Sustainable data center water treatment

Water is a critical resource in data centers, where it is used for cooling, humidification, and other processes. However, the demand for water has raised concerns about sustainability, particularly in regions that are already experiencing water scarcity. To address this issue, data centers have started adopting sustainable water treatment solutions that enable water recycling, reuse, and recovery. This blog explores data center water treatment options available, including direct nanofiltration (dNF), reverse osmosis (RO), water softening, and other methods, as well as the pros and cons of the types of water treatment for data centers.

Data center water usage in the United States

According to a study conducted by Virginia Tech, data centers rank among the top 10 water-consuming commercial industries in the United States, using approx. 513 million cubic meters of water in one year alone, and a quarter of that was used for direct cooling. To put that in context, this is equivalent to the annual water usage of a city of around 1 million people, meaning that around 130 million cubic meters of water are being used yearly for data center cooling. This is the equivalent of a small city with a population of 250,000 people.

The main issue with water usage within data centers is that many tech companies build centers in areas such as Arizona, where there is an abundance of inexpensive power from renewable energy sources, such as solar energy and/or wind energy. However, the availability of water in areas such as Arizona, where there are currently 52 data centers, is very scarce. In California, where water is a precious commodity due to devasting wildfires, there are an estimated 240 data centers.

Data center water treatment and technologies to combat carbon footprints and increasing water scarcity are vital. With the average data center within the United States using approximately 1.8 liters of water per kilowatt-hour of electricity, the need for sustainable water treatment solutions for data centers becomes ever-more obvious. If current trends continue, data center water usage in the United States is expected to rise by 25% by 2025, highlighting the pressing urgency for sustainable water treatment practices.

Why is water treatment important for data centers?

Water is an extremely efficient and cost-effective method for cooling data centers due to its high specific heat capacity compared to air. This means that water can absorb more heat without experiencing a significant temperature increase. For instance, let’s consider the amount of water and air required to cool an 8kW server rack. While 3200 m3/hour of air would be needed, only 2 m3/hour of water would suffice, demonstrating the significant difference in heat transfer efficiency.

The importance of data center water treatment cannot be overstated. Because water is such an effective medium for cooling, it is often used in cooling systems. However, if the water is not properly treated, it can become contaminated and cause problems in the cooling system. Contaminants such as minerals, bacteria, and algae can build up in the water and cause corrosion, clogging, and other issues. Implementing a comprehensive water treatment program is crucial to avoid issues caused by contaminated water in the cooling system. Water treatment for data centers keeps the water clean and free from contaminants and can help maintain the cooling system’s efficiency and reliability, which is essential for the operation of the data center.

Make-up water used in cooling towers for data centers often contains inorganic salts such as potassium, sodium, calcium, and magnesium, all of which are cations and other dissolved solids like bicarbonates, carbonates, sulfates, chlorides, and nitrates which are known as anions. These contaminants can lead to issues such as fouling, scale formation, corrosion, and biological growth. In addition, pathogenic microorganisms like Legionella bacteria need to be neutralized. Therefore, effective treatment and disinfection of cooling tower water are crucial for meeting the unique demands of data center cooling, which differ from those of other industrial sectors.

Types of water treatment for data center cooling

There are several water treatment technologies for data centers, and each serves a specific purpose in maintaining water quality and protecting equipment. The following are some common water treatment methods used in data centers, with each explored in the next sections:

  • Water softening
  • Reverse osmosis
  • Direct nanofiltration (dNF)
  • Filtration and other methods

Water softening

Water softening can be achieved through ion exchange technology which involves passing water through a resin bed that exchanges hardness ions with sodium ions using an ion exchange resin. This process results in soft water that is free of minerals that scale build-up, which can reduce cooling efficiency and damage equipment over time.

By using water softening, the cooling equipment can operate more efficiently and effectively, leading to lower energy costs and reduced downtime due to equipment failure. It also helps to prolong the lifespan of the cooling equipment, which reduces maintenance and replacement costs over time. However, traditional water softener systems often carry high running costs, requiring large volumes of salt and water for regeneration processes. Most of the costs are associated with running regeneration cycles too long, and a lack of automation and monitoring of effluent flows. Cycles often work on a timer basis so in periods of lower flow, you could be creating excess waste streams.

Next-generation water softening technologies offer a cost-effective way of preventing scale while limiting the cost of salt and water for regeneration processes. The technology incorporated into Envirogen’s EcoSave high efficiency water softener system takes the guesswork out of regeneration cycles, realising the full benefits of water softeners. Advanced conductivity sensors detect the moment the ion exchange resins are regenerated and stop the rinsing cycles. This, combined with a counter-current regeneration flow, means EcoSave systems generate up to 80% less effluent water and use up to 60% less salt than conventional softeners.

One of Envirogen’s core EcoRange products, EcoSave is the most efficient water softening plant on the market. Its compact, space-saving design provides a high flow of softened water for use across many data center processes.

Reverse osmosis

Reverse osmosis water system technology (RO) uses a semi-permeable membrane to remove dissolved solids, organic matter, and other impurities from water. It is a commonly used treatment method in data centers, where it’s often used to treat the makeup water that is used in the cooling system. Makeup water is the additional water that is added to the cooling system to replace any water that is lost due to evaporation or leaks. If the makeup water is not properly treated, it can become contaminated with minerals, bacteria, and other impurities that can cause scaling, corrosion, and other issues in the cooling system.

RO is an effective way to remove these impurities and ensure that the makeup water is clean and free of contaminants. It’s also an environmentally friendly solution, as it reduces the need for chemical treatments that can be harmful to the environment. One potential downside of using RO for data center water treatment cooling is that it can be energy intensive. The process requires a significant amount of pressure and energy to force the water through the membrane, which can increase the energy consumption of the cooling system. However, the benefits of using clean, high-quality water in the cooling system may outweigh the energy costs associated with using RO.

Envirogen reverse osmosis water systems are based on various fundamental features, depending on the product and application. Our systems typically recover around 75% of incoming water streams. For even greater efficiency, nanofiltration modules can be added to filter the concentrate and achieve an overall 90% water recovery rate, which ensures that only a small amount of the incoming water stream is sent to drain as waste. We also offer a range of optional variable-speed pumps for improved process control and energy efficiency.

Direct nanofiltration – water recovery, water recycle and reuse with advanced hollow fiber membranes

Direct nanofiltration (dNF) is a membrane filtration technology that uses a semi-permeable membrane to remove dissolved solids, organic matter, and other impurities from water. It is a sustainable solution that can be used to treat wastewater and produce high-quality water that can be reused for non-potable purposes such as cooling.

Envirogen’s PureSep NF systems are highly innovative and are often used as a single-step replacement for multiple process stages, including coagulation, clarification, sand filtration, ultrafiltration and reverse osmosis. The PureSep nanofiltration plant also has a low chemical requirement and delivers significant energy savings and carbon footprint reductions too, when compared with conventional technologies, such as reverse osmosis, adsorption, and oxidation.

For performance assessment and for optimal system design we offer lab-scale bench-top pilot testing; and skid-based PureSep NF membrane pilot plant trials for on-site testing. The PureSep NF pilot plants are mounted to skids with forklift slots for easy offloading and on-site positioning. They allow for long-term testing, allowing you to gain thorough insights into the behaviour of our dNF membranes for data centre water treatment, over a longer period, continuously. Datalogging allows for in-depth analysis of the test results.

Envirogen PureSep NF is a unique new membrane-based filtration process that leverages the strengths of hollow fiber membrane technology and nanofiltration membranes (NF) into a sustainable membrane filtration solution. Nanofiltration remains unique in the water treatment industry with only very few nanofiltration companies worldwide offering similar nanofiltration systems.

Filtration and other water treatment for datacenters

Filtration is a key method for removing impurities and contaminants from water. There are several types of filters available, including sand filters, activated carbon filters, and multimedia filters. These filters can be installed at various stages of the water treatment process, depending on the level of filtration require and can be used alone or in combination with other treatment methods to produce high-quality water that can be reused for cooling and other operational purposes. Other treatment methods that can be used including UV disinfection and ozonation.

Envirogen water technical support services

At Envirogen we offer a range of services to help data centers optimize their cooling systems and improve their water and energy usage. Led by our expert process engineers, we will collaborate with you, helping clarify your specific needs, from initial consultation, through to post-installation service and maintenance support:

  • FREE INITIAL ASSESSMENTS to identify the most efficient methods for saving energy, water, waste, and money.
  • A core range of proven for your entire water treatment process.
  • Remote water monitoring technology, designed to optimise performance and minimise downtime. PureCare RemoteView is secure, resilient, and created with the highest level of end-to-end cybersecurity in line with international security standards, plus industry 4.0 guidelines to ensure that your operation is fully resilient.
  • Retrofit and plant refurbishment or plant upgrade services to extend the life of your data center water treatment plant by reviewing and upgrading specific parts of your system.
  • Mobile water treatment systems guarantee streams of purified water even if your demand or current supply changes dramatically, such as when switching from surface water to groundwater. Envirogen can provide temporary rental or permanent mobile equipment to help maintain the water quality used in the cooling system.
  • After sales support – comprehensive support from our team of expert engineers who can provide maintenance checks and emergency breakdown cover, should you need it.

Overall, we provide agile thinking, quick decision-making, and many years of expertise to each project and we will work with your team to design flexible and innovative solutions to meet your exact data center water treatment needs.

Summary: Sustainable water treatment solutions for data centers

Water usage is a significant sustainability challenge that requires innovative and sustainable solutions. Water treatment technologies for datacenters, such as dNF, RO, and water softening can be used to produce high-quality water that can be reused for cooling and other operational purposes. These technologies have their own advantages and disadvantages, and data center operators need to consider their specific needs and operational requirements when choosing a water treatment solution. The adoption of sustainable water treatment solutions for data centers can not only reduce water consumption but also promote water sustainability in the data center industry.

As businesses continue to move to the cloud and consumers demand more data-hungry services, the demand for water will only increase. That is why it’s important for businesses to be aware of the impact their move to the cloud could have on our environment and take steps to mitigate it. Fortunately, there are many conscious companies working on innovative solutions to reduce water usage in data centers. So, while there is still work to be done, there is reason for optimism when it comes to reducing the impact of the data centers on our environment.

Get started on your data center water treatment plan.  Request your FREE, no-obligation assessment on how you can save energy, water, waste, and money. Contact Us Today.