Composting And Organics Recycling vs. Bioreactors: Another Perspective

Last modified: March 23, 2019

[pre-publication draft for BioCycle May, 2003]
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Composting and organics recycling vs. bioreactors: Another perspective - Editor’s View by Nora Goldstein
Waste Management Inc. response, by Ed Skernolis and Gary Hater
Authors [briefly] respond to Waste Management Inc., by Bill Sheehan and Jim McNelly

Composting And Organics
Recycling vs. Bioreactors: Another Perspective - Editor's View

by Nora Goldstein

Probing the arguments on both sides provides valuable insights and clarification — and perhaps a new framework for future discussions and analyses.

In the January 2003 issue of BioCycle, Bill Sheehan of the GrassRoots Recycling Network in Atlanta, and Jim McNelly of Renewable Carbon Management in St. Cloud, Minnesota, authored a “Composting View” column on a rule proposed by the U.S. Environmental Protection Agency that would give states authority to issue exemptions to the federal Subtitle D landfill requirements for research and development purposes. Noted the authors: “EPA claims that the purpose of the proposed rule (“State Research Development and Demonstration Permits for MSW Landfills”) is to encourage innovation. However, in view of the fact that EPA already has federally supervised experimentation procedures in place and functioning, this claim can be seen for what it really is: a thinly disguised ruse to deregulate most of the minimum national standards for landfill permitting and open the flood gates to the most ill-considered bioreactor designs built on the cheap to insure that composting will not be able to compete in the 21st century….”

In response to this Composting View, Ed Skernolis and Gary Hater of Waste Management, Inc. sent a “Letter to the Editor” in March (see the accompanying response in this article). In turn, BioCycle invited the “Composting View” column’s authors to respond to the Waste Management letter (see the accompany rebuttal by Sheehan and McNelly). Concurrently, BioCycle editors explored some of the issues raised over the course of these various exchanges of views.

What Exactly Is The Proposed Reg?
EPA’s proposed regulatory change to the federal Subtitle D landfill rules has not yet been finalized, although what was originally proposed has been revised to reflect comments received during the public comment period. According to Dwight Hlusick of the U.S. EPA Office of Solid Waste, the rule that will be finalized shortly is more restrictive than what was proposed. It does cover research development and demonstration (RD&D) permits that states can issue to Subtitle D landfills to test the bioreactor technology. The permits would be site specific, depending on the terrain and other factors. Currently, the Subtitle D rule does not allow the addition of liquids to Subtitle D landfills. Under the RD&D permit, nonhazardous liquids could be added to achieve the moisture content needed (typically 40 percent or greater). The permit also would allow experimentation with liners and final covers (e.g. vegetation for phytoremediation), and different gas collection systems.

“The Resource Conservation and Recovery Act (RCRA) does give EPA authority to propose a rule that would delegate authority to states to waive certain Subtitle D requirements for purposes of carrying out research and development,” says John Skinner, Executive Director of the Solid Waste Association of North America (SWANA). “RCRA also specifies which requirements cannot be waived, such as groundwater monitoring and gas collection and treatment.”

Four bioreactor demonstration projects (of the 20 currently underway) have been permitted under EPA’s “Excel” program which requires federal permit review and approval. Two of these projects are in Virginia, one is in North Carolina and the other in California. “EPA has put a couple of hundred thousand dollars into testing and monitoring at these bioreactors,” says Hlusick, adding that the agency has not spent millions of dollars in research on bioreactors, as was stated in the January “Composting View” column. .

A companion regulation to the RD&D permit would allow leachate to be recirculated in landfills with alternative liners, adds Skinner. “Currently, you can use an alternative liner, but you can’t recirculate with an alternative liner. This gives the ability, under certain circumstances, to recirculate leachate when an alternative liner is in place.”

George Garland, formerly with EPA’s Office of Solid Waste, is very familiar with the tensions created between landfill bioreactors and composting. He also is very familiar with federal regulations regarding solid waste. The bottom line, says Garland, is that the states, not EPA, regulate solid waste landfills. “They are the ones with their fingers on the trigger, not EPA. EPA issued the regulation that allows for the demonstration of landfill bioreactors; but it is up to the states to decide whether or not they will allow it. That is where the composting community needs to focus its outreach, to give facts and build credibility for the organics side of the argument.”

What About The Epa Hierarchy?
Another issue raised in the commentary and responses is how EPA’s support for landfill bioreactors — which could negatively impact composting initiatives — is counter to the agency’s solid waste management hierarchy, which places source reduction at the top, followed by recycling and composting. Landfills are at the bottom of the hierarchy. Has the agency’s support for the hierarchy waned? No, says Garland. “EPA’s official policy is that the most important thing to do with solid waste is not to have it, to pursue waste reduction. Next is to recycle. If you can’t do either of those things, then you can think about burning or landfilling it because both are at the bottom of the pyramid. EPA is not moving bioreactors to the top of the pyramid as some are alleging. They are saying states can experiment with bioreactors.”

We asked John Skinner of SWANA where he viewed landfill bioreactors on the EPA hierarchy. “I put it below energy recovery and above landfilling,” he says. “You probably can’t get as much energy out of a bioreactor as you will out of a burner plant and you won’t get all the gas out of the landfill but it will be produced faster and collected more efficiently than if it were being done in a Subtitle D mode.”

Stepping back from the trenches, it appears that landfill bioreactors are mostly a technological evolution from the current generation of landfills. “It depends on what the data shows,” notes Skinner. “From an environmental perspective, a landfill would be brought to a stable condition over a shorter period of time. From a business perspective, there is the potential that more capacity could be created at a site. That is a big question – will you get settlement and how much. There also is the point that in order to add liquids to a landfill, the side slopes would need to be decreased to keep liquids from breaking out. If that were necessary, then you may not be increasing capacity.”

Competition For Composting?
So what really are the threats, if any, to composting, anaerobic digestion and other organics recycling technologies and systems? First, it would be competition for nonhazardous liquid waste streams such as biosolids, food processing residuals and other recyclable high moisture content feedstocks. But with less than two dozen bioreactors, all in the demonstration phase, in existence, that threat isn’t looming at this time.

What is looming, however, is access to the organic residuals that are still in the waste stream. Here’s the deal. Characterization studies of municipal solid waste are finding an average of 30 to 40 percent organic residuals — primarily food, yard trimmings and wood. Add the paper fraction to that (37 percent according to EPA’s 2000 MSW characterization study), and we find that way over 50 percent — almost two-thirds — is degradable. The disposal industry wants that waste stream to stay in business, and they don’t mind if it’s all mixed in with the other garbage. The organics recycling industry — including composters, anaerobic digestion facilities and ethanol producers — needs those feedstocks as the basis for their operations (and in reality, much of the paper may have higher and better end uses as raw material for recycled paper). Some technologies are designed to handle organics mixed in with the inorganics. In other cases, a source separated stream is preferred, especially for high value compost markets.

So what the issue boils down to at this time is how to most efficiently and effectively compete for those biodegradable feedstocks. The mix of organics recycling systems and equipment now available — plus the operational experience and research achievements over the past 25 years — makes that prospect less daunting, if not in fact, downright exciting. The key is to frame the discussion around the advantages of organics recycling.

“Instead of attacking bioreactors, the organics recycling industry needs to continually stress the comparative advantage of composting and other recycling technologies,” says George Garland. “They can’t panic just because a possibly better idea is being put forward for landfilling. That is what advancing technologies is all about.”

For example, adds Garland, focus on the value in the compost. “Flood and erosion control, storm water management, agronomic benefits, soil remediation, filtration of contaminants — this is where the discussion should be focused. The story is about the markets for compost, and to the extent that we attack others in the waste management industry about competition for organics, we are in trouble. We must continue to be aggressive in developing strategies to capture and convert the organics in the waste stream into products with market value.”

There is, however, a very significant perception issue that must be addressed immediately. Neither the authors of the Waste Management response, nor John Skinner of SWANA, take issue with composting as a technology. But what they do argue is that even with aggressive composting, a lot of organics still will be going into the landfill. “It depends on what the data show, but if bioreactors fulfill their potential, they are probably a better way of landfilling,” says Skinner. “But that doesn’t mean you shouldn’t compost if it’s possible. If you can source separate clean organics and can compost those, you should do that, but if you look at the current level of composting, e.g. five percent of the waste stream, you could quadruple that and still have organics going into ground. We will reach certain limits with respect to composting and it will be based on the extent you can get people to source separate. I am optimistic when I see what is going on in San Francisco, and there will be other places where we can push further and further to divert organics. But there also will be places where it won’t be applicable. As a result, I think the majority of organics in the next ten years will still go into the ground.”

Clearly, this view is held by Waste Management officials as well. For example, in their accompanying response, Skernolis and Hater, write: “If 100 percent of all food waste (the next likely target for diversion programs) were diverted from landfills, the organics disposal volume would decrease by only 15 percent (about 25 million tons).”

Highest And Best End Uses
In the end, this discussion needs to focus on two questions: 1) What are the highest and best end uses for the residuals left in the waste stream?
2) What are the highest and best uses for current and future waste management technologies. Ultimately, whether it is today or 20 or 50 years from now, there will come a time when we have to follow the solid waste management hierarchy out of necessity, not out of choice. The residuals in the waste stream are going to be needed to rebuild and remediate unproductive soils, generate energy efficiently and provide raw materials for manufacturing. Landfill space will have to be preserved for what truly can’t be recycled or recovered in some fashion, as developing new disposal capacity will be more and more difficult and costly. That will be the highest and best end use for landfills in the long run. Solid waste and wastewater treatment managers will be in the natural resource creation and preservation industry. Current revenue streams from disposal will be replaced with sale of commodities such as energy and agricultural inputs (and during the transition from waste managers to natural resource managers, processing fees).

In the short term, the following points may help in shaping arguments and discussion related to landfill bioreactors:

--If the bulk of the MSW stream continues to be managed via landfilling (a rate of about 60 percent according to BioCycle’s 2001 State of Garbage in America survey data), a much greater mix of biodegradable feedstocks will be disposed. That creates a more volatile environment in the landfill. To control that situation, the disposal industry is advocating an accelerated route to degrading those feedstocks, i.e., adding massive volumes of liquids and then working to control impacts related to leachate, increased gas generation, and strong enough liners. In other words, bioreactors (as conceived) almost become a necessity as the organic fraction being disposed is higher than when dry tomb technology was developed.
--Unlike bioreactors, however, composting is definitely a proven technology for these degradable feedstocks. (So is paper recycling but we’ll save that discussion for another day. Suffice it to say that paper recycling is an allied technology.) Knowledge and technologies have advanced to the point where any potential negative environmental impacts can be controlled. Anaerobic digestion of MSW is less proven in this country, but has a long operational track record overseas.
--To a certain extent, the real discussion when it comes to bioreaactors is a comparison to anaerobic digestion (AD) technologies. There are AD systems designed to take the mixed waste stream, high liquid streams, etc. The goal is to maximize gas generation and recovery. That is probably a better apples to apples comparison to bioreactors (versus composting).
--When AD is put in the mix, and ethanol production for nonrecyclable paper streams (or even clean thermal energy recovery systems not just for the paper but also for biomass), that leaves landfills at the right place in the hierarchy – which is really to take wastes that don’t have a higher and better end use or value above the ground.
-- Right now, the current waste management climate favors landfilling. According to Chartwell Information (www.wasteinfo.com), the average landfill tip fee (weighted) in the United States is $36.93/ton. Skinner of SWANA notes that in some regions on the West Coast, tip fees are below $20/ton. Not much is being added in the way of new landfills; instead, Skinner is mostly seeing expansion of existing landfills. One could make the argument that given that scenario, landfill owners are underpricing their available disposal space (i.e., filling it up on the cheap but it will be more costly to replace).
--Organics recyclers are a savvy bunch. Having competed against low landfill tip fees for so many years, many operations have figured out successful economic formulas, from collection through developing high value end markets. That formula includes tapping the same liquid residuals streams (including biosolids) that bioreactors would be pursuing.

So in the end, we as advocates of composting and recycling approaches to residuals management, have a lot working in our favor. The key is clarify our alliances and be consistent — and aggressive — in our message.

Sidebar #1
Waste Management, Inc. Response
Ed Skernolis and Gary Hater

BIOCYCLE readers deserve a more balanced and informed perspective on the development of bioreactor landfill technology than that presented by Messrs. Sheehan and McNelly in their “Composting View” (see “Bioreactors And EPA Proposal To Deregulate Landfills,” January 2003). A fair assessment of bioreactor landfill technology should consider the following:

Environmental improvements must be examined for all aspects of waste management. The disposal of organic wastes in landfills is a fact of life for waste managers and landfill operators and will be for the foreseeable future, even with the implementation of massive organics diversion programs. Municipal solid waste landfills (MSWLF) already contain perhaps five billion tons of organic waste that are undergoing some level of biodegradation. Each year, an additional 125 million to 150 million tons of organic waste are added to landfills, even with the successful diversion of greater than 50 percent of the major biogenic organic materials in the waste stream (cardboard, newsprint, yard waste). If 100 percent of all food waste (the next likely target for diversion programs) were diverted from landfills, the organics disposal volume would decrease by only 15 percent (about 25 million tons). If there are now new methods to potentially lower the environmental impact of landfills in light of the organic waste disposal situation, it would be irresponsible for the U.S. EPA and landfill operators not to explore them, and this effort ought to be supported by those truly interested in environmental progress.

Bioreactor landfills pose no threat to recycling or composting programs. The purpose of the bioreactor is to accelerate degradation of the organic fraction of the waste stream in order to enhance environmental performance, regardless of the percentage of organic waste remaining after diversion programs. The environmental benefits of the bioreactor are potentially greater with a higher percentage of disposed organics, but there is no obligation for a landfill to operate as a bioreactor if not suitable for its waste stream. The landfill can accommodate a wide variety of circumstances, which is one of its fundamental values in any integrated waste system. Some landfills — due to climate, waste streams, and moisture availability — may not be generally suitable for bioreactor technology. Landfills that manage largely inert materials, such as construction and demolition wastes or combustion ash, have no need to undertake accelerated degradation.

The Composting View’s reference to European policy on organics diversion suggests that the Europeans are depending on composting as the alternative to the organics disposal issue. Indeed, it is waste combustion in waste-to-energy plants or in simple incinerators that allows the European Union (EU) to even consider significant diversion programs. European nations, due to population densities and land use issues, had already committed to waste combustion as the primary management method well before the EU organics diversion standards were developed. As a result, the policy impact is far less significant than would be the case in the United States, where waste-to-energy combustors account for the management of only about one-sixth of the waste stream. The authors also fail to point out that the EU diversion program does not reach fruition for another ten years (which leaves open the question of whether it will be achieved or not), and does not require 100 percent degradable organic waste diversion as an outcome. In short, European policy envisions some significant level of organic waste disposal far into the future. It is fair to assume that bioreactor landfill technology, if successfully demonstrated, will be adopted by European waste managers to complement their diversion programs.

The authors’ concern that landfill operators may walk away from a closed landfill after 30 years, leaving behind an ongoing environmental threat for decades or centuries to come, is based on a clear misunderstanding of the federal regulations and the oversight power of states. It is true that the 30-year benchmark that EPA laid out in its original regulations was somewhat arbitrary, but the whole of the cited provision makes clear that states may extend the postclosure oversight period indefinitely as long as the landfill presents a threat. Landfill operators are required to have financial assurance arrangements in place for postclosure care, even if the term changes, in order to prevent such threats, and any corrective action requires additional financial assurance. It is important to note that EPA, the states, and the industry all want to investigate bioreactor technology specifically because it holds the promise of substantially reducing, if not eliminating, any potential threat posed by the waste mass in the closed landfill.

Any objective observer would recognize that there are clear environmental purposes for the U.S. to be investigating bioreactor technology. In addition to an overarching interest in treating and stabilizing the waste mass more effectively through accelerated biodegradation, the technology allows for developing more cost-effective methane recovery programs, for treating landfill leachate to an environmentally benign state, for minimizing the demand for more land for landfilling purposes, for revitalizing the land used for landfilling, and for addressing the treatment of special wastes, such as nonhazardous liquid wastes, which would otherwise burden our municipal wastewater treatment works. Given concerns with ammonia and organic emissions issues from compost operations, composting advocates ought to be especially sensitive to improving the environmental performance of all integrated waste system programs.

EPA’s proposed regulation give communities and waste service providers the opportunity to fully develop the potential of bioreactor landfills under the strict oversight of state regulators. It allows for alternative operating and design practices at landfills but it does not authorize any relief from the environmental performance standards of the existing landfill regulations. The groundwater protection standard must be maintained, and EPA has already promulgated new regulations to enhance the air pollution controls at bioreactor landfills.

In sum, bioreactor landfill technology offers the potential for substantial environmental improvement of our integrated waste management systems without posing any risk to organics diversion programs or the evolution of waste management policy in the United States. The authors’ opposition is at best shortsighted and environmentally irresponsible.

Ed Skernolis is Director of Government Affairs for Waste Management, Inc. Gary Hater is Senior Director, Bioreactor/Biosite Technology at Waste Management, Inc.

Sidebar #2
Authors Respond To Waste Management, Inc.
Bill Sheehan and Jim McNelly

CONTRARY to the claims of Messrs. Skernolis and Hater, bioreactor landfills, as promoted by Waste Management Inc. (WMI), are not an environmentally friendly alternative for managing the organic fraction of municipal garbage. Nothing in their comments lessens the legitimate concern that bioreactors represent a threat to protecting our water supply, air quality and the future of composting and recycling. Here is our response to Waste Management’s rebuttal:

Both landfilling in bioreactors and composting have been put forward as strategies to stabilize the organic fraction of our garbage; bioreactors producing methane and inert fill material and composting producing heat, humus and organic fertilizers. If there were any hope that bioreactors were a properly designed or controlled or managed process capable of recovering anywhere close to 100 percent of the methane derived, many environmental concerns such as global warming and air pollution would be lessened. In the guise of renewable energy production, however, bioreactors with at best 50 percent recovery of methane are an inefficient and uncontrolled method of converting organic resources into valuable resources, actually increasing air pollution, furthering global warming and wasting the nutrient potential of organic material.

In the worthy goal of generating renewable energy through more uniform decomposition of mixed waste, bioreactors will add massive volumes of liquids and recirculate them. This new liquid fraction has problems of its own regarding the structural stability of bioreactors. Nothing in the WMI rebuttal addresses these concerns and the long-term liabilities associated with management of liquefied garbage. On face value, given the problems associated with bioreactors regarding air quality, inefficiencies of methane capture, and a net increase of global warming gasses, bioreactors appear to be a thinly veiled attempt to recirculate highly contaminated landfill leachate rather than pay for proper treatment and disposal.

The rebuttal fails to address our concerns about the fatal flaw in “dry tomb” technology: the elaborate barrier systems of modern landfills only delay, but do not prevent pollution. As EPA’s technical staff has repeatedly stated, any liner "will ultimately fail," and WMI’s silence essentially concedes this point. All that liners do is postpone the time when liquids will reenter the site until some time decades in the future. When liquids finally do infiltrate the cover, this moisture will reignite a second wave of leachate and gas generation from decomposition of the undegraded organic material remaining in the waste. As collection systems are long gone when this happens, most of this second wave will escape uncontrolled into the environment. Adding even more leachate to a failed leachate control technology makes no economic or environmental sense.

Research into optimal methods for managing organic fractions would be welcomed, including research into controlled methane production. But to support research that blatantly rejects the current integrated waste hierarchy, which ranks composting far above landfilling for treating organics, is unacceptable. We are not convinced that peer reviewed and controlled research is what is being proposed in the EPA deregulation initiative.

Furthermore, deliberately introducing massive volumes of liquids into a landfill in an attempt to accelerate decomposition requires increasing moisture levels from 20 percent to as much as 65 percent, according to EPA. This has significant implications for the stability of the site because, in the U.S., landfills are typically not buried in holes in the ground, but rather are manmade mountains several hundred feet high, contained behind little more than a two foot thick dirt berm and plastic tarp. One of the critical safety factors used to stabilize these manmade mountains is a limit on the steepness of the side slopes. EPA rules for “dry tomb” landfills restrict side slopes to a ratio of 3:1 (horizontal to vertical). However, several states have found from observation that 3:1 is too steep to reliably stabilize, and instead require a 4:1 side slope at “dry tomb” landfills in which, for the short to mid-term, the waste mass is in fact very dry and stable.

It would seem obvious that when a landfill’s site stability will be significantly compromised by such enormous liquid additions, the very first thing that would at least be evaluated is the need to decrease the steepness of the side slope to 4:1. After all, there is already a major body of professional engineering opinion that 4:1 slope limitations are even required in dry tomb landfills. Yet formal requests to EPA to add 4:1 side slopes to the research agenda have been rejected. How can this be reconciled with an honest research design? Reality is that shallower sidewalls mean less volume of waste overlying the same footprint. The difference equates to a 25 percent loss in the overlying air space. Essentially, the shallower sidewall ratio needed to lessen the chance of catastrophic collapse causes volume losses that make the design uneconomic.

It is useful to lay WMI’s position out on the table. On the one hand, they successfully oppose any design, no matter how essential for safety, that would increase bioreactors’ net costs. On the other hand, they turn around and claim that composting may be “nice,” but, even if it is higher on the hierarchy, it can’t compete economically with bioreactors. Their position is that lowest cost is the only viable option. Imagine what the world would be like if we took that position on every environmental issue?

That transparent sophistry is the reason why bioreactors pose the most serious threat to composting. Composters must engage themselves in the debate over bioreactors, including whether research into essential safety features may be excluded just because that might mean composting would prevail in the marketplace. Otherwise, we will relegate ourselves to another decade of patently unfair competition that cannot be won. The bottom line is that the greater the differential in tip fees made possible by ‘bioreactors on the cheap’, the larger the damage to composting and recycling, not to mention the environment.

Bill Sheehan directs the Grass Roots Recycling Network (GRRN)in Atlanta. Jim McNelly is president of Renewable Carbon Management LLC in St. Cloud, Minnesota. The authors’ complete response to Waste Management’s rebuttal can be found at www.grrn.org/WMI.