Can a Sewage-Contaminated Aquifer Naturally Clean Itself?

The answer may be yes, but it might take much longer then scientists originally guessed. USGS scientists are studying the natural restoration of an aquifer that was contaminated by 60 years of land disposal of treated sewage. Studies at the abandoned sewage-disposal facility at the Massachusetts Military Reservation on Cape Cod have shown that:

• The natural cleanup in the aquifer on Cape Cod is taking longer than USGS scientists had expected.

• Although the natural ground-water flow has flushed away some contaminants in the aquifer under the disposal area, continuing biodegradation of organic materials associated with the aquifer sediments is maintaining low oxygen levels and elevated pH.

• Some contaminants, such as phosphorus and zinc, are expected to remain at elevated levels in the sewage-contaminated zone for many years because of the persistent low oxygen levels and elevated pH.

• Geochemical models developed for the studies at the site predict that restoration to pre-contamination conditions may take many decades.

The Department of Defense is using the predictions of the long natural-cleanup time to develop plume-management strategies that protect the environment and drinking-water supplies in the Cape Cod sole source aquifer.

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• Monitoring Volatile Organic Compounds in Ground Water with Diffusion Samplers
• Hydrogen Measured in a New Test for Determining Subsurface Microbiological Activity at Contamination Sites
• New Report Presents a Framework for Assessing the Sustainability of Monitored Natural Attenuation
• What Mobilizes Arsenic in Ground Water
• Decades Required for Natural Processes to Clean Wastewater-Contaminated Ground Water
• New Information on the Long-Term Fate of Ammonium in Ground Water
• Land-Use Activities Release Naturally Occurring Arsenic
• Phosphorus Doesn't Migrate in Ground Water? Better Think Again!

More Information

• Natural Aquifer Restoration
• Sewage-Contaminated Ground Water Investigation-- Cape Cod, Massachusetts

References

• Natural restoration of a sewage plume in a sand and gravel aquifer, Cape Cod, Massachusetts, by D.R. LeBlanc, K.M. Hess, D.B. Kent, R.L. Smith, L.B. Barber, K.G. Stollenwerk, and K.W. Campo
• Evolution of a ground-water sewage plume after removal of the 60-year-long source, Cape Cod, Massachusetts--Changes in the distribution of dissolved oxygen, boron, and organic carbon, by L.B. Barber and S.H. Keefe
• Evolution of a ground-water sewage plume after removal of the 60-year-long source, Cape Cod, Massachusetts--Fate of volatile organic compounds, by K.W. Campo and K.M. Hess
• Evolution of a ground-water sewage plume after removal of the 60-year-long source, Cape Cod, Massachusetts--Inorganic nitrogen species, by R.L. Smith, B.A. Rea Kumler, T.R. Peacock, and D.N. Miller
• Evolution of a ground-water sewage plume after removal of the 60-year-long source, Cape Cod, Massachusetts--pH and the fate of phosphate and metals, by D.B. Kent and Valerie Maeder

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