FISH FARMING TECHNOLOGY
by Pedro Gómez, CEO of Apria Systems and German Santos Bregel at APRIA Systems
Apria Systems is a technologybased company with more than 10 years of experience specialising in consultancy and engineering services.
A cutting-edge recirculating aquaculture system With a determined sustainable and environmental commitment, Apria Systems are strongly focused on innovation to provide advanced efficient solutions –mainly based on membrane and advanced oxidation technologies– for the purification of industrial streams in the chemical and related industries to fulfill the environmental regulations. At present, one of the company’s most ambitious and innovative activities relates to the aquaculture sector. Over the last few years, the implementation of recirculating aquaculture systems (RAS) has increased worldwide. However, these systems are expensive to purchase and operate, and require high biomass culture densities, implying the fast accumulation of toxic metabolised compounds in low water volumes, and, hence, demanding significant volumes of fresh water. Thus, RAS end-users need cost-efficient technologies able to work under these conditions. The current solutions available on the market are mainly bio-filtration and ozone treatments. Unfortunately, they cannot properly work under these challenging conditions, showing efficacy fluctuations and start-up periods that increase the production stages and their costs. This framework encouraged APRIA Systems to develop a novel technology for the treatment and reutilisation of marine and brackish water in RAS: the ELOXIRAS System. The high innovative potential present in ELOXIRAS has been recognised by the European Commission through the Executive Agency for Small and Medium-sized enterprises (EASME), which awarded the development of the product through the Horizon 2020 funding program’s SME instrument call SFS-08-2014/2015 ‘Resource-efficient eco-innovative food production and processing’ (Grant agreement Nº 698494). It is based on electrochemical oxidation, generating a mixed oxidant without the addition of chemicals, purely by applying an electrical potential between two electrodes in the water to be treated. This technology achieves high removal rates of contaminants such as total ammonia nitrogen (TAN), nitrite, and organic matter, also presenting a high disinfectant efficacy. (Photo 1) The novelty of the treatment system is its ability to contribute to enhancing the productivity of different marine species and reducing the environmental impact: • Allowing higher culture densities. • Reducing new water intake consumption and, thus, proportional wastewater generation. • Removing whole key pollutants in an efficient way (> 90%). ELOXIRAS is a modular and versatile solution, which integrates three main steps in the treatment process: (i) pre-treatment by filtration of the water, (ii) main treatment by means of electrochemical oxidation reactors for the removal of pollutants and pathogens, and (iii) posttreatment for the removal of undesired byproducts. (Photo 2) The untreated water from the culture tanks flows by gravity. To guarantee the removal of solid particles in the main treatment, it is filtered by a drum filter with a minimum filtration level of 50 microns. Then, the water flows to a buffer tank that acts as accumulator, where the use of an auxiliary skimmer can contribute to enhancing the separation process of solid particles. As a final pretreatment stage, the water is pumped from the buffer tank to a security filter. In case the main treatment is not necessary, the water pretreated by the drum filter - and the skimmer - can be pumped directly to the culture tank, thus, saving on energy costs. The water flows then to the main treatment area, which is formed by ELOXIRAS electrochemical reactors comprised of electrode pairs coated with a special catalyst material. The oxidation reactions are promoted in the 54 | May 2018 - International Aquafeed