Site Map

ABOUT NETL

KEY ISSUES & MANDATES

ONSITE RESEARCH

TECHNOLOGIES
Oil & Natural Gas Supply E&P Technologies Gas Hydrates T&D and Refining
Contacts Coal & Power Systems Industrial Capture & Storage Carbon Sequestration Hydrogen & Clean Fuels

ENERGY ANALYSIS

NETL-RUA

TECHNOLOGY TRANSFER

SOLICITATIONS & BUSINESS

EDUCATION

AWARDS & RECOGNITION

NEWSROOM

CONTACT NETL 

## Produced Water Management Technology Descriptions Fact Sheet - Ion Exchange

Salt is the key parameter that determines how produced water is managed onshore. A separate fact sheet describes membrane processes for removing salt. This fact sheet describes ion exchange, anoth er common process that removes salt and other inorganic chemicals fro m produced

water.

Many consumers are familiar with home water softeners that remove iron and manganese from tap water. Water softeners use ion exchange columns filled with a specific type of resin. The resin is charged with sodium ions by passing a concentrated salt solution through the column. As water loaded with iron and manganese moves through the column, those ions are attracted to the resins, which prefer to bind with the iron and manganese. Sodium is released when the resin attaches to the iron and manganese. Once stripped of the undesirable iron and manganese, the water is piped into the home water supply. Periodically, the resin-exchange sites are all used. Then, the column is backwashed and regenerated with fresh salt solution.

The water softener example is provided to explain the principle of ion exchange. Exchange resins can be designed to selectively remove different types of chemicals. IOGCC and ALL (2006) provide a descrip tion of the different types and applications of ion exchange resins.

In the case of produced water, the most common use of ion exchange is to preferentially remove sodium. For that application, resins are chosen that are regenerated with hydrogen ions. As the produced water passes through the column, sodium ions are removed from the water. They replace the hydrogen on the resin's exchange sites. The treated water contains more hydrogen ions, and therefore its pH drops. Often the pH is raised by contact with calcium carbonate, which in turn h elps to control the sodium adsorption ratio or SAR (for more discussion of the SAR, see the fact sheet describing agricultural use).

However, ion exchange can be used to remove other contami nants too. At one treatment plant in the Powder River Basin, ion exch ange is used to preferentially remove divalent cations
which would otherwise form scale on the reverse osmosis mem branes that do the bulk of the sodium removal. Further, special ion exchange resins have been developed to remove radium (NORM) from produced water.

One version of ion exchange for treatment of coal bed methane produced water in the Rocky Mountain region is the "Higgins Loop." Dennis (200 6) and IOGCC and ALL (2006) describe the process. The Higgins Loop uses a contin uous countercurrent ion 

### PWMIS Home

Intro to Produced Water

Technology Descriptions

Basic Separation

Mechanical Blocking Devices

Water Shut

- Off Chemicals

Downhole Separation

Sea Floor Separation Injection for Oil Recovery Injection for Future Water Use Injection

- Hydrologic Purposes Agricultural Use

Industrial Use

Domestic Use Discharge Injection for Disposal Evaporation

Offsite Commercial Disposal

Membrane Processes Capacitive Deionization

Thermal Distillation Physical Separation

Coalescence

Flotation Physical/Chemical Processes

Solvent Extraction Adsorption

Combinations of Technologies

Feedstock

Oxidation pH Adjustment



### Fed & State Regulations

Technology Identification Home water softener column with salt tank for regenerating the column and sodium hydroxide tank for neutralizing low pH; Source: J. Veil, Argonne National Laboratory.

Ion exchange equipment at Argonne National Laboratory; Source: D&D - Nuclear Engineering Division of Argonne National Laboratory 

# Page 1 of 2 NETL: Produced Water Management Information System

3/13/2012 http://www.netl.doe.gov/technologies/pwmis/techdesc/ionex/index.htmlexchange contactor for liquid phase separations of ionic co mponents. The contactor consists of a vertical cylindrical loop, which contains a packe d bed of resin separated into four operating zones by butterfly or "loop" valves. T hese operating zones - adsorption, regeneration, backwashing, and pulsing - f unction like four separate
vessels.

Produced water containing high sodium levels is fed to the adsorption zone within the Higgins Loop. There, it contacts strong acid cation resin, which accepts sodium ions in exchange for hydrogen ions. Treated water containing less than 10 mg/L sodium then exits the loop. In the lower section of the Higg ins Loop, resin filled with sodium is regenerated with either hydrochloric or sulfuric acid. T his generates a small, concentrated spent brine stream. Regenerated resin is r insed with water prior to reentry into the adsorption zone to remove acid from its pores. As resin in the upper layer of the adsorption zone becomes loaded with sodiu m, the flows to the Higgins Loop are momentarily interrupted. This allows advancement of the resin bed ( pulsing) through the loop in the opposite direction of liquid flow. Liquid flows are restarted after resin pulsing is complete.

Beagle (2006) reports that 17 ion exchange units are op erating in Montana and Wyoming to treat produced water. Emit Water Discharge Technology uses a Higgins L oop as part of an overall treatment system to treat produced water for subsequent reuse or discharge. The volu me of water treated in this fashion has steadily increased from a few hundred thousand bbl (barrel = 4 2 gal) in August 2003, to nearly 5 million bbl in Aug ust
2006.

The backwash stream from ion exchange treatment of produ ced water will contain high levels of sodium. Therefore, disposal requirements for the concentrated brine should be considered when selecting ion exchange treatment technologies.

Other Versions of Ion Exchange Technologies Other companies offer technologies that use ion exchange in different configurations. However, only a few have actually treated produced water. Descriptions of these tech nologies can be found in CSM (2009). Examples
include: the Drake Process, a continous ion exchange process that tar gets sodium bicarbonate. the Eco-Tec: Recoflo® compressed-bed ion exchange process

Additional versions of ion exchange technology may be par t of combined treatment systems.

References Beagle, D., and R. Dennis, 2007, Continuous Countercu rrent Ion Exchange Applied to CBM Produced Water Treatment in the Powder River Basin of Wyoming and Mo ntana," presented at the 14th International Petroleu m Environmental Conference, Houston, November 5-9. Availab le at http://ipec.utulsa.edu/Conf2007/Abstracts% 202007/Beagle_40.pdf [PDF].

CSM, 2009, “Technical Assessment of Produced Water Treatm ent Technologies,” prepared by the Colorado School of Mines as part of RPSEA Project 07122-12, Nove mber. Available at http://aqwatec.mines.edu/produced_water/treat/docs/Tech_ Assessment_PW_Treatment_Tech.pdf [PDF}

Dennis, R., 2006, "Coal Industry Turns to Ion Exchange T echnology for Wastewater Minimization," Industrial WaterWorld, PennWell Corporation, Tulsa, OK, Sept. A vailable at http://ww.pennnet.com/Articles/Article_Display.cfm? Section=ARTCL&PUBLICATION_ID=41&ARTICLE_ID=276178&C= colmn

.

IOGCC and ALL, 2006, "A Guide to Practical Management of Produced Water from Onshore Oil and Gas Operations in the United States," prepared for U.S. Department of Energy, National Energy Technology Laboratory, by the Interstate Oil and Gas Compact Commiss ion and ALL Consulting, Oct. Available at http://www.all

- llc.com/IOGCC/ProdWtr/ProjInfo.htm

. Higgins Loop water treatment system; Source: Severn Trent Services

USA.GOV | U.S. DEPARTMENT OF ENERGY | DOE OFFICE OF FOSSIL ENERGY DOE OFFICE OF ENERGY EFFICIENCY & RENEWABLE ENERGY | OFFICE OF ELECTRICITY DELIVERY & ENERGY RELIABILI TY
Disclaimer | Privacy Policy | Web Policies | FOIA/Privacy Act | Employees Only 

# Page 2 of 2 NETL: Produced Water Management Information System

3/13/2012 http://www.netl.doe.gov/technologies/pwmis/techdesc/ionex/index.html