Remediation of soil and groundwater by vacuum-enhanced recovery

A literature review and case study of Vacuum Enhanced Recovery (VER) technology, also known as bioslurping, is presented in this project paper. The literature review was conducted to investigate historic and current VER design and pilot study practices. The case study presents the field activities and results of an actual VER pilot study conducted at an operating retail petroleum facility. The results of the pilot study were used to assess the feasibility of VER technology to remediate hydrocarbon impacted soil and groundwater and to design a full scale VER system for the site.; The pilot study results indicated a high level of contaminant mass removal from the subsurface and a large zone of groundwater influence. Consequently, VER was deemed an acceptable remediation technology for the case site. The full scale system was designed to draw 8.60 am3/min (300 acfm) of air and 57 Lpm of water from the subsurface at an operating vacuum of 457 mm Hg. (18 in. Hg). The system employed a 30 hp oil-sealed liquid vacuum pump attached to eight individually plumbed extraction wells. An initial mass removal rate of 1,430 kg/day of total petroleum hydrocarbons was estimated.; VER is a relatively new subject in the field of remediation engineering. Additional research should focus on methods to limit the uncertainty in design due to site-specific heterogeneities, less onerous methods of applying numerical modeling to simulate multiphase flow in the subsurface, and additional case studies to improve pilot study protocol and VER system design.