Pilot project is desalinating seawater in South Texas

Transcript

Noe Cantu - Manager, Laguna Madre Water District

The way I describe it is, we're at the southernmost tip of Texas in the Rio Grande Valley, and we provide water to South Padre, Port Isabel, Laguna Heights, Laguna Vista, and Long Island Village. The biggest thing to remember about our area is that we have year-round residents, and we're also a tourist area.

We draw our water from the Rio Grande, which is fed through the Falcon and Amistad Reservoirs. Over the last few years, it's gradually declined as far as the reservoir levels go. The biggest thing is drought condition. And it's been ongoing for over five years, and we need to make sure that we have a sustainable water source. You want to widen your portfolio, you want to make sure that we have other resources than just the one to make sure that we continue to be able to provide water to our community.

Seawater desalination hit all of our markers, our close proximity to one of our current plants, you know, unlimited supply. We're a coastal area. We take advantage of what we have available to us.

Charles Ortiz - District Engineer, Laguna Madre Water District

We have salty water. I mean, that's our source. You got to get the salt out to be able to drink it. And we're right on the coast.

We have nice channels that have been built in the 1930s that are 30, 40 feet deep. So, we have access to good source water from a seawater standpoint. The tides help us; there's a lot of circulation here. So, it's an available resource that we can put to use without any adverse environmental impacts.

The TCEQ has public drinking water rules that are based on conventional systems. And this is an innovative alternative treatment. The rules aren't written. So, we have to demonstrate it through actual data collected from our proposed water source, which is the Port Isabel Channel Turning Basin.

Our Port Isabel Turning Basin is considered part of Laguna Madre Bay. We're also just north of the Brownsville Ship Channel, and the Brownsville Ship Channel is what goes out to the open Gulf. But because of our close proximity to the Gulf, especially here south of the causeway, if you're familiar with South Padre Island, it behaves the same as being out in the open waters. So, all that tidal exchange that's constant here is just really beneficial for our water quality source.

David Pettry - Principal, NorrisLeal Engineering Water

Over on the dock is where we have our temporary pilot intake set up. And so, it's drawing in water from the Laguna Madre, bringing it into the mixer, mixing it with chemicals to make it clear. We're bringing it into the clarifiers so everything can settle out.

To my left, we have the microfiltration which is the step to help prior to the saltwater RO [reverse osmosis] to make sure the water is as sediment free as it can be. And then over here, in this container, we have the saltwater RO which is the membrane where the raw water is going across the membrane, taking the salt out, and leaving the potable water ready for entrance into a potable water system.

Charles Ortiz - District Engineer, Laguna Madre Water District

We're at our existing water plant in Port Isabel. Our current diversion today is from the Rio Grande. And we're going to co-locate our seawater improvements to the same spot, where we'll have a diversion from the bay, the Port Isabel channel, and it'll essentially comingle with our diversions from the river so they can supplement each other.

We have existing facilities, and we'll be able to run the systems in parallel to feed our existing entry point into the system. So, there's a lot of infrastructure that's already here to just make the project more efficient and save costs for our taxpayers.

We're actually planning to use reverse osmosis for both the river and the bay. It's the first time we've got to a reverse osmosis level of water quality, feeding the system regardless of the source. So, we're going to have the best water quality we've ever had upon completion of this project.

David Pettry - Principal, NorrisLeal Engineering Water

We've done several environmental surveys to find that the location we've selected inside the turning basin has the least impact. We're not impacting seagrasses. The environmental footprint that we're taking up has been minimized to the greatest extent possible.

Charles Ortiz - District Engineer, Laguna Madre Water District

What we do have is we have an outfall in place for our municipal sewer plant with diffusers. So, it just releases the water at a low flow, prevents erosion, protects the environment. So we don't have any effects with the discharge. And so, we mix with our treated effluent and the concentrate to get a dilution. We have our tides that exchange every six hours or so. And with all those conditions, you reach a dilution that makes it safe to return back to the bay.

David Pettry - Principal, NorrisLeal Engineering Water

The people of Port Isabel and Laguna Madre Water District have entrusted us with ensuring that they have water security not only today, but, you know, 20, 30, 40, 50 years from now.

Noe Cantu - Manager, Laguna Madre Water District

This ensures that we don't only have to rely on the Rio Grande, that seawater desalination, for us, is our answer to be able to provide for generations to come.