US Army Corps of Engineers
Far East District U.S. Army Corps of Engineers Website Website

FED builds environmentally-friendly contaminated soil treatment facilities

Published Nov. 29, 2012
A nearly complete Biopile build-up at K-16 Airfield.  A biopile system uses naturally occurring, living organisms such as plants, bacteria, or fungi to break down hazardous substances. The basic biopile system includes a treatment bed, an aeration system, an irrigation/nutrient system and a leachate collection system.

A nearly complete Biopile build-up at K-16 Airfield. A biopile system uses naturally occurring, living organisms such as plants, bacteria, or fungi to break down hazardous substances. The basic biopile system includes a treatment bed, an aeration system, an irrigation/nutrient system and a leachate collection system.

In September 2011, the Far East District’s Geotechnical and Environmental Engineering Branch, Environmental Section, awarded an environmental services contract to Beautiful Environmental Construction Co., Ltd. to construct permanent two-celled biopile systems at both K-16 Air Base and U.S. Army Garrison Yongsan.

A biopile system uses naturally occurring, living organisms such as plants, bacteria, or fungi to break down hazardous substances. The basic biopile system includes a treatment bed, an aeration system, an irrigation/nutrient system and a leachate collection system.

Within one year, construction of both biopile systems was complete. To kick off the post-construction operations phase, FED Environmental conducted an Operations Instruction and Demonstration event at the K-16 Airfield Nov. 29.

The instruction and demonstration event fulfilled a portion of the requirements of the inter-governmental agency contract between the Yongsan Department of Public Works Environmental Division and the FED Environmental Section to “Provide on-site instruction and monitoring and operations manuals.”

Though biopile systems were constructed at both USAG Yongsan and K-16, the on-site instruction and demonstration was conducted only at K-16 since it was the only site with a significant quantity of contaminated soil awaiting treatment at the completion of construction of both biopile systems. FED staff who participated in the event was Sarah Woo, supervisory oversight; Mark White, project manager and contracting officer’s representative; Dr. Chon, Song U, Technical Lead; and Dr. Craig Hunter, Technical Support.

The biopile systems designed for this project each consist of: 1) an impermeable base to reduce the potential migration of leachate (a liquid containing soluble material removed from the contaminated soil through which water has passed) from the pile; 2) perforated, flexible, drainage piping installed above the base and connected to a blower/vacuum to induce air flow through a soil pile constructed over the piping; 3) a cover to prevent the effects of uncontrolled hydration (by precipitation) and wind erosion; 4) in-pile monitoring equipment; 5) an off-gas treatment system; and 6) a separate leachate collection sump. A drainage pipeline was added to the USAG Yongsan system so that excess storm water run-off flows from the biopile structure can be carried to a pre-existing, on-site oil and water separator.

The primary purpose of the demonstration was to ensure that the customer, USAG Yongsan DPW Environmental, received sufficient instruction to properly and efficiently operate the biopile systems after final transfer of the treatment structures into their possession.

 Additional members of the project delivery team that were present for the instruction and demonstration were Yi Yong Hun, USAG Yongsan DPW Project Manager, Chon Song Sam, K-16 Air Base DPW Program Manager; Han Sun Hyang, researcher (Hankook University of Foreign Studies); Yoon Sang Dae, BEC Project Manager; Lee Gyo Taek, BEC Technical Support; and supporting sub-contract laborers. Han was brought on board the project by USAG Yongsan DPW to perform treatment monitoring and to study biopile system performance for the purpose of discovering contamination-specific methods of enhancing treatment.

By the close of business Nov. 29, the first biopile had been built and covered atop one of the two cells for the commencement of treatment for the removal of elevated total petroleum hydrocarbon-diesel range organics.

Some natural biological treatment processes will begin right away, however, optimized treatment of various types of contaminated soil will commence in April 2013; the start time preferred by USAG Yongsan DPW Environmental. Among the project deliverables, FED provided the customer with a user’s manual for guidance on how best to control biopile system features from the accompanying electronic control room, and an operations manual for instruction to users on how to best manage biopile treatment and monitoring processes for various types of contamination.

FED congratulates the Environmental Division of USAG Yongsan DPW on becoming U.S. Government stewards of two of the most advanced biopile systems in the Republic of Korea.