Using an Environmental Footprint Analysis To Evaluate the Sustainability of Remedial Alternatives

摘要

Traditional feasibility studies for remediation projects consider factors including cost, implementation risks, reliability and environmental protection. However, traditional studies do not address corporate and stakeholder desires for more sustainable business practices. Approaches are needed to compare the overall environmental footprint of alternatives. This study is a case history evaluating a recently completed remediation project at a former waste oil recycling facility in southeast Texas. The former Force Road Oil and Vacuum Truck Company facility recycled waste oil with a process that incorporated five unlined ponds, with associated above-ground storage tanks (ASTs) and underground storage tanks (USTs). The ponds contained hydrocarbon sludges and affected sediment. In addition, groundwater at the site was affected with benzene and chlorinated hydrocarbons. The facility was assessed and remediated under the Texas Commission on Environmental Quality’s (TCEQ) Texas Risk Reduction Program (TRRP) rules. The remediation of the site included stabilization and on-site containment of pond sludges and sediment, phytoremediation and monitored natural attenuation of groundwater, and ecological restoration/enhancement of the property. The evaluation used the approach provided in the Environmental Protection Agency’s (EPA) guidance document, Methodology for Understanding and Reducing a Project’s Environmental Footprint (EPA 542-R-002), February 2012. Two remedial approaches were considered; a “base case” consisting of off-site disposal of affected materials and hydraulic containment of groundwater using conventional pump and treat technology and the implemented approach of on-site containment of affected materials, phytoremediation and monitored natural attenuation. The evaluation developed metrics for (1) materials and waste, (2) water, (3) energy, and (4) air. Several aspects of the remediation approach had significant environmental footprint benefits as compared to the base case. On-site disposal of waste materials reduced the impacts for energy and air, as did the use of on-site materials for a clay and topsoil cover. Green construction practices were implemented, including the use of biofuels, recycling and carpooling. Additional property adjacent to the former recycling facility was acquired to facilitate the groundwater response using phytoremediation and monitored natural attenuation. The ecological value of the property was enhanced by restoring native grasses, wetlands and hardwoods. The largest process pond was remediated, then deepened to provide aquatic habitat. This property will become valuable habitat for birds and mammals as residential development increases in the area. This case history provides examples of how the environmental footprint approach can be applied to specific projects. The approach provides a basis for quantifying the sustainability of alternatives, and allows for more refined allocation of resources to achieve corporate and stakeholder sustainability goals.