Trash Talk – They Do What With My Green Waste?
05 May 2012 |
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By Gary Hedden, Margie Suozzo and Joe Eyre.
Ever wonder what happens to the yard waste, clippings and food scraps that you put into your green organics tote?
Carl Mennie, Republic Services, and Margie Suozzo, acting director GreenTown Los Altos, discuss the composting process. Photo: Gary Hedden.
If you live in Los Altos, it heads to Newby Island in Milpitas. Republic Services has a 16 acre site adjacent to the Newby Island landfill dedicated to turning green waste into compost. Carl Mennie, Recyling and Composting Manager, explained it all as he led a tour organized by Teresa Montgomery of Mission Trail Waste System for several GreenTown Los Altos volunteers, Los Altos Environmental Commissioners; Joe Eyre, Steve Anderson and Zahra Ardehali, and City of Los Altos staff Jim Gustafson and Gil Fletcher.
It all starts with truck after truck bringing in the loads, 800 tons a day on average. Eight different haulers from Santa Clara, Alameda and Contra Costa counties bring their greenwaste to the Newby Island Composting Facility, including Mission Trail, carrying organic waste from Los Altos. (GreenWaste Recovery, which serves Los Altos Hills, delivers its organics to Z-Best, a Zanker company, located in Gilroy where a similar process takes place).
Freshly pulverized green waste shot out of the grinder. Photo: Joe Eyre.
After the loads are dropped, the material goes through a grinder. This huge metal beast pulverizes the waste into small shredded bits which are then laid out in long rows aimed in the direction of the prevailing wind, hence called “windrows”. These rows are big – 8 feet tall x 20 feet wide. The combination of moist organic waste and naturally occurring micro-organisms starts the process. No starter or other additives are necessary. Temperatures in the windrows of at least 131 degrees are needed to destroy pathogens. Republic Services typically sees temperatures of 145 degrees within the first day that the material is windrowed, which promotes healthy and rapid decompostion.
Compost lined up in long windrows undergoing the 3 month process. Photo: Joe Eyre.
The windrows are turned every three days for the first 15 days and then every week to ensure complete conversion. After 85 days the decomposition process is complete and the finished compost is screened several times to finer degrees. At each point, air blowers remove plastic scraps and the big organic pieces are sent back through the entire composting process. The final screening takes place in a rolling machine called a trommel that further screens the material to 3/8 or 1/4 inch. The resulting product is sold primarily to wholesalers who package it, bag it and resell it in retail outlets, such as Lowe’s. It meets the Organic Materials Review Institute (OMRI) standards and is OMRI-Listed for use in organic gardening or agriculture.
Final impressions. It is really great to see all this waste broken down and reused in a productive, healthy product. By the way, we saw the trash coming in from Los Altos and it looked clean. Much less plastic than the loads from other cities. Way to go Los Altos!
4 Responses to “Trash Talk – They Do What With My Green Waste?”
Laura Flair
Pesticides and other chemicals from non-organic and GMO food scraps are surely lurking in that “compost.” Worse yet, when the wind blows along the windrows, surrounding communities must be breathing chemical-laden dust. And their yards and homes, cars and driveways must get sprinkled with it. Are those mechanically blown-away plastic particles getting captured for proper disposal?
Teresa Montgomery
Good comments/questions Laura. They do capture the plastic contaminants (and others) and send those to the adjacent landfill. And they do have wind fences up around the perimeter to keep contaminants from blowing into the Bay or other surroundings.
As for the chemicals, I’m sure you’re right. OMRI must tolerate some minimal level.
This is a good time to remind all to use non-toxic methods of fertilizing and controlling pests.
I’ve found these sites to have helpful Bay-friendly gardening info:
http://BayFriendlyCoalition.org/http://www.ipm.ucdavis.edu/
http://www.stopwaste.org/home/index.asp?page=150
http://www.ipm.ucdavis.edu/
GreenTown
Valid concerns Laura. The compost meets the Organic Materials Review Institute (OMRI) standards and is OMRI-listed for use in organic gardening or agriculture. To justify this the compost is tested for many qualities and in particular is tested to be below EPA allowable limits for pathogens (coliform and salmonella) and heavy metals. The actual test results are well below the limits. Pesticides sold in California for home use are required to be biodegradable and the low levels in residential green waste are further reduced in the composting process. Genetically modified food products are also broken down in the process. OMRI and the US Compost Council have researched both of these issues and determined that residential green waste is a suitable feedstock for composting. If you are interested in digging deeper into this research we would welcome your help. The dust in the composting operation is controlled by operating water trucks 10hr/day to keep the windrows moist and minimize dust on the roads. I hope this explanation helps. Thank you for your interest.
Lesli Lee
Nice article–thanks! I was curious about what happens to our green waste. Kudos to all those in the cycle who contribute to this process. Also, great reminder/resources to eat/compost organic produce and use non-toxic gardening methods. For more info, check out http://www.commonground.com in Palo Alto as well.