By Anne Magnuson

Landfill Gas Trends
The New Interest in Aerobic Bioreactors
EPA Regulatory Trends
Industrywide Competition
Review of MSWLF Criteria

The biggest movement of ideas in landfilling now and for the immediate future, from both cost and scientific points of view, is the increased understanding and utilization of bioreactive technologies, both aerobic and anaerobic. Meanwhile, landfill owners—the giant merging corporations as well as the smaller merchant and public facilities—will continue reevaluating their operations in order to remain competitive. What tipping fees will do will remain a worrisome uncertainty. Facilities will face rising costs associated with the ambiguous flow-control court decision, some by disposing at regional megafills as transportation firms offer attractive long-haul rates. Well-heeled landfill owners will improve on existing computer programs for monitoring and controlling selective operations.

On the regulatory front, few rules and guidelines are expected to dramatically change in the next five years. The landfill gas (LFG) industry will continue trying to reinstate the Section 29 tax credit that expired in mid-1998 by lobbying for a change in the IRS Tax Code. With recycling diversion rates stabilizing after remarkable success 10 years ago—a national obsession that increased landfill capacity—there will be increasing efforts to find viable markets for compost and/or to encourage greater diversion of greenwaste, leaves, and Christmas trees. Maybe even source reduction will assume its rightful place in the disposal hierarchy via governmental procurement policies and by educating Americans to reuse rather than throw away so many commodities.

For a look ahead, MSW Management interviewed consultants and industry leaders for their opinions on choices facing landfill owners in light of recent trends. Discussions follow concerning LFG, bioreactors (especially aerobic technologies), regulatory trends, and industrywide competition.

Landfill Gas Trends

"The general business trend to restructure and try to lower costs is particularly acute in the landfill gas business because—and this is an important theme—it is tough to make a buck in this business without the Section 29 tax credits," says James Walsh, senior vice president of solid waste for SCS Engineers in Cincinnati, OH. This can include restructuring of ownerships, operators, banks, and financial institutions. "People are looking at landfill gas systems and thinking about who can own and operate these things," he explains. Some LFG developers such as Detroit Edison and Zapco are refinancing their projects and restructuring their ownerships. Walsh says such companies either internalize their operations or externalize while hiring such firms as SCS Engineers to run their gas systems.

Computerization of LFG monitoring and even of collection operations by remote control are fairly recent innovations that will continue into the new millennium. Walsh believes that these technologies will become more available when the procedures are further site-tested and when they become less costly, as computer systems usually do. "More and more we are seeing automated systems in which one operator may be on-site a couple of hours a week," he notes. "The systems run with controls that may be monitored over the telephone." Walsh expects that as a trend for the next five years, these types of computerized LFG systems to be installed, not just by the well-capitalized corporations, but also as an alternative for smaller companies. "A significant advantage of computerizing is lower labor costs, but there are also constraints," he points out. "Essentially you have to program the computer to think like a human in adjusting the system. It is not cheap, and it is not simple. It is complicated."

The biggest stumbling block for the LFG industry, with the loss of the Section 29 tax credit, is the failure so far (at least at the time we go to print) of Congress to reinstate the incentive. The combined efforts of landfill industry leaders with the wind-to-electricity lobby almost succeeded in including a tax credit through Section 45 of the IRS Tax Code. As Walsh explains, the tax credit for wind is also due to expire. Landfill and wind organizations were unable to persuade Congress by September 1999 to renew the measure. President Bill Clinton veto of the government's overall tax code in late September gave the tax-credit lobby the opportunity to add the amendment to the revised law, Walsh says. (Results of the lobbying efforts were not available at press time.) Without tax-credit renewal, projects already qualifying for the incentive may use it until 2007, but new projects are ineligible. One aspect of LFG regulations sometimes overlooked is the large number of landfills that, to the surprise of many, were not required after all to install LFG collection systems under the 1996 New Source Performance Standards (NSPS). It was discovered, as the Environmental Protection Agency (EPA) initiated NSPS, that some provisions allowed landfills to avoid implementation. One of the provisions allowing landfill owners to end-run the standard was the 1997 EPA directive that lowered the gas rate for arid landfills. The average gas rate for arid landfills may be calculated with a k default value of 0.02 down from 0.05 when using EPA’s gas model equation. Dry areas were defined as those with less than 25 in. of annual rainfall. That's a lot of rain, Walsh agrees. Many landfills were not obligated to collect the escaping gas, including most sites in southern California, New Mexico, Arizona, Texas, and parts of Colorado.

Pilot studies demonstrating new uses for LFG are underway. Walsh notes two or three demonstrations for producing electricity from LFG-generated fuel cells, such as that in the City of Industry, CA, have shown that the process is clearly feasible, but it isn't cheap. "I haven't seen anyone take the plunge to go full-scale yet with fuel cells."

Jeffrey Pierce, a project director for SCS Engineers in Long Beach, CA, has written a 1999 research summary, "Emerging Landfill Gas Utilization Alternatives," which presents the recently researched status of the technological and economic feasibility of pipeline quality gas, vehicle fuel, hydrogen production, methanol production, and fuel cells. Tables 1 and 2 compare energy-production yield and estimated gross-revenue yield for the various technologies.

The New Interest in Aerobic Bioreactors

A place in wet-tomb landfilling exists for both aerobic and anaerobic refuse degradation, but that of the recently reexamined aerobic technologies is the less reported. The addition of water (or leachate) and air to an MSW landfill mass accelerates the aerobic decomposition of the waste to generate carbon dioxide and little, if any, methane gas. The addition of only water (or leachate) to the MSW mass accelerates the decomposition less rapidly but greatly accelerates the production of methane gas as compared to traditional dry-tomb decomposition. Accelerating stabilization by the aerobic method creates rapid settlement and, as with anaerobic digestion, reduces the organic constituents in leachate, partially removes some salts and metals, greatly eliminates offsite disposal of leachate, and shortens monitoring time after closure. The aerobic method could also prepare the site for landfill mining. Stabilization of the mass for both types of bioreactors occurs more rapidly than in dry tombing, but the aerobic method promises nearly complete settlement in far less time.

David Hansen, chair of the SWANA Aerobic Processes Subcommittee and vice chair of the SWANA Bioreactor Committee, points out those areas of aerobic research being pursued as interest in the process gains ground. "We need to identify the research questions as we expand aerobic practice in the field," he says. High on the list of research questions while testing both aerobic and anaerobic methods are ways to evenly wet the garbage and to characterize and deal with emissions created by the procedures. Usually a bioreactive landfill is wetted through pipes or conduits. "These methods have been successful in some cases and have led to failures in other cases," reports Hansen. Sometimes part of the trash becomes saturated, the lines might plug up, or the garbage might cling around the lines. "Certainly you don't get perfectly even distribution of the liquid," he says, "because you can't put in enough pipes." Additional questions concern quantifying the rates of stabilization and settlement, especially for the aerobic method, and investigating methods to prevent landfill fires.

Experiments with other leachate-application methods include spraying the liquid onto the waste or applying the leachate or water on a daily basis during waste placement. Hansen, also president of Landfill Services Corporation in Apalachin, NY, says they now have a major piece of equipment that takes the leachate and dumps it in small doses at different spots every hour on the working face as the trash arrives. Research attempts to evenly wet the garbage thus raise the question of what are the gas emissions as the leachate is applied to the surface of the trash? A related research question arises when air is injected directly into the buried trash: What are the exhaust emissions as the air displaces gases from void spaces in the trash?

The experimental application of leachate as the garbage is dumped onto the working face, termed topical application, first started up full-scale last fall at Middle Peninsula Landfill and Recycling Facility in Glens, VA. On rainy days, explains Hansen, when it is too wet to apply the leachate onto the working face, it is piped via horizontal injection lines in a sort of belt/suspender configuration. These lines will also extract LFG.

Evenly distributing the leachate will technologically improve both aerobic and anaerobic bioreaction and stabilization. "Even if we succeed, we believe we will run out of leachate," states Hansen. "I really believe that leachate disposal will no longer be a problem. Five years from now no one will be disposing of leachate. All the leachate will be hungrily soaked up by the garbage in order to enhance biostabilization. In fact, there will be a leachate shortage. That's what I think will occur once these questions are answered."

Hansen reviewed the history of aerobic research on request, a list that includes only those US investigations known to the SWANA subcommittee. Ralph Stone, president of Ralph Stone Inc. in Los Angeles, CA, at the time of his research, blew air into garbage in an aerobic process as early as 1969. A full-scale investigation by Hansen et al. at Rapp Road Landfill in Albany, NY, occurred during 1989-1995 with water added to large quantities of shredded garbage to cause rapid volume reduction. A lab-type study on aerobic digestion with lysimeter testing was performed by Richard Stessel in 1990 and 1992 in conjunction with Robert Fahey's investigations of landfill mining at Collier County Landfill, FL. Dennis Fagan et al. shredded garbage at a site in Chemung County, NY, during 1995-1998 in order to replicate Albany results. This full-scale project is still ongoing in a modified way.

Waste Management and Environmental Control Systems (ECS) of Aiken, SC, conserved airspace by aerobic stabilization in 1997 at Live Oak Landfill in Atlanta, GA. That same year, American Technologies (ATI), also in Aiken, began conserving airspace through aerobic digestion at Baker Road Landfill in Columbia County, GA. ECS has taken over this research. In 1998, ATI started up another aerobic project in Langley, SC, called the Aiken Project, now taken over by ECS.

Beginning in October 1998, a 90-day aerobic trial was accomplished by Hansen et al. to replicate the Albany work using nonshredded rather than shredded MSW trash. Another project came on-line last fall by Debra Reinhart et al. in Gainesville, FL. Both aerobic and anaerobic landfill processes will be included in this large research project, financed by a $3-million grant from the government of Florida. For a thorough summary of "The Bioreactive Landfill," see the MSW Management September/October 1999 article by John Pacey, Don Augenstein, Richard Morck, Debra Reinhart, and Ramin Yazdani.

As for costs, Augenstein, research engineer with IEM in Palo Alto, CA, is preparing a SWANA paper estimating potential financial benefits of landfill bioreactors. His figures are only rough estimates at this point in time, he emphasizes, because bioreactors are not measured in a way that makes this type of information easily available. "People say, 'Oh yeah, we put water in the last 40 acres and we seem to be able to get 20 percent more waste in there.'" In other words, says Augenstein, "The situation is not as well measured and quantified as we would like. We are working to accumulate information."

Nevertheless, Augenstein makes certain rough cost comparisons to help clarify the financial issues. With 10-20% usable extra airspace at a $20-$40/ton gate fee, if you pack in that much waste, it could be worth $4-$8/ton of gate waste, for example.

Further, Augenstein estimates that it roughly costs an additional $1-$2/ton to operate a bioreactor. This agrees closely with the estimate of Donald Gambelin, David Cochnane, and Bill Clister. Their paper, ''Life Cycle Analysis of a Bioreactor Landfill in California," suggests extra costs in the neighborhood of $1.50-$1.70/ton, with a double composite liner (if required) raising the cost to $2.40/ton.

EPA Regulatory Trends

Discussions abound within EPA on many aspects of Subtitle D, but no entity has submitted any formal proposal or petition whatsoever to change the rule, reports Robert Dellinger, director of EPA's Municipal and Industrial Solid Waste Division. "We have received no petitions from any source of any kind, including citizens, industry, states, or local governments."

In the immediate future, however, Dellinger says EPA is required under Section 610 of the Small Business Regulatory Enforcement Fairness Act (SBREFA) to review how Subtitle D impacts small businesses and small governments (see sidebar). It is mandatory that this review be completed within 10 years of the rule's passage: i.e., by October 9, 2001. Of course, EPA also participates in many discussions concerning Subtitle D–style criteria, such as those ongoing about leachate recirculation. Some owners and engineers would like the regulations in general to be less specific than Subtitle D. Since recirculating leachate requires specific landfill and liner design, Dellinger noted last fall that comments about leachate recirculation design would be initiated in the Federal Register by the new year.

An EPA request for comment concerning effluent limitations into surface waters dates back to February 1998, with the final limits to be promulgated in November 1999. Michael Ebner, the EPA Office of Water landfill effluent guideline request manager, said he could not release these limitations ahead of time because they had changed a little after comment in line with EPA's database. The pollutants to be limited were BOD5, TSS, ammonia, zinc, alpha terpineol, benzoic acid, p-cresol, and phenol. There is also a new limit for pH. New effluent limits were also to be promulgated in November for Subtitle C hazardous landfills.

The LFG industry would like to see a credit trade system used for offsetting greenhouse-gas emissions at specific sites. Reporting of greenhouse-gas reductions is in place on a volunteer basis now under US Department of Energy auspices. A credit system cannot be promulgated without legislation by Congress, and it would still be voluntary, according to a spokeswoman from EPA's Office of Policy. The only question is whether or not to keep track of credit already reported, so if it ever happens, these facilities would get credit, she says.

Thus, no new federal regulations are expected in the next few years unless the SBREFA review leads to changes in Subtitle D that might enhance the competitive opportunities of small merchant landfill owners or local governments. State regulations are anticipated to continue changing as state environmental agencies interpret Subtitle D for their regions. The growing understanding of what it means to operate under performance rather than strict design standards will continue into the new century.

Industrywide Competition

The 1994 Carbone flow-control decision that local governments cannot restrict the flow of waste caused the solid waste industry to rethink the questions of who owns the waste and where can we constitutionally place it?

As the industry enters the next five years, two means have emerged for local governments to skirt flow control, according to Dexter Ewel, a Potomac, MD, attorney who represents municipalities and firms with waste-related transactions. A local government may create a solid waste district (authority), essentially taking over ownership of the waste, or it may become a market participant.

When a municipality sets up a solid waste district and contracts out for disposal services, the local government may arrange for the refuse to be disposed at its chosen site. The district first takes over the market for waste disposal and collection. In most instances it will then ask for bids from waste collection companies while designating the preferred disposal site. "What we want," proposes the district manager, "is for bids from companies to pick up refuse at point A and take it to point B." Because the disposal service will contract with the municipality, it is constitutional, Ewel states.

Haulers prefer a wide-open market so they can bid on a job and take the trash wherever they please. If a municipality asks for bids from collection services to take the waste to point B, and that is where the hauler prefers, he may place a bid to perform the service by contract. On a related issue, haulers are finding it more difficult to select a disposal site because the large solid waste corporations, such as US Waste and Allied Wastes, have constructed megafills dealing with up to 3,000-10,000 tpd. Such corporations procure as many collection districts as possible in order to fill these giant regional sites.

Further, continues Ewel, when a municipality sets up its competing disposal options, such as a waste-to-energy-plant or a composting unit, that detracts from a hauler’s ability to truck the MSW where he wants. Another way for local governments to avoid the flow-control conundrum, says Ewel, is through economic flow control. "For instance, if a municipality decides to construct, own, and operate its own landfill, it is not a problem for the municipality to allow local people and local haulers to dump there free and then charge outside haulers a fee. If you become a market participant, you can discriminate in favor of your own constituents."

A third alternative on the table for municipalities is to dispose of local MSW by building a transfer station and contracting for long-haul services to a regional landfill. "They say, 'Why should we go to the expense of constructing our own landfill when very attractive rates are being offered by long-haul companies?' Municipalities look long and hard at long haul because it's so cheap," Ewel points out. Yet long haul has created a quandary for some solid waste plans, because in the early and mid-1980s, many, many landfills were shut down. Municipalities were required to prepare comprehensive solid waste management plans. "A lot of local governments took their responsibilities seriously and implemented their plans," Ewel explains. "Now the large regional landfills are on-line, and the set of options from the integrated management plan are much more expensive than just a plain old long haul to a regional landfill."

John Skinner, executive director and CEO of SWANA, has written that municipalities should push public policies that enlarge the field of competition and reflect community values and not just rely on profit/loss calculations. This will ensure a beneficial mix of public and private services, he states.

Ewel agrees. "In the long term, you can't count on long-haul disposal to be in place forever." He believes a municipality should plan for the future, not just for the immediate, short-term economic benefits of long haul. "My feeling is that a municipality's obligations are greater than just economic; they are also environmental, for example."

As for the economics of using different disposal systems in the present competitive climate, it was difficult for MSW Management to ferret out what role the numerous recent mergers of giant solid waste corporations will play. What is clear is that the mergers have great potential for altering competition between haulers and merchant and corporate regional landfills. It is too early to say what effect this will have on the disposal plans of local governments. But as one analyst pointed out last fall, when one giant corporation believed it had taken over the northeast landfill market share in 1998, tipping fees rose from 40% to 138% in some instances. This analyst suggests that the giant corporations have been able to consummate these hugely expensive mergers because of the economic boom the nation has been experiencing. To continue paying for these purchases, it will be necessary for the corporations to depend on Wall Street, to raise prices, and to possibly fall back on private investment pools.

US Waste/Waste Management declined to comment about the mergers but did agree to relate those areas of landfill research that they consider top priority. Yes, they are experimenting with aerobic and anaerobic processes and are investigating various uses for LFG.

MSW