Sandia announces completion of mixed waste landfill cover construction

Nov 03, 2009
Environmental managers Mike Mitchell and Don Schofield are on the evapotranspirative cover of the Mixed Waste Landfill. Credit: Photo by Randy Montoya

The Environmental Restoration Project at Sandia National Laboratories reports the successful construction of an alternative evapotranspirative cover at the Mixed Waste Landfill (MWL) in September. The 2.6-acre site is located in Technical Area 3 in the west-central part of Kirtland Air Force Base.

The protective cover consists of four engineered layers, including three layers of compacted soil and a biointrusion rock barrier that will keep burrowing animals out of the former disposal areas. Together, these four layers and the native plants will control water infiltration, thus isolating the wastes from the accessible environment. Because the cover is constructed without rigid layers, it can accommodate differential subsidence without undue impairment of its performance.

The MWL was established in 1959 as a disposal area for low-level radioactive waste generated by Sandia's research facilities. Low-level radioactive waste and minor amounts of hazardous waste were disposed in the MWL from 1959 through 1988. Approximately 100,000 cubic feet of waste containing about 6,300 curies of activity (in 1989) were disposed of in the landfill. Over time, the in the landfill decay and become less hazardous.

The MWL has been monitored since 1969 and actively studied since 1991. An extensive investigation effort provided the technical foundation for the determination that the landfill is not expected to contaminate groundwater and does not represent an unacceptable risk to human health and the environment. After the extensive investigation, public meetings and a public hearing, the New Mexico Environment Department (NMED) Secretary issued the final order in 2005 selecting an evapotranspirative cover with a biointrusion rock barrier as the selected remedy. After a review of competitive bids, Sandia awarded the construction contract to a local, small business. Cover construction was completed on schedule, near budget and without any safety incidents.

Environmental managers Mike Mitchell and Don Schofield check on the establishment of the new vegetation on the MWL cover. Credit: Randy Montoya

The NMED regulates the corrective action of the MWL as well as the implementation of institutional controls and long-term monitoring and maintenance. Sandia and DOE continue to provide quarterly progress reports to the NMED. In addition, the final order requires compilation of a report that re-evaluates the feasibility of excavation and analyzes the continued effectiveness of the selected remedy every five years. Construction of the MWL alternative cover will be documented in the Corrective Measures Implementation Report which will be submitted to the NMED for approval.

According to NNSA Sandia Site Office Federal Project Director Joe Estrada, "If it had not been for the personal perseverance of the project team, this mission would have withered. Now that the remedy is in place the team is looking forward to sharing lessons learned from the project."

The implementation of the selected remedy at the MWL is a critical step forward for the site. More than a decade of work and many personnel contributed to the success of the project. Although the cover is now constructed, monitoring work continues at the MWL. "The groundwater, soil gas and the cover will be monitored long-term to ensure performance and the protection of human health and the environment," said ER project task leader Mike Mitchell.

Source: Sandia National Laboratories (news : web)

Explore further: Weird weather lingers in Alaska's largest city

add to favorites email to friend print save as pdf

Related Stories

Landfill cover soil methane oxidation underestimated

Apr 27, 2009

Landfilled waste decomposes in the absence of oxygen and results in the production of methane. Landfills are classified as the second-largest human-made source of CH4 in the U.S. Additionally, landfill gas contains numerous ...

Why GNEP can't jump to the future

Apr 23, 2007

Congress is now considering whether to approve or zero out the $405 million that President Bush is proposing to spend in fiscal year 2008 on the Global Nuclear Energy Partnership (GNEP)—a program aimed at rendering plutonium ...

Recommended for you

New challenges for ocean acidification research

7 hours ago

Over the past decade, ocean acidification has received growing recognition not only in the scientific area. Decision-makers, stakeholders, and the general public are becoming increasingly aware of "the other carbon dioxide ...

Compromises lead to climate change deal

7 hours ago

Earlier this month, delegates from the various states that make up the UN met in Lima, Peru, to agree on a framework for the Climate Change Conference that is scheduled to take place in Paris next year. For ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.