3 minute read
Bringing Solutions to the Surface
NorthWestern employee helps keep our commitment to the environment with manufactured gas plant cleanup.
For more than 25 years, Bill Thompson, Senior Technical Advisor at NorthWestern Energy, has been involved in managing environmental characterization and remediation projects at historic manufactured gas plants for NorthWestern Energy. One such plant is the former Aberdeen Manufactured Gas Plant in South Dakota.
From the early 1800s until the 1950s, prior to the availability of natural gas, communities relied on manufactured gas – or town gas – to produce fuel for street lamps, cooking, heat and lights. Energy companies throughout the United States commonly manufactured gas from coal using technology of the day. At least 1,500 manufactured gas plants (MGPs) operated within the U.S. at the time, including several in South Dakota. The Aberdeen Gas Company operated a plant in Aberdeen from 1888 until 1926 when it was sold to NorthWestern Energy. NorthWestern Energy ended the MGP operations in 1948 as natural gas pipelines installed in Aberdeen replaced the need for the plant.
Coal tar is a byproduct of the gas manufacturing process. Coal tar is a black liquid similar in appearance and consistency to driveway sealer and has different industrial uses. Environmental impacts from coal tar due to historical MGP operations are common.
Bill has been working in cooperation with the South Dakota Department of Agriculture & Natural Resources for several years characterizing the environmental impacts due to the former Aberdeen MGP and implementing remedial actions.
NorthWestern Energy’s commitment to environmental responsibility at the former plant is illustrated by the successful implementation of remedial actions such as the installation of a water treatment system to prevent coal tar discharge to the storm sewer; lining a nearby section of the sanitary sewer to prevent coal tar from entering the sewer system; removing contaminated sediment from a nearby creek; and installing collection trenches and recovery wells to remove coal tar from the ground.
Looking ahead, NorthWestern Energy is considering new approaches in order to enhance coal tar recovery in 2024 and 2025 and will be continuing its ongoing operation, maintenance and ground water monitoring responsibilities.
NorthWestern Energy’s dedication to environmental stewardship is unwavering and is encapsulated in our overall environmental policy statement. Through collaborative efforts with resource agencies and stakeholders, the company integrates compliance into daily operations, balancing energy needs and environmental responsibility.
