Case Study – A Solution for Site Closure

Case Study: A Solution for Site Closure

View of system design / installation by others. Monitoring Well (round manhole) in close proximity to ART remediation well. Trenching for ART system is darker asphalt. Piping for ART system is shown to the left.

A regional bank client had foreclosed on a property impacted by petroleum contamination to the soil and groundwater. Working with another consultant, a cleanup had been underway for several years when the client received a shut-down notice from the local air regulatory agency saying that permit conditions had been violated. The client wanted Nova to review existing information and either take over the cleanup, come up with a better solution to get site closure, or manage the other existing consultant.

Following review of the existing documents, Nova concluded:

• The cleanup system implemented by the original consultant is not generally given much merit within the consulting community. It is a closed-loop system that offers air sparging, soil vapor extraction, and groundwater pump and treat—all in one 4” well. 

• The original consultant had been air sparging into free product, or very close to free product. The sparging created a mound around the sparge well, which pushed free product away rather than capturing it. Therefore, while the system was working to remediate dissolved contamination, the free product, which is much more concentrated, was not being abated. 

• Another issue that Nova discovered was the consultant’s proposal for additional source removal. The source removal would have been right next to an existing building, potentially compromising that structure. Nova did not consider this a viable option. 

View of vacuum extraction knock out tank (55 gallon drum), with control panels that are wall mounted, and first of two granulated activated carbon (GAC) filters in the exhaust stream (blue container).

Since Nova started approximately eight weeks ago, copies of both groundwater and air permits have been obtained and Nova has discussed these permits with project managers at the appropriate regulatory agencies, offering new contact information. Better communication makes better projects.

Nova and its new subconsultant have reviewed all of the existing documents. We anticipate operating the soil vapor extraction portion of the system to maximize VOC removal in vadose zone and pull free product to the extraction wells. We have performed the first sampling event and are in the process of analyzing that data while working toward getting the system operational.

Of importance, we have the blessing of both regulatory agencies. Needless to say, the client is happy, and we are delighted to have been able to assist them.

Author

Mike Minett

VP – Mid-Atlantic Regional Manager

Phone: 704-258-5196 | Email: Mike.Minett@novagroupgbc.com