Compost Confidential

Ten years ago, over a third of the garbage that cities in Alameda County sent to the landfill was food scraps and food-soiled paper. If Berkeley and other cities were to reach their goals of reducing the amount of landfill-bound waste by 75 percent by 2010, as mandated by 1990’s county-wide Measure D, it was clear that cities would need to capture and divert food waste.

In 1999, Berkeley launched a pilot project that took food waste from the city’s restaurants and grocery stores and sent it to a composting operation. By 2007, all Berkeley residents were given the opportunity to compost their moldy produce, bones, and greasy napkins by tossing them in the green rollaway carts the city provides for yard debris collection. The food waste composting program
proved wildly popular from the start; the city received thousands more requests for five-gallon kitchen green bins than it had anticipated. By 2009, the city was diverting over 12,000 tons of food and yard debris from residences and nearly 6,000 tons of commercial food scraps per year to Grover
Environmental Products, a composting facility located in Vernalis, near Modesto.

Berkeley’s gardeners have been especially pleased with the program, as the food and green waste is transformed into rich—and free—compost for schools, community gardens, and residents. Once a month for most of the year, a huge heap is given away at the marina, where residents fill their trunks
and truck beds with boxes and bags of WonderGrow, Grover’s black gold.

Yet as popular as the program is, the large-scale composting of city food and yard waste faces growing challenges, some related to the materials that city dwellers toss in their bins, others to the evolving competition for food scraps. Good ideas—like enriching the soil of organic farms with compost made from urban food waste—are not necessarily meshing with other good ideas, like using
compostable plant-based plastics rather than disposable petroleum-based plastics. Pesticides approved for use on lawns are persisting all the way through the industrial composting process and contaminating the end product, making it unsuitable for organic agriculture. And the development of alternative composting technologies—namely biogas digesters—is provoking a debate over what food and yard waste should be used for.

Broken wheel
Americans like take-out food, and environmentally conscious consumers and businesses increasingly offer “compostable bioplastic” containers—clamshells, cups, and utensils made from renewable raw plant materials like potato or cornstarch. But some of these products offer more hope than reality. For a bioplastic product to be considered “compostable” by the American Society for Testing & Materials, it has to meet three criteria: It must break down into carbon dioxide, water, and biomass at the same rate as paper; it must disintegrate into small pieces that are indistinguishable from surrounding compost; and it must not produce toxic residue that would prevent the compost from supporting plant life.

While compostable bioplastics will break down in a backyard compost pile, it takes a very long time—longer than makes sense for most backyard composters. Most purveyors of compostable bioplastics recommend that their products go to commercial composting facilities, where the piles reach higher sustained temperatures.

In October 2009, a contingent of Ecology Center staffers toured the Grover composting yard, where Berkeley’s municipal food and yard waste is carefully cooked and turned in long piles called windrows. The staffers were curious about the fate of the SpudWare sporks and Natureworks cups that are optimistically tossed into green carts throughout the city. At Grover, they observed employees picking all plastic items—both petroleum- and plant-based—out of the dumped materials. Any smaller plastics that made it through the initial screening were removed later, as the material was sent through a trommel and a sorting station.

Here’s the reason: even if bioplastic items are suited to break down in a commercial facility, they look nearly identical to the petroleum-based plastic they are meant to replace, which makes it difficult for workers at the plant to distinguish between the two. Because of the quantity of waste they are sorting, and the difficulty of identifying the types of plastics that arrive at the facility, laborers remove all plastics, including most compostable bioplastics, which are then hauled off to the landfill along with the other contaminants. (The exceptions to the identification problem are Biobags, the green trash bags made of non-GMO plant starches that many people use to line kitchen compost bins. No petroleum-based trash bag is bright green, so BioBags are easy to spot.)

However, the USDA’s National Organic Program (NOP) has not approved bioplastics to be used in organic compost, so even the readily identifiable BioBags are not used in WonderGrow, Grover’s compost that is approved for organic farming. “The wheel is broken,” says manager Adam Grover. “A lot of the people who buy organic food are the same ones pushing bioplastics, but organic farmers can’t buy compost made of bioplastics.”

Pesky pesticides
Grover Environmental Products provides both a waste hauling service for cities and a high-quality soil product for farmers and landscapers. This double-focus comes naturally; the company’s composting facility grew out of a landscaping business that Adam Grover’s father started in 1970. Over time, the family business branched out to include a tree service, a nursery, and the composting operation. Because the Grovers have been involved in a panoply of horticultural activities, they know the value of great compost. “We use the waste stream to get to that finished product,” says Adam Grover, “but we go to great lengths to consistently make a quality finished product.”

According to Brian Mathews, food scrap program manager for the Alameda County Waste Management Authority (, Grover’s focus on the quality of the end product is unparalleled. “Grover is considered by the industry to be one of the top producers of organic compost. He’s not associated with any garbage company; he’s totally independent and makes a high quality product that is excellent for agriculture. He cares about his product he’s making. He’s concerned about the feedstock. He is making a product that he can sell to repeat customers who are growing vegetables and everything else,” says Mathews. That is high praise indeed, considering that Mathews is a former competitor; before joining, Mathews ran the Gilton Resource Recovery Composting Facility, which had the City of Berkeley’s composting contract until it was awarded to Grover.

Unfortunately, even the most diligent composting operations can’t entirely control what substances make it into their scrap heap. Farmers constitute a significant part of Grover’s client base, which is why it was such a blow when the California Department of Food and Agriculture (CDFA) announced last fall that Grover’s WonderGrow compost was prohibited for use in organic farming because the department found it contained bifenthrin residues. Bifenthrin is a pyrethroid insecticide used in products like Talstar, Capture, Brigade, and Ortho Home Defense Max to kill ants, spiders, roaches, termites, and bees. Bifenthrin is also found in Scotts LawnPro Step 3, a popular lawn fertilizer that kills all the bugs in your grass.

Bifenthrin persists in soil for quite some time, so when your neighbor treats his turf with Scotts LawnPro Step 3, then cuts his grass and dumps it into his green curbside cart, the compost made with that municipal yard waste will most likely contain residual bifenthrin. “Every composter who
uses yard waste in America has this problem,” Grover sighs. “It’s a huge problem.” The CDFA also banned Clean City Compost made by Feather River Organics and Nortech Gold Compost made by Nortech Waste LLC, two other brands of compost that use yard waste.

It could not have happened at a worse time. The CDFA alerted organic growers to the bifenthrin problem right before fall, when most farmers apply compost to their fields. Grover had just delivered fifteen truckloads of compost to Yolo County’s Full Belly Farm, which sells organic produce at Bay Area farmers’ markets and through a popular CSA. “We ended up hauling those fifteen truckloads back off Full Belly Farm,” Grover recalls. “The farmers were very disappointed.”

Paul Muller, one of the Full Belly partners, explains that after that incident they were reticent to buy compost from other operations, fearful that other products would be contaminated, too. “We did buy some other compost and frankly, it wasn’t the same quality,” Muller says. “We have had to rethink our strategy. We have relied on compost a lot for fertility.” As an alternative, Full Belly planted cover
crops like vetch that can be tilled back into the soil. In Muller’s opinion, “There are a lot of persistent pollutants out there that should be taken out of home garden use because it ends up in the compost.”

But for composters, city yard waste provides an otherwise ideal product that they can turn into cheap compost. “Organic farms aren’t exactly rich,” Grover explains. “That’s the beauty of using green waste from cities—it makes compost affordable to small-scale organic farmers.”

The bifenthrin contamination was discovered under unusual circumstances that illustrate some holes in the regulatory framework for organic compost. In this case, the pesticide was discovered when a wheatgrass farmer in Placerville had his product tested by the California Department of Pesticide Regulation. “The wheatgrass farmer figured out that wheatgrass grew really well in straight compost. The wheatgrass was shipped to the grocery store in a tray full of soil,” says Grover. Because it was sold in that manner, he says, the testers threw both the wheatgrass and some of the attached soil in a blender for testing in the lab. “When they tested just the wheatgrass, it was free of bifenthrin,” says
Grover. “But when it was mixed with the compost, it was not.” This is significant because most wheatgrass customers only eat the plant itself, which is typically sheared from the growing tray. In the case of bifenthrin, the pyrethroid can attach itself to soil but does not get taken up into the plant.

Clear rules govern the testing of organic produce: the EPA sets acceptable levels of synthetic pesticides, and the California Department of Pesticide Regulation conducts random testing of organic produce to make sure the guidelines are being followed. Yet according to Renee Mann, review program manager of the Organic Materials Review Institute (OMRI), “There is no clear authority that
tells us how to test compost.” OMRI is the Oregon-based nonprofit that determines which agricultural inputs are allowed for use in organic production and processing. The National Organic Program of the USDA sets the standards for what is allowable, and OMRI carefully reviews products against those standards for inclusion on its list of approved products, on which organic growers rely.

The National Organic Program has neither set acceptable levels for bifenthrin in compost nor has it determined how and when to test for bifenthrin. The only composts that were prohibited by the CDFA last fall were the ones associated with the testing of the Placerville wheatgrass, even though many other composts that use yard waste as a feedstock could be contaminated with bifenthrin as well.

The National Organic Program has neither set acceptable levels for bifenthrin in compost nor has it determined how and when to test for bifenthrin. The only composts that were prohibited by the CDFA last fall were the ones associated with the testing of the Placerville wheatgrass, even though many other composts that use yard waste as a feedstock could be contaminated with bifenthrin as well.

Composters who use yard waste in their mixes are eager to get their composts out of regulatory limbo. The CDFA continues to prohibit WonderGrow for organic growing, while at the same time, WonderGrow continues to be listed in OMRI’s directory of approved products. The NOP, which has the last word, remains silent. According to Adam Grover, “at the EcoFarm Conference in January, Miles McEvoy of the National Organic Program promised to see if he could institute a timeout period during which more testing could be done on finished crops rather than on the compost and inputs.” Recently, OMRI posted a notice on its Web site: “Most yard waste composts will remain on the OMRI Products List until a full investigation is completed for each compost. This is based upon OMRI’s due process, which allows our clients to be informed of an investigation, provide further information to defend their product listing, and contest OMRI’s final decision.”

The NOP is aware of the problem, says Mann, but it may be many months before guidelines are issued regarding bifenthrin in compost. “It’s a pretty big issue,” says Mann. “The levels that they ultimately set may lead to us delisting some or all of the yard waste compost on our list.”

Power politics
Composting is an up-and-coming industry, likely to follow on the heels of recycling as an environmentally and economically preferable municipal waste option. Just as corporate waste haulers expanded into the recycling business, they are now expanding to composting operations. This January, Texas-based garbage giant Waste Management, Inc. announced that it will “expand organics recycling facilities across the US and Canada” by investing in Harvest Power, the largest food and yard waste composting facility in North America.

Waste Management intends to pursue both aerobic and anaerobic digestion technologies, two very different methods that use municipal food waste for different ends: fertilizer or fuel. Grover practices aerobic composting, which means that bacteria, in the presence of oxygen, rapidly consume the plant matter. The waste products of the process are carbon dioxide, heat, water, and humus, the soil amendment that growers covet. Carbon dioxide builds up in the bottom of the windrows as the piles heat up. If there is too much of it, the piles will start to decompose anaerobically and generate methane, a greenhouse gas that the EPA deems 21 times more powerful at warming the atmosphere than carbon dioxide. To avoid that, Grover carefully checks the carbon dioxide levels within the compost piles and turns them with a giant rolling machine to re-inject oxygen into the long brown heaps of organic matter.

On the other hand, the methane produced by anaerobic digestion can be diverted to a combined heat and power unit and transformed into electricity. The East Bay Municipal Utility District (EBMUD) is using food waste from the City of San Francisco for that very purpose. San Francisco’s waste management utility, Recology, sells nearly 25 percent of its commercial food scraps to EBMUD for biogas (methane) generation. The food scraps are combined with sewage, wastewater, and bacteria in EBMUD’s two-million-gallon bio-digesters. The heat and methane produced from the anaerobic digestion is transformed into electricity that meets ninety percent of the power plant’s operational energy needs. Some days, EBMUD even sells back surplus electricity to PG&E.

After the noxious stew has served its methane generation purpose, EBMUD spins the excess water out of the waste material. Solid wastes are carted off to be used as alternative daily cover—the mulch that is spread over the garbage at the landfill to reduce blowing litter, animal attraction, and noxious odors. At this point, the biosolids from EBMUD’s digester cannot be used as an agricultural soil amendment because of prohibitions regarding the use of sewage sludge.

Not all anaerobic digesters are the same. The technology is changing at a fast clip, mostly driven by European companies. Some digesters, like EBMUD’s, add food scraps to sewage to up the methane production. Others use animal manure and other agricultural wastes as the methane-producing feedstock. Still other digesters, which use less water, can employ food and yard waste to produce methane. This last version can both produce energy from methane yet emerge with an end product that can be used as a soil amendment.

In the last fifteen years, the development of anaerobic digesters in Europe has exploded, spurred by the European Union Landfill Directive of 1999 that required member states to stabilize organic material prior to land-filling. If the US were to follow suit, in the pursuit of minimizing methane from landfills and maximizing energy production from renewable resources, anaerobic digesters could indeed be the next big thing. Waste Management is betting on it.

In fact, as more anaerobic facilities are developed, debates are breaking out over which processing method constitutes the “best and highest use” of municipal food scraps. Adam Grover is not concerned that the biogas generators will claim too much of the spoils; he thinks there will be plenty to go around. In fact, he says, it is possible for aerobic compost operations to have too much food waste, since the process relies on a careful ratio. “You can hardly compost food waste by itself—it’s too rich. You need to mix it with green waste, so we might get more food waste than what we can compost soundly. You might get too high of nitrogen count and have odor problems. But,” he concedes, “I don’t know how it’s all going to pan out. [Anaerobic digestion] could be competitive in time, but the technology is not there yet. Maybe in ten years.”

At present, Tania Levy, associate management analyst from the City of Berkeley’s Solid Waste Management also sees no competition between the two methods. “They’re not competition, they augment one another!” she says. “We don’t have enough permitted composting facilities to handle all the organic materials, so adding more facilities of either kind is a good thing.”

Meanwhile, the amount of waste material being diverted from the landfill and trucked to the compost yard continues to rise. Since the Berkeley residential food scrap program debuted three years ago, Levy says that the amount of residential food scraps and yard waste captured has increased 39 percent, while the amount of commercial food scraps has increased 24 percent. Composting is a burgeoning industry, and challenges are an unavoidable aspect of that growth. But the vexations of persistent pesticides and indistinguishable bioplastics may be small bumps on the way to urban food and yard waste becoming a valuable commodity.

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