Large scale intensive recirculation systems and their potential development within England
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Large scale intensive recirculation systems and their potential development within England

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By Dr Mark Burdass

By Dr Mark Burdass

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Large scale intensive recirculation systems and their potential development within England Large scale intensive recirculation systems and their potential development within England Presentation Transcript

  • The Potential for Recirculation Aquaculture Dr Mark Burdass
  • Recirculation Systems • Systems used worldwide • Production capacity depends on treatment system • Defining Recirculation Systems: – System that recycles and renovates water for the culture of aquatic organisms!
  • Global Perspective • Successful large scale recirculation aquaculture facilities in UK, Norway, Europe, US, Canada & Australia. • Highly intensive recirculation facilities used in Scotland to produce salmon smolts
  • Definition • Original definition 95% recycle (based on flow), means 5% exchange per pass • More recent systems defined by daily volumetric exchange rates (10% per day) • Lots of challenges with systems recirculating water at < 5% per day
  • Advantages • Controlled Environment – Controlled temperature environment – Allows controlled product growth rates – More efficient food conversion – Predictable harvest routines – Allows production all year round – Biosecurity advantages – Enclosed environment means production free of predators and other damaging wildlife – Allows efficient inventory control • The systems designed to conserves heat and water through water reuse – Reconditions the water through filtration processes • Allows effective economies of scale – This results in high production per unit area – Save on handling equipment as used more intensively.
  • Advantages • Environmentally sustainable – Use up to 99% less water than a conventional aquaculture facility – Less than 1% of the land area – Allows waste to be managed in an environmentally safe manner – Allows waste to be further processed or used for hydroponics – Producing tropical fish locally has low carbon footprint because of low food foodmiles in production
  • Advantages • Not restricted to traditional aquaculture production locations • Not restricted to traditional UK aquaculture species – Species such as barramundi, tilapia and catfish possible in UK • Allows production to be placed near to market
  • Why Recirculation Systems • Challenges – High Initial Investment • Compared to other production methods – Financing can be an issue because investors often want fast returns – Technology is not well known • Getting better – Very short response time – Reliability of electricity supply critical – Lack of track record • Failures common • Hard to finance
  • Challenges • Not as yet able to compete with large scale aquaculture production • Most Recirculation farms are under 500 tonnes in size • Don’t have the economies of production volume – Supermarket product volume requirements often above production of a single unit
  • Other Challenges • There have been a number of high profile failure in UK and across Europe • Often difficult to determine why they failed, however: • The reasons are various but have included: – Technology was labour intensive and therefore running costs were too high – Poor Design • Often under-capitalised – Poor management decisions – Over optimistic market forecasts for product sales – Inexperienced staff
  • System Comparison • Conventional intensive tilapia • Recirculation tilapia farm farm • 17.4 tonnes per ha • 1,340 tonnes per ha per year per year • Water use: 21 m3 per • Water use: 0.5m3 per kg of production kg of production
  • Uses for Recirculation Systems • Hatchery • Nursery • Quarantine • Advanced fingerling production • Purging market sized product • Grow-out table production • Near market site holding system
  • Running Costs • Food and labour are the still the two main costs • Heating and pumping often amount to less than ¼ of the above • Initial capitalisation is a very significant cost compared to conventional aquaculture • Possibility for large units of using renewable energy supplies thereby reducing costs in the long term
  • Systems • High Stocking densities do not constitute an efficient recirculation system! • High feed rates per day do! • It takes feed to grow fish! • Food is the main consideration when designing and predicting the capacity of a system. • An intensive recirculation system has a high capacity to grow fish rather than hold them
  • Technology • The technology has been available for over 30 years • Reliable • Efficient • Most failures are down to mismanagement of systems or producing inappropriate species
  • Filtration System must: • Remove solid wastes – Settleable, suspended and dissolved • Convert ammonia and nitrite to nitrate • Remove CO2 • Add oxygen • Maintain acceptable pH • Control Pathogens • Keep up with the generation of waste
  • Recirculation Process Diagram MAKE-UP WATER BIOFILTER NH3 CO2 REMOVAL AIR BLOWER REMOVAL OZONE DESTRUCTION O3 BY UV MONITOR O2 ADDITION O3 ADDITION CULTURE TANKS CLEAN WATER FROM BOTTOM DRAIN UPPER LEVEL IN TANK 15% (SIDE BOX) 85% DRUM FILTER SWIRL SEPARATOR PUMP SUMP FILTRATE BOTTOM DRAIN 15% SLUDGE TO SEPTIC TANK WASTE
  • Key Water Quality Parameters • Dissolved Oxygen + • Ammonia-Nitrogen (NH3 & NH4 ) - • Nitrite-Nitrogen (NO2 ) • pH • Alkalinity • Carbon dioxide (CO2) - • Nitrate-Nitrogen ( NO3 )
  • Misperceptions • Overly complicated • Prone to catastrophic failure • Only suitable for high value species • Needs highly educated staff to run
  • Key Issues for success • Use proven technology in system construction • Ensure system has effective monitoring systems • Build in back up systems to key processes • Most success has come from small units which have scaled up • Use species with a track record in recirculation systems • Be sure of the market
  • Key Issues for success • Business plan assumes market prices will drop once production starts • Grow species with a short production time to improve cash flow • Ensure product is fit for market • Ensure have the trained staff to operate the systems