Service Lines: PFAS Treatment

Municipal and Residential Well Treatment System Corrective Action

US Army Corps of Engineers (USACE) Omaha District awarded this delivery order to one of Bristol’s joint ventures to perform an immediate response (IR) action to provide clean drinking water to private residences, mobile home parks, and commercial properties at locations adjacent to Peterson Air Force Base (AFB), Colorado, where current water supplies were identified as being contaminated with perfluorochemicals (PFCs). Specifically, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) were found at concentrations exceeding the U.S. Environmental Protection Agency’s (EPA’s) Lifetime Health Advisory (LHAs) of 70 ppt individually or combined. PFCs are chemicals found in consumer products including non-stick cookware and stain-resistant fabrics, as well as in aqueous firefighting foam used in both civilian and military markets. Evolving science has identified a potential risk to humans from these emerging contaminants. 

Within days following award, our team successfully contracted with multiple local vendors to begin provisions for clean drinking water to the nearby farm, six commercial properties, 24 private properties, and two mobile home parks consisting of more than 60 taps and 170 people. 

Following the successful execution of the required IR actions, our team received a contract modification to provide time-sensitive corrective actions for municipal, commercial, and private drinking water wells where current water sources were contaminated with PFOA and PFOS at concentrations exceeding the EPA LHAs. The modification included installation of granular activated carbon (GAC) and Ion-Exchange Resin point of entry treatment (POET) systems capable of treating flows from 50 gallons per minute (gpm) at the mobile home parks and up to 500 gpm for the three municipal drinking water supply wells; and point of use (POU) treatment systems for residential properties. Additional efforts included the collection of water samples from private and commercial wells not previously sampled by the El Paso County Department of Health (DOH) for PFOA/PFOS analysis to determine the need for mitigation. Prior to the execution of project requirements, our team generated a Uniform Federal Policy for Quality Assurance Project Plan (UFP-QAPP) covering all aspects of the proposed project execution. This document was submitted to Peterson AFB, USACE Omaha District, Colorado Department of Public Health and the Environment (CDPHE), El Paso County DOH, and the EPA for review and approval. Our team provided additional support to the USACE and Peterson AFB with the generation of an Action Memorandum for the project. 

In all, our team installed 27 reverse osmosis units for POU treatment at residential properties, installed an ion-exchange resin system capable of treating 350 gpm on one municipal well, and two GAC treatment systems on two additional municipal wells (capable of treating up to 500 gpm). The two GAC treatment systems were plumbed in series with sample ports located pre-treatment, between filters, and post-treatment which allows for regular monitoring for PFOA/PFOS in the influent (raw) and effluent (treated) water to develop breakthrough curve specific to each location and to assist in determining future operations and maintenance.

PFOS/PFOA Sampling and Mitigation

US Army Corps of Engineers (USACE) Omaha District awarded one of Bristol’s joint ventures this time sensitive response action project at Joint Base Lewis-McChord (JBLM), Washington, where groundwater was found to be contaminated with perfluorochemicals (PFCs), specifically perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) as well as concerns over metals in the water. PFCs are chemicals found in consumer products including non-stick cookware and stain-resistant fabrics, as well as in aqueous firefighting foam used in both civilian and military markets. Evolving science has identified a potential risk to humans from these emerging contaminants. The five wells originally in question included: North, South, East wells, Housing Well #2, and Golf Course Well #22, which all tested near or above the U.S. Environmental Protection Agency’s (EPA’s) Lifetime Health Advisory (LHA) of 70 ppt. 

Prior to implementation of mitigation measures at each well site, Bristol coordinated numerous planning sessions with the project delivery team (PDT), including the USACE Omaha District, USACE Seattle District, Washington State Department of Health (WA DOH), and JBLM Department of Public Works (DPW). During these planning sessions Bristol provided multiple alternatives for treatment, including ion-exchange resin and granular activated carbon (GAC) treatment, along with the pros and cons associated with each. Based on the information provided, the PDT selected GAC as the approved method for treatment at each of the potable well sites.

The Bristol team provided a fast-track project delivery to develop and implement the approved GAC treatment method. Services included:

  • Initial site reconnaissance and sampling at identified well system sites.
  • Development and installation of treatment systems to remediate the groundwater, including associated housing and facilities.
  • Development and implementation of ancillary infrastructure required for connection to the existing water treatment/distribution systems.
  • Performance of all startup requirements, training, prove-out/shakedown of the approved mitigation measures, and sampling/testing. 

A total of three (3) GAC treatment systems were constructed at the North, East, and Housing Well II sites. Treatment systems included bag filters for pre-treatment of the influent (raw) water, two (2) GAC treatment vessels, system manifolds and air actuated valving to allow for operation of the GAC vessels in lead/lag or parallel configuration and for backwashing; 43,723-gallon backwash supply and holding fiberglass reinforced plastic vessels; and programmable logic controls for system operations and monitoring (O&M). 

The systems were constructed to be fully automated in order to place less of an onus for O&M on the JBLM DPW. Treatment systems were brought on-line the week of June 1, 2020, with training for O&M of the systems provided to JBLM DPW personnel soon after.