Engineered Horizontal Remediation Wells Achieve Hydraulic Control of Capped RCRA Hazardous Waste Landfill

Engineered Horizontal Remediation Wells were successfully designed and installed by Directional Technologies to achieve hydraulic control of a capped Resource Conservation and Recovery Act (RCRA) hazardous waste landfill.

Introduction

A closed RCRA landfill containing residues from the manufacture of organic chemical products is capped with a synthetic geomembrane that cannot be penetrated. However, post-closure monitoring activities revealed a developing hydraulic imbalance within the capped landfill that required corrective action.

Directional Technologies was contacted by an environmental engineering firm to review plans and inspect the capped RCRA landfill in order to develop and design a hydraulic balancing plan using engineered horizontal remediation wells.

Technical challenges:

• Horizontal remediation wells had to be long – on the order of 700 feet – to accommodate the capped landfill’s footprint;
• Landfilled residues were chemically aggressive, limiting choices for horizontal well/screen material selection;
• Landfilled residue depth would create significant mechanical loads on the horizontal wells, further limiting material selection;
• Submersible pumps were to be installed in the horizontal wells, requiring 10-inch diameter riser well material. This presented a significant engineering design challenge due to the need for an achievable bend radius for the 700-foot long horizontal well.

Engineered Horizontal Remediation Wells 

DTI designed two 700-foot long horizontal remediation wells of stainless steel employing a multi-diameter design (10-inch, 6-inch, and 4-inch). Stainless steel was selected to withstand the chemically aggressive environmental and significant mechanical forces. The multi-diameter configuration was used to accommodate the need for submersible pumps and horizontal well bend radius.

DTI employed the entry-exit (continuous) well installation method, which consists of advancing a horizontal pilot bore under the landfill cap, “daylighting” beyond the cap, reaming to the desired final bore diameter and pulling the riser and well screen into position. The two 700-foot long engineerined horizontal wells were successfully installed under the Capped RCRA Hazardous Landfill.

To bring this level of knowledge to your next horizontal remediation well project, please contact us at drilling@directionaltech.com or 1-877-788-4479.

PDF: Directional Technologies Installs HRWs at Capped RCRA Landfill