Recycling paradise: Composting on maui hits its stride

0

Courtesy of Morbark, LLC

Lush, green and ever-inviting, the Hawaiian island of Maui is the vacation destination of choice for more than 2.2 million people each year. Maintaining that pristine, idyllic look comes with a price, however: a year-round growing season yields a massive stream of green waste from non-stop cutting, trimming and pruning. While the resultant green waste was, for years, simply landfilled along with the 500 tons of trash generated each day on the island, one company has been aggressively taking in green waste — 35,000 tons annually — and turning it into high-quality compost products. Today, that company, EKO Compost, operates an award-winning, cutting-edge composting facility, ships product throughout the island chain, and is exploring new opportunities for taking composting to the next level.

Montana to Maui
Despite a multi-island Hawaiian presence, EKO Compost actually traces its roots back to 1985 in Missoula, Montana. At that time, Tom Pawlish, EKO's current president, was working with a Denver construction firm active in privatization of wastewater treatment plants.

“We were looking for an economical way to get rid of biosolids or sludge,” he says. “A contact I had in Salt Lake City suggested I go to Missoula to see someone who had been using a unique biosolids-based composting process since 1977. He called his company EKO Compost and I went there, saw that it worked well, and formed a partnership with him. In 1990, after five years of partnership, he chose to leave but we kept the name and grew the business.”

Pawlish adds that the popularity of the product created at that Missoula site quickly led to the establishment of a second location in Lewiston, Idaho; and a startup operation in California's San Joaquin valley (which has since been sold).

“Then, in 1994, Maui County had a pilot program that wasn't going as well as they would have liked, so they put out an RFP for a full-fledged operation. We placed our bid, were selected, and started up in July of 1995. I retired from contracting in 2001 to dedicate my time fully to EKO Compost and it's been an amazing experience.”

Location, Location, Location
The process at EKO Compost's Maui site starts with material being brought to what is undoubtedly one of the industry's more-unique locations: the base of a stone quarry, adjacent to both a concrete plant owned by Ameron Hawaii and the island's largest municipal landfill. EKO Compost does not collect material but, rather, is under contract to Maui County to accept and manage the county's green waste, according to Rubens Fonseca, EKO Compost's Maui Plant Manager.

“We have a Morbark Model 1300 tub grinder in that pit to grind up the green waste that arrives here all day from both commercial and residential customers,” he says. “Our presence there is all part of a larger, more complex plan that starts with Ameron leasing a parcel of land from the sugar cane company and quarrying it until all the material has been removed. The county then steps in and buys that land, relieving Ameron of the lease. With a large pit already in place, Maui County has a head start on building the next phase of its landfill. As a result of this setup, Maui is one of the only islands in the chain that doesn't have an urgent landfill problem right now. It's a bit unusual, but it really works to everyone's benefit.”

In that arrangement, Fonseca says that EKO benefits not only from its location but also from the initial acquisition of the sugar cane fields by Ameron.

“About a year before the land can be quarried, the sugar cane company stops growing its crop and we buy the now-barren topsoil from them. It's a bit rocky due to its volcanic nature — which can be tough on our screens — but it still makes an excellent additive for our compost process.”

Waste Not . . .
To make its proprietary compost and soil blends (EKO currently offers three different formulas), the company first grinds green waste at the quarry site, then trucks it back about a quarter-mile to a 5½-acre area which, in addition to the composting operation itself, also houses its bagging and maintenance building, storage areas, and more.

“Our primary composting operation involves the mixing of that newly-ground mulch with biosolids delivered here by the county from wastewater treatment plants on the island — anywhere from two to six trucks of it per day. In addition to the sludge, we also receive FOG (fats, oil and grease) diverted from the wastewater collection stream, as well as residue recovered from a biodiesel plant, also located adjacent to our compost site. Because we are able to effectively use the green waste, FOG and sludge, this is a win-win situation for both Maui County and EKO Compost.”

All in the Mix
Using a proprietary formula, EKO takes mulch and sludge, and mixes it in a converted feedlot truck with four internal augers and a specially-fitted water injection system. The sludge adds nitrogen to the mix which, when combined with the carbon-rich mulch allows a much faster breakdown. Even though the sludge is 85% liquid, adding water to the sludge/mulch mix is still critical to the overall static aerobic process, says Fonseca.

“The combination of four or five loader buckets of mulch for each one of sludge, coupled with the air drawn through the piles from below, can yield a very dry mix. That mixture will stay on the pile for two to three months, so adding that water in the early stages is definitely needed.”

To enhance the aerobic process during this first stage, a compliment of 24 biofilter-equipped fans draws air beneath the piles. One third of them — eight fans — will yield one batch of what will eventually be about 2,500 cubic yards of compost. After roughly 60 days, each batch of material is moved to a curing pile where samples are pulled and sent to a lab in Oahu to be tested for fecal coliform and heavy metal content.

“We also do daily temperature probing and logging to ensure that each batch maintains temperatures of 131° and above for three consecutive days, then 121° and above for 14 consecutive days, to pass Part 503 requirements,” says Fonseca. “Material is then run through a 3/8-inch screen where the overs are reintroduced to the process and the fines are sent for final curing. Altogether, we go from the beginning to final product in about six months.”

He adds that EKO will rotate through its full set of 24 fans roughly 2½ times each year, generating between 15,000 and 20,000 yards of material.

At the Heart of it All
In addition to the suet/sludge/mulch composting operation, EKO is also in the early phases of a windrowed-and-turned green waste composting operation. Fonseca says that effort is driven by the sheer volume of material they have, by a need to reduce fire hazards, and by the availability of space in the open-pit area. Like the sludge-based operation, this one starts with primary-grinding green waste in the company's Morbark 1300.

“For about the first four years of work here on Maui, we had a grinder from a different manufacturer,” says Fonseca. “But as time went on, it just wasn't able to stand up to the workload and it was replaced with our first Morbark unit. Since that time, we bought this second Morbark 1300, a used unit; our first machine has been refurbished and is working in Hilo; and, because the Big Island is essentially the size of two, we bought another 1300 for use in Kona. We need grinders that will produce for us and we have that now.”

Palms in Paradise
As one might imagine, the green waste stream on an island like Maui is heavily-laden with fronds from a host of different palm species, each a challenge to grinder throughputs. Fonseca says the Morbark 1300's inherent capability coupled with some innovative loading, resolves that issue nicely.

“To offset the effects of the high palm volume, we simply don't segregate that material from the pallets and other wood products we get. We've found that doing so keeps production levels much higher.”

He adds that EKO generally grinds for three or four days a week at the Maui location. Unforeseen downtime at that site, on the other hand, could set the operation back two weeks.

“There is a constant steam of residents, landscapers, tree services, and so on, dumping material here — it builds up extremely fast. So we need reliability in our equipment. When choosing a replacement grinder, I went to Morbark's plant and liked what I saw as far as parts availability and follow-up. I felt that, since our business prefers to buy low-hour used equipment, there would be an advantage to buying direct from the manufacturer — and we've found that to be true. There's no denying we face challenges other operations don't, simply because of our location, but Morbark has shown us a willingness — and ability — to minimize the miles between us.”

Replace Your Divots
EKO Compost currently offers the landscapers and golf courses that comprise its customer base three grades of product: an original formula compost, a topsoil/compost blend, and a formula designed specifically for lawn topdressing. While those mixes represent the overwhelming majority of the product shipped to each of the three main islands — Oahu, the Big Island and Kauai — the company offers special blends as well.

“A while back we went to one of the larger courses on Maui with the intent of selling them compost,” says Fonseca. “Instead they asked for a special sand-added blend. But, because of the type of mowers they used, they needed it free of even the smallest rocks to avoid dulling their blades. So now we create the mix they need and run it through a screener with 3/16-inch screens.”

Unfortunately, because of existing PGA rules, that special blend can only be used as a divot mix, but Fonseca feels it is still a way to show their adaptability and is a nice add-on to the list of PGA-sanctioned courses on the island for which they already supply compost.

“We've come a long way as a company since our roots in Missoula — today we handle about 85% of the green waste from the island. And with the grinding operation on the Big Island probably adding a composting function in the near future, we have no doubt that our role in keeping waste out of the landfills and providing a needed, proven product will continue.”

Customer comments

No comments were found for Recycling paradise: Composting on maui hits its stride. Be the first to comment!