The Introduction of Ozone andIntensive Water Treatment Systems for Purification into the UK Mandy Pyke
The authority on seafoodOzone (O ) is: A colourless, unstable, toxic gas with a pungent odour and powerful oxidizing properties Formed from oxygen by electrical discharges or ultraviolet light. It differs from normal oxygen (O2) in having three atoms in its molecule (O3).
The authority on seafoodO Used for purification in: Italy Spain France Japan UK Crustacea FAO Bivalve hatchery + Purification Plants
The authority on seafoodDepuration is The removal of low level bacteria( 4,600 cfu E.coli) Animals purge themselves Optimum metabolism Control environment in tank UV is meant to keep the water clean during process
The authority on seafoodFrom 1995 most systems based on 6 x Seafish designs 42 Hours minimum immersion time for all species Using UV only No attempt to remove ammonia or introduced suspended solids and contaminants
The authority on seafoodEffiacy of UV can bereduced Suspended solids Discolouration of Quartztube Age of lamp Operating Temperature Inappropriate flow rates
The authority on seafoodCross- contamination in tanks When clean seawater is introduced into a tank of shellfish, the animals inoculate that water, with material from the harvesting grounds and continue to do so Faecal material from one animal and its by-products may be ingested by other animals in the tank. O could reduce this cross contamination
The authority on seafoodOzone (O ) Is a powerful oxidising agent Used for disinfection of water and air inactivates pathogens, oxidize organic wastes (including colour) and nitrite, or supplement the effectiveness of other water treatment units. Very unstable, half life in seawater reported as = 5.3s Oxygen is produced as a reaction end productSource: Steven T. Summerfelt 2002.Ozonation and UV irradiation*/an introduction and examples ofcurrent applications. Aquacultural Engineering 28 (2003) 21/36
The authority on seafoodO O = Release of Energy = Breaks Cell Wall http://understanddolphins.tripod.com/dolphincaptivehabitat.html
The authority on seafoodProduction of ozone By electricity Also by U.V. Produced at UV < 200 (nm) nanometer Destroyed at 254 (nm) UV used for purification = 254nm as biocidal optimum Therefore insert O before UV
The authority on seafoodApplication of ozone into apurification tank Via venturi Bubble diffuser integrating a micro- bubble generating a gas-liquid dispersion device ensuring maximised mass transfer
The authority on seafoodHow much O should be applied FAO state... Ozone at a Difficult to measure concentration not exceeding 0.5 mg/l (in order to minimize O directly bromate production see Advise use below) can be used to treat seawater in batches for Oxidation/ Reduction periods up to 10 minutes. Potential (ORP) CEFAS ...or suitable Measured in mV using time/dose equivalent has Redox meter been added.FAO. Fisheries Technical Paper 511. Bivalve Depuration : Fundamental and Practical Aspects.A. Younger. CEFAS. Ozone Potential Application in Depuration Systems in England & Wales.Discussion Document . June 2010.
The authority on seafoodSetting an O doseOzone Redox E.coli / Commentconcentra Pot 100mltionMg/l mV Untreated Seawater(approx) ~200mV (remember,0.0 50 - Below 50mv, anaerobic 100 sediment, bacterial sludge. pH and t c variability)0.1 200 300 Poor quality natural water FAO: ~600mV0.2 300 30 Good quality natural water FSA: no un-reacted desired minimum level for aquaculture O to reach animals0.3 400 3 Upper limit for aquaculture and aquariums Seafish: 10%0.4 500 2 Damage to the epithelial tissues if aquatic life above, untreated0.5 600 1 Severe damage to aquatic life, near 100% disinfection starting point mV Control = Use to much and the animals0.6 700 0 Above 700mv complete die.Source: disinfection. Swimming pools,(http://media.live.harnesslink.com/files/f1038953 potable water treatment.750.pdf
The authority on seafoodDegassing un-reacted O Protein skimmer by itself adds nothing, will remove suspended solids and proteins Apply the O into protein skimmer Any un-reacted O is degassed to atmosphere
The authority on seafoodBromate formation Potential for brominated organic by-products Potential carcinogen No evidence take up by shellfish Requires bromide salts (are present in natural seawater ) Bromate level allowed in tap water = 10µg/l Not high risk in artificial seawater(Bromide not in the salts) Granulated activated carbon filter will remove from seawater.
The authority on seafoodLive Biological filter a substrate is provided for the growth of a biofilm that utilizes oxygen to convert ammonia and nitrites to nitrates, and oxidize organic matter It cleans the water Maria Teresa Gutierrez-Wing, Ronald F. Malone. 2006. Biological filters in aquaculture: Trends and research directions for freshwater and marine applications. Aquacultural Engineering 34 (2006) 163 171
The authority on seafoodAll operations can be incorporated No firm Seafish Bio- O advice on design filtration It depends CEFAS discussion Activated Protein document on web Carbon Skimmer Challenge your supplier UV Speak to your EHO
All unit operations incorporatedtogether The authority on seafood
The authority on seafoodNorovirus Can it bein Oysters removed by O ?? Gills 14.71% should be eliminated Cilia of mantle from water Labial palps May be eliminated from surface organs Stomach 13.97% Unlikely to be Digestive diverticula eliminated from 13.24%Wang et al. 2008. New target tissue for food-borne virus detection in oysters.Letters in Applied Microbiology ISSN 0266-8254 intestinal tract
The authority on seafoodNo apparent evidence to date o will guarantee total virus inactivationSOLUTION ISTO STOP CONTAMINATING FOOD GROWING AREAS
The authority on seafoodRichard EmansGerardo SaggiomoAdriatic SeaGroup Azzurra PescaFSACEFAS
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