A Powerful Idea: Could Food and Farm Waste Fuel the Fair?

Project Overview
How much of the Minnesota State Fair's waste comes from animal waste?
Cleaner Energy (and Air!) from State Fair Waste
Anaerobic Digestion and the Kindness of Bacteria
Cadaverine and Putrescine: much cooler names than pentamethylenediamine and butanediamine
Corndogs versus Mini-Donuts
Everything but the Oink? State Fair Recycling
Burning Calories in the Compost Pile
Microbrew and Other Fair Fuel
Test yourself with our Virtual State Fair Stumper Quiz!

Project Overview — August 26, 2010

The Minnesota State Fair is an increasingly popular 12-day event. With 2010 attendance records expected to beat 2009’s record-setting 1.79 million visitors, it’s no secret that the “Great Minnesota Get Together” generates a lot of waste from food, packaging, and livestock.

In fact, in 2009, fairgoers and animals produced nearly 5.5 million pounds of waste.

In collaboration with the University of Minnesota (U of M), the Minnesota State Fair hired SEH to figure out if they can put this refuse to re-use.

Each day of the 2010 Minnesota State Fair, SEH environmental scientist George Johnson, State Fair facilities staff and U of M researchers will collect samples of the Fair’s organic waste. In addition to making daily visits to the agricultural buildings to collect manure samples, the team will also collect samples of food waste from fair vendors and samples from general waste receptacles.

SEH will assess detailed information about the waste composition, quantities, and availability to learn whether they could be combined with waste from the nearby U of M campus and converted to electricity and hot water through anaerobic digestion technology.

Anaerobic digestion is a closed system that breaks down organic materials like food and animal waste. Methane gas created in the process can be used to fuel generators that produce electricity and heat for use at nearby facilities. Solids remaining from the process are dewatered and reused as animal bedding, compost, or fertilizer.
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How much of the Minnesota State Fair's waste comes from animal waste? — August 27, 2010
Nearly 60%! In 2009, the State Fair animals - from chickens to llamas, from the coliseum to the Miracle of Birth Center - produced a whopping 3.26 million pounds of manure and soiled bedding of the Fair's total 5.5 million pounds of waste. The SEH waste-to-energy study will assess the potential energy in both the animal and food waste from the fair for potential reuse at the adjacent University of Minnesota St. Paul campus.
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Cleaner Energy (and Air!) from State Fair Waste — August 28, 2010
If you’ve ever taken a road trip into the country, you may have passed a farm operation that made your nostrils stand at attention. That “evocative” aroma comes from methane, which is classified as a Greenhouse Gas (GHG). In fact, methane is a GHG that is 25 times more potent than carbon dioxide in terms of global-warming potential.

Methane is flammable and is therefore attractive from the energy creation standpoint. The methane can be burned in a system to generate electricity or to create heat. As icing on the cake, when burned, methane transforms into the less potent carbon dioxide and good old H2O (that’s water for those of you who have been out of school for a while).

That means that if the University of Minnesota, for example, is able to create a waste-to-energy system can that captures methane from organic materials (like food and animal waste from the Minnesota State Fair) as fuel, the system has a double benefit. For one, the University could reduce its energy costs by using a readily available, renewable energy source. Secondly, the waste-to-energy process reduces the volume of GHG going into the atmosphere.

Could we call it a “Goldy Gopher Two-fer”?

Yes.

Will we call it that?

No.

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Anaerobic Digestion and the Kindness of Bacteria — August 29, 2010
Much maligned, methane is simply a by-product of the natural decomposition process, but an abundance of methane is unhealthy for us oxygen breathers – and for that whole global-warming thing.

How would the Minnesota State Fair and the University of Minnesota capture methane from the millions of pounds of organic waste material (manure, scrap food, animal bedding, etc.) in order to convert it energy?

The secret is a decomposition process known as anaerobic digestion.

Put quite simply, anaerobic digestion relies on the kindness of bacteria to break down cow pies and pronto pups from organic polymers to sugars and amino acids, and then into gases and acids until, finally, the process yields methane and carbon dioxide.

The methane can be piped to boiler systems to heat water or create electricity, but it can also be compressed for use in vehicles. The more solid remnants of the anaerobic digestion process can be used as fertilizer and soil amendments, and, because the University of Minnesota’s St. Paul Campus boasts a thriving agricultural program with many greenhouses and field test plots, they can put soil to good use!
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Cadaverine and Putrescine: much cooler names than pentamethylenediamine and butanediamine — August 30, 2010
When George Johnson is mixing his organic waste samples (by hand) at the Minnesota State Fair, he can feel heat of up to 150 degrees Fahrenheit through his protective gloves. That heat is the result of microorganisms, like aerobic bacteria, which consume carbon and nitrogen, oxidizing organic material like pronto pups and sheep droppings.

At some point, the aerobic bacteria become less active because there amount of oxygen drops below 5%, but that’s when anaerobic bacteria to take over. Whereas aerobic bacteria produce nutrients that plants could use, the anaerobic bacteria produce organic acids and amines with cool names cadaverine and putrescine. Like their names suggest, they stink, but the process continues until, eventually, the materials look a lot like soil — with a more pleasant aroma — that can be used as soil amendment.

The Minnesota State Fair and the University of Minnesota will soon find out if the thousands of tons of organic waste produced annually at the Fair are suitable for anaerobic digestion to produce methane, a biogas suitable to produce heat and electricity for the University of Minnesota St. Paul campus.
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Corndogs versus Mini-Donuts — August 31, 2010
Which is the bigger seller at the Minnesota State Fair: corndogs or mini-donuts? If you’re thinking that “anything-on-a-stick” is wildly popular with fair-goers, you are correct! In fact, each year approximately 500,000 corndogs are consumed compared to 338,000 bags of mini-donuts.

Those 500,000 wooden sticks supporting the delicious battered hot dogs don’t make good additions to an anaerobic digestion process, though. It takes longer for woody and fibrous material like a stick to break down compared to other organic material.

The actinomycetes and fungi responsible for breaking down the cellulose and lignin that help make a stick a "stick" prefer cooler temperatures. That means those microorganisms don’t tend to be very active until towards the end of the composting process. So, although sticks aren’t ideal candidates for organic material in a waste-to-methane project because of a slower decomposition process by more temperamental microorganisms, less-picky bacteria love the hot dog and breaded portions of your wildly popular corndog. 

They’re crazy about the mini-donuts, too.
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Everything but the Oink? State Fair Recycling — September 1, 2010
The Minnesota State Fair has been recycling myriad materials since the mid-1980s, from paper and glass to plastic shrink wrap and laser toner cartridges. Recycling at the Fair removes a lot of material that might otherwise end up in landfills. For example, in 2009, the Fair recycled 256,000 pounds of cardboard. That’s 8,533 cubic yards – enough to fill 14 railroad cars – of just cardboard. That’s a lot of corrugation that might otherwise have landed in a landfill.

Here are some other fun Fair recycling facts, courtesy of the Minnesota State Fair:

• In 2009, the fair composted about 2,300 tons of animal waste.
• Dairy cows generate the most waste, because they are lactating, requiring more food and water, which results in more manure.
• Traditionally, the manure from the Fair’s animals was taken off site to compost; but the SEH waste-to-energy study will help determine if manure and other organic waste can be converted into energy.
• Grease from the fair is recycled and turned into biodiesel.
• The Fair’s 8,000 pounds of meat scraps go through a rendering process that separates the protein and fat. The protein is then used as an ingredient in animal feed. Fat later goes into cosmetics and soap.
• 70 tons of food waste was collected during the 2009 fair and recycled.
• 400 bottle recycling receptacles were placed around the fairgrounds in 2009.
• More than 300,000 plastic bottles were collected and recycled during last year’s fair.

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Burning Calories in the Compost Pile — September 2, 2010
One of the most commonly heard expressions at the Minnesota State Fair is, “I’ll try it. Heck, the State Fair is only once a year.” And try it, we Fair-goers do! From Big Fat Bacon to Camel-Meat-on-a -Stick, we all know that much of the food we “try” at the Fair isn’t exactly healthy for us, but can you guess which single State Fair food item has the most calories?

Imagine you couldn’t finish your entire order of Fudge Puppies (who are we kidding, right?). You would dutifully put them in the nearest waste receptacle and move along to your next gastronomic adventure. But what happens to those discarded Fudge Puppies?

The short answer: microscopic living organisms eat them. The organisms use carbon for energy and they release carbon dioxide (and a great deal of heat). All those calories that you’re not really worried about because you’re going to get in shape right after the Fair are units of food energy – specifically, the amount of energy required to raise the temperature of 1 gram of water by 1° Celsius. So when you “burn” calories, you are releasing heat. When bacteria eats your Fudge Puppies and other organic waste like straw and cattle manure, the decomposition process can heat the center of pile of organic material to more than 160° F.

Eventually, the little organisms die, and then the nutrients stored in their “bodies” are food for another round of organisms, and so on, until those poor little Fudge Puppies resemble soil more than delicious chocolaty goodness.

Who’s hungry?
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Microbrew and Other Fair Fuel — September 3, 2010
Congratulations to B.J. Haun for taking Best in Show for the Minnesota State Fair’s Beer Brewing competition. B.J.’s entry, called “Nightcap”, took the prize with a Scottish light ale.

Never tried one of those? According to the Beer Judge Certification Program guidelines, a Scottish light ale has a “low to medium malty sweetness…accentuated by low to moderate kettle caramelization…low hop aroma, light fruitiness, low diacetyl, and/or a low to moderate peaty aroma”.

That's a fancy way of saying it tastes great.

Did you know that the alcohol produced in beer and wine comes primarily from yeast? Yeast cells eat sugars like maltose, fructose, and sucrose and convert them into alcohol and carbon dioxide.

“But what,” you may ask, “does beer making have to do with our waste-to-energy study at the Minnesota State Fair?”

Basically, it takes a village of microorganisms to transform a pile of food and animal waste into usable energy in the form of methane gas and the soil-like solids that gardeners love. In that microscopic village, there are many varieties of bacteria and fungi, like yeast. Although bacteria are the dominant consumers of food and animal waste during decomposition, comprising upwards of 90% of the village, they operate best at certain Ph levels (7.0 and above).

Yeast tend to be active at a lower Ph (4.5-5.0) than bacteria, and because their activity reduces the overall acidity of waste material, yeast can reduce the time it takes for thermophilic bacteria to fire up the waste pile.

If the material is too acidic, the hard-working bacteria can’t do their thing and the pile poops out. Part of the SEH study is to determine an appropriate ratio of waste materials that keeps the micro-village happy.
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Test yourself with our Virtual State Fair Stumper Quiz!
Simply move your pointer over each question to reveal the correct answer.

Public Project Documents: 

Informational Flyer — 198.76 KB