Recirculation and Depuration Technology

Recirculation and Depuration Technology

Recirculation

Recirculation technology allows the reuse of water within aquaculture facilities and often includes treatment systems to ensure that water quality is retained at the highest standards. BIM has supported the adoption of this technology by the aquaculture sector through research, funding and technical support to bring the technology to commercial viability.

One project where BIM worked with industry to trial an innovative freshwater integrated multi-trophic aquaculture (IMTA) system in Ireland was on the RAMPS project – Recirculation Aquaculture Multitrophic Pond Systems. The aim was to assess suitability of split ponds for production of fish in Irish conditions. The utilisation of duckweed and algae to treat wastewater and potential ancillary benefits was also assessed.

If successful, the technology had the potential to:

• Significantly expand Ireland’s freshwater sector through the utilisation of marginal agricultural land and peatland for aquaculture production.
• Diversify freshwater production traditionally based on salmon and trout to include perch and thereby increase aquaculture production 

A trial was conducted by BIM in conjunction with Keywater Fisheries Ltd.

• These RAMP systems involve the use of modified split ponds to produce fish
• European perch were spawned out of season by Keywater Fisheries in their state of the art hatchery
• The perch eggs develop quickly and hatch within days
• The juveniles are kept indoors in a controlled environment until big enough to be placed in the RAMPS system
• The fish are weighed, counted and transferred to the pond systems
• The systems are based on split pond systems developed by the US Department of Agriculture National Warmwater Aquaculture Station in Mississippi
• In the RAMPS system the fish are curtailed in part of the pond whilst the remaining part of the pond utilises algae and duckweed to treat any waste products
• Water is circulated using paddlewheels or airlift systems
• Environmental parameters are constantly monitored.

The Results

The fish were harvested, and initial results were very promising with high survival and growth. Future work will concentrate on modifying the systems to improve yield, energy efficiency and system performance. These learnings can then be fed back into Industry.

Depuration

Depuration of seafood is the process by which marine or freshwater animals are placed into a clean water environment for a period of time to allow purging of biological contaminants (such as Escherichia coli) and physical impurities ,such as sand and silt. The most common subjects of depuration are  bivalves, so oysters, clams, and mussels.

BIM assist those that wish to set up one of these units in the area of technology required, HACCP plans required and verification testing. We can also advise on available funding.

As depuration units are required to enable shellfish for sale for human consumption from Class B waters, BIM has taken the initiative to develop a depuration workshop for aquaculture operators.

Note: Due to Covid – 19 workshop dates are yet scheduled.

Key Workshop Aims

• Review the shellfish safety systems in Ireland over the past ten years.
• Provide a forum for the partners in the Irish Shellfish Monitoring system to meet and take stock of  developments and ongoing issues.

• Continue to build a shared understanding of risks/data on biotoxin and microbiology issues, in order to support risk management decisions.

• Provide an opportunity to present key research and to encourage scientific collaboration with agencies/researchers.

• To work with the Irish shellfish industry and state agencies in the promotion of high quality and safe shellfish and generate key questions for research and debate.

• Strengthen our focus on shellfish microbiology, including viruses, water quality and risk management.

Recirculation and Depuration Technology projects are funded through the Knowledge Gateway Scheme which is established under Union Priority 2 of Ireland’s Operational Programme under the EMFF and is co-funded by the Irish Government and the EU.