The state Department of Health is concerned that Maui County’s landfill plans don’t meet with accepted design standards or federal regulations. And because of that, the DOH has been holding up the opening of Phase IV of Maui’s Pu`unene landfill and the overdue closing of Phases I and II.
Until the county reconciles conflicting plans regarding the different phases of its landfill and corrects design flaws, it will continue to push the envelope of what is already a bad situation: Right now, the county is undergoing enforcement action by the DOH for violations stemming from inadequate management of Phases I and II, violations that have recurred for more than a decade.
While the county has conceded to making some changes to its Phase IV landfill, it has told the DOH that some of its biggest sticking points are non-issues.
For the most part, “Phase IV will remain as constructed,” says Elaine Baker, engineer for the county’s Solid Waste Division. Because Phase IV has been “over-engineered” rather than under-engineered, Baker says, there shouldn’t be any environmental problems. And the DOH, she says, should allow Phase IV to open as is, and “let us see and give us time” to find out if the design problems the DOH is so concerned about actually surface.
A Fine Mess
As Environment Hawai`ireported in the April 1999 cover article, “[url=/members_archives/archives_more.php?id=678_0_25_0_C]Costs Increase, Size Shrinks as Maui Redesigns Phase IV of Pu`unene Landfill[/url],” Maui County’s Public Works Department did the unheard-of when it built Phase IV of its Pu`unene landfill without a permit from the state Department of Health’s Office of Solid Waste Management. That was only the start of many irregularities associated with the expansion.
The county had paid local engineering company Masa Fujioka and Associates and SHN Consulting Engineers and Geologists of Oregon some $200,000 to design the Phase IV expansion of the central Maui landfill. A bid package was issued based on MFA/SHN’s specifications. Rojac Construction, Inc., of Maui won the bid in August 1997.
Through a process called value engineering, where a consultant tries to cut costs by making design changes, Rojac and its consultant, Washington engineering firm Parametrix, Inc., proceeded to drastically change MFA/SHN’s designs. While one expert believed the design required only “minor changes,” Parametrix criticized it wholesale, saying that the leachate collection system and lagoon were too small and its bottom slopes were too steep. Using Honolulu precipitation and temperature data, Parametrix concluded that the dry landfill just outside Kahului should be designed to handle deluges.
The new design reduced the MFA/SHN’s multi-layer liner system to a single-layer “alternative” liner. In addition, the leachate collection system was expanded from a 25-gallon-per-minute leachate pump, designed for a dry climate, to two 200-gpm pumps. This change was made because Parametrix predicted maximum leachate flows of 1.5 million gallons a day, whereas Masa Fujioka predicted only 10,867 gallons a day, or less than one percent of the Parametrix estimate.
By agreeing to these changes, the county was flouting procurement laws that require public projects to be advertised in requests for proposals and then are put out to bid. Instead, the county contracted directly with Parametrix to redesign the landfill in 1998. After Parametrix was finished, Masa Fujioka’s 26-acre landfill with a capacity of 2.2 million cubic yards and a lifetime of six to seven years had become a mere 10-acre landfill with a capacity of 600,000 cubic yards and a projected life of just two and a half years. What’s more, despite the downsizing, the cost increased from $5.7 million to $7.2 million. Parametrix and Rojac eventually plan to build Phase IV out to more than 20 acres, but that will be under another application.
During construction in 1998, plans for the first 10 acres of Phase IV changed constantly, and since its completion, the county has had its hands full stamping out problems DOH engineers have discovered.
Design Problems
On June 12, 1998, Maui County applied to the DOH’s Office of Solid Waste Management (OSWM) for a permit to operate Phase IV, whose construction was by then well under way. The county anticipated opening Phase IV in 2002, giving DOH engineers sufficient time to review plans and an operations manual submitted by the county.
Twice in 1999, the DOH asked the county to resubmit its application to include a “Basis of Design,” a document providing the rationale for the landfill’s particular construction. This was never submitted, and the OSWM was wary to proceed without it.
By June 2001, the county was getting anxious.
“The clock is ticking for us and we need to get this plan resolved. It is possible that we may need to be operation in Phase IV as early as February of next year, but likely no later than June of next year,” David Goode, director of Maui`s Department of Public Works and Waste Management wrote to OSWM’s Lene Ichinostsubo that month.
Although the Basis of Design was never submitted, because of Goode’s urging, the OSWM reviewed what documents it had from the county, mostly reports prepared by Parametrix. After its review, OSWM staff detailed some of the problems in a July 6, 2001, letter to the county. Among them were the following:
Discrepancies: The Engineering Report states that Phase IV, at full build-out, will be 27 acres, and when Phases V and VI are complete, the total area will be 90 acres. The Operations Manual, on the other hand, says Phase IV will be 20.4 acres, and the total area after V and VI are built will be 56.7 acres.
Stormwater management: Phase IV includes no surface water control system. Without any diversions, stormwater will filter through the waste and become leachate, which may “significantly increase the need for leachate management when it could easily be avoided.”
Operational Layer: This layer protects the underlying leachate collection system and liner from puncture and fire. The thickness Parametrix instructed Rojac to use was 18 inches – a thickness Rojac thought was too thin and would jeopardize the liners. The DOH wrote that it would accept no less than 36 inches and recommended 48, if possible.
Composite layer: Phase IV uses a single geosynthetic clay liner (GCL), which is typically used for systems that routinely have to deal with small amounts of water. Yet Phase IV as a whole has been designed as if the landfill were in a wet environment, the DOH wrote, where the volume of leachate and pooled water would be considerable. “With the quantity of leachate estimated, was a double-lined system considered? If so, why was it not selected?”
Subgrade: This is the surface beneath the liner. It should be smooth and firm, without imperfections that would puncture or tear the liner. The maximum rock size typically used is half an inch large or less. Phase IV allowed rocks twice as large to be used.
Leachate: The DOH said the landfill should be double-lined with leak detection and monitoring systems and have the ability to pump out liquids.
The DOH also was concerned that the leachate pond needed a bottom liner that was self-sealing (usually by having a layer of clay built into it). Without one, “any leakage in the bottom liner will allow relatively free movement of leachate to the subsurface. We understand that the leaking of the pond is already confirmed.”
In an August 9, 2001, letter, DOH deputy director of environmental health Gary Gill informed the county’s Goode that Phase IV’s design violated state and federal requirements for municipal solid waste landfills. “Through the use of [a computer] model, the leachate head on the liner system was estimated at 105 inches under a leachate recirculation scenario, which exceeds the 12-inch regulatory requirement. In addition, leachate recirculation with an alternative liner design is not allowed under federal or state rule. Based on the information presented in the POC [Point of Compliance] document, the alternative liner design is unacceptable.”
Comparing Phases
Still, the county’s biggest problem in obtaining DOH approval comes from comparing Phase IV design documents with those relating to Phases I and II.
One Phase IV document estimates 353,000 gallons per acre year – about 1,000 gallons per acre day – of leachate. According to one DOH engineer, that’s about the amount produced at Kaua`i’s landfill in Kapa`a, which gets about 60 inches a rain a year.
Back in October 2000, Maui County released the scope of work for closure of Phases I and II, which state, “The climate at the landfill is hot, high 80s, and dry with annual average rainfall of 20″ produced mostly by winter storms.”
Because of these dry conditions, a 1994 Master Plan Report for the vertical expansion of Phases I and II estimated that the 40-acre site would generate 29 gallons a day or 10,000 gallons per year of leachate.
Because Phases I and II are adjacent to Phase IV, the DOH told the county in July and August 2001 that the disparity in assumptions about leachate and climate had to be reconciled before proceeding further.
Phases I and II are near capacity. Original plans called for them to stop receiving waste in January 2002. As problems dragged on, it became February, then June at the latest. To date, although closer to a solution, the DOH approvals have not yet been given for closure. (Phase III of the Central Maui landfill receives compost, not waste.)
In January, the county submitted a Basis of Design report for the closure of Phases I and II. This, too, the DOH feels, has problems, and not just because of conflicting with assumptions regarding Phase IV.
For one thing, the county’s plans had not described how the proposed cap – a liner under two feet of soil – would be adequate. Such a cover might work, but only “if appropriate site-specific conditions including soil classification, climate, soil chemistry and the composition of the final cover system are taken into consideration,” the DOH wrote.
Resolution
While the county is trying to address its design problems, it has also been grappling with DOH’s efforts to enforce regulations regarding the management of Phases I and II.
Piles of garbage have remained uncovered at Maui Central landfill for days at a time, despite laws that require refuse to be covered with soil or other cover material at the end of each day. Wild dogs and flies reportedly plague the site, and OSWM records show that the landfill has repeatedly violated state laws and permit conditions for inadequate daily cover as well as a host of other infractions.
The DOH issued a warning letter to the county in January 2000, and has been working since then with the county on a consent agreement, which will likely require the county to do mitigation and pay fines. The warning came after a December 1999 DOH inspection found that the county was violating terms of its 1996 consent agreement with the DOH, which addressed many of the same issues (litter, inadequate daily cover, etc.).
Baker says the violations are being handled separately from the design/permitting issues. Since the DOH expressed its concerns last year, the county has rerun computer models using DOH-recommended parameters. The results seem to justify Phase IV’s current design. The county also plans to increase the thickness of its operations layer, revise its operations plan to divert as much stormwater as possible, and to create two four- to five-acre “sub-phase” within Phase IV to further reduce leachate.
The DOH’s Gary Gill wrote the county in May 2002, that the DOH was willing to accept the county’s wet landfill design, so long as “the design of the landfill and appurtenant facilities [are] consistent with these assumptions.”
But design problems still exist, Gill continued: bottom slopes of the landfill are not steep enough to prevent ponding and clogging of leachate (they should be at least 2 percent; the landfill’s ranges from 4 to 1.2 percent), the county is still allowing half-inch ruts in the surface beneath the liner, which the DOH feels may allow “protrusions to the subgrade.”
On July 26, Baker sent to the DOH a point-by-point rebuttal to Gill’s letter.
The DOH’s insistence that Phase IV was assumed to be wet “was an error of interpretation,” Baker told Environment Hawai`i. Phase IV was not modeled to be a wet landfill, but was designed to accommodate the maximum amount of water it could receive in a large storm, she said. “Why not design for capacity?”
Regarding the rut issue, Baker says the liner installer accepted the subsurface. The DOH’s concerns are that angular rock will distress the liner, she says, but “I sent pictures showing we weren’t using angular rock and that there was a cushion layer of soil.” Furthermore, she said, “the DOH is not the accepting authority for subgrade material, it is the liner installer.”
The shallow bottom slopes aren’t a problem, either, she says. The landfill is steep enough where it needs to be, she says, and “We didn’t model the landfill as wet so ponding should be a non-issue.”
By late last month, Baker was still waiting to see if the DOH agreed with her take in the design issues. In the meantime, the county is expanding the side slopes of Phases I and II. The county’s consultant on the closure found additional capacity that should prevent the need for closure for another year and a half, Baker says. She expects a permit to open Phase IV will be granted “at least within the next year.”
— Teresa Dawson
Volume 13, Number 3 September 2002
Leave a Reply