Page 5 of the PAERAB's Summer 2008 TAPP Contractor Newsletter

A revised draft final remedial design for Area B was submitted to regulators on July 17, 2008. The revised design was also the topic of a meeting held in Trenton, New Jersey to review the remedial design. This meeting was reportedly held at the request of the NJDEP. The original proposed plan for the area was finalized in September 2005. This plan called for two alternatives as follows: 5B – enhanced bioremediation to address volatile organic compounds and 8 – enhanced bioremediation with

ORC to address xylenes. The proposed plan was formulated prior to the implementation of the performance-based contract between the Army and Arcadis and also before changes in cleanup levels for two of the contaminants of concern. The groundwater quality standard for xylenes went from 40 ug/L to 1,000 ug/L and that for vinyl chloride decreased from 2 ug/L to 1 ug/L. The road to a final remedial design in Area B got off to a rocky start with drilling of pre-design wells temporarily suspended due to the detection of UXO. Obstacles to the well installation were overcome and installation was finally completed in April 2008. The wells were

sampled immediately after installation. Although sampling prior to two weeks after well installation is contrary to NJDEP guidelines the NJDEP appears to have accepted the results. The army and Arcadis explain that these results were used to assist design efforts rather than to achieve legal compliance. The army and Arcadis elaborated further with the explanation that a full round of data samples was collected in accordance with all NJDEP protocols in May of 2008 and that the results were consistent. Based on those results Arcadis concluded that Alternative 5B was still appropriate but

that Alternative 8 is no longer necessary due to the increased cleanup level for xylenes and the decreases in groundwater concentrations that have occurred since 1998. Arcadis proposes three injection barriers requiring the installation of at least nine more injection wells. They propose to complete three injection events per year utilizing a number of tanker trucks to deliver the estimated 3,300 gallons of 2 percent molasses solution that will be required for