Can Treated Wastewater Cool a Texas Data Center? How to Cut Potable Demand and Plan the Blowdown

Yes, in many cases treated wastewater can supply a Texas data center's cooling needs, which lowers its demand on drinking water. The catch is that every source has its own questions, and the money question is who funds the build first. Here is what we covered on our Live Show.

What water can a data center use besides drinking water?

Besides potable water, a data center can look at wastewater plant effluent, groundwater and rainwater collection. Each has pros and cons, and each has its own Texas rules.

Potable water is water treated at a water treatment plant to a drinking water standard. Towns are pushing back on sending it to data centers, so we expect potable demand to be limited to the workers. Data centers will need to bring most of their water supply themselves.

Even a closed-loop system needs refill water. The figure we have heard is about 10% lost. On a loop holding two million gallons, that is roughly 200,000 gallons of makeup. Some say 10% a day, and we would like to know the exact answer.

Does a nearby well mean my site has water?

No. Geology in Texas is hyper-local. Some sites sit on aquifers and others do not, and some are affected by drought more than others.

The state water board publishes drilling logs. You can draw a radius map around your site, download the logs and see what people actually got at each depth. We can help with that.

Check drought performance too. We have seen a well rated at a thousand gallons per minute test at about 20 gallons per minute during a drought.

How do we find a wastewater plant worth tapping?

Start with plants that have tight discharge limits. Those plants already treat to a high level, so the water may reach data center quality with something like reverse osmosis added.

TCEQ publishes a discharge map viewer online. Look at the permits near your site. Limits of 5 BOD, 5 phosphorus and 5 nitrogen, tighter than 10 BOD, point to plants already treating heavily.

You can also use EPA's ECHO site to see which plants are near their permitted flow. Under the Texas Administrative Code, a plant must start planning an expansion at 80% of permitted flow. At 90% average flow for three months, it must be in construction. Taking flow off that system could help avoid the upgrade.

If you sit at the downstream end of a collection main, a data center could draw off that line and build its own plant to reuse the water. We see this in Arizona more than in Texas, but it could happen here.

What can reuse water be used for, and how is it authorized?

TCEQ authorizes reuse for many uses. Blowdown, irrigation, fire suppression tanks and similar uses are options. Reuse is approved fairly easily where the water does not enter another water body.

One path is a 210 authorization. The 210E path lets a site reuse its own blowdown water and get a treatment system authorized to send it back into its own processes.

Data centers also have a lot of metal roof area. We are seeing more rainwater collection systems, which can feed blowdown, irrigation, fire suppression or even a public water system set up with TCEQ.

Permitting work like this often starts with a preliminary engineering report and TCEQ design submittal for a wastewater plant.

Who pays, and what happens in a drought?

The bigger question is not price per gallon. It is who funds the reuse build before the flow and the customers are there.

On another project, the client already holds the reuse permit. A data center, homes and an industrial park nearby all need water, but on different timelines. Who builds first is the hang-up. Even with permits in hand, reuse water needs potable water feeding the system. A data center should ask the utility about current growth in the area.

Plan for drought too. If reuse and rainwater are not enough, consider water hauling contracts or an emergency tap agreement with the city or water district.

Watch the full episode

The full episode is on YouTube: https://www.youtube.com/watch?v=JzN6Iq6SmxM

Frequently asked questions

Can a data center use treated wastewater for cooling in Texas?

Yes. TCEQ has paths to authorize reuse, including a 210 authorization. Source, quality and where the blowdown goes all need to be worked out.

How much makeup water does a closed-loop data center need?

Even closed loops need refill. We have heard about 10%, so a two million gallon loop would need roughly 200,000 gallons. Some say 10% a day.

Does a well next door mean I have groundwater?

No. Geology is hyper-local in Texas. Check the state drilling logs and how wells performed in the last drought.

I'm a small water district manager in Texas and a data center wants capacity. What should I check first?

Pull your plant's discharge limits and recent flow. Check how close you are to the 80% and 90% planning and construction triggers. Tight limits make reuse worth raising before potable capacity.

I'm a data center developer in Texas looking at a site with no nearby supply. What are my options?

Look at nearby plant effluent, groundwater tested against drought, and rooftop rainwater collection. Plan a drought backup and decide where the blowdown can go.

Related Resources

• Data Center Water Supply in Texas: How to Find More Water Before You Rely on Electricity
• Data Center Water Supply in Texas: How to Build a Water Plan That Holds Up
• Industrial TPDES vs. TLAP: Which Wastewater Permit Path Fits Your Texas Facility?

Not sure which water source fits your site?

We help developers and utilities sort out water options, reuse authorizations and discharge permits before they commit. Bring us your site and we will help you work out the questions.

We specialize in:

• Wastewater plant design and permitting
• Preliminary engineering reports
• TCEQ design submittals
• Water supply and well studies
• Site civil engineering for land development
• Construction administration

Modern Engineering Solutions, McKinney, Texas. Contact: (214) 833-6748 or mod-eng.com