聖地牙哥自2001年開始進行廚餘堆肥, 至2010年每年堆肥化2000噸, 在2010年初進行"可堆肥食具"的堆肥試驗以確定可以批准市民將他們丟入堆肥桶中.
Trash goes to greener pastures
City tests waste for compatibility as compost
By Mike Lee
12:04 a.m., Feb. 12, 2010
Paige Hailey pulled out a bag of compost at the Miramar Landfill that contains kitchenware that is being tested to see how long it takes to decay. — K.C. Alfred / Union-Tribune
GARDEN BOOSTER
Compost can improve soil texture, increase nutrients and boost water-holding capacity. Here’s how:
• Amend garden soil by mixing one or two inches of compost about six inches deep. Thoroughly irrigate the area twice before planting.
• Cover planters with compost to help reduce water loss and protect root systems.
• Use compost — along with sand, vermiculite and peat moss — as potting mix for growing plants in containers.
For information about San Diego’s composting program, including how city residents can get some compost for free, visitsandiego.gov/environmental-services.
MIRAMAR — San Diego recyclingspecialists dug through a steaming pile of kitchen trimmings and shredded greenery yesterday morning at the Miramar Landfill, searching for answers.
Specifically, they were testing whether serving ware and utensils marketed as compostable really do break down quickly enough for the city to include them in a food-waste program, along with partly eaten burgers and trimmings from about half a dozen industrial-sized kitchens.
San Diego runs the only food-wastecomposting center in the county, according to the state agency that oversees waste management. The city’s residents can get a certain amount of the compost for free or pay for larger quantities.
Until now, the project’s leaders had little evidence to support companies’ claims about their supposedly biodegradable spoons, plates, cups and related items. Before allowing schools, hotels and stadiums to regularly toss those products into compost bins, they wanted to make sure residents wouldn’t end up with forks sticking out of their compost.
San Diego is ramping up its food-waste composting to minimize what’s carted to the fast-filling Miramar Landfill. Once the dump closes, probably in 2019, the city will have to use private facilities at a higher cost to taxpayers.
“We are looking for the future,” said Kenneth Prue, a recycling specialist for the Environmental Services Department. “We want to have a list of products that work for us. If we put it in (the compost rows), it needs to be broken down and basically gone after our process is done” in about 90 days.
San Diego’s experiment involves 32 mesh bags filled with kitchenware labeled as compostable. Each bag was numbered and its contents were recorded before being buried. The bulk of the research will be done in April, though officials expect to continue testing new products as they come on the market.
The $350 study, now in its third week, suggests there are dramatic differences in the rates of decay. Some cups already were reduced to shards of corn-based resin, while some utensils remained largely intact in the heaping piles of compost that heat up to 165 degrees.
“We (had) expected the paper products to go first,” said Renee Robertson, a city recycling specialist.
Food-waste composting is an old concept, but it’s rarely practiced on a large scale partly because it’s smelly and requires extra work by food managers and recycling agencies.
Californians throw away about 5 million tons of food scraps each year, or roughly 16 percent of the waste in landfills, according to state recycling managers. About a dozen facilities statewide, including Miramar, are permitted to compost food scrap.
Dumps take in an estimated 140,000 tons of food waste generated by San Diegans each year, making that category a major target for San Diego’s recycling managers. The city’s crews compost about 2,000 tons of food waste annually, a number that Prue hopes to double over roughly the next year.
San Diego started collecting food scraps in 2001, and its participants include San Diego State University, SeaWorld and Petco Park. It also accepts food waste from major events such as the county fair and EarthFair, the annual Earth Day event in Balboa Park.
There are no plans to extend food-waste recycling to residential neighborhoods.
Many existing clients want the flexibility to recycle serving ware because that makes it easy to collect food scraps without having to scrape plates clean.
“We have had so much pressure to take these (products) and handle them,” Robertson said. “The demand is already out there.”
Mike Lee: (619) 293-2034; mike.lee@uniontrib.com
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