Composting - Summer 2008
From June 10th to July 25th we saved one ton of food waste from going into the landfill.
The number of people eating in the River Rock Café fluctuated throughout the summer, but the average was 1027 people a day and the average total food waste that we composted (pre-consumer plus post-consumer)* was 67.1 pounds per day. The larger groups which included Student life and Christ in Youth did not have to return their dishes because they used disposable dish wear, which means they did not walk by the compost sorting station on the way to dispose of their plate. Their average compostable waste was 41 pounds per day and the compostable waste per person was a half ounce. The smaller groups used reusable dish wear and did walk by the composter to return their dishes. Their average compostable waste was 71.12 pounds and 3.2 pounds per person. The average compostable waste per person during the 07-08 school year was 2.6 oz.
Take a look at the graphs:
Summer-08 Food Waste
Food Waste Per Person
*Food waste voluntarily collected in the compost sorting station (post-consumer) and the food waste collected in the prep station in the kitchen (pre-consumer).
Compostable Tray Pilot Project
During the summer different church camps come and stay at Fort Lewis for one week at a time. In June there were two separate groups of Christ in Youth and in July there were two separate groups of Student Life. Each camp consisted of more than 1,000 people. The River Rock Café stays open for different groups and events but for these large groups Sodexho opens the Hungry Hawk Snack Bar. In order to feed the entire group in one hour (along with other factors) Sodexho uses disposable dishware. To help offset the waste from these groups and to experiment with the compostable trays, New Ice Inc. 16,000 donated trays for Sodexho to use. New Ice also helped the Environmental Center hire Caryna Pourier as our summer compost coordinator. The compost coordinator developed a program to collect and compost the trays used in the Hungry Hawk Snack Bar.
(Student from the Student Life program composting tray)
Before the trays are put into the composter they need to be snapped in half, shredded or broken. Substrates need to be exposed to the elements and the smaller the pieces, the easier it is for the mircrobes to eat through the trays.
The main ingredient in the trays is starch derived from water extracts of tapioca or potatoes. The second ingredient is raw cellulose derived from managed forests or plantation grown trees. Some trays are coated with a compostable wax. A project conducted at McGill University determined that wax corrugated products can be composted and the wax can also contribute to temperature generation in the compost pile.
(collection station for the compostable trays)
New Ice Inc. produces their trays right here in Durango. The trays will be used in the Hungry Hawk Snack Bar for the 2008-09 academic year.
New Ice hopes to extend their product to local restaurants. However, there will need to be municipal composting programs in place that can handle large amounts of the trays. The Environmental Center is currently researching municipal/different composting systems for the City of Durango.
How the Trays are Made
1) The ingredients are mixed together into a batter
2) The batter is compressed and baked into heated molds
3) Sheets produced consist of four or six trays
4) Some of the sheets are cut into trays then coated with the film; some are coated with the film then cut; some are not coated at all and are cut
Degradable, Biodegradable and Compostable
The difference between degradable, biodegradable and compostable can be confusing and many businesses and now using these terms to market their products. There are also very few regulations over what these terms mean. The Environmental Center has been doing some research to help people understand what these terms mean.
The difference between degradable, biodegradable and compostable has to do with the time it takes to break down and what's left over at the end of the process.
Plastic will eventually degrade after thousands of years but will leave traces of compounds that are not found in nature. If O2 and fatty acids are integrated into the plastic it will speed up degradation. Organisms found in nature can get into the plastic through the pockets of O2 and eat the fatty acids, breaking down the plastic into smaller pieces but still leaving traces of the compounds.
If the shreds of plastic gets small enough to where microorganisms can attack them then the product becomes biodegradable. When microbes eat a biodegradable product it becomes part of their body and is turned into "biomass." Biodegradable products might leave small carbon based compounds that are not visible to the naked eye.
Compostable products will break down into CO2, water and biomass (meaning it will be fully digested by microbes). If a product is compostable it will meet the ASTM D-6400 standards which require that 80% of the product will biodegrade in 180 days within a commercial composting facility. Two other tests are important for something to be compostable. Compostable products must not have traces of heavy metals. Tomato and watercress seeds, which are very sensitive to toxins must also be able to germinate in the finished product.
Verdepack trays are a great carbon source because the high amounts of starch and 100% will biodegrade well before the 180 day requirement. In our composter the trays disappeared within two weeks.
Compostable:
Materials that undergo degradation by biological processes during composting to yield CO2, water, inorganic compounds and biomass at a rate consistent with other compostable materials in commercial/industrial conditions.
-ASTM D6400 Standard Specifications of Compostable Plastics
Biodegradable:
Biodegradation is the process by which microorganisms (microbes such as bacteria, fungi or algae) convert materials into biomass, carbon dioxide and water. Biomass is a general term used to refer to the cells of the microorganisms that are using the material as a carbon source to grow on.
http://www.packagingknowledge.com/degradable_biodegradable_bags.asp
There is no legal definition of “biodegradable,” but the American Society for Testing and Materials defines the term as “a degradation caused by biological activity, especially by enzymatic action, leading to a significant change in the chemical structure of the material.” The European Union deems a material biodegradable if it will break down into mostly water, carbon dioxide and organic matter within six months.
But despite such precise sounding definitions, the term “biodegradable” has been applied to a wide range of products—even those that might take centuries to decompose, or those that break down into harmful environmental toxins.
http://environment.about.com/od/earthtalkcolumns/a/biodegradable.htm
“Degradable/biodegradable/photodegradable:..
An unqualified claim that a product or package is degradable, biodegradable or photodegradable
– should be substantiated by competent and reliable scientific evidence
1. show that the entire product or package will completely break down and return to nature, i.e., decompose into elements found in nature
2. within a reasonably short period of time
3. after customary disposal
Source: US Federal Trade Commission”
http://www.bpiworld.org/Files/Article/ArttWVHOh.pdf - page 4 of 28
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