Baseline Risk Assessment
A baseline risk assessment is an assessment conducted before cleanup activities begin at a site to identify and evaluate the threat to human health and the environment. After remediation has been completed, the information obtained during a baseline risk assessment can be used to determine whether the cleanup levels were reached.
Biopile is an aerated static pile composting process in which soil is mixed with amendments on a treatment area that includes leachate collection systems and aeration with blowers or vacuum pumps. It is used to reduce concentrations of petroleum constituents through the use of biodegradation. Moisture, heat, nutrients, oxygen, and pH can be controlled to enhance biodegradation.
Bioreactors use microorganisms in attached or suspended biological systems to degrade contaminants in water. In suspended biological systems, such as activated sludge, fluidized beds, or sequencing batch reactors, contaminated water is circulated in an aeration basin where microbes aerobically degrade organic matter and produce carbon dioxide, water, and biomass. In attached systems, such as rotating biological contactors and trickling filters, a microbial population is established on an inert support matrix. The cells form a sludge, which is settled out in a clarifier and is recycled to the aeration basin and disposed of.
Bioremediation refers to treatment processes that use microorganisms such as bacteria, yeast, or fungi to break down hazardous substances into less toxic or nontoxic substances. Bioremediation can be used to clean up contaminated soil and water. In situ bioremediation treats contaminated soil or groundwater in the location in which it is found. For ex situ bioremediation processes, contaminated soil is excavated or groundwater is pumped to the surface before they can be treated.
A biosensor is a portable device that uses living organisms, such as microbes, or parts and products of living organisms, such as enzymes, tissues, and anitbodies, to produce reactions to specific chemical contaminants.
Bioslurping is the adaptation of vacuum-enhanced dewatering technologies to remediate hydrocarbon-contaminated sites. Bioslurping combines elements of both bioventing and free-product recovery to simultaneously recover free product and bioremediate soils in the vadose zone. Bioventing stimulates the aerobic bioremediation of hydrocarbon-contaminated soils and vacuum-enhanced free-product recovery extracts light nonaqueous phase liquids (LNAPL) from the capillary fringe and the water table.
Bioventing is an in situ remediation technology that stimulates the natural biodegradation of aerobically degradable compounds in soil by the injection of oxygen into the subsurface. Bioventing has been used to remediate releases of petroleum products, such as gasoline, jet fuels, kerosene, and diesel fuel.
Brownfields sites are abandoned, idled, or under-used industrial and commercial facilities where expansion or redevelopment is complicated by real or perceived environmental contamination.