McKim & Creed Knowledge Hub

Recirculating Aquaculture Systems: Fish Farming of the Future

Recirculating Aquaculture Systems (RAS) are advanced fish farming systems that use a closed-loop water circulation system to maintain a controlled aquatic environment for fish, shellfish, and other aquatic organisms. Indoor RAS has gained popularity in Europe over the last decade, with European countries at the forefront of developing and implementing RAS technology. Gaining popularity in the United States, Indoor RAS are often smaller and more specialized focusing on niche markets or specific types of fish such as salmon, trout, tilapia, and shrimp. Indoor RAS is extremely efficient, enabling year-round fish production regardless of weather or environmental conditions. They also have the benefit of being able to operate in both urban and rural settings.

McKim & Creed Project Manager Nicole Stafford and Senior Project Engineer John Van Gehuchten PE, share their expertise on this emerging industry.

What role does RAS play in our lives?

Meet our ExpertsVAN GECHUCHTEN: The Recirculating Aquaculture Systems (RAS) are a growing form of fish husbandry. More and more of the food you buy at the grocery store will start to come from these kinds of systems.

The traditional way of farming fish takes place in what’s called offshore aquaculture facilities, or sea cages, that sit outside in the water. Boats go through and provide food and antibiotics and whatever else the fish need, and the currents would carry everything away.

While sea cages are still legal, they are controversial due to concerns about environmental impacts. As a result, regulations governing the use of sea cages may be strict, and in some cases, the use of these facilities may be prohibited in certain areas or for certain types of fish. Problems can arise from fish being in sea cages. They could get parasites that will infect the fish and there’s always worry about wildlife ripping through the cages and getting at the product.

There are environmental and health benefits to the Indoor RAS as well as production benefits because these facilities are land-based and can be basically anywhere. We could put one in New York and it’s going to grow fish from New York. You can put one in Texas and grow fish in Texas. You’re not growing fish in Chile or Norway and then having to fly 3,000 miles to the United States.

STAFFORD: I think there’s a negative connotation with farm-raised fish in general because of how the cages have impacted the environments around them.

But I think Indoor RAS has the potential to reverse that connotation as people become more educated on RAS and how much better they are for the environment.

Do you see RAS as the way of the future and what will that look like in the next 10-20 years? 

STAFFORD: You can already see the change in where the fish are coming from in the grocery stores. If you buy packaged salmon at Costco or ALDI, it says where it comes from and for example, a lot of the Chilean salmon is farmed in sea cages. But a lot of the Norwegian salmon is already being taken from land-based RAS farms. So, it’s just kind of cool to see the difference in the quality of fish that you get.

With RAS, you have a lot more control over the environment that the fish grow in. You can control the water quality and have more control over the quality of fish that you’re putting out, which allows you to certify the product as organic which is really attractive to consumers in the United States and even worldwide. I’m sure RAS will be growing in popularity over the next several years and in the next 10 to 20 years they’ll be popping up all over the place.

How long have you both been working with RAS for McKim & Creed?

VAN GECHUCHTEN: I want to say we started this about three years ago.

STAFFORD:  Over the course of the past three years, we’ve worked with multiple clients on multiple opportunities, which has given us a lot of time to familiarize ourselves with the existing technology. John and I have done a very good job of learning the background over the last few years.

VAN GECHUCHTEN: There are two major components. There was the way that RAS had been running to date and there has been a growing pain in the industry as the scale of aquaculture systems grows.

There’s an older way of doing it with a small-scale system that doesn’t reuse the water much.  That was where the system started and now, they are evolving. We’re still at the early stage of the growth curve in terms of technology and in terms of what benefits can be provided. And we have gone from getting our understanding that in three years we’ve gone from getting our start in the project and understanding where people are coming from to actively innovating and trying to make the systems better, improving efficiency and cost effectiveness, from both capital expenditure and operating expenditure points of view.

RAS technology has been in existence, but it’s evolving. What considerations, especially in the United States, need to be taken?

STAFFORD: The biggest thing for us has been trying to learn from experiences others have had over the past several years of implementing this concept. It’s a European technology or rather a technology that’s been primarily implemented in Europe, so a lot of Americanization needed to happen to the design.

Through the years since the RAS has been implemented in Europe, they’ve made little tweaks every time they’ve constructed one and we’ve been privileged to see the difference in how they operate based on those adjustments. We’re confident we can take lessons learned from existing operational systems to increase efficiency and value with our designs.

VAN GECHUCHTEN: There are regulatory differences, but some of it is also climate and environmental. If we have a process in Texas or in Florida growing salmon that likes to be in 54-degree water, you’ll have a much higher cooling load than if you were in New York because the climates are different. So, there’s some climactic changes to water quality, water use and reuse and disposal. We’re also encountering some of the leading-edge indicators like treating the water for various parameters of concern prior to use to make sure contaminants don’t get cycled up in the fish. We’re also evaluating health impacts throughout the fish’s life cycle.

STAFFORD:  There are a lot of different industries overseas that make use of the waste products from fish farms. There’s a large industry in Europe that takes fish guts and turns it into fertilizer. And while that is done and can be done in the U.S., it doesn’t seem like there’s quite as big of a market for it, so we’re challenged in applying a reuse methodology to get rid of some of the waste products that come from these systems. 

VAN GECHUCHTEN: That’s a really good point. There’s not a comfort to reusing those waste products here as much as in Europe.

What about this industry is exciting to you?

STAFFORD:  There’s a pioneer aspect to it. Growing fish or fish farming is not necessarily a new thing, but the technology is new and especially in the U.S., even if we’re not the first ones to build an RAS, we can be one of the first. It’s exciting to be involved at such an early stage.

VAN GECHUCHTEN: In our industry, we’re always chasing the leading edge of where technology is moving or what the next big thing is. I think this is going to be one of them because there are economic incentives, environmental incentives and health incentives that are all driving these products and we want to be part of that. What makes RAS exciting is that no one has quite figured out how to do this at scale cost effectively to the point to the point where everyone feels comfortable. There are a number of things that come close, but there is a lot of room to improve and I think that’s part of what interests us. It’s thought-provoking and exciting.

STAFFORD: Nobody wants to be the first, but they want to be the first ones to do it right. That’s what we’re trying to do.

Have there been any unexpected challenges that you’ve encountered?

VAN GECHUCHTEN: The biggest challenge right now is that we don’t have direct control over how long it takes fish to grow. Typically, by the time you start a project you can begin seeing a return on that investment, and that is the major holdup right now. For example, if I start building, it’s going to take me, let’s say, a year to build the thing. And then it’s going to take another two years to grow the fish. So that means if I spend money this year, it will be three years before I even start seeing a return on investment.

RAS development requires a long runway, and I think that has been the biggest challenge for our clients. How do you finance these kinds of projects? Yes, at the end of that three-year period you’ll start seeing a return, but that remains a large obstacle.

Any way we can, we use technology to try to accelerate that curve or drop the capital expenditure to make it more palatable and then we can drop the time to market. We’ve been looking at things building hatcheries first and then building grow facilities so that we can stagger construction. Taking fish from the egg all the way to a full-grown fish requires a number of steps. If we can do anything to accelerate growth to essentially start to see a return on your investment, that could help the viability of this project.

STAFFORD: Construction scheduling versus economics has been the biggest challenge. We’ve done a lot of value engineering over the last couple years to try to beat down the capital expense a little bit and get costs as low as we can while still performing at the quality that we need. But there’s only so much you can remove CapEx-wise before it starts to not be the level of quality that you need.

Has there been any discussion that will allow fish farms in the United States to become more sustainable?

VAN GECHUCHTEN: When we design, we always look for ways to incorporate sustainability. For example, one project is looking to use solar power to augment the system or use a groundwater helper and thermal loads to reduce how much chilling energy you need. We’re always looking for ways to improve energy efficiency and capital efficiency and that also has bottom line impacts.

STAFFORD: There are options in the U.S. for reusing fish waste products as well. It’s just a matter of finding the right partners and having those partners be in the right proximity to the farm.

What makes McKim & Creed the best choice to design these systems?

VAN GECHUCHTEN: A lesson learned from some of the systems that were unsuccessful was to use people that have good existing experience in the water industry and not rely entirely on fish farmers or technology vendors to put these packages together. Part of what makes McKim & Creed a great place to start is that we have municipal water and industrial water system experience of treating water, moving water, processing water. We have engineers that design tank systems and provide entire packaged facilities. We also have the industrial capacity to design systems that are not directly municipally involved.

At a drinking water plant, your main product is water. On the industrial side of water treatment, the water is not the prime product. We are supporting the production of a widget. If we’re working on a steel mill, we’re supporting production of steel. If we’re doing an auto plant, we’re supporting the manufacturing of autos; a food plant, we’re supporting the production of food. RAS combines water engineering with industrial engineering. While water is not the prime product, water is a much bigger part and component of aquaculture.

We’re in a very good place with respect to technological experience and industrial and water experience that goes back more than 40 years.

STAFFORD:  You nailed it. I mean, these farms are essentially just one big water treatment plant. And that’s one of the things that we do best, especially on the industrial side. We’re very good at bringing together multiple components that are outside of these water treatment plants and designing a functional system. Through experiences challenges to make one big seamless machine, we’ve been fortunate throughout the last couple of years to make a lot of good connections in the aquaculture industry to support our water treatment experience.

VAN GECHUCHTEN: We have very good perspective and technology partners that we can lean on to deliver. We have experience delivering private projects, which is different to delivering municipal projects.

Are you seeing anything that you’ve learned through designing aquaculture that you can apply to different markets? Or vice versa?

VAN GECHUCHTEN: There’s absolutely cross-pollination between the various systems.

Let’s take solids management and all the solids that get removed from that system. That type of system is very similar to what we use. So, our experience with water and managing solids is one aspect that can be reused. We’re working with our Buildings, Energy and Infrastructure (BEI) group to bring the best technologies for cooling systems into the fish farm. Some sources of water might have PFAS in them and we’re taking our experience with advanced water treatment to find a solution to treat the water before it comes into the RAS system. Our municipal water experts are already designing to eliminate those contaminates to make safe drinking water.

STAFFORD: The thing about water treatment plants is while the technologies are always developing, the basic process never really changes. So just taking solids removal for example. The unit processes are all there and since we have such great experience with designing treatment facilities, there’s a lot of technological overlap there.