ESTIMATING VOLATILE AIR EMISSIONS & ODORS AND ASSESSING AMBIENT AIR IMPACTS FROM A LARGE-SCALE ENVIRONMENTAL DREDGING PROJECT

Attention to the potential effects of volatile emissions from dredging contaminated sediment on ambient air quality has increased in recent years with the promulgation of EPA's list of Hazardous Air Pollutants and establishment of related state guidelines or standards. Exceeding very low concentrations (sometimes 50,000 times lower than allowable OSHA limits) in the surrounding community is sometimes a basis for shutting down expensive remediation operations. This has led to a need to accurately assess what it takes to meet these standards before full scale remediation, during risk assessments, feasibility studies and design. A regulatory agency in the northeastern United States has selected a remedy with dredging of more than two million cubic meters (>2.6 million cy) of contaminated sediment from a fresh water lake located the area. The impacted sediment will be placed in a confined disposal facility (CDF) located in near the lake. The potential for emission and odor release resulting from the remedial activities is being studied as part of a multi-phased pre-design investigation. The scope of the air and odor investigation includes: measuring emission rates and odors from dredging and placement operations, modeling the dispersion of the emissions and odors into the atmosphere, assessing the overall impacts to potential receptor areas, evaluating available mitigation technologies that may be incorporated into the design, and developing a plan that mitigates potential impacts to the surrounding community as necessary. This paper describes the first phase of the process.