Tech Bulletin: The Benefits of Using Selective Ion

Exchange Resin for Wastewater Treatment

Ion exchange resins are small porous beads that have negatively or positively charged functional groups on them to grab ions. These resins are insoluble in water or solvents and they range in diameter from 0.3 to 1.5 mm. Resin is placed in a vessel or “column” and submerged in water where it forms a layer or “bed” on the bottom. It absorbs water and swells when first immersed and becomes “conditioned”. When fully conditioned the resin beads contain 50 – 70% water. Water is passed through the resin columns and the resin bed is gently agitated as the water flows uniformly around the resin beads. These resin beads are porous. This increases the amount of surface area in contact with the wastewater and the number of functional groups available to interact with ions in the waste stream. There are two main types of resin cationic and anionic. Cationic resins are negatively charged and remove positively charged cations and anionic resins are positively charged and remove negatively charged anions. An example of these resins and the ions they remove is in the chart below.

www.chemalliance.us 864.201.5418

bfstacy@chemalliance.us

Cationic Resin (remove positive ions) Anionic Resin (remove negative ions)

Chrome (Cr) Chorides (Cl) Nickel (Ni) Sulfates (SO4) Zinc (Zn) Nitrates (NO3)

Copper (Cu) Carbonates (CO3) Lead (Pb) Phosphate (PO3)

Calcium (Ca) Bromide (Br) Ammonia (NH3) Hydroxide (OH)

Tech Bulletin: The Benefits of Using Selective Ion

Exchange Resin for Wastewater Treatment (cont’d)

www.chemalliance.us 864.201.5418

bfstacy@chemalliance.us

We will design the most effective system. If column exchange is selected ship us spent ion exchange columns and we will replace them with freshly regenerated ones. The resin columns are often not recognized as hazardous, so the expense of shipping them can be drastically reduced*. We also will design and build a self regenerating ion exchange system if you prefer. *NOTE: Local water regulatory agencies need to be consulted to help determine if the spent resin is considered hazardous or not. ChemAlliance will help you with this determination.

Ion exchange resins are unique when it comes to wastewater treatment. They are ideal for treating waste streams that are generally lower in TSS (Total Suspended Solids) and contaminant levels than a chemical program. Other advantages are: 1. No sludge is generated and if the water being treated is from a electroplating

operation the sludge is considered F006 hazardous. 2. Hazardous sludge can be very expensive to haul off 3. Less labor intensive than chemical treatment 4. Much smaller space requirements than a chemical treatment system. A system that

treats 10 gpm – 20 gpm can easily fit in approximately a 5 x 10 footprint. 5. Lower overall operation cost

There are two main types of ion exchange resin systems used for wastewater treatment: 1. Column Exchange – This is the simplest and least expensive system, requiring low capital outlay and flexibility in installation - columns are swapped with vendor for regeneration 2. Self Regenerating Ion Exchange – These are more complex, more expensive and require more space. It is necessary to have strong acids and bases on sight and be able to dispose of them after use.

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