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?
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).
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.
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!