May 1, 2008

Mr. Renaldo Crooks

California Air Resources Board

1001 I Street

Sacramento, CA 95814

Re: Early Action Measures for Landfill Gas Emissions

Dear Mr. Crooks:

Sierra Club California supports CARB’s proposed regulation on methane emissions from municipal solid waste landfills. We strongly oppose any weakening of the key components of that proposal, especially the 200 ppm standard, monitoring frequency and spacing, and reporting requirements.

We also strongly urge the Board to broaden the focus of its early action efforts directed at landfill gas. If the focus is not shifted to preventing the de facto changeover from dry to wet cell operation, the resulting massive increases in uncontrolled methane will dwarf the improvements presently contemplated.

Understanding Methane

At the outset, it is first necessary to recalibrate how critical methane reductions are to addressing climate change. In the tipping point’s short term horizon, the standard protocols for comparing methane’s warming potential to carbon dioxide grossly understate methane’s impacts.

Methane’s residence time in the atmosphere is approximately 13 years, while CO₂’s is between 50 - 200 years, typically centered on 100 years. To standardize comparisons of the several different greenhouse gases (GHG) around the most prevalent gas, carbon dioxide, a calculation is performed to make it possible to compare one to the other on an equivalent basis. It is not unlike the use of common denominators used to add complex fractions. In this manner, methane’s extremely powerful warming potential, which is also concentrated over a very short time frame, is calculated on an assumed 100 year basis to coincide with carbon dioxide’s, which results in a multiplier for methane of 23 times to express its warming impact on a CO₂ equivalent basis.

While methane’s 23 times long-term multiplier is very substantial, it hides something far more significant in the short term for tipping point considerations -- methane’s actual short term impact is diluted by pretending it is spread over 87 more years than it persists before decaying. In the brief window of time that we have to avoid irreversible climatic changes, methane’s warming potential works out to more than 100 times that of carbon dioxide.

This is why NASA’s Jim Hansen has strongly stated that, if we are to avert that point of no return, aggressive measures to reduce methane are absolutely essential, a fact compounded by the fact that fully implementing CO₂ reduction measure reductions are decades off.

Change to Methane-Enhancing Wet Cell Operation

Without any consideration of its impact on air pollution and climate change, landfill practices are rapidly shifting from Subtitle D’s traditional “dry tomb” principles, in which efforts are focused on minimizing leachate and gas generation by isolating wastes from moisture, to “wet cell” operation, in which moisture is deliberately increased to improve profitability.

It is unprecedented that at the same time as there is an urgent need to reduce methane quickly, the landfill industry is attempting to move to significantly increase both the amount of near-term gas generated from landfills as well as the fraction of methane in it. This is being done for financial reasons by increasing high Btu landfill gas, recovering airspace, reducing leachate treatment costs and shortening the time for postclosure care via major operational changes that seek to accelerate decomposition and increase methane generation.

These design and operational changes include recirculating leachate, leaving filled cells uncovered to encourage infiltration from rainfall, adding outside liquids, reconfiguring gas wells from the periphery to the core where more high Btu gas can be harvested, reducing vacuum pressures on the gas collection wells in order to not draw in oxygen from the surface and poison methanogenic microbes, and rotating off gas wells in order to give gas fields time to recharge the necessary moisture for high Btu gas to be regenerated.

Increasing the methane concentration in landfill gas and shifting the production of gas from the future to the present has extremely debilitating impacts on efforts to avoid catastrophic climate change, for some portion of that significant increase in methane generation will escape.

In dry tomb landfills, if the best systems are assumed, and, even then, only during the time that collection systems are installed and functional, then EPA assumes that 25% will be released. If, however, average systems are considered over a landfills’ entire life, then as much as 80% will escape, according to the Intergovernmental Panel on Climate Change, and, according to Region 9 EPA, 70% will escape.

Moreover, in wet cells, under saturated conditions of rapid differential settlement, and where gas collection is compromised to maximize the economics of energy recovery, it is far more likely than not that net gas collection efficiency will be degraded further. EPA states that accelerating decomposition increases gas generation by 2 to 10 times, and gas well monitoring records indicates that dry tomb landfills might have 35-40% methane concentrations and wet cells 55%-60% methane – two-thirds more.

Thus, on average there may be 10 times more methane generated in wet cell landfills than traditional ones, and the ability to capture that magnitude increase in methane is very likely to be further compromised as well. Just correcting for EPA erroneous capture rate assumptions in order to reflect typical long term conditions increases landfills’ responsibility for greenhouse gases to almost 8%. In the short term, when methane has four times the warming potential, landfills bear more than 30% responsibility – even when dry tomb principles are maintained. Wet cell practice, if not prevented, will drive landfills’ responsibility to unprecedented levels especially in the short term.

This change in practice calls out for regulatory attention. We understand that there may be some Regional Water Boards that have unilaterally discouraged leachate recirculation in some cases, but this matter is of such import, it demands being codified and standardized across the state.

Expanding Organics Diversion

In addition to preventing massive increases in near term methane releases, the next big step that the agency should take to make positive gains in reducing current greenhouse gas levels from the waste sector is to follow the lead of the European Community (EU) in keeping organics out of landfills. In 1999, the EU issued its Landfill Directive that is phasing out the burial of decomposable discards in the ground, because it concluded that organics cannot be safely managed in landfills.

If we keep organic discards out of landfills where anaerobic conditions exist, there will be no methane generated in the first instance. In California, 42 cities, led by San Francisco, are following this path; in the rest of the U.S., there are another 26 similar cities, and 42 in Canada.

The experience of Toronto – a city of 4.5 million people – demonstrates that 75% of the organic discards can be diverted through collection innovations, at minimal net costs, when the government makes a firm commitment.

In conclusion, we strongly urge the Air Resources Board to bar the door to wet cell landfill practices to prevent a dramatic increase in near term greenhouse gases, and move to the San Francisco approach of expanding organics diversion to substantially decrease existing GHG emissions from the waste sector.

Respectfully Submitted,

Bill Magavern

Director