How To Reduce TDS In Wastewater

Total dissolved solids (TDS) is a measure of all the molecules contained in a liquid; TDS is often synonymous with dissolved solid matter. High levels of TDS may lead to water that appears cloudy and feels slippery, like soap or detergent. As TDS increases, the taste of drinking water may change due to an increasing number of non-nutritional ions dissolved in it. The recommended limit for TDS content in tap water is 500 mg/L (usually expressed as 500 ppm).

The most common source of high total dissolved solids (TDS) concentrations in tap water is an underlying aquifer containing significant quantities of minerals which are easily dissolved. This can be naturally occurring or result from anthropogenic activity such as mineral extraction or surface water impoundment behind dams. Dissolved TDS may also come from household or industrial wastewater being discharged directly into waterways, resulting in direct addition of TDS to the receiving stream.

How Do You Reduce TDS In Wastewater?

There are several basic methods used to remove TDS from water: chemical coagulation, reverse osmosis (RO), demineralization or deionization (DI), and electrodeionization (EDI). Some processes use more than one of these technologies in sequence while some companies have developed proprietary technologies that accomplish both RO and DI simultaneously. Although each technology has its own strengths and weaknesses

In order to determine which method(s) are right for you, there are a few questions you should ask yourself before designing a system.

What Concentration Must My Final Effluent Be? 

This is specific to your facility, but it is important to remember that the EPA does have discharge standards. Be aware of these standards and try not to exceed them. If you are planning on discharging water into a public system or well then be aware of their limits too!

How Does Reverse Osmosis Work?

What Are Some Advanced Methods Of Filtration?

Chemical Coagulation

Chemical coagulation is typical in wastewater applications. Basically, chemicals remove the dissolved ions into particles that can be filtered out which lowers the total dissolved solids count.  Ions bond to each other chemically and form molecules such as sodium hydroxide (NaOH), sodium carbonate (NaCO), calcium hydroxide (Ca(OH)), and calcium carbonate (CaO). These substances are removed with the sediment filters.

Demineralization or Deionization (DI) 

This is another type of waste treatment that removes ions from drinking or wastewater. There is no membrane in DI, but rather used special resin beads that have an ionic charge on them. Ions in the water attach themselves to the resin and are removed from the water via this ionic charge.

Electrodeionization (EDI)

Chemical-free deionization methods use electricity to constantly clean the ions off the resin beads described above.  The concept is the electrical field clears the ions off the resin beads at the same rate as the resin beads attract and remove the ions from the water. This method requires electricity to function; however, chemical-free deionization is more environmentally friendly than chemical means.

Reduce Your Impact and Call A Professional

The experts at MAC Water Technologies are ready to help your business create less of an impact on the planet. Call today to get help with all of your high purity and wastewater needs!