Subtitle D: Compacting the Years

November 1, 2001

12 Min Read
Subtitle D: Compacting the Years

John T. Aquino

As parents know, the first 10 years can seem like a long time as a child matures. A youngster itself, Subtitle D celebrated its 10th birthday this year. But the landfill regulations soon will be heading into their teens. And like most teenagers, there will be some adjustments.

But before a child knows where it's going, it first must understand where it's been.

Initial Conception

Subtitle D, with its emphasis on landfill containment, was proposed by the U.S. Environmental Protection Agency (EPA), Washington, D.C., in Aug. 1988 and became effective in Oct. 1991, although various implementation deadline extensions ran through 1997. The rules established minimum landfill criteria for:

  • Location;

  • Operation, including daily cover requirements;

  • Design, including liner and leachate collection system installation, with a recirculation option for landfills with composite liners;

  • Groundwater monitoring and corrective action;

  • Closure and post-closure care; and

  • Financial assurance.

Subtitle D established the minimum landfill management requirements states had to meet. Each state was required to submit plans proving that it met the minimum criteria. The principal thrust of the regulations is landfill containment through daily cover, liner requirements and a final cap.

But how states have dealt with the regulations 10 years after they were made effective is, to some extent, a history lesson.

Just a Toddler

In the late 1980s, Subtitle D was designed to address the number of open dumps in the country and concerns about leachate contaminating the water table. Initially, states were slow in complying. But for the most part, open dumps have been shut down, and some smaller landfills were closed because their owners could not finance the cost of Subtitle D compliance.

In fact, the number of landfills declined from an EPA estimate of 20,000 in the 1970s to 2,893 in 1995, according to a Washington, D.C.-based Environmental Industry Associations study, “Solid Waste Disposal Trends: 1999 Update.”

Ed Repa, director of environmental programs for the Environmental Industry Associations (EIA), Washington, D.C., says, “The dramatic change in the number of landfills in the United States over the past 10 years primarily is attributable to the promulgation and implementation of the federal MSW landfill criteria.”

“Today, all states have [Subtitle D] approved programs, except Maine,” says EPA official Dwight Hlustick [See “All Alone” above]. A handful of states are not fully approved, he adds, but states are in compliance overall. Several states even have more stringent criteria in place, he says.

Overachieving Child

In Pennsylvania alone, there currently are 51 double-lined landfills permitted to operate — although Subtitle D does not require a double liner.

In fact, Pennsylvania protected its landfills through a statute passed in 1988, before Subtitle D was established, that requires a subbase, a secondary liner, a leachate detection zone, a primary liner, a protective cover and leachate collection zone.

Delaware also requires two liners. “Our latest MSW design requirements are equal to those of Subtitle C [the federal law governing hazardous waste],” says N.C. Vasuki, chair of the Delaware Solid Waste Authority, Dover.

Michigan requires municipal landfills to have a composite liner; a leachate collection system for new landfills and for some expansions; and a second liner, either composite or compacted soil, unless the landfill is located over a natural soil barrier on a site where groundwater can be monitored. The two-liner system must be capable of detecting and collecting any leakage through the first liner. If groundwater below the landfill cannot be monitored, a leak detection system also is required.

New York, on the other hand, requires double composite liners. Robert J. Phaneuf, chief of the Eastern Facility Section of the Bureau of Solid Waste and Land Management within the Department of Environmental Conservation in Albany, has attributed the more stringent requirements of New York and other northeastern states to groundwater contamination concerns.

“Seventy percent of our state depends on groundwater, so we have to be extra careful,” DSWA's Vasuki adds. “It's good that some states have more stringent requirements than Subtitle D because we don't want a repeat of Superfund [federal legislation that addresses sites contaminated with hazardous waste]. We need to pay more attention now for the good of our children.”

Tweaking the Rules

In the quest to protect their water resources, “a number of states have picked up and tweaked Subtitle D to make it work for them,” EIA's Repa says. “These laws are hybrids, sometimes carrying things over from the way their laws were before Subtitle D.”

Vasuki says Delaware's landfill regulations were Subtitle D equivalent in 1974. Jim Warner, executive director of the Lancaster County (Pa.) Southwestern Authority, notes that Pennsylvania's regulations were established in 1988.

“Pennsylvania's regulations were a reaction to particular problems we had — a fair-sized population, a number of landfills and a climate that could produce contamination from infiltration,” says Richard Bodner, president of the Chambersburg, Pa., consulting engineering firm Martin and Martin Inc. “Other states — Missouri, Oklahoma and New Mexico, for example — have climates that are different from the east coast, with less population and fewer landfills, and didn't run the same risks. The more stringent regulations of some states rose out of necessity to protect the environment.

“While Subtitle D did not really impact Pennsylvania, because its requirements already exceeded Subtitle D, for other states — Virginia, Alabama, Maryland, for example — moving to liner systems was relatively painless,” Bodner adds. “Expensive perhaps, but painless.”

Oozing with Danger

With Subtitle D or a more stringent regulation in place, the sleeper issue then becomes what to do with the leachate.

In Pennsylvania, leachate must be collected and handled by direct discharge into a permitted publicly owned treatment works facility following pretreatment, or the leachate must be collected and handled onsite and discharged into a receiving stream under a permit. If neither is possible, leachate must be handled by treating and stream irrigating.

Other states use a simpler system, designing a liner system, collecting the leachate and moving it offsite for treatment. This works if there is an economical place to put the leachate and if there is enough containment, Bodner says.

If an operation calls for storing the leachate in a 500-gallon septic tank, the system won't work if 27,000 gallons of leachate are being produced for every inch of land, he notes. “The tank would fill up almost immediately.”

On the other hand, bioreactors may be a key to addressing leachate management. “[It] may be one of the answers for the future,” Bodner says.

Changing the System

A bioreactor landfill sometimes is called “wet-tomb” because it recirculates liquid (including leachate), back into the waste to keep the garbage moist and enhance microbial decomposition. Usually, the amount of leachate is insufficient, so additional water must added.

Bioreactor landfills may be an effective leachate treatment system. But recirculating leachate, an option under Subtitle D, still is contrary to the principles on which the federal regulations were founded.

“Subtitle D was conceived with the ‘dry-tomb landfill theory,” EIA's Repa explains. “You didn't want to landfill liquid waste because that would just turn to leachate, which under Subtitle D is collected or — with certain requirements met — recirculated. So, Subtitle D won't allow you to add liquids. The rules in place won't allow you to get where you want to go with bioreactors.”

However, a bioreactor could be seen as an extension of the Subtitle D leachate recirculation option. And the advantages can be substantial, Repa says.

“You might be able to get out of the site in 10 years rather than 20, thus saving yourself 20 years of post-closure care,” he says. “Because of the rapid decomposition, you are able to deposit more waste, perhaps a third more, into the permitted airspace.”

Bioreactors also address the issue of conventional Subtitle D landfill liner failure. With the rapid waste stabilization, environmental risk and liability resulting from settlement, leachate, and gas are minimized. Even with a partial liner failure, there should be little or no risk of increased gas generation or worsening leachate, according to industry experts.

“Bioreactors are very important in that they can eliminate pre- and post-closure costs, extend the life of the landfill and generate methane, which can be captured and used,” says Bruce Parker, EIA president.

Alternative Lifestyle

Despite Subtitle D's seeming restrictions against bioreactors, some states have specifically allowed them.

For example, a Washington state statute reads: “Bulk or noncontainerized liquid waste may not be placed in MSWLF [municipal solid waste landfill] units unless [the] waste is leachate or gas condensate derived from the MSWLF unit or water added in a controlled fashion and necessary for enhancing decomposition of solid waste, as approved during the permitting process of WAC 173-351-700, whether it is a new or existing MSWLF or lateral expansion.”

The Delaware Solid Waste Authority also has operated Sandtown, the largest landfill in the state, as a bioreactor for 10 years. The landfill has been operation since 1994.

“Subtitle D was created as a containment requirement” DSWA's Vasuki says, noting that bioreactors may not contradict the regulations. “Bioreactors make Subtitle D landfill waste decompose more safely and faster. We know so much more about landfills than we did 10 years ago. Thanks to the chemical industry and manufacturers, there are geosynthetic clay liners and other products that just weren't available in 1991.”

“By increasing landfill life and reducing the time and cost of post-closure care, bioreactor landfills may be the next great advance in landfill technology, which could permanently change the way landfills are designed and operated,” John Skinner, executive director and CEO of the Solid Waste Association of North America (SWANA), Silver Spring, Md., told Waste Age in “Bioreactor Landfills: But Does It Save Money?” [July 1, 2000, page 18.]

“I'm not sure how the EPA will deal with the issue of bioreactors from an overall regulatory perspective,” Bodner says. In his state, “The door is more open for the Pennsylvania Department for Environmental Protection to entertain it, and Pennsylvania is working in that direction,” he says. “It gets away from the dry tomb concept and stabilizes the mass before fears of liner deterioration spread.”

Growing Maturity

Meantime, the EPA has authorized a few bioreactor projects under Project XL, which stands for “eXcellence and Leadership.”

A national pilot, Project XL al-lows state and local governments, businesses and federal facilities to develop, with the EPA, innovative strategies to test better or more cost-effective ways of protecting the environmental and public health. In exchange, EPA will issue regulatory, program, policy or procedural flexibilities for the experiment.

Yolo County's proposed 12-acre bioreactor landfill module near Davis, Calif., is one such project. Through Project XL, the county requested the EPA grant it regulatory flexibility from the liquid restrictions and from state regulations requiring bottom linings, based on project performance, available controls and environmental safeguards that were demonstrated at a smaller-scale, 9,000-ton test program at the Yolo County Central Landfill. A previous study of two cells showed a cell size-reduction of 19 percent using the “wet-tomb” approach vs. the a “dry-tomb.”

The site-specific rule to implement the bioreactor landfill under Project XL was published in the Federal Register on Aug. 16, 2001.

The Federal Register also published on Aug. 22, 2001, a site-specific rule to implement a bioreactor at the Buncombe County Landfill in North Carolina, under the Project XL program. At this landfill, recirculation in cells 1 and 2 were authorized because they used the prescribed composite liner. The site-specific rule further authorized recirculation in cells 3 to 19 over an alternative liner.

Additional Project XL bioreactor projects include Houston-based Waste Management Inc.'s Maplewood Landfill in Virginia; the King George County, Md., Landfill, whose final project agreement was signed on Sept. 20, 2000; and the Anne Arundel County, Md., landfill, whose project agreement was signed on Dec. 17, 2000. And more projects could be on the horizon.

On its 10th birthday, Subtitle D was preparing for adjustments. In Nov. 1999, the EPA asked for feedback in a mandated, 10th anniversary review of Subtitle D. The EIA, SWANA, the National Recycling Coalition, Alexandria, Va., plus other associations and organizations around the country responded. And as a result, Hlustick says that the EPA plans to advance a proposed or draft regulatory change in the Federal Register.

Hlustick says he hopes the draft will ready by Dec. 2001 to allow states to research and develop permits for demonstration projects such as bioreactor landfills. He also hopes another proposed or draft regulatory change will allow leachate recirculation atop liners.

These changes, he says, should address some of the reactions to Subtitle D during its first 10 years and will keep states informed and prepared for the second decade of landfill containment regulations.

John T. Aquino is an attorney and journalist, former editor-in-chief/publishing director of Waste Age Publications, and a Waste Age contributing editor.

All Alone

To date, Maine is the only state that does not have a Subtitle D-approved program, according to Washington, D.C.-based U.S. Environmental Protection Agency (EPA) official Dwight Hlustick.

Maine's rules are substantially consistent with Subtitle D and were comprehensively revised in 1998, says Susan M. Clary of the Maine State Department of Environmental Protection. But the state got caught up in an “administrative de-loop,” she says.

Maine law prohibits adoption of a statute by reference, which required Maine to revise its landfill rules to be equivalent to Subtitle D, explains Clifton Eliason, environmental specialist for the Maine division of solid waste. As a result, Maine took that opportunity to revise all of its solid waste rules, including recycling. And this delayed the law.

The only differences between Maine's landfill rules and the Subtitle D minimum requirement is that Maine “treats the landfill engineering specifications and monitoring with much more emphasis on the geology of the site,” Eliason says. “Our liner requirements are no less stringent.”

According to Mike Hill, municipal solid waste coordinator for EPA Region I, “Absent the public comment period, which has been delayed, we anticipate proposing that Maine's solid waste program is adequate.” Rhode Island just received approval in fall 1999.
John T. Aquino

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