Research Areas and Projects

Water Research Areas

Industries

  • Oil and gas
  • Mining¬†
  • Power plants
  • Paper and pulp

Municipalities

  • Drinking water
  • Potable reuse
  • Wastewater
  • Groundwater
  • Surface water

Water, Energy, and Food

  • Fate and transport in plants
  • Sustainable water uses

Emerging Contaminants

  • Per- and Polyfluoroalkyl Substances (PFAS)
Direct Potable Reuse Demonstration

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Direct Potable Reuse Demonstration Trailer Mock-up

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Design of Mobile Direct Potable Reuse Demonstration Trailer (one side of trailer)

Colorado Springs Utilities, the Colorado School of Mines, and Carollo Engineers have joined forces to develop an innovative mobile direct potable reuse demonstration. Unlike previous mobile DPR demonstrations, the system uses ozone and biologically active filtration instead of reverse osmosis (RO). The process is designed with the flexibility to incorporate additional unit processes.

To foster public awareness and engagement for future implementation of direct potable reuse (DPR), Colorado Springs Utilities (Springs Utilities), the Colorado School of Mines (Mines), and Carollo Engineers, Inc. have joined forces to design, construct, and operate an innovative mobile demonstration. Unlike previous mobile DPR demonstrations, the system uses ozone and biologically active filtration instead of reverse osmosis (RO). The process is designed with the flexibility to incorporate additional unit processes.

DOD, ESTCP

Implementation of absorption technologies for the treatment of PFAS.

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PI & Key Personnel

  • Prof. Chris Bellona, Department of Civil and Environmental Engineering, Colorado School of Mines
  • Prof. Tzahi Y. Cath, Department of Civil and Environmental Engineering, Colorado School of Mines
  • Dr. Michael Donovan, CETCO Minerals Technologies
  • Conner Murray, PhD Candidate, Department of Civil and Environmental Engineering, Colorado School of Mines

Companies Acting as Industrial Partners

  • CETCO Minerals and Technologies, Hoffman Estates, Illinois

Testbeds

  • WE2ST Water Technology Hub, Denver, CO

Project Objectives

The overall objective of these ongoing PFAS treatment projects is to evaluate the PFAS adsorption capacity of traditional adsorbents, GAC and IX, and novel adsorbents in continuous flow systems at environmentally relevant conditions.

Project Summary

With growing concern surrounding per- and polyfluoroalkyl substances (PFAS) contamination of nationwide water supplies, some of the strongest candidates for PFAS treatment are adsorption technologies which have demonstrated adequate adsorption capacity while also being cost effective and easy to implement. Research related to improving treatment longevity of traditional adsorbents such as granular activated carbon and ion exchange resin is paralleled by new adsorbent screening to evaluate new adsorption technologies entering the market on a variety of PFAS contaminated waters. While PFAS removal performance remains the most important metric for treatment selection, other treatment variables such as cost and operational parameters are also being explored to provide guidance on treatment selection in a variety of remediation scenarios.

Zoma Foundation

Advanced biological pre-treatment of produced water for sustainable desalination and reuse.

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PI & Key Personnel

  • Prof. Tzahi Y. Cath, Department of Civil and Environmental Engineering, Colorado School of Mines
  • Dr. James Rosenblum, Department of Civil and Environmental Engineering, Colorado School of Mines

Companies Acting as Industrial 

  • Bayswater, Denver, CO
  • Lawrence Berkeley National Lab, Berkley, CA

Testbeds

  • WE2ST Water Technology Hub, Denver, CO

Project Objectives

  • Study the long-term efficacy and cost-effectiveness of a lab-scale MBR on the removal of organic carbon from PW as a pre-treatment to reduce fouling of RO membranes
  • Examine the limitations of an MBR on the removal of persistent organic carbon species
  • Identify the chemical metabolic pathways used by microorganisms to biodegrade organic carbon in PW

Project Summary

Hydraulic fracturing has been on the rise in the U.S. for the last several decades. This process can be water intensive, with multi-stage fracturing of a single horizontal well, using millions of gallons of water for hydraulic fracking of a single well. Additionally, the water produced from these wells throughout the lifetime of the wells, referred to as produced water (PW), is highly contaminated, usually contain significant concentrations of salts, hydrocarbons, and other toxic compounds. The traditional method of disposing this waste stream is through deep-well injection. This method increases the likelihood of underground freshwater sources becoming contaminated and the process can cause seismic activity.

While some treatment systems, such as reverse osmosis (RO) have been shown to effectively remove these contaminants, the high levels of organic carbon found in PW can increasing fouling of expensive RO membranes.

In this project, we explore the viability of the use of a submerged membrane bioreactor (MBR) in the pre-treatment of PW before the use of RO desalination.

Barriers to Reinvention

  • The current method of PW disposal, underground injection wells, is inexpensive
  • Operating costs of an MBR have been shown to be higher than conventional activated sludge systems
  • Microorganisms used in this system must be acclimated to the high salinity found in PW, increasing time to treat
  • The use of an MBR will still require additional processes to properly treat the PW before it can be reused

DOE, NREL

Seawater desalination driven by hydrokinetic energy from the ocean: Assessment of membrane integrity subjected to long-term simulated waves.

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Project Objectives

Wave powered desalination systems are proposed water treatment systems that involve reverse osmosis of seawater powered directly by wave motion. Such a configuration would result in drastic feed pressure fluctuations. For a technology conventionally operated with a constant feed condition. the effect of these variable pressures on membrane integrity and performance is unknown. Understanding the impact on the membrane is germane to performance predictability, particularly if this system is to operate in a developing community with limited resources. Before further development or implementation of a purely wave-driven RO system, there must be fundamental research considering if the membrane can handle the abuse of irregular feed conditions and any impact on permeate quality.

Project Summary

To investigate the impact of variations in feed pressure on membrane integrity and permeate quality, this research presents results from several experiments with different feed compositions and wave conditions on a commercial RO membrane and elemental analysis of the product water. Feed composition included 5, 20, and 35 g/L NaCl, and a synthetic seawater blend (Instant Ocean) at normal and 1.5x concentration. The variable feed conditions included sine-like waves of pressure swings from 200-500 and 500-900 psi with frequencies of 1.25, 7.5, and 12 waves/min as well as a model-generated random waveform. Between each wave experiment, membrane integrity tests were performed at 650 psi and 25 g/L NaCl and permeate samples were collected for analysis. Hydrokinetic energy coupled with reverse osmosis has the potential to drastically reduce the energy and cost required for reverse osmosis provided the membrane can take the abuse. However, further research considering implementation of such a system will be necessary before energy and cost reductions can be realized.

DOE, Solar Energy Technologies Office

Energy Where it Matters: Delivering Heat to the Membrane-Water Interface for Enhanced Thermal Desalination

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PI & Key Personnel

  • Prof. David Jassby, Department of Civil and Environmental Engineering, University of California, Los Angeles
  • Prof. Eric Hoek, Department of Civil and Environmental Engineering, University of California, Los Angeles
  • Prof. Tzahi Y. Cath, Department of Civil and Environmental Engineering, Colorado School of Mines
  • Prof. Nils Tilton, Department of Mechanical Engineering, Colorado School of Mines
  • Dr. Craig Turchi, Thermal Sciences Group, National Renewable Energy Laboratory
  • Dr. Kurby Sitterley, Department of Civil and Environmental Engineering, Colorado School of Mines

Companies Acting as Industrial Partners

  • MembranePRO Services, inc., Los Angeles, California

Testbeds

  • WE2ST Water Technology Hub, Denver, CO

Project Objectives

The overall objective of the project is the development of a solar-driven MD process that can treat high salinity brines a a cost below $1.5/m3. The MD process will be evaluated for its ability to desalinate high-salinity hydraulic fracturing flowback and produced water under realistic conditions with the only driving force for the desalination process being externally generated heat.

Project Summary

Membrane distillation (MD) is a treatment technology capable of producing high quality water from highly saline streams, even at low temperatures. In MD, a difference in partial vapor pressures between a hot feed stream and cooler permeate stream drives water vapor through a membrane. This process has inherent inefficiencies that limit its application, such as significant heat loss and membrane fouling, but they can be mitigated by applying heat directly to the membrane surface.

Solar heat is an attractive driving force for this process due to its availability and low cost. Recent advances in materials technology has produced high thermal/electrical conductivity surfaces suitable for incorporation into MD membranes. These include percolating carbon nanotubes (CNT) and metal and carbon fiber mesh. Once these materials are applied to the membrane surface, they can serve as efficient heat and electrical conducting pathways, delivering heat and electric charge to the membrane surface.

Incorporating CNT onto the membrane surface produces a hydrophilic membrane and further reduces the incidence of fouling. By attaching the CNT layer to a solar powered heat source, the process is more sustainable and less expensive. The technology is expected to reduce the cost of MD by reducing the number of heat exchangers necessary, minimizing fouling and heat transfer losses, and reducing energy costs.

A prime application of this technology will be to treat hydraulic fracturing flowback and produced water to enable some type of beneficial reuse of the treated water. By coupling MD technology to solar power, the need for expensive and fossil-fuel generated thermal energy will be reduced.

Preliminary Results

  • Demonstrated capability to fabricate a thermally and electrically conducting MD membrane and use when connected to external heat source.
  • Application of low potential to significantly reduce sulfate scaling as measured by significantly reduced flux decline.
  • Generation of finite volume model that shows membrane surface temperatures can be elevated to generate water vapor by introducing heat to the membrane surface.

Treatment and Characterization of PFAS at Mines

What is PFAS?

Perfluoroalkyl substances (PFAS) are very stable anthropogenic chemicals that have properties that allow them to repel both water and oil. The different PFAS have different lengths and/or differ in their properties at one end, which can change the toxicity and characteristics of these complex chemical class. The most commonly found and best studied PFAS are perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), yet there are an estimated ____ that exist in the environment.

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PFAS Analytical Services

We have internal standards, allowing for the quantification of more than 40 PFAS chemicals. In addition to these targeted PFAS we also employ high-resolution mass spectrometry to perform non-targeted analysis of hundreds of additional PFAS chemicals that we have found in the environment.

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Treatment Assessments

We perform a variety of treatment technologies using absorption, concentration, and destruction. These activities occur at the lab-, pilot-, and demonstration-scale.

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Technical Services Related to PFAS