Wednesday, July 16, 2008

Thank Garbage

TGIW – Thank Garbage It’s Wednesday

Today we thank the trash we throw out for its energy content and value. The USA is the world’s greatest waster of materials. Over 251 million tons a year of municipal solid waste was generated in these United States in 2006. We consume and discard vast amounts of paper, food, plastic, cans, bottles, and other consumer goods. I had this thought what if we could turn this waste into energy or other useful material. Well I have to admit others have beaten me in the race to recycle.

The cities of San Francisco and Oakland are now recycling food scraps from restaurants and making composted material for fertilizing the vineyards in Napa and Sonoma. Yes some 300 tons a day of organic material that can be composted is hauled to a Vacaville where a facility run by Jepson Prairie Organics turns this waste into useful fertilizer. Composting is an aerobic process, meaning air is added to the pile of waste to help decompose the material. http://www.jepsonprairieorganics.com/ What is not reported is that the gas emitted from a compost heap is carbon dioxide. However had the waste been placed in a landfill it would be more likely that an anaerobic (without air) breakdown of the trash would emit methane gas. Pound for pound methane gas has over twenty times the greenhouse effect of carbon dioxide.

Another way to reuse the food scraps is what the Mount nelson Hotel in Capetown South Africa is doing. This stately hotel with five acres of gardens is feeding food scraps to its worm farms. These worms breakdown the food scraps into a liquid fertilizer as well as a nutrient rich mulch. Also the worms grow at a prolific rate and are a source of protein for birds and poultry. http://biophile.co.za/recycling/worms-at-the-mount-nelson

It is amazing to me that we here in the USA have a recycle rate for aluminum cans that is less than half. If you consider that the amount of energy needed to fabricate an aluminum can will power a 32” LCD TV for three hours, this is perhaps the most wasteful item in our trash. The good news on the recycling front is that we recycle over 99.0% of the lead acid batteries we have for our vehicles and data centers. The following recycle rates have been reported by the US EPA for various materials for the year 2006: Steel Cans 62.9%; Yard Trimmings 62%; Paper and Cardboard 51.6%; Aluminum Cans 45.1%; 34.9%; Plastic Milk Bottles 31.0%; Plastic Water Bottle 30.9% and Glass Containers 25.3%. http://www.epa.gov/garbage/facts.htm

One may ask why do recycle more steel cans than aluminum cans even though aluminum is more valuable pound for pound? My educated answer is that steel is magnetic and it is much easier to extract steel from a pile or garbage by simply running the garbage over a magnetic separator. The recycle rates for aluminum cans and plastic bottles are higher in states that have enforced a deposit law and hence placed a greater value of the container. Many states do not have deposit laws or cash redemption values for beverage containers. The California Refund Value (CRV) is 5 cents for containers less than 24 ounces and 10 cents for containers greater than 24 ounces. The Golden State has a combined recycle rate for all aluminum, plastic, glass, and steel beverage containers of over 70% (14.7 billion out of 21.9 billion in 2007). This proves one man’s trash is another’s treasure.
http://www.conservation.ca.gov/DOR/Pages/Index.aspx

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