31 May Voltea CapDI and Water Reuse- How it Works and How it Can Help Globally- CINET Book

In 2015, the term that seems to define the needs of populations around the world, and that has become a mission in its own right, is water reuse.

Sassenheim, November 2015- Authored by Heather Leighow

In 2015, the term that seems to define the needs of populations around the world, and that has become a mission in its own right, is water reuse. From residential to commercial and industrial consumers, water reuse is becoming more and more essential to our daily survival. The earth’s population is expected to climb fully 35%, that’s 2.5 billion more people, by 2050, meaning that pressure on global water resources is increasing at an even faster rate than ever before. The need for technologies that cost-effectively enable water reuse is currently at its peak of importance. Voltea has developed a new technology that removes TDS (total dissolved solids) more cheaply and efficiently than any other technology, and does so at high temperatures. The introduction of this technology means water reuse can become an affordable and viable option today.

Over the last 15 years, innovations in many fields have so rapidly developed that keeping up with the ever-changing technologies has not only been difficult, but also very expensive. In the water reuse field, there have been numerous technologies that have been developed in order to help solve the water issues we have at hand; the same issues that we have been dealing with for many years now. These technologies are particularly important for industries that consume significant amounts of water during normal operation such as commercial laundries and textile cleaning.

Water reuse not only helps save the planet by consumers and businesses becoming more environmentally friendly, but it also saves costs in both personal and industrial applications. Voltea, a water technology company located in the Netherlands, has proven a way for water reuse to be a more commonly practiced concept around the world. Voltea’s Capacitive Deionization technology, CapDI©, deionizes brackish water at the lowest economic and environmental cost of any globally available technology. CapDI© is a simple, innovative, and most importantly cost-effective way to remove TDS from water.

In commercial laundry, TDS above 750-1,250 ppm causes dull, gray linens, so effective use of recycled laundry water has been limited by the inability to affordably and reliably remove TDS at high temperatures. Current technologies, such as reverse osmosis (RO), require water to be cooled below laundering temperatures before TDS removal, which means it must then be reheated for laundering. This is expensive, time consuming, and now unnecessary. By removing TDS at laundering temperatures, Voltea customers realize exceptional operational, chemical, and energy costs savings. Commercial laundries across the globe have reduced their total water consumption up to 90% per year by implementing Voltea’s CapDI© technology. This technology recovers up to 90% of the water it treats, and does so at the high temperatures that commercial laundry facilities operate (140°F/60°C).

CapDI© is a simple 2-step process wherein water flows between electrodes, where the electrode surfaces are separated from the water by membranes that selectively allow positive or negative ions to pass. In the first step, purification, saline water passes between oppositely charged electrodes which electrostatically remove dissolved ions, leaving pure water flowing out of the cell. In the second step, regeneration, feed water flushes through the cell at a lower flow rate, while electrode polarity is reversed. Ions are then rejected from the electrode surface, concentrated in the flow channel, and flushed from the cell before the cycle is repeated. Moreover, a critically important feature of the technology is that the amount of TDS removed from the water is tunable.

For example, a laundry operator could set an upper limit of 1,000 ppm TDS, above which recycled water would no longer be suitable for laundering. In such a case CapDI© would remove TDS as the water was recycled for repeated washes without allowing the water to reach the upper limit of 1,000 ppm, and if the laundry operator wanted an even lower threshold, CapDI© would simply remove more salt with each recycle loop. The addition of CapDI© to the treatment system provides a longer run time and an increased number of recycling cycles before the water reaches the TDS limit, thus saving the facility on water intake and recovery, as well as providing essential energy savings by doing so at laundering temperatures.

Voltea reuse solutions work across all laundry intakes, such as healthcare, hospitality, uniforms/industrial, and food & beverage. These commercial laundry intakes make up the approximately 90,000 commercial laundry facilities globally, which combined wash an estimated 55 million tons of textiles annually. If the commercial laundry field alone entirely converted their operations to adopt Voltea’s water reuse solution, CapDI©, they would make a monumental difference in water usage around the world.


CapDI© is special in more ways than one, starting with and most importantly that it removes TDS at high temperatures. No other technology, globally, has the ability to do so. CapDI© is also environmentally friendly in that there are no chemicals used for treatment, which ensures that any unrecovered water flows back into the ecosystem safely. Unlike RO systems that can waste more than 60% of treated water, CapDI© can recover up to 90% of the water it treats, resulting in long-term water conservation. Also unlike RO systems, CapDI© is tunable, meaning that the extent of which salts and other ions are removed can be customized to the consumers needs, depending on the application. It is important in certain applications that not all of the dissolved salts and other minerals are fully removed because their presence in low concentrations is necessary for certain types of usage. This is where the tunable removal feature of CapDI© differentiates itself.

Voltea’s technology is scalable, treating water for residential consumer appliances all the way up to industrial treatment at large factories. Voltea recently built their largest system to date, an IS36, for an industrial facility located in Ohio. With minimal pre-filtration this system is capable of treating up to 150,000 gallons of water a day, which is used for industrial equipment requiring exacting water quality specs that exceed drinking water in many aspects. The Ohio-based company has witnessed exceptional advancement in their water reuse process due to the addition of Voltea’s CapDI© system. Facility General Manager Jesus Galinda stated, “We selected the Voltea system for three reasons: 1) fully-automated remote operation; 2) no chemicals required for usage; 3) low ongoing operating costs. System performance has exceeded our expectations in every way.”

Voltea’s CapDI© experts have developed the technology and performance metrics so methodically that their predicted performance data graphics are near perfectly in-line with actual results of each system they install. This allows launderers to make accurate estimates of laundering times, water usage, and TDS removal while running the CapDI© system. Similar data graphics are also made to represent each launderers current treatment system without CapDI©; detailed business case analysis shows just how effectively this technology can help the facility.

All of the benefits of applying Voltea’s CapDI© technology to a laundry facility’s process come at a low price using minimal space. The simple modular design provides the flexibility to treat a few mL/min up to thousands of m3/hr in a compact, containerized footprint. Voltea has deployed systems allowing up to 48 modules in a single 40-foot container, delivering over 435,000 US gallons of deionized water everyday.


In June 2011, Voltea received a €1.2M order from the Dutch Ministry of Infrastructure and the Environment after successfully completing a feasibility study showing that CapDI© technology can deionize wastewater more efficiently than other competing technologies, such as RO. As part of the project, Voltea built a full-scale pilot treatment line, featuring CapDI© technology, which desalinated 5-10 m3/hr of effluent from the Harnaschpolder Wastewater Treatment Plant near Delft, and reached the targets of water recovery, TDS reduction, and power consumption. The project’s goal was to produce deionized water that can be reused for irrigation of local greenhouses.
Following this project, in 2013 CapDI© was trialed in a Singapore wastewater reclamation system and successfully showed competitive performances to RO. This project was aimed at recycling industrial wastewater to produce industrial and NEWater (high quality, reclaimed) water.
In recent years, regulations have become stricter regarding the quality of effluent discharged from wastewater treatment plants into rivers or the sea. This regulatory environment makes wastewater reuse for agricultural purposes an attractive option for farmers, wastewater treatment plant operators, and companies providing wastewater reuse solutions.
In residential applications, CapDI© is a chemical-free, low-cost, and environmentally friendly alternative to conventional water softening systems. From coffee makers to washing machines, appliances benefit from the tunable output water quality and hardness reduction that CapDI© delivers. Voltea has leveraged the same ruggedized, industrial technologies for these smaller scale consumer appliances. CapDI© systems are the first to offer consumers the benefits of no salt water softening combined with low TDS for better tasting water and longer lifetime appliances. Design freedom and flexibility allows customization of module size, shape, and geometry for the consumer’s specific application.

CapDI© can be used as a POE (Point of Entry) treatment in larger residential projects, such as apartment complexes, hotels, and residential neighborhoods. A single system can be used to deliver treated water to up to 100 apartments at once. The anti-scaling effect is helpful for the longevity of all residential appliances, and CapDI© systems produce high quality drinking water with better health benefits.

In industrial applications, cooling towers use large quantities of water and chemicals. A cooling tower carries away heat through the evaporation of water. This water contains natural salts such as calcium, bicarbonate, chloride, and sulfate. The salts do not evaporate and build up over time, thus causing corrosion and scaling. To prevent this, chemicals are added to the cooling water. Eventually this water is discharged, and the cooling tower is refilled with clean water.

In cooling towers, the CapDI© system treats water before it enters the cooling tower, reducing salts from the incoming water stream by 80%. The cooling tower does not need to be adapted since CapDI© is placed before the cooling tower, treating only the incoming water, because the composition of the recirculating water remains unchanged. This allows the water to remain in the cooling tower up to five times longer, resulting in lower overall water consumption and wastewater production. Fewer scale and corrosion inhibitors are required to treat the water because of the decreased water consumption. For cooling systems that face existing problems with corrosion and scaling, CapDI© can also be used to reduce the scaling and corrosion potential of cooling tower water. Once installed, CapDI© is essentially risk-free since it does not change the chemical treatment program, the conductivity levels, or the settings of the cooling tower.

Voltea’s easy-to-implement CapDI© systems improve cooling tower efficiency by reducing water and chemical usage for both industrial and institutional systems. Installing CapDI© in the cooling tower make-up enables make-up water savings of up to 40%, blow-down water savings of up to 60%, scaling and corrosion inhibitor chemical savings of 50%, plus overall improved performance. Lower water usage and lower chemical discharge make CapDI© an exceptional environmentally friendly water reuse leader for industrial facilities that rely on cooling towers. The amount of water that cooling towers use annually, about 30,000 m3 for a small cooling tower, is enough to supply over 200 households with water for an entire year. As with commercial laundry facilities, if industries using cooling towers were to entirely convert their operations to adopt Voltea’s water reuse solution, CapDI©, they would make a monumental difference in water usage around the world, and set an incredible precedent of how to jump-start other efforts towards solving global water challenges.

 About Voltea

Voltea has been delivering electrochemical water-conditioning equipment to institutional, commercial and industrial customers for over 6 years. Voltea’s CapDI© systems remove dissolved salts from water using electricity at a lower economic and environmental cost than any other available technology. Voltea was recognized as one of the 21 Technology Pioneers 2013 at the World Economic Forum, listed in the 2011 Global Cleantech 100 and won the best new technology award at the 2010 Global Water Summit.