Across the United States, thousands of hazardous waste sites are contaminated with chemicals that prevent the underlying groundwater from meeting drinking water standards. These include Superfund sites and other facilities that handle and dispose of hazardous waste, active and inactive dry cleaners, and leaking underground storage tanks; many are at federal facilities such as military installations. While many sites have been closed over the past 30 years through cleanup programs run by the U.S. Department of Defense, the U.S. EPA, and other state and federal agencies, the remaining caseload is much more difficult to address because the nature of the contamination and subsurface conditions make it difficult to achieve drinking water standards in the affected groundwater. Alternatives for Managing the Nation's Complex Contaminated Groundwater Sites estimates that at least 126,000 sites across the U.S. still have contaminated groundwater, and their closure is expected to cost at least $110 billion to $127 billion. About 10 percent of these sites are considered "complex," meaning restoration is unlikely to be achieved in the next 50 to 100 years due to technological limitations. At sites where contaminant concentrations have plateaued at levels above cleanup goals despite active efforts, the report recommends evaluating whether the sites should transition to long-term management, where risks would be monitored and harmful exposures prevented, but at reduced costs.

This manual provides practical guidance for the design and operation of soil vapor extraction (SVE) and bioventing (BV) systems. It is intended for use by engineers, geologists, hydrogeologists, and soil scientists, chemists, project managers, and others who possess a technical education and some design experience but only the broadest familiarity with SVE or BV systems.

This book provides environmental managers and their supporting technical specialists with a comprehensive strategy for cost-effectively cleaning up soils and groundwater contaminated by petroleum releases. It includes the most recent advances in site investigation techniques, low-cost remedial approaches, and technologies. It uses a "risk-based" process to answer key questions involved in developing a remediation or closure plan for a petroleum spill site. Several approaches are described that include risk management methods which use institutional controls to isolate contaminants from human contact and long-term monitoring to verify that natural attenuation is reducing future risk. More traditional risk evaluations and simplified RBCA methods are also presented that use site-specific exposure assumptions to develop risk-based cleanup objectives. Case studies illustrate how various combinations of land-use control, site-specific risk analysis, natural attenuation, and focused source reduction technologies have been used to obtain risk-based closures at sites across the United States.