Wastewater Filtration

Introduction to cation exchange procedures that can be operated at an industrial level, deals with the removal of NH₄+ from municipal and industrial wastewater.

Research on the abilities for natural Zeolites for removal of heavy metals from water and soil shows how chemical and structural features make Zeolites a very powerful tool for the decontamination of soils and waters containing radionuclides.

2. Molecular Sieves

Zeolites have the ability to exclude certain cations depending on the size of their microporous channels and cavities within the Zeolite structure. Those cations that are larger than the internal cavities are excluded from all or part of the internal surface of the Zeolite. Whereas, cations that do “fit” into the internal structure can be exchanged (through isomorphous substitution or ion-exchange) into the structure and become part of the Zeolite Framework. Hence, natural Zeolites are renowned for their molecular sieve properties (Tsitsishvili it al., 1992).

The first practical applications of Zeolites were performed in the 19th century (Breck, 1974). The applications for molecular sieve and cation ion exchange applications have been known for hundreds of years.

“Various aspects of work revolving around the Bakken Oil Patch can benefit from the use of Zeolite. The Cation exchange and Molecular Sieve properties allow for cleanup and capture of oil, hydrocarbons, ammonia, methane, radionuclides, radioactive isotopes, and heavy metals; as well as an array of positively charged elements and compounds. Zeolite can play a role in site remediation, landfills, spill cleanup, municipalities, air filtration, wastewater filtration, and radiation capture.”

This photo shows a 3000x zoomed in view of Zeolite mined from the Sheaville Deposit in Idaho. Note the large amount of surface area and “tunnels” within the structure.

Cleanup needs around drill sites and accident sites can utilize Zeolite for wastewater treatment. Ida-Ore Mining has the ability to manufacture blends of wood and Zeolite to take advantage of both the lightweight and absorbent characteristics of wood chips. Or it can be used directly to capture radio-nuclides and hydrocarbons.

Wood blends will reduce disposal costs at landfills and still take advantage of the binding and capturing capabilities Zeolite has to offer.

The volumes of fracturing wastewater that are being produced are creating value added means of disposal. The Oil and Gas Research Council approved a study for Dust Control by identifying oil wells that produce salt water that is high in calcium and low in sodium for the counties to use as a dust control method on gravel roads. Zeolite is already used as a water conservation tool in dust control. If NORMs are present at all in this wastewater, bio-accumulation can easily occur in roadside ditches. Spreading 7+ mesh Zeolite on roads prior to dust treatment will have a twofold advantage both with increased water utilization and capturing of NORMs.

4. Solidification

Zeolite is similar in Pozzolanic characteristics to Fly Ash, without the inconsistencies and additional harmful compounds, including radioactive isotopes, being added to the equation. Some Fly Ash has even been downgraded to Hazardous Material by the EPA. Zeolite is found in a consistent deposit, meaning product delivered will be of consistent quality over time.

Zeolite has the ability to be pre-mixed into other stabilization products such as wood pellets or mixed over the top of pellets or sawdust, fly ash, kiln dust, recycled cardboard, and any other type of absorption materials.

The conclusion of a study titled: Industrial Sludge Solidification by Using Clinoptilolite Zeolite, done by the Institute of Environmental Sciences in Turkey reinforced the use of Zeolite to consolidate industrial style sludge using Zeolite. The study was based on three parts: preparation of materials to be solidified, unconfined compressive strength values of the solidified material (UCS), and leaching characteristics using a standard Toxicity Characteristic Leaching Procedure (TCLP). The summary stated that hazardous components in industrial sludge was successfully locked and immobilized in the structure formed by the solidification. For the same reasons that Zeolite is commonly used a pozzolan, high UCS values obtained measured 4448 kPa. Leaching test results were compared to limits given by the Hazardous Waste Control Regulation, it was observed that there is not any leaching problem and the solidified products can be land filled safely (Balkan) & Kocasoy, 2004).

The study concluded that solidified sludge samples were safe to dispose of in landfills, although the potential to be used as a beneficial product such as a concrete pozzolan does exist, which would convert waste into a product with benefits and value.

Each mesh size of Zeolite allows for different characteristics to be taken advantage of. Smaller sizes such as 14-40 sand yielded a 60% – 70% sludge addition, but a lower UCS value. Larger Zeolite size of 7-14 or +7 yielded a lower percentage of sludge absorption, but a higher compressive strength.

Tests done on retention ponds routinely find levels of 200 pCi (Donovan). Zeolite will trap those NORMs in place and prevent leachage.