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Photo: CWQ Mill

For nearly two decades, the city of San Diego has worked to not only divert waste from its Miramar Landfill but to turn the yard trimmings, fallen tree branches, foodwaste, rotting wood, and other waste products its residents generate into wood chips, compost and biomass that the city can then sell to consumers, landscapers, and cogeneration plants.

This process has two benefits: It’s kind to the environment, and it brings extra dollars to the city.

Today, the city of San Diego’s Environmental Services Department diverts more than 52% of its municipal solid wastestream from the Miramar Landfill. It also transforms this waste into more than 15 different products, including a rainbow-colored array of wood chips, rich compost, and biomass that can be converted into energy to power all or part of local cogeneration plants, says Dana Armstrong, disposal site supervisor for the city.

“These are all products that will not clog up our landfill,” Armstrong says. “This is what green waste processing is all about. And I think it is an industry that will only continue to grow.”

The city of San Diego is far from alone. A growing number of municipalities are seeking to divert waste from their landfills. And as part of this plan, they are transforming a greater amount of their solid wastestream into green products for residents, who can purchase mulch and wood chips from their municipalities at often lower rates than they can from commercial sources, and for manufacturers, who can use old plywood and other biomass material to create a fuel source for their onsite cogeneration systems.

To help meet their waste-diversion goals, these municipalities are turning to the manufacturers of shredding equipment, equipment that solid-waste employees use to grind up yardwaste, fallen trees, organic waste, and other materials into compost, mulch, wood chips, and biomass.

The best news is that this continued and growing focus on green, environmentally friendly ways to handle waste processing has provided a financial boost to companies that manufacture and sell grinders and shredders.

But that doesn’t mean that greenwaste processing doesn’t face some challenges. There is certainly potential trouble on the horizon, thanks to the ongoing collapse of the homebuilding industry.

While this slowdown means that municipalities are seeing less construction waste thrown their way—a positive for those trying to slow the amount of trash sent to their landfills—it may also mean that solid waste districts won’t need to purchase as many shredders, mulchers, or grinders. And that, of course, is not welcome news to the manufacturers of this equipment.

The bad news is that there is no end in sight to the housing industry slowdown. The National Association of Realtors reports that existing-home sales, a grouping that includes single-family homes, townhouses, condominiums, and co-ops, fell 5.3% in January when compared with December 2008. The numbers are even worse when comparing January sales to the same month one year earlier. Home sales dropped 8.6% across the country from January 2008 to the same month this year.

With fewer people buying homes, homebuilders have significantly slowed their construction of new residences, too. The National Association of Home Builders reported that new-home production fell by 16.8% in January. That’s the seventh consecutive month during which production has fallen.

A Changing Market
The decline in construction has collided with the still-growing interest among municipalities and the public in anything labeled “green.” This has helped keep the greenwaste processing industry at a fairly consistent level, even as the national economy continues to struggle.

“Our primary business is working with municipalities seeking to reduce the amount of waste they put into their landfills,” says Pat Crawford, vice president of products with Diamond Z Manufacturing.

The Caldwell, ID–based company manufactures tub grinders, horizontal grinders, and trommel screens, all used by municipalities to shred and grind portions of their wastestreams.

This doesn’t mean, though, that Diamond Z officials aren’t watching the housing industry closely. The wood that home builders and developers discard, not to mention the trees and shrubs that they clear when erecting new homes and subdivisions, are prime candidates for greenwaste diversion. As municipalities receive less of this construction waste, their thirst for grinders and shredders may not be as high.

“It’s amazing the impact that the housing industry has,” Crawford says. “It trickles down to everything you can imagine. Construction workers who aren’t working aren’t buying as much as they once did. You are not producing the debris from a construction site. Demolition work has slowed down. The construction and demolition materials are reduced. The land clearing, the trees and shrubs they have to clear from a piece of ground to build a new structure, has all been reduced. The housing slowdown has had a very broad impact on our industry. It’s amazing when you think about the impact that housing has on just about every industry.”

Still, Crawford expects the greenwaste movement to continue to build. And when the housing industry does eventually rebound, that, combined with the continued demand for waste diversion and biomass products, will provide a boost to companies providing grinding and mulching equipment.

Crawford sees the biomass market, where waste is transformed into material suitable for biofuels, to be a market that is also growing steadily.

“The cogen market has been strong for us,” Crawford says. “It’s a good, cheap fuel source. And we are seeing a growing demand for it.”

Greenwaste Processing in San Diego
Greenwaste processing has long been the norm in San Diego, as has diverting waste from the Miramar Landfill, which the city owns. In 1989, the state of California required all state landfills to divert 50% of their solid waste to salvage and recycling efforts by the end of 2005.

The Miramar Landfill achieved this goal ahead of schedule when, in 2004, it diverted 52% of its solid wastestream.

Recently, the San Diego landfill has seen market forces generate a significant dip in the amount of trash it receives. According to a story in the Los Angeles Times, haulers sent 66,000 tons of trash to the Miramar Landfill in December 2008. That’s a 12% dip from the same period one year earlier.

The Times story also reported that construction and demolition waste fell 80%. The landfill took in 7,000 tons of this type of waste in December of 2008 after taking on 36,000 tons of it in the same month in 2007.

Today, the city transforms waste into wood chips and compost that it sells to the public or gives to the city. It also transforms waste into biomass that it sells to cogen plants. It also uses waste, which has been run through grinders that the city has purchased from Diamond Z, for erosion-control and weed-abatement efforts, Armstrong says.

Consumer demand for the city’s green-waste-generated compost has been strong, Armstrong says. This is probably due to its price. While a truckload of compost from a store like Home Depot may cost $60 to $100, the city charges just $10 for the same amount, Armstrong says.

“Our biggest issue is that we have limited air space in the landfill,” Armstrong says. “Our main goal is to divert as much of the city wastestream from the landfill as we can. And we try to do that in as many ways as possible.”

The city also sells its greenwaste to avocado growers, tomato growers, and a large trucking firm that runs its own composting facility.

“We started small with our green waste, but now we are diversifying,” Armstrong says. “We now make from 15 to 20 different products.”

The Growing Demand for Biomass
Business has been strong for Flowery Branch, GA–based FAE USA, a manufacturer of mulching, rock-crushing, and soil-stabilizing equipment. Wes Hall, the company’s territory manager for the Southeast region, cites a growing demand for biomass as one reason.

Biomass is especially in demand at facilities that rely on onsite cogeneration systems to power part or all of their operations, he says.

“We are seeing a lot of growth and more talk of biomass now,” Hall says. “There are plans to build biomass plants right here in Georgia. This is definitely a market that is growing today.”

The biomass market is strong enough that FAE USA is now developing a new product designed specifically to help contractors and waste haulers participate in it, says Giorgio Carera, chief executive officer of the company.

The new biomass collector, which is still in development and has not yet been named, would work best in tandem with other shredding or mulching equipment, Carera says. Operators, for instance, could clear trees or shrubs from an area with one of FAE USA’s mulching machines. They could then run the biomass collector over the area to quickly pick up the mulch.

Operators would be able to download the mulch into a trailer or any other location, Carera says. FAE USA plans to debut this new product in the United States by the end of the summer, according to Carera.

The biomass market has the potential to be a lucrative one for private contractors and the manufacturers who make the equipment serving them, Hall says. And it’s a field that he says will become more crowded in the near future.

“This is an important market for us,” Hall says. “People might not remember, but the price of fuel was very high very recently. That has helped spur the drive for more biofuels. We’re looking for alternatives to our traditional fossil fuels, and biofuels might be the solution. I think we’ll see a lot of interest in this field. Everyone is looking for a way to get into something that they can make a lot of money doing. Something new like biomass can put a lot of work on the table for today’s contractors. It’s a new field, and we really don’t know yet just how big it’s going to get.”

As states and the federal government both encourage municipalities to divert more waste from landfills—waste that solid waste districts usually recycle, turn into compost or convert into biomass—they are helping to increase the business at manufacturers such as FAE USA, Hall says.

After all, contractors and municipal solid waste officials can’t grind up their wastestreams without the grinders, mulchers, and composting equipment that these manufacturers produce.

This can be seen in the eclectic client list that FAE USA enjoys. The company serves everyone from grading and excavating contractors to agriculture companies to specialized forestry clients, Hall says.

“The green initiative we are seeing in this country now is a great help to our industry,” he explains. “The more push we get from the government to go green, the more the contractors are going to respond to it.”

Handling the Mix
With its five rotary-drum in-vessel composting system supplied by A-C Equipment Services of Milwaukee, WI, Sevier Solid Waste Inc. (SSWI) at Sevierville, TN, operates the largest mixed solid waste composting facility in the US, capable of processing 375 tons per day of a combination of MSW and sewage sludge.

SSWI opened the facility in 1992 with three digesters, adding a fourth digester in 1996 and then investing in two additional rotary drums in 2006—one as a replacement for digester no. 3—and one to increase the throughput potential of the operation.

“The original three units had doors separating the material that had to be manually opened and closed,” says SSWI’s Tom Leonard, who has been with the project since 1999, “but when the new units were installed, A-C Equipment refurbished the remaining units, bringing them up to the latest spec.”

A mixture of MSW and sewage sludge stays in the digester for three days, with roughly a third of the material loaded and unloaded on a daily basis. The output is then sent through a primary trommel that separates out 1.25-inch inerts for landfilling. The bulk of the material is then placed in windrows, where it remains for a minimum of 21 days (“Forty days is even better if we have the option,” Leonard points out). After the material has sat for an initial 10 days, it is turned twice a day by a Backhus 1750 machine until it is finished.

In the wake of a fire that destroyed much of the facility two years ago, SSWI opted to install four Cover-All Building Systems fabric buildings, adding a low-voltage anti-rust system to counteract corrosion in its metal framework.

“Composting produces a really corrosive environment, making it nearly impossible to contain all of the fumes” Leonard explains.

After the finished material is again screened—this time to within one quarter-inch—SSWI wholesales it to brokers, who in turn blend it for sale to farmers and landscapers. “We don’t make a profit,” says Leonard, “but at least we cover some of the costs.”

The Benefits of a Stable Market
The demand for compost material is also increasing. This, too, can be tied into the housing market’s struggles.

Mark Lyman, president of Salem, OR–based West Salem Machinery, says that landscapers who traditionally preferred to work with bark materials are more open today to compost products.

As home building slows, and as the home-construction industry shows little signs of shaking its long slump, contractors are producing less lumber and woodwaste. This means that there is less of this material to be made into the bark products that landscapers most often rely upon for their projects.

Compost, then, is becoming a more popular alternative for landscaping professionals, Lyman says.

“We are seeing some shortages of some of the landscape materials,” he says. “I think that once they start working with compost, the landscapers will understand that it is a very nice material to work with. Compost is more economical, for one thing. That’s very important in these times. And there’s more of it available. It’s becoming a top choice of more landscapers now.”

Like other manufacturers, West Salem Machinery is also benefiting from the increased push for greenwaste management. As municipalities face strict regulations calling for them to decrease the amount of waste they send to landfills, they have little choice but to boost recycling efforts.

And that often requires an investment in the kind of equipment that West Salem manufactures.

The company’s horizontal feed grinder, for example, is a popular one among municipal solid waste officials. Greenwaste can be bulky and difficult to handle, Lyman says. The horizontal feed, though, can compress and feed this material directly into the actual grinding chamber.

“That’s a key feature that makes these machines suitable for that type of material,” Lyman says. “You can grind materials at high volumes, and you benefit from really good feed control.”

West Salem even provides some municipal and private contractor clients with machines that perform a secondary grinding function, Lyman says. These high-speed grinding machines are designed to convert waste into extremely small particles.

Municipalities can then combine this waste material with food waste and a co-composting agent. This produces a higher-quality compost material, Lyman says.

“The diversion of waste from landfills is a continued market development that’s only going to become more common,” he says. “The market options have continued to improve for composting. We are seeing some co-composting applications, too, where you mix that product with manure or foodwaste and add a co-composting agent or a bulking agent. You have fuel options that are starting to open up. There is a big increase in the demand for biomass-fueled power. There are good markets for that industry.”

And Lyman is excited, too, about the potential for anaerobic digestion. Haulers simply have to divert what could be a mix of greenwaste and foodwaste to an anaerobic digester. The digester would then transform that mixture into a gas that plants can use for heat or power.

“There is a lot to be excited about when it comes to greenwaste processing,” Lyman says. “We’re only at the very beginning of this industry’s growth.”

Not All Waste Being Diverted Just Yet
Of course, not everyone in the waste-processing industry is seeing the same commitment among municipalities to diverting waste from their landfills.

Tim Wenger, president of Sabetha, KS–based CW Mill Equipment Co., which manufactures a line of electric and diesel grinders, says that while more municipalities each year commit to diverting a larger percentage of waste from their landfills, many more continue to rely on the traditional method of burying their waste.

“Some of the municipalities are more proactive, while others aren’t,” Wenger says. “That hasn’t changed. I suppose every year there are probably some municipalities that get involved in diversion and greenwaste processing. But many more are still doing things the way they always have done them.”

The hurdle for many municipalities in focusing more on recycling, compost, and biomass is an obvious one, Wenger says: money.

Setting up wide-scale diversion programs isn’t inexpensive.

“For some municipalities, it’s probably easier for them not to do this,” he says. “They face some serious budget constraints. It costs money to implement these programs and to buy the machinery you need for them. It’s expensive to hire the manpower to do it. I would imagine, as with anything, it comes down to money. If there is money available to divert material, they’ll do it. If there’s not, they won’t.”

Setting an Example in Ohio
At first glance, the city of San Diego’s Environmental Services Department would seem to have little in common with the Logan County Solid Waste Management Division.

Logan County’s division, based in Bellefontaine, OH, serves a largely rural area. It’s far smaller than is San Diego’s department. And it constantly has to deal with the challenges inherent in serving a large number of vacationers visiting the county’s several lakes and campgrounds.

Yet both Logan County and San Diego are striving to meet impressive diversion goals. According to the last annual report that the Logan County division filed with the Environmental Protection Agency—in 2007—the county diverted 79,806 tons of waste from its landfill, says Alan Hale, coordinator of the solid waste district.

The county achieved much of this through an enhanced drop-off recycling program, Hale says. For about a decade, the county operated five part-time drop-off centers that were open Saturdays from 8 a.m. until noon.

Unfortunately, that left only a small window of opportunity for people to drop off their recyclable materials. Faced with such a limited amount of time to recycle, residents instead chose to pack most recyclable materials with their regular trash, which, of course, ended up at the local landfill.

Starting in 2007, the county made a significant change. It began opening 24-hour-a-day drop-off centers that were monitored by onsite video cameras. The new sites are larger and house more drop-off containers, Hale says. By the end of 2009, the county will be operating 20 of these full-time centers.

Thanks to this, the amount of materials the county will divert from its landfill will increase seven times from the amount it is diverting now, Hale says.

“The message is definitely getting out,” Hale says. “If you are going to live in the 21st century, you have to face the trash issue by not creating so much of it. You have to deal with it properly. You have to recycle more, and you have to stop consuming so many things that can’t be recycled.”

The county also has plans to add organic composting to its diversion efforts in the next three to five years, Hale says. This way, Logan County will be able to divert foodwaste from the wastestream, he says, something that isn’t done today.

“We don’t have organic composting in this county right now,” Hale says. “The foodwaste goes down the sewer if people have garbage disposals in their homes, or it goes to the landfill.”

The county does not usually do much with yardwaste, Hale says. But in January of 2005, Logan County did boost its mulching efforts significantly, he adds.

That’s when a devastating ice storm swept through the county, snapping trees and dragging down hundreds of electrical lines with them. Thousands of county residents were without power as cleanup crews hustled to clear away the tree debris and repair downed power lines.

The county collected 14,000 tons of yardwaste and tree debris that year. It mulched all of it, converting it into fertilizer and selling it commercially. The county sent none of this debris to the landfill, Hale says.

“I hate ice storms,” he says. “I lived this one every day for six months. I remember seeing those guys cutting away trees every day. It took us a year-and-a-half to clean the debris from that storm.”