Conventional and emerging technologies perpetuate the status quo of discarding organic materials with mixed waste and fail to address the potential to eliminate greenhouse gas emissions from biodegradable discards. Landfills are the number one source of human-derived methane in the US, and also contain hazardous air pollutants and volatile organic compounds that can adversely affect public health and the environment. Landfill gas capture systems are not as efficient as claimed, and the contribution of landfill gas to climate change may be dangerously understated. Bioreactors are an emerging landfill technology that generates methane much earlier and at a much higher rate than traditional landfills. These methodologies are “not COOL”, so they’re not endorsed by the Zero Waste International Alliance.
Several conventional and emerging technologies perpetuate the status quo of discarding organic materials with mixed waste and fail to address the potential to nearly eliminate the greenhouse gas emissions from biodegradable discards by keeping them out of landfills and incinerators. All of the practices and technologies below also neglect the potential to use organic materials to produce much-needed soil amendments. Applying compost products to soil decreases fertilizer and pesticide use, improves soil structure, reduces irrigation needs, decreases the effects of high salinity, increases soil productivity, limits erosion, and helps store carbon in our soils. Long-term soil health and sustainable agriculture are essential to the health of our environment and economy, and we must develop and support organics recovery infrastructure to meet these goals.
Modern landfills isolate our discards from water and air, and in particular, oxygen. This creates an anaerobic (oxygen-depleted) environment ideal for the proliferation of methanogenic bacteria. As these bacteria break down the organic (biodegradable) materials, the bacteria in turn release methane gas, a greenhouse gas 72 times more powerful than carbon dioxide over a 20 year period. Landfills are the number one source of human-derived methane in the U.S., more than livestock emissions and wastewater treatment facilities.
Landfill gas also includes hazardous air pollutants and volatile organic compounds, including known carcinogens. According to the U.S. EPA, “landfill gas contains carbon dioxide, methane, [volatile organic compounds] VOC, [hazardous air pollutants] HAP, and odorous compounds that can adversely affect public health and the environment…exposure to HAP can cause a variety of health problems such as cancerous illnesses, respiratory irritation, and central nervous system damage.” When landfill operators capture landfill gas and either burn it off or use it for energy, human health and environmental concerns from the gas are reduced. However, the removal of organic materials from the landfill would dramatically decrease gas production, taking a major step toward protecting public health.
Organic materials in the landfill also lead to the production of leachate. The liquids produced from the biodegradation of these organic materials seep through the landfill and, along the way, collect toxic chemicals and heavy metals from the other contents of the landfill. This leachate migrates to the bottom of the landfill and eventually leak through the liner, potentially contaminating local groundwater. By removing organics from the landfill, a community can minimize the production and migration of leachate, therefore protecting its groundwater and potentially saving itself tens of millions of dollars in groundwater remediation and hazardous waste cleanup.
A community committed to source separating organics for composting will greatly reduce or eliminate its landfill’s generation of methane over the future life of the landfill. Landfills that produce energy from waste depend upon organic materials to generate the methane, and then convert the methane into energy. If no methane is generated, there is no energy to produce. Future landfill gas projects and gas volumes are therefore threatened by the removal of organic material from the landfill, and a landfill invested in gas recovery retains a financial interest in maintaining the status quo of landfilling compostable materials. Relying upon landfills for “renewable energy” stands in direct opposition to the recovery of organics for composting, which is recognized universally as a higher use of resources on the waste hierarchy, and which promotes a community benefit by returning valuable nutrients back to our soils.
Landfill gas capture systems are not the efficient collection mechanisms peddled by the industry. This means the contribution of landfill gas to climate change may be dangerously understated. First, the incredible heterogeneity of municipal waste and the wide variety of geographic conditions at landfills across the country are the primary factors preventing the use of a default calculation model for landfill gas production. However, it is the collection efficiency of landfill gas systems that may be the greatest source of discrepancy. The U.S. EPA assumes 75% gas collection efficiency in its calculations, but measured efficiencies have been reported as low as 9 percent. The 2006 Intergovernmental Panel on Climate Change (IPCC) report on greenhouse gas inventories suggests a default estimate of recovery efficiency of 20 percent. The IPCC cites studies measuring collection efficiencies ranging from 9-90 percent, representative of the many uncertainties involving modeling gas generation and collection efficiency.
The landfill industry itself attests methane emissions are not accurately tabulated: “Waste Management has determined that it is infeasible to make reliable measurements of methane emissions at the 243 landfills it operates…and the extraordinary diversity among landfills has made it impossible to develop a useful, broadly-applicable model of fugitive emissions.”
Bioreactors are an emerging landfill technology that seeks to accelerate the decomposition of waste by circulating liquid (leachate or water) and frequently air (oxygen) throughout the landfill. In theory, the forced decomposition produces methane emissions along a shorter time frame, stabilizes the waste, and increases landfill capacity. Most bioreactors attempt to optimize methane production so as to recover the gas for energy. This means a bioreactor will produce methane much earlier in the landfill’s life and will generate methane at a much higher rate than traditional dry tomb landfills. In fact, the industry actually promotes the increased methane production as a step forward. Estimates of the collection efficiency of landfill gas systems differ widely among experts and models, and due to heterogeneity of the waste mass, there may be no clear model of landfill gas production and capture.
On top of increased gas generation, several other concerns surround bioreactor technology. Most notably are the physical instability of landfills and the instability of (and stress upon) liner systems meant to prevent leachate seepage, both due to the additional weight and momentum of the increased moisture content. More than a dozen bioreactor landfills currently operate in the U.S. as pilot projects to evaluate the economic, environmental and engineering feasibility of this technology. Learn more on the flaws of bioreactors and the risks to deregulating landfills. Since bioreactors demand higher capital costs and more diligent monitoring, securing renewable energy tax credits are a must for the industry to justify the increased operating and construction costs. Learn more on why landfills and incinerators are inefficient sources of renewable energy
Burning our discards releases harmful pollutants into the air, recovers only a fraction of the energy used during the products’ life cycle, and perpetuates the cycle of destroying natural resources to make new products. Incinerators produce dioxins, heavy metals such as mercury and lead, particulate matter, and hundreds of other byproducts, only a handful of which have been identified or studied. When air pollution controls are installed to capture these hazardous substances, the materials are just transferred from the air emissions to the fly ash and the scrubber residues, simply moving the hazardous waste problem from one medium to another without addressing the pollution generation.
A 2008 lifecycle analysis performed for the City of London on the greenhouse gas emissions of varying waste management strategies concluded, “The incineration scenarios modelled were amongst the worst performing on greenhouse gas emissions, with all but one of the scenarios being a net contributor to climate change.” A 2006 report by Eunomia Research and Consulting (UK) found greenhouse gas emissions from incinerators were actually higher than those from conventional gas-fired power plants. In U.S. EPA life cycle assessments from 2006, recycling was shown to provide greater net energy and greenhouse reductions than incineration across a wide range of materials, including biodegradable materials such as corrugated cardboard, magazines/third class mail, newspaper, office paper, phonebooks, textbooks, dimensional lumber, and medium-density fiberboard.
Because incineration destroys materials, more resources must be continually extracted and manufactured to provide new materials. While incineration may replace power produced from fossil fuels, it also burns the fossil fuels embodied in the discarded products-fuel used to grow or extract, manufacture, transport, and consume these products. Furthermore, the non-biodegradable portion of the waste stream is primarily derived from fossil fuels, a non-renewable energy source, so burning these materials cannot be considered “green energy.” Subsidizing incineration as “green energy” will only ensure more materials are sent to incinerators for destruction, contrary to the goals of sustainable resource management. Learn more about the false claims of waste to energy.
Cellulosic ethanol offers incredible potential for replacing petroleum use in the transportation sector and reducing greenhouse gas emissions through sustainably harvested feedstocks. In the push to find cost-effective, environmental alternatives to fossil fuels, a number of potential feedstocks have been suggested, including municipal solid waste. Other technologies propose creating syngas, typically a combination of carbon monoxide, hydrogen and methane, which can be used to produce heat or electricity. These technologies do not exist beyond demonstration levels and therefore there is little performance data to support assumptions based on their performance efficiency, pollution levels and waste byproducts.
In a 2004 review of thermal treatment of MSW in the UK, Fitchner concluded, “In terms of energy efficiency of standalone plants when optimized for power generation, existing gasification and pyrolysis technologies are less efficient than modern combustion technology. Standalone power generation plants, using gasification or pyrolysis technology to supply fuel gas to a combined cycle gas turbine for power generation, may ultimately achieve higher energy efficiencies than combustion technology using a simple steam turbine. However, this application has yet to be successfully demonstrated anywhere in the world and ensuring that such applications comply with WID [Waste Incineration Directive] is a significant obstacle to their development.”
Tax breaks or renewable energy credits (REC) for landfills and incinerators create an incentive to continue the burying and burning of valuable organic resources and directly oppose the goals of long-term soil health and sustainable agriculture. Read more on why garbage is not renewable energy.
Recycling paper reduces GHG emissions in several ways:
- Manufacturing paper from recycled paper eliminates the need to cut down trees which saves the energy, waste and GHG emissions associated with harvesting, transporting and processing the lumber. Every ton of 100% post-consumer recycled content copy paper saves 3 tons of wood, the equivalent of 24 trees.
- Manufacturing with recycled paper uses less energy than manufacturing with virgin paper, reducing our consumption of fossil fuels and avoiding GHG emissions. Every ton of 100% post-consumer recycled content copy paper saves 17 million BTUs and 2108 lbs. of CO2.
- The trees left standing continue to act as a carbon sink, pulling carbon dioxide out of the atmosphere for respiration and transpiring oxygen in return.
- Lastly, paper products discarded in the landfill release methane when decomposing, a final potent contribution to climate change.
Paper recycling is full of other environmental benefits as well: It saves water, produces fewer toxic releases, reduces the use of chlorine bleach, and reduces the demand upon our forests which support wildlife habitat and biodiversity, soil stabilization, water filtration, climate balance and several other incredibly valuable ecosystem functions. Every ton of 100% post-consumer recycled content copy paper saves 1,124 lbs. of solid waste and 8,750 gallons of water.