The zeolite mineral plays an important role in the cleanup of oil field waste.

Professor Colella Pansini of the University of Naples in Italy reviewed Natural Zeolites as Cation Exchangers for Environmental Protection.

Pansini’s review is divided into four major sections:

• A description of how cation exchange procedures can be used in industrial settings.
• NH4+ is removed from municipal and industrial wastewater.
• Zeolites are natural materials that are useful for removing heavy metals from water and soil
• Zeolites are a very effective decontaminant of soils and water containing radionuclides because of their chemical and structural characteristics. Through its ion exchange and sieving capabilities, zeolite makes an excellent option for oil field cleanup.

A system of exchanging ions

Zeolite’s molecular structure gives it a magnetic charge, which nets a negative charge on the Zeolite Framework, called Isomorphous Substitution. In solution, these areas have a negative charge, so they are ideal sites for adsorption of exchangeable cations. In the absence of a suitable site or if it is already occupied, cations occupy the water molecules’ sites during ion exchange. By virtue of this property, Zeolite softens and filters wastewater that passes through it.

Sieves for molecular analysis

Due to the microporous structure of Zeolites, certain cations can be excluded. Zeolite excludes all or part of the internal surface from cations larger than the internal cavities. In contrast, cations which do not fit into the internal structure of the Zeolite Framework can be exchanged (either by isomorphous substitution or ion exchange) into it. Therefore, natural Zeolites are renowned for their molecular sieve properties (Tsitsishvili et al., 1992).

Zeolites were first used in practical applications in the 19th century (Breck, 1974). Cation ion exchange and molecular sieve applications have existed for centuries.

“Various aspects of work within the Bakken Oil Patch can benefit from the use of Zeolite. With cation exchange and Molecular Sieve, pollutants such as oil, hydrocarbons, ammonia, methane, radionuclides, radioactive isotopes, and heavy metals can be cleaned and trapped. Geolite can be used for site remediation, landfills, spill cleanup, municipalities, water filtration, and radiation capture.”

Zeolite can be used to treat wastewater around drilling sites and accident scenes. To take advantage of wood’s lightweight properties and Zeolite’s absorbent qualities, mines can produce blends of wood and Zeolite. It may also be used directly to capture radionuclides and hydrocarbons.

By using wood blends, landfill disposal costs can be reduced while taking advantage of Zeolite’s binding and capturing properties.

Fracturing Wastewater

The fracturing industry produces billions of gallons of wastewater every year. Several processing plants exist that allow for oil to be separated from water and water to be re-used for additional fracturing or cleaned and entered back into the ecosystem. It is possible to properly filter fracturing water of heavy metals, radiation, and hydrocarbons by using zeolite. It is possible to filter streams using Zeolite as part of the process to reduce the level of contamination in streams. Natural Zeolites were shown to remove 90% of heavy metals from wastewater contaminated with mixed metals by using the Clinoptilolite conditioning process. As fracturing wastewater is produced in large quantities, alternative disposal methods are being developed. An oil and gas research council has approved a study on Dust Control that was done by finding oil wells that produce high-calcium, low-sodium salt water for the counties to use. Zeolite is already used as a water conservation tool in dust control. Bioaccumulation can easily occur in roadside ditches if NORMs are present in this wastewater.

Zeolite spread over roads prior to dust treatment has a dual benefit of increasing water utilization and capturing NORMs.

Zeolite Water Filtration

As water softeners, zeolites were used to remove radium from mine water, allowing the removal of various ions from salty waters and brines. Not only did they discover promising techniques for removing radium isotopes, but also other ions (barium, iron, manganese). We tested the removal efficiency for natural radionuclides in several different water samples. Both barium ions and radium isotopes were removed very effectively. Based on the study, it can be concluded that the purification results were excellent. For all samples, the efficiency of radium removal from water exceeded 90% (Application of Zeolites, 2013).

Solidification

Unlike Fly Ash, which contains inconsistencies and radioactive isotopes, Zeolite has similar Pozzolanic characteristics. It has even been downgraded by the EPA to a hazardous material. Zeolite deposits are consistent, so products delivered will be consistent in quality.
Zeolite can be pre-mixed into other stabilization products such as wood pellets or mixed over pellets or sawdust, fly ash, kiln dust, recycled cardboard, and any other type of absorption material.
Zeolite has been found to consolidate industrial style sludge using clinoptilolite in a study by the Institute of Environmental Sciences in Turkey titled: Industrial Sludge Solidification by Using Clinoptilolite Zeolite. The study consists of three parts: preparation of the materials to be solidified, unconfined compressive strength values (UCS), and leaching characteristics using the standard Toxicity Characteristic Leaching Procedure (TCLP). In the summary, it was noted that hazardous components in industrial sludge were successfully locked and immobilized in the solidified structure. Zeolite is commonly used as a pozzolan due to its high UCS values of 4448 kPa. Comparing the leaching test results with the Hazardous Waste Control Regulation, it was observed that no leaching problem exists and the solidified products can be landfilled safely (Balkan) & Kocasoy, 2004).
It was concluded that solidified sludge samples could be safely disposed of in landfills, although compounds such as concrete pozzolan could be used, which would turn waste into a useful, valuable product.
Zeolite has different mesh sizes that offer different characteristics. Smaller sizes of sand produced sludge additions of 60 – 70%, but lower UCS. In general, larger Zeolite sizes of 7-14 or +7 resulted in less water absorption and more compressive strength.
Testing of retention ponds routinely finds levels of 200 pCi (Donovan). Those NORMs will be trapped by the geolite, preventing their leaching.