be taken to a wastewater treatment plant where it will be added to a methane digester (they won't pay you for it, but at least you don't have to pay to dispose of it). :)


If You Have a Failed Batch of Biodiesel:

• Have a used oil collector to come and haul it.

• Biodiesel waste can be composted by mixing in organic matter such as leaves, grass clippings, straw, and twigs. Toss the mixture around every couple weeks to oxygenate it in order to help it decompose. This will also allow any remnant methanol to evaporate. In a few months you can add it to your garden!


Remnant Methanol:

• Excess methanol can be boiled off the glycerin within a closed container and directed into a condenser. It can then be reused in the next batch of biodiesel!
Click here to learn more about methanol recovery.


Waste Water

Waste water is produced by those who wash their biodiesel with water.

• If you are producing biodiesel for your personal use, the quantity of the biodiesel waste water is likely to be acceptable to dispose of down the drain.

• If you are producing larger amounts, you may need an industrial waste water discharge permit, and the sewage treatment plant may want to test the water so they are aware of what biodiesel chemicals are in it.

• For more information on how to dispose of biodiesel waste or biodiesel chemicals your local health department should be contacted.

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