Chlorinated Solvents Removal with 10 Remote Wells

Soil and groundwater remediation using a 300 gallon per minute treatment system connected to 10 remote recovery wells

PROBLEM: Local water table contaminated with chorinated solvents over a period of 40 years.

SOLUTION: MAE2 was tasked with the construction of a 300 GPM ground water treatment system to remediate a Chlorinated solvent plume at a manufacturing facility in South Carolina. The facility site is approximately 65 acres and located in a mixed industrial, residential area. The treatment area included the site property and other areas extending ¼ – ½ mile down gradient of the plant.

The project required remote communication with 10 recovery wells from a centralized control panel located at the treatment facility.

The treatment system was constructed in a prefabricated 10 x 40’ steel frame building and consisted of an equalization tank, pH adjustment, tandem 150 GPM stainless steel tray air strippers, bag filtrations and PLC controls.

The well field consisted of 10 extraction points, each with a 3 HP electric submersible pump placed approximately 200’ below grade. Each of the pumps had local PLC controls to power the pump and provide the communications loop back to the Main Control Panel (MCP) at the treatment system.

In addition, each well included submersible transducers, water flow transmitters and positioning ball valves all controlled by the MCP to maintain a constant water level in the recovery wells. Due to the distance of the wells from the main treatment system, fiber optic cable was chosen as the means of data communication between the well field controls and the MCP at the treatment system.

This is a large project that has been in preparation for about 8 years! The first demonstration tests took place August 2016, and the project will last about 20 years before remediation is complete!

Chlorinated Solvents Removal

The extracted groundwater required treatment before it could be discharged. The discharge water is used to fill a 2,000 gallon tank and used to support the chiller units used at the factory. The water not used by the facility is discharged to the local storm water network.

In order to meet the discharge requirements all chlorinated solvents and any suspended solids had to be removed. The influent water is pumped into an equalization tank where caustic was added to adjust the pH so that the treated water could be discharged.

Two 250 GPM removable tray air strippers were installed in parallel. Each Air Stripper has 6 removable trays that provide plenty of residence time to strip the solvents from the groundwater. Each air stripper has a 10 HP pressure blower to provide the air to water ratio needed to clean the water and a 10 HP centrifugal transfer pump. Any suspended solids or other particulate is removed from the air stripper discharge by two sets of 3 bag filtration vessels plumbed in series.

The clean water then leaves the groundwater remediation building and is directed through an automated valve to either the chiller holding tank or the storm water system as needed.

This Chlorinated Solvents Removal Systems uses the following components and subsystems