Concrete Tanks for the Fish Farming
Posted by Admin - 20 August, 2018
In 2017, Norway’s fish and seafood exports amounted to the equivalent of 36 million meals every day, year round, the Norwegian Seafood Council reports. A large portion of this is cultivated in fish farms which, at an increasing rate, are being moved onshore, out of the sea.
Protecting and waterproofing the concrete tanks used in land-based fish-farming requires very specific solutions – Hans Kristian Kobel, Key Account Manager at Master Builders Solutions in Norway, explains why.
Hans Kristian Kobel, why are fish farmers in Norway moving their facilities onshore?
Last year, Norway exported 2.6 million tons of fish and seafood, 70 percent of which was Salmon, and one million tons of which were sourced from aquaculture. Fish farming is an important industry in Norway, and the global market of course expects healthy fish. Increasingly, in sea-based fish farming, the latter has started to pose challenges: Treating the fish in order to make them more resistant to certain bacteria has led to the development of other diseases and to the transmittal of those back into the environment. An unacceptable situation for many reasons, farmers started to look for solutions, and, ultimately, began moving their aquaculture facilities onshore.
How does land-based fish farming work? What benefits does it provide?
First and foremost, the farming of salmon – a species that accounts for the major share of Norway’s fish farming – has always been a primarily land-based operation. It was only during the last stage of their growth that the fish were transferred to the sea. Similarly, today, the fish spend most of their life in freshwater tanks, and only for the last stage the tanks are filled with saltwater that, in terms of its composition and temperature, is very similar to seawater. The health of the fish also vitally depends on the simulation of real daylight conditions – long days in summer and long nights in winter – inside the aquaculture facilities.
One advantage of land-based fish farming is that the sea as an eco-system remains completely untouched by the operation. And land-based fish farming has even more benefits in terms of the environment: Prior to pumping it into the tanks, the water is cleaned to provide a healthy environment for the fish, and any wastewater is conducted through efficient treatment facilities before it is re-used or fed back into the natural water cycle. In summary: Moving the entire operation onshore means higher fish production, less loss, less waste, less to none environmental pollution, and significantly less medication for the fish which, nevertheless, stay much healthier.
What exactly does such a land-based fish farm look like?
They are large structures – many of them with thousand square meters or more of surface area – that greatly facilitate monitoring and controlling environmental conditions. These vast halls contain a high number of tanks of up to eight meters in diameter and five meters in depth. The tanks are made of concrete, either cast as a whole or assembled from individual elements. And the concrete used for this requires very specific protection – for the benefit of the salmon as well as against the impact of the water and, even though the water is changed frequently, fish excrements.
In this highly particular environment, what is the best kind of concrete protection?
Our MasterSeal M 689 polyurea coating is the optimal solution here: The product can be applied very quickly and without any seams and – with a service life at least equal to that of the concrete tank – it also is a de-facto maintenance-free solution, unless damaged mechanically by pointed or sharp-edged objects. Epoxy-resin coatings would not be able to withstand the structural movements of the tank, resulting in cracks. MasterSeal M 689 provides very good crack-bridging properties. In fact, fish farms are also working with epoxy-resin-based products, but there is an additional problem next to the insufficient bridging of cracks: Although it generally seems to cause no harm to the fish, in some cases there were detectable traces of epoxy in the animals. MasterSeal M 689, on the other hand, has been certified for contact with potable water, and is thus completely unharmful to fish. And the smooth surface without any joints or ridges also ensures the animals cannot injure themselves.
It seems that immaculate surfaces are a key property here. Are there any specific tips and tricks in this regard?
Yes, there are – but they are the exclusive domain of the specialists. Coating the inner surfaces of fish tanks with MasterSeal M 689 requires application expertise specially-certified by Master Builders Solutions. Such applicators have the necessary know-how, which includes the application method required to obtain extremely smooth surfaces. We are acutely aware of our responsibility here and sell MasterSeal M 689 for fish-farm application to certified professionals only. Because it is only through technically sound application that we can ensure the best-possible performance for our product – including waterproofing and protective properties, perfectly smooth surfaces, and freedom from maintenance.
How are fish farmers in Norway responding to the proposal?
Very favorably. Right now, there are some 75 projects being planned or under construction, many of them to use MasterSeal M 689; and this does not include the many projects successfully completed in the past few years.
Of course we also benefit from the fact that we can offer complete solution packages. While our MasterSeal M 689 waterproofing and protection coating is the key component of those packages, large fish farms, like any other industrial facility, require other construction-chemicals solutions for their operation as well: additional waterproofing solutions, floor coatings, or precision grouts, for instance. We offer premium-grade, complementary solutions. The data sheets and certification documents we can provide potential customers with often address not just individual products but complete system solutions – many of them particularly suitable for application in large-scale fish-farming facilities.
