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Development and Validation of an Acid Mine Drainage Treatment Process for Source Water
Project Number
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The goal of this project is to research and optimize a Floatation Liquid-Liquid Extraction (FLLX) water treatment system to process and repurpose water of lesser quality, i.e., acid mine drainage (AMD water) for use in hydraulic fracturing (HF) operations and assess the feasibility of using the system byproducts for flowback water processing. The objectives of this project are to (1) develop an innovative treatment process to support the use of AMD water for HF, (2) to evaluate the use of the (FLLX) process byproducts in flowback water treatment processes and (3) determine the environmental, regulatory, and commercial implications of using treated AMD as source water during HF.


Battelle, Columbus, OH 43201


Persistent pressure on public water resources and an increase in drought conditions in the U.S. have underscored the need for a novel technology to remediate and repurpose a non-potable water source to meet requirements for HF applications. Well injection for an HF application requires around five million gallons of fresh water. The increasing yearly demand on the public water system and the unconventional gas industry’s continued focus on reducing their environmental footprint have made producing a commercial technology capable of reducing potable water consumption essential to the continued success of unconventional resource development. The U.S. Department Of Energy (DOE) is also interested in increasing the effectiveness of flowback water treatment processes because conventional water treatment technologies such as chemical treatment, filtration, reverse osmosis, distillation, etc., must be adapted to treat a range of flowback water chemistries and have disadvantages such high cost, significant energy consumption, and low efficiency.

The research under this award will be performed to optimize a 3,400-bpd water processing system to provide freshwater from AMD sources for HF. The immediate outcome will be a commercial-ready system operated by a water services company at a throughput volume useful for HF operations and an optimized technology ready for deployment at additional sites. More than 30 billion gallons of freshwater have been used for HF since 2011 in efforts to recover the estimated 293 trillion cubic feet of gas trapped in unconventional deposits. Because the development of these unconventional resources is still in its early stages, it can reasonably be assumed that the demand for fresh water will increase in the coming years, taxing local supplies and creating demand for commercial-ready alternative technologies to reduce fresh water usage.


Providing an alternative hydraulic fracturing technology designed to cost-effectively treat environmentally hazardous AMD water will help reduce the use of and strain on fresh water resources. The technology developed during this project will provide a new freshwater source for HF operations in the unconventional resource development industry and concurrently assist in mitigating AMD, a legacy source of pollution.

Accomplishments (most recent listed first)

Process byproduct generated during the field testing was characterized in the laboratory and used in comparative testing as a chemical treatment for the removal of barium and other constituents from produced water. The results indicate that the HydroFlex process byproduct achieves a similar performance to current industrial chemicals used in the treatment of produced water. This may positively impact the process economics if the process byproducts can be dispositioned at cost. 

The HydroFlex field demonstration system was operated for several months supporting Test Campaign 1 (TC1) as well as a Confirmatory Test Campaign (CTC). It was demonstrated that the system was able to reduce sulfate levels in the AMD to below 100 mg/L, which is the target value which project stakeholders have identified as a key metric for the use of AMD as a source water. The stakeholder committee was briefed on the test campaign results. 

The project SOPO was modified to include a GO/NO GO decision point between the two originally planned field test campaigns. Based on the results of TC1 and the system status, a NO GO decision was made to not proceed with the originally planned Test Campaign 2 (TC2). Instead the remainder of project funding was used to complete the project activities, as well as to conduct discrete tests in the field, as outlined in the CTC, focused on reduction of operational costs.

A source water stakeholder committee was established and provided preferences for the quality of water to be used in hydraulic fracturing operations. The project team anticipates that the HydroFlex platform will be capable of meeting the water quality parameters for reuse in oil and gas operations based on completed laboratory and bench-scale tests.

Current Status

All research has been completed and the final report is available below under "Additional Information".

Project Start
Project End
DOE Contribution


Performer Contribution


Contact Information

NETL –  David Cercone ( or 412-386-6571)
Battelle – Anne Lane ( or 614-424-3266)

Additional Information

Final Project Report [PDF-3.23MB]