Small County, Big Impact
Situated on the leeward side of Washington’s Cascade Mountains, Kittitas County has a relatively small population of 39,000 and a correspondingly small amount of green waste collected on an annual basis. According to Patti Johnson, director of the county’s solid waste programs, that green waste—roughly 2,000 tons per year—was previously handled traditionally.
“We would get the material into our site—mostly self-hauled as it is today, but also from a number of commercial accounts—and have a contract grinder come in periodically to grind the material for us. We did that for many years until some changes occurred which forced us to rethink our whole approach to green waste.”
One of the changes to which Johnson refers was a Washington State Department of Ecology ban prohibiting residents from burning green waste in urban growth areas. The bans, largely put in place to minimize the detrimental health effects of burning upon area residents, were also instrumental in getting governmental agencies to be proactive in seeking alternatives to burning.
“So, as a result of those actions, we started researching different ways to handle and process the green waste we take in,” she says. “Composting seemed a real, viable alternative, and, armed with a grant from the Department of Ecology, we were able to begin working in that direction.”
While neither Johnson nor Matt Peebles, her landfill operations manager, knew exactly which grinder to buy, they knew from experience which type was not a good fit for their needs.
“The contractor we had been using relied upon a huge tub grinder, which, while it would grind almost anything we put in there—including stumps and large logs—tended to throw debris a pretty good distance. Unfortunately, people like to feel that, if the material was in their yard once, it must still be yard waste, regardless of what’s mixed in with it. As a result, we’ve found shoes, t-posts—you name it—and I’ve had metal stakes, and other material thrown from that tub grinder hit the roof of my office. We could not have that continue as we grew the green waste program, so we needed a different approach.”
While researching which grinder would best suit their needs, Johnson looked at all possibilities. That prompted a bit of “out of the box” thinking concerning how the grinder should even be powered. Because they are situated in the Kittitas Valley, which has an almost constant downdraft from the adjacent Cascades, wind farms are a huge—and ever-growing—presence.
“We have wind farms all around our landfill and have actually leased some of our landfill property to have turbines installed,” says Johnson. “So we felt that going with an electric grinder would be more environmentally friendly. Also, because of all the available wind and hydropower, electricity in the Pacific Northwest is fairly inexpensive—going that route that just seemed to make sense for us. We placed the grinder proposal out for bid, reviewed the bids and, based on what we got, chose an electric Morbark 3800 Wood Hog.”
Purchased through the Yakima, Wash., branch of Papé Machinery, the 3800 Wood Hog is powered by a trio of electric motors: a 100-HP unit to power the hydraulics and two 300-HP main drives. Though a dedicated electrical line and transformer had to be run to power the new grinder, Johnson says the savings have been steady and significant since startup more than four years ago.
“We are averaging utility costs for the grinder at about $1,700 per month, which is a fraction of what we would be paying for fuel and upkeep, given the recent fluctuations in the price of diesel. However, the savings run much further than just fuel. Maintenance on the electric is also a fraction of what it would be otherwise; hours a day less.”
Peebles concurs, saying that much of the work generally associated with diesel engines is eliminated with the electric unit.
“Running a diesel unit, you are always worried about the radiator, about oil changes, about new piston rings, and so on. In fact, though it varies from engine to engine, there is generally a lot of maintenance and upkeep associated with diesel engines. Not so for us. In the four years, we’ve had the grinder, we’ve had no issues with the motors at all, we’ve only had to replace a belt and a couple of bearings on the discharge conveyor—that’s it. What’s also important is that I can do most of the maintenance on the unit myself. If we had to tear down a diesel engine, that definitely wouldn’t be the case.”
Despite it being one of the smaller horizontal grinders in the Morbark line, Peebles adds that the 3800 Wood Hog fits perfectly in the scheme of their operation. “We just can’t say enough about its performance. Though we try to keep the material size down to 12-inches in diameter or less, it is capable of doing much larger material, it has always been able to grind anything we’ve fed it, and it gives us a nice consistent product ready for composting. Also, because it is a horizontal grinder, we’ve eliminated the risk of flying material that haunted us with the tub grinder. The 3800 has been a key part of our success out here.”
Making a Product
While some of the material at the Ellensburg, Wash., site comes from city curbside collection, the overwhelming majority of it is self-hauled to the site by Kittitas County residents. There, it is run through the grinder, discharged onto the pad, scooped up using a John Deere 7130 tractor and placed in piles in preparation for windrow turning.
“We really don’t track the tonnages we put through the grinder,” says Peebles. “However, we usually like to stockpile about 80 tons of material before grinding it once a week and the longest I’ve ever had to grind at one time was just over three hours. This machine is capable of handling between 30 and 50 tons of material an hour, so we’re not taxing it at all.”
For the latter part of the season, when the volume of tree waste goes down, and the green waste stream is mostly grass clippings, the solid waste group keeps a pile of land clearing debris on hand to grind up and act as a bulking agent when added to the mix. Windrowing is done with a Midwest Biosystems turner pulled along by that same John Deere tractor.
Windrows are turned every three days for fifteen days to meet pathogen reduction requirements. Because Kititas County is located on the leeward side of the Cascade Mountains, the climate is actually quite dry—much different from the steady rain commonly associated with its neighbors in the western part of the state. Therefore, moisture has to be added with each windrow turn. In addition to the green waste, the county is also permitted to accept manure from local farmers.
“The green waste site is essentially designed to be a one-man operation,” says Johnson. “So Matt is able to control the grinder from within the John Deere 135D excavator he uses to feed it, then use the tractor to create the piles, windrow them, turn them and move it aside for sale. The only part of the operation we don’t do ourselves is the screening of the compost—the last step before setting it aside for sale to the public. We contract out that part of the operation.”
Once screened and readied for sale, roughly a year after the green waste was first dropped off, composted material is available in two different sizes: ½-inch minus, which is ideal for plant and flower beds, and 2-inch minus, which serves well as a decorative mulch product. Since the introduction of the products, the public has proven very receptive, taking all the material the solid waste group can create. For pickup, Johnson says area residents come in driving everything from cars with trailers to dump trucks.
“We even provided a five-gallon pail of compost to someone who wanted it for a small flower bed,” she says. “Area residents know that the material we provide is high-quality, will not generate weeds in their beds, and will serve them well.”
Peebles adds that a strict quality-control procedure—everything from monitoring and inspecting material before grinding, to temperature and moisture control in the composting process itself—helps ensure that there are no complaints about the nature of their product. Temps are checked regularly using a ReoTemp temperature probe.
“I had one person come in and try to claim that our compost resulted in weeds,” he says. “I pointed to the compost pile from which his material came and said, if that were the case, that pile would be covered in weeds. He couldn’t argue with that.”
The Solid Waste group leases the John Deere 135 excavator, also from Papé Machinery, to maximize both efficiency and economy in their operation. Doing so has provided them a number of benefits.
“We are not a year-round operation, so in late fall, we turn in our excavator to Papé and get a new one again come spring,” says Johnson. “That not only ensures that the machine will be in great working order, it also keeps our operational costs down. There’s little point in owning a machine that will sit idle for six months out of the year; leasing is a great option for us.”
Peebles adds that Papé has been a great organization to work with, always providing exceptional service and being responsive to the solid waste group’s needs.
“Although we haven’t really tested them with any major repair issues, we know that they are always available and that parts have been affordable and available as well,” he says. “Both Papé and the service people from Morbark seem to share my passion for keeping machinery in top working order and understanding that doing so improves overall reliability.”
Johnson says they never second-guess themselves on their decision to go with an electric grinder, but, if they ever did, a simple look at the month’s utility bill and maintenance costs makes their case for them.
“In so many ways, there is just no comparison between this electric, horizontal grinder and a diesel unit,” she says. “Operational costs are, of course, one issue. But also, my maintenance file now consists of nothing more than a few pages; if it were a diesel, it would be a sizeable book. Based on what we’ve seen these last four years, I feel good that we’ve met the burn-ban challenge with a creative, environmentally-positive solution and, in the process, ensured that our area residents will always have a nice supply of compost to meet their needs.”