by James Leigh, Head of Business Development, Evoqua Water Technologies, USA
Sustainability is a hot topic but as well as ensuring environmental and regulatory compliance, the focus of any sustainability programme should also be on solutions that deliver wider business benefits, including cost and operational efficiencies. And this is certainly true when it comes to the aquaculture sector and disinfection for water treatment. Getting the right technology solution is critical for environmental protection and the health of fish but it has the potential to offer much more.
In any fish farming environment, effective filtration and disinfection is critical. It is essential to remove or control waste products for successful production, disease management and yield using effective biological and mechanical filtration and disinfection systems that recycle and treat the used water from aquatic farming. Two highly effective, proven methods of disinfection are ultraviolet (UV) and ozone.
Innovative technology that delivers more
UV is one of the most highly effective and sustainable disinfection methods. It works by applying light in wavelengths that damage and destroy DNA of biological organisms. This prevents the build-up of harmful populations of heterotrophic bacteria and opportunistic pathogens. The effectiveness and efficiency of the UV disinfection unit depends on the turbidity of the water, size, and species of the target organism. Although UV is highly effective, it cannot inactivate 100 percent of bacteria. Therefore, UV is best used in combination with mechanical filtration that effectively removes organic matter from the water.
Beyond their disinfection performance, one of the great benefits of UV systems, such as Evoqua’s ATG™ UV branded Wafer™ system, is their sustainability credentials. They are low energy, and the high-quality lamps have a long operational life, minimising replacement costs. And, with large scale fish farming increasing, UV technology’s ability to disinfect water in one cycle provides advantages for efficiency by increasing throughput.
When UV is combined with ozone technology, an aquaculture disinfection system can be strengthened further. Ozone is one of the most powerful commercially available oxidising agents. Oxidation and disinfection occur when ozone meets substances including bacteria, viruses, parasites, and algae that exist in fish farming systems. It breaks down long complex protein molecules and damages cell nucleic acids of microorganisms.
It works by ozone gas simply mixing into water creating the solution for disinfection. The gas quickly dissolves in water, contacts with wetted surfaces, and then decomposes back to oxygen in solution, effectively leaving no residuals in the treatment system.
Performance and wider operational and sustainability benefits make ozone and UV superior disinfection solutions. They are not only effective at removing pathogens and parasites but also reduce water usage by increasing recirculation rates, support farming growth levels and are chemical free and safe for the environment and operators. Importantly though, using industry-leading technology systems will reduce operating costs, minimise maintenance requirements and support ongoing sustainability initiatives.
A case in point: ozone disinfection
Ideal Fish, the only producer of branzino in the United States, operates a recirculating aquaculture system (RAS). Controlling the quality of the water is of utmost importance, as this process, left untreated, can create a breeding ground for virus and bacteria growth, as well as a generally poor environment for the fish to grow in. As the fish grow, they are graded and transferred to larger tank volume systems which then requires larger more complex disinfection and cleaning processes. The larger the fish grow, or the more biomass in the tank(s), the more waste is produced, ultimately further increasing the loading of suspended solids and dissolved nutrients both in the tanks and in the general system itself.
The team at Ideal Fish required an efficient and economical disinfection solution to improve water purity and create a more biologically efficient environment for growing a live product. Evoqua identified the solution was ozone technology. The micro flocculation of fine solids created by ozone was of importance in this application, as it will improve the farm’s particulate removal efficiency via their filtration process. Ozone will also change the characteristics of dissolved organic compounds (DOC) by oxidation and precipitation, making it easier to remove DOC by biofiltration and sedimentation.
Evoqua’s disinfection team provided one MNG8X34 Ozone Generator to meet the needs of Ideal Fish. The team at Ideal Fish saw a definite increase in water clarity and fish performance, enabling them to further increase the growing and performance parameters with controlled and precise use of the ozone facility. Its operational parameters are now more concisely used for either individual or group tanks, due to the separate SEP systems capabilities and ramping up or down in percentage use requirements which have enabled Ideal Fish to have a more focused concise production control from the unit, than any previously utilised. With the unit’s compact modular design and easy to operate features, the solution will meet today’s and tomorrow’s water quality needs.
Navigating the impact of climate change
Today, UV and ozone disinfection systems are also proving highly effective in supporting the aquaculture sector as it navigates the impact of climate change. In sea-based farming environments, such as recirculating aquaculture systems (RAS), global warming is increasing the number of parasites present, meaning new strategies for water disinfection are vital to protect operations and the environment.
The new Vibrio bacteria species found in UK waters is evidence of this. Research scientists from the University of Exeter have found the presence of a wider diversity of the bacteria. Species V. rotiferianus and V. jascida have never been found in UK waters before, and usually inhabit warmer waters. The presence of these two previously absent species in the region provide evidence that as sea-surface temperatures rise, UK waters are becoming increasingly hospitable for a wider variety of invasive bacteria and micro-organisms.
Looking ahead
It’s important not to overlook the importance of water treatment when it comes to sustainability. Whether the initial aim is to navigate the impact of growing parasite populations, improve fish welfare, or ensure environmental compliance – or all the above – we must prioritise innovation and the technology solutions that can deliver against these objectives and more. A sustainable future starts today. Partnering with the right treatment partner that has the experience, expertise, and advanced technology, not only supports environmental initiatives but also helps the aquaculture sector simplify operations, increase efficiency, and improve costs. It’s time to take action.
