Case Study 4

Case Study:  Non Point Source Product Recovery via Alternative Energy Power System

General Location:  Texas Panhandle

Client Type:  Mid-Size Engineering and Environmental Consulting Firm

End User Type:  National Railway Operating Company

Climatic and Site Conditions:  Semi arid tall grass environment with few native trees,
Undeveloped field surrounded on three sides by residential development, bordered on one side by a small watershed and a rail yard.

Project Goals:  Provide a quick turnaround, low cost, limited installation effort, interim recovery system without grid power.

Project Specification:  Recover LNAPL from five extraction wells at depths between thirty and forty feet bgs. Provide equipment easily mobilized, set up, and demobilized for an initial period of 2 months to aggressively target subsurface product during the design and installation stage of a permanent multi area remediation system.

Technology Selected:  Programmable controller operated pneumatic product recovery pumps with hydrophobic oleophillic intake screens. UL listed product recovery tank with pneumatically controlled failsafe high level shutoff device and emergency vent. DC driven control system and Air supply system. Wind and solar hybrid power generation with 1200 lb battery bank. Equipment packaged on a secured and covered trailer with wind generator and solar array mounted to allow two-man configuration between mobile and operational positions.

Implementation of Technology:  Equipment was prepared for travel and mobilized to the site by a crew of three technicians. Equipment was placed for optimum use of wind and solar energy conversion. Conduit was laid out and air supply and product return were installed within the conduit. Well-head modifications were made with well security, well integrity, site safety, and functional efficiency all being factors in the well head completion. The impacted wells were gauged. The pumping rate for each well was established and a pumping frequency and duration program was written and implemented for each well.

Results:  The client’s implementation of the permanent system was unexpectedly delayed resulting in the uninterrupted operation of the Alliance interim hybrid product recovery system for a period of six months. Low levels of product flow into the well were the only limiting factor pertaining to the recovery of LNAPL. Maintenance issues were minimized by the simplicity of the system as well as the quality of components and innovative design features. Bi-weekly site visits were found to not be necessary following the first month. The frequency of visits was then reduced to once per month. Out of the average four hours spent onsite for well gauging, system data collection, and maintenance 20 minutes or less per visit was devoted to system maintenance.

Findings:  Alliance has proven that remote site LNAPL recovery can be implemented very quickly, with low operating costs, and without grid power. For sites where product removal only is the priority and power is either not available or extended periods of operation are expected, this technology is a safe and viable option.