This paper describes the test results of a demonstration study on the use of vitrified soils as highway construction aggregates. It is based on a bench- and pilot-scale feasibility study of the remediation of chromium-contaminated soil through cold top ex situ vitrification, making glass from wastes. Based on bench-scale tests, approximately six tons of chromium-contaminated soil from two different sites were vitrified. To determine the suitability as construction aggregate, vitrified soils were subjected to several tests. The bench- and pilot-scale test results were compared with New Jersey Department of Transportation (NJDOT) and ASTM specifications for construction aggregates. The results showed that the vitrified soils could be accepted as an aggregate material. Then the vitrified chromium-contaminated soils were used as aggregate in hot mix asphalt (HMA). Mix designs were performed to determine the maximum amount of vitrified chromium-contaminated soils that can be added to make satisfactory hot mix asphalt concrete mixes. The test showed that it is possible to include up to 58.8% of vitrified chromium-contaminated soils from both sites in HMA mixes. In order to evaluate the performance of HMA made with vitrified chromium-contaminated soils, the Marshall test, the durability test, and the hydraulic conductivity test were performed. The hot mix asphalt concrete mixes made with vitrified soil performed very well, suggesting the suitability of using vitrified chromium-contaminated soils in construction.

The potential presence of indoor air pollutants in fire damaged buildings, stemming primarily from fire soot deposits, raises major concerns in relation to potential long-term health impacts on building occupants. Litigation claims often occur as a result of perceived ineffective remedial activities and the potential hazards of indoor air quality after the remediation is completed. This paper describes environmental remediation activities at an office building in the China Basin district of the city of San Francisco following a fire accident at a nearby wharf, which severely damaged the building. Based on an air quality sampling and chemical analysis program, a health-based hazard assessment was conducted to evaluate the health effects of indoor air quality on building occupants. The hazard assessment consisted of identification of indoor air pollutants and exposure pathways, and the quantification of exposure. The results of the exposure assessment are combined with chemical-specific toxicity information to characterize the potential health hazards at fire damaged buildings.

This research involved the synthesizing of a reactive polymer, long alkyl quaternized poly(4-vinylpyridine) (PVP), and coating it onto the surface of silica gel to produce a granular sorbent to remove Cr(VI) from water. Batch experiments were conducted to determine the kinetics, sorption isotherm, pH effects, and desorption of the sorbed Cr(VI). The research demonstrated that the synthesized PVP-coated silica gel (referred to as coated gel) could successfully remove chromium(VI) from solution. The adsorption of Cr(VI) by the coated gel was strongly influenced by the pH. The maximum sorption occurred at about pH 4.5–5.5 under the test conditions. The removal efficiency was 100% when the initial Cr(VI) concentration was 2.5 mg/L, with 2.5 g/L of coated gel at pH 5.0. The concentrations of Cr(VI) had a pronounced effect on the rate of sorption. Compared with ion exchange, the sorption kinetics of Cr(VI) was fast (about 5 h). The equilibrium sorption data fitted the Langmuir isotherm model. Chromium adsorbed on the coated gel was easily recovered under certain conditions. A continuation of this work dealing with the effects of concentration of Cr(VI) and of other anions on the Cr(VI) removal by PVP-coated silica gel will be published in a subsequent issue.

A small fraction of the solid waste generated during the demolition of buildings contains chemicals hazardous to human health and the environment. Examples include mercury-bearing fluorescent and high-intensity discharge lamps, polychlorinated-biphenyl-containing lighting ballasts, lead-acid and nickel-cadmium batteries, and lead roof flashings. While these components represent a small mass of the total demolition waste stream, they are very concentrated sources of hazardous chemicals and may present a risk to human health and the environment upon disposal or recycling. A study was conducted to evaluate the policy alternatives for ensuring removal of hazardous building components from structures prior to demolition. The parties involved include demolition contractors, those contracting demolition work, environmental regulators, building code officials, and demolition debris facility operators. Prohibition of disposal of hazardous building components in landfills is probably insufficient to ensure removal prior to demolition. A system where the property owner and the demolition contractor have some degree of accountability is needed. Efforts to address this issue are currently underway in two states, Florida and Minnesota, and are cited as examples.

In this study, the relationship between the release characteristics of contaminants from soil and the biodegradability of the contaminants was evaluated. The soils used were from a large-scale field site. A batch rate of release procedure was used to quantify the release of polynuclear aromatic hydrocarbons (PAHs) from manufactured gas plant site soils before and during bioremediation in a field land treatment unit (LTU). This evaluation assessed the performance of the field-scale LTU with respect to changes in the soil PAH concentrations and to changes in chemical release parameters. The practical implications of the evaluation are discussed. During 147 days of LTU operations, the concentrations of specific PAHs were reduced 39–93%. ROR studies were conducted on LTU soil samples obtained at Days 0, 58, 72, and 147 of treatment. As a result of 147 days of treatment in the LTU, the fraction of a PAH released rapidly (F) had decreased for 8 of 10 PAHs, and the value of k₂ (the first-order rate constant describing slow release) had decreased for 5 of 10 PAHs. There were no increases in F or k₂ for any of the PAHs as a result of treatment in the field LTU. The results indicated that (1) only a fraction of the total concentration of the individual PAHs in the LTU samples was readily available to be released from the soil; (2) the remainder was released at a much slower rate; and (3) the mass of PAH released from the LTU soils to the aqueous phase decreased considerably. In addition, the fraction of the chemical released rapidly (F) for the Day 0 soil sample provided a reasonable prediction of the extent of PAH loss during 147 days of biological treatment in the field LTU.