Environmental Waste Management

Issues surrounding the quality of our environment are big issues that call for big solutions. At WM, merely complying with laws and regulations designed to stop environmentally damaging practices is not enough. WM invests time and resources in the development of innovative ideas that stop, and possibly help reverse, environmental damaging practices. Here is a sampling of just a few of Waste Management's Innovative Environmental Projects. Contact our Environmental team to learn more.

Alternative Cover Systems

In recent years alternate caps or ACAPs (i.e., all-soil caps) have become increasingly acceptable in lieu of prescriptive membrane caps on a hydraulic equivalency basis. WM has pursued permitting and construction of these caps and has completed several successful projects across the county. There is potential to develop caps on a basis other than equivalency and for broader use of alternate caps in our industry. There is also great potential to use soil caps as a means to attenuate odors and landfill gas emissions.

Alternate caps, in general, offer both short-term and long-term benefits over traditional membrane caps. The short-term benefits include first and foremost reduced unit capping materials and construction costs. These cost reductions can range from 20% to 80% on a unit basis. The long-term benefits include reduced maintenance costs, a cap capable of reducing odors and attenuating landfill gas emissions which may lead to reduced long-term care costs of these systems.

WM has an opportunity to pursue approvals in a variety of climates and thus pave the way for this technology to be increasingly mainstream in the near future.

Measuring and Improving Landfill Greenhouse Gas Performance

WM has undertaken a study to measure methane emissions from a number of its landfills using state-of-the-art measurement techniques. The purpose of the study is to gather data on the amount of methane emitted from landfills with different operational and climatic features. As part of the study, WM is working with the USEPA to develop the use of a tunable diode laser (TDL) emissions measurement tool for use at landfills. This work is part of the cooperative research and development agreement (CRADA) between WM and USEPA on bioreactor landfill technology.

Surface methane emissions from the landfill are measured using the TDL system as well as traditional static chamber techniques at WM landfills across the U.S. Additionally, the amount of methane that is oxidized by soil bacteria present in the soil covering the landfill is also being quantified by using stable isotope techniques. The data that is gathered is being used to develop models by researchers at Florida State University to predict methane emissions and methane oxidation at landfills, which will ultimately lead to design and operational practices that will minimize methane emissions.

Understanding the Carbon Balance of Landfilling

Landfills are a known source of methane and other greenhouse gas emissions, but did you know they also store significant amounts of carbon? This storage, or “sequestration, ” is important because it removes carbon from the natural carbon cycle indefinitely, reducing net emissions of greenhouse gases. Carbon is naturally removed from the atmosphere and stored in forests (and then in harvested wood products, e.g., paper, lumber, furniture), yard trimmings, and food scraps via photosynthesis. Once these materials are disposed of in a landfill, only a portion of them will decompose, while a portion will remain stored in the landfill indefinitely. Decomposition of the waste creates landfill gas, which is primarily composed of methane and carbon dioxide, as well as small amounts of volatile organic compounds. The proportion of the solid waste in landfills that decomposes depends on the type of waste, the amount of moisture, and other factors that affect the growth of microbes that break down the waste, and whether the landfill is operated to retard or enhance waste decomposition. The landfilling of harvested wood products, yard trimmings, and food scraps stores a significant amount of carbon that would otherwise decompose and release carbon to the atmosphere. Thus landfill carbon storage should be accounted for in greenhouse gas inventories. The Intergovernmental Panel on Climate Change recommends doing so and the EPA follows that recommendation in preparing the annual U.S. national greenhouse gas inventory by accounting for carbon storage associated with disposal of harvested wood products, yard trimmings, and food scraps in landfills. For the sake of transparency, comparability, consistency, and completeness, we believe that all state inventories should do the same.

Measuring Our Carbon Footprint

WM recently established a Carbon Footprint Team to collect data and establish the information management processes for conducting a company-wide inventory of our direct and indirect (from electricity use) greenhouse gas (GHG) emissions. Our goal is to inventory 2009 emissions for public reporting in 2010 and annually thereafter. WM has already taken important steps in developing our carbon footprint. As a member of the California Climate Action Registry (CCAR), WM committed to inventorying and reporting our GHG emissions for all our California-based operations. We submitted our calendar year 2006 carbon dioxide (CO2) emissions inventory of California operations to the CCAR in 2007 for certification and have committed to reporting our California emissions of all six GHGs to the CCAR in 2009.