Removal of nitrogen elements in culture water is one of the major concerns in recirculating aquaculture system (RAS). Maintaining a low concentration of nitrogen compounds is essential for a good quality of aquaculture production. Due to fish is very sensitive to the toxic ammonium/ammonia, nitrification biofiltration tank is often an integrate part of filtration in RAS to remove ammonium via nitrification. However, nitrate accumulation via nitrification in RAS is often observed during the operation, which is usually solved by replacing with the fresh water into the system. With the concern of water consumption, bio-electrochemical system (BES) is introduced in this study to realize simultaneous nitrate removal for the system while generating the electricity through electron transferring. A microbial fuel cell (MFC) with an anion exchange membrane (AEM) was constructed. The removal of nitrate from aquaculture water generated from RAS was achieved by nitrate migration across the AEM and heterotrophic denitrification in the anode chamber. To further investigate the potential application of BES in RAS, the cathode chamber was incubated with biofilm to do the nitrification while the denitrification processing in the anode chamber. The study gave a total inorganic nitrogen removal efficiency of 38.72% ± 4.99, and a COD removal of 86.09% ± 9.83. The average daily electricity generation was 67.98 A m-3 ± 13.91, and nitrate-nitrogen concentration remained at 21.02 ± 2.62 mg L-1 throughout the experiment. These results of treating aquaculture water indicate that BES has a potential to install within RAS for enhanced nitrogen removal. / MS

Fler svenskar vill konsumera mer inhemskt producerad fisk. Scandinavian Aquasystems odlar och försöker introducera fisken tilapia på svenska marknaden. Tilapia är en fisk som precis börjat göra intåg i Europa men är stor runtomkring resten av världen. En smakprofil som berättar hur länge produkten är sensoriskt tjänlig kan vara av hjälp. Denna undersökning syftade till att skapa en sensorisk smakprofil för fisken tilapia och till att se hur smakprofilen förändrades vid lagring i vakuumförpackning. För att skapa smakprofilen användes metoden QDA. Resultatet gav många egenskapsord var av vissa kunde klassificeras som färskhetsrelaterade och vissa som förskämningsrelaterade. Det kunde även konstateras att färsk, odlad tilapia har en antydan av saftigare och mer mjäll textur. Vid lagring finns en möjlighet att tilapia får en intensivare smak av dy och metall, samt en intensivare doft av dy. / A large amount of Swedes has a desire to consume more nationally produced fish. Scandinavian Aquasystems produces and tries to introduce tilapia into the Swedish market. As a fish, tilapia has just begun making ways into Europe but is already a big commodity around the rest of the world. In addition, a sensory profile which tells how long the product remains sensorially suitable could be of help. This study aimed to create a sensory profile and to study its inherent effects of vacuum packaging over time. In creating the sensory profile, a QDA method was used. The study resulted in a variance of different attributes which of some could be categorized as either fresh related or spoilage related. It was found that fresh, farmed tilapia carried an indication of having a juicier and more tender texture. With storage there is chance of tilapia getting a more intense flavor of mud and metal, as well as a more intense odor of mud.

The Central Queensland University developed an on-site wastewater treatment and reuse technology. Septic tanks were used for primary treatment and the discharged effluent was then pumped though a series of contained channels. The channels were designed to be a modified evapotranspiration trench; they were comprised of an aggregate layer and a soil layer in which were planted a variety of plants. The aggregate and the soil provided physical filtration, the microorganisms within the effluent, aggregate and soil provided nutrient reuse and transformation and the plants also used the nutrients and reused the treated effluent through evapotranspiration. Any effluent that was not transpired was returned to a holding tank and pumped through the evapotranspiration again. The treatment technology was assessed in relation to its ability to treat effluent in a sustainable manner. The water and soil was examined for concentrations of nutrients, heavy metals, salts, sodium, and organic carbon %. The pH, temperature and number of colony forming units of certain microorganism potential pathogens were also inspected in the soil and the water. The plants grown within the evapotranspiration channels were assessed in regards to their health, water usage, and in some cases potential pathogens on fruit. The infrastructure that was used to construct the wastewater treatment and reuse system was also evaluated in regards to reliability and maintenance. Certain limiting factors, in particular sodicity and salinity were identified, but the trial was successful and a sustainable form of on-site wastewater treatment and reuse technology was developed.

Zeolite membranes are formed as a thin zeolitic layer on the supports. They are usually synthesized by hydrothermal methods in batch systems. In this study, MFI and SAPO-34 type zeolite membranes were produced on macroporous tubular alumina supports in a recirculating flow system at elevated temperatures for the first time in the literature. During the synthesis, the synthesis mixture is flown between the reservoir and the membrane module which includes the support material. The synthesis temperatures were 180&deg / C and 220&deg / C, and the corresponding system pressures were approximately 20 and 30 bars for MFI and SAPO-34, respectively. The CH4 and n-C4H10 single gas permeances were measured through MFI membranes and the performance of membranes was investigated in the separation of equimolar CH4/n-C4H10 mixtures. The best MFI membrane had a CH4 single gas permeance of 1.45x10-6 mol/m2-s-Pa and CH4/n-C4H10 ideal selectivity of 35 at 25oC. The membranes preferentially permeated n-C4H10 in the separation of mixtures. The n-C4H10/CH4 separation selectivity was 43.6 with a total permeance of approximately 0.8x10-6 mol/m2-s-Pa at 25oC. The ideal selectivities of CO2/CH4 of SAPO-34 membrane synthesized in stagnant medium were 227, and &gt / 1000 at 220 and 200oC, respectively. Formation of amorphous structure and the additional secondary phases (impurities) were observed on SAPO-34 membranes synthesized in recirculating flow system. The results showed that it is possible to produce SAPO-34 and high quality MFI membranes by a recirculating flow system operating at elevated temperature.

Aims of this thesis were to assesed the impact of feeding, temperature of water and fish size on ammonia excretion and oxygen consumption in Clarias gariepinus in recirculating system. Fish were divided in 8 weight categories from 21 to 2495 g. Experiments were performed under four temperatures: 22°C, 25°C, 28°C and 30°C. Fish were acclimatized, light conditions were: 14 hours of light period and 10 hours of dark period. Feeding was provided fed four times a day. Starved fish were measured. Measurements were held every two hours. Oxygen consumption was measured by multimeter and ammonia excretion using Nessler?s method. Average daily oxygen consumption in fed fish was dependent on temperature and average individual weight of fish, varied from 10.5 to 96.6 mg O2/kg/h and in hungry fish from 4.3 to 61.8 mg O2/kg/h. TAN excretion varied from 0 to 59.9 mg TAN/kg/h in fed fish and from 0 to 60.8 mg TAN/kg/h in hungry fish. Oxygen consumption increased with increasing temperature. Ammonia excretion was very unstable at all temperatures in all weight categories. Fish had higher ammonia excretion in light period of experiment.

O intenso desenvolvimento da aquacultura tem sido acompanhado de um aumento nos impactos ambientais causados por esta atividade. As descargas de efluentes da aquacultura em ecossistemas aquáticos são uma fonte de deterioração da qualidade ambiental e podem causar eutrofização. O presente trabalho investigou e avaliou o desempenho de um sistema de tratamento e recirculação de efluentes de aquacultura em relação à sua eficiência em manter e restaurar os parâmetros de qualidade da água em níveis adequados ao ciclo produtivo, considerando as implicações desta técnica na conservação dos recursos hídricos. O experimento foi conduzido em dois sistemas funcionando paralelamente, simulando situações com e sem tratamento e recirculação de efluentes. Os sistemas aquícolas, em escala experimental, foram compostos pelos tanques e pelas unidades de tratamento e recirculação. Os tanques de cultivo foram povoados com juvenis de tilápia-do-Nilo (Oreochromis niloticus). Os sistemas sem recirculação e com recirculação receberam, respectivamente, 65 indivíduos (biomassa total inicial = 477g) e 64 indivíduos (biomassa total inicial = 491g). O sistema de tratamento e recirculação de efluentes foi composto por um filtro biológico de leito flutuante granular (floating beads biofilter) e duas colunas de aeração, com diferentes meios de preenchimento. Ao longo dos seis meses de experimento foram medidos os principais parâmetros de qualidade da água para a aquacultura e para a estimativa do funcionamento e desempenho do sistema de tratamento e recirculação de efluentes. O desempenho zootécnico obtido nos tanques foi também avaliado e comparado. Análise de variância (ANOVA) foi utilizada para comparar os dados. Na comparação entre a água de cultivo dos tanques, os seguintes parâmetros apresentaram um valor mais elevado (p<0,05) para o sistema com recirculação: nitrato, carbono orgânico total, fosfato, cloreto, sulfato e condutividade. A água de cultivo do tanque sem recirculação apresentou maiores valores de nitrogênio amoniacal, sólidos suspensos e turbidez (p<0,05). As duas colunas de aeração usadas no experimento não apresentaram diferenças significativa entre si (p>0,05), apresentando uma eficiência de aeração de 67%. O sistema com recirculação foi caracterizado por um uso semanal de água significativamente menor (p<0,05), utilizando apenas 36% do volume de água que foi necessário para o tanque sem recirculação. Indícios de nitrificação foram identificados em ambos os sistemas, porém este processo apresentou uma importância maior sobre a qualidade da água no sistema com recirculação e filtro biológico. O sistema com recirculação produziu efluentes (através da retrolavagem do filtro) mais concentrados (p<0,05) em relação a nitrato, alcalinidade, carbono orgânico total, fosfato, sólidos suspensos e dissolvidos, cloreto, sulfato, condutividade. Em relação à carga de resíduos lançada ao ambiente, o sistema sem recirculação obteve valores maiores (p<0,05) de nitrogênio amoniacal, nitrato, carbono orgânico total, fosfato, sólidos suspensos, sólidos dissolvidos, fluoreto, cloreto e sulfato. Para os demais parâmetros, não houve diferenças significativas quanto à carga de resíduo do efluente produzido (p>0,05). Não houve diferenças significativas entre os dois sistemas comparados (p>0,05) quanto ao ganho de peso das tilápias durante o período de avaliação do desempenho zootécnico. A partir da biomassa total de peixes produzida nos dois tanques durante todo o período experimental calculou-se que o sistema sem recirculação fez uso de 4053 litros de água para cada kg (L/kg) de peixe produzido e o sistema com recirculação usou 1129 L/kg. O sistema de aquacultura com recirculação estudado, construído a partir de materiais nacionais e de baixo custo, obteve êxito como forma de criação de peixes, oferecendo uma significativa redução no volume de água usado e na carga de alguns resíduos em seus efluentes, quando comparado a técnicas convencionais de aquacultura. Apesar de haver significativas necessidades de aprimoramento do protótipo usado e de estudos complementares em relação ao assunto tendo em vista a realidade brasileira, principalmente contemplando a sua viabilidade econômica em diferentes cenários, o experimento conduzido oferece subsídios para o desenvolvimento da tecnologia de aquacultura com recirculação em âmbito nacional. / The active aquaculture growth that has been observed over the last few decades has been accompanied by important environmental impacts. One main concern is the discharge of aquaculture effluents in aquatic systems. Since these effluents contain nutrients, their discharge can contribute to the eutrophication of the receiving water bodies. The present work describes an investigation in which the aquaculture effluent was treated and recycled back to the system. The treatment process was evaluated with respect to its capability to remove contaminants and restore water quality to levels that were adequate to the fishing productive cycle. Such a system can contribute to the conservation of water resources by saving water and discarding fewer pollutants. The experiment was conducted in two pilot systems working in parallel, simulating fish culture processes with and without effluent treatment and recycling. The culture tanks were populated with Nile tilapia (Oreochromis niloticus). The systems with and without recirculation were populated with 65 (initial total biomass = 477g) and 64 (initial total biomass = 491g) individuals, respectively. The effluent treatment and recirculation system were composed by a floating bead biofilter and two natural aeration columns, each filled with different media. The experiment was conducted along six months, during which the systems were monitored for water quality parameters and zootechnical performance. Analysis of variance (ANOVA) was used to compare data collected in the culture tanks. The following parameters presented a higher value (p<0.05) in the recirculation system: nitrate, total organic carbon, phosphate, chloride, sulfate and conductivity. Culture water without recirculation presented higher values for total ammonia nitrogen, suspended solids and turbidity (p<0.05). The two aeration columns used in the experiment had about 67% aeration efficiency. Water use in the recirculation system was significantly lower (p<0.05) than the system without recycling, using just 36% of the water needed by the latter. Nitrification occurred in both systems, but had greater importance in the process with recycling and biological filtration. Filter backwashing from the recirculating system produced effluent that was more concentrated (p<0.05) than the system without recycling with respect to nitrate, alkalinity, total organic carbon, phosphate, suspended and dissolved solids, chloride, sulfate and conductivity. On the contrary, the residue loads discharged from the system without recirculation were higher (p<0.05) for total ammonia nitrogen, nitrate, total organic carbon, phosphate, suspended and dissolved solids, fluoride, chloride and sulfate. For the remaining parameters, no significant difference in the residue loads of the two systems was observed (p>0.05). One important observation was that no significant difference occurred between the two systems (p>0.05) regarding tilapia weight gains in the experimental period. Based on the fish biomass growth and water use measured on both systems, it was calculated that the system without recirculation used 4053 liters of water per each kg of produced fish. On the other hand, the system with recirculation used 1129 liters per kg. Considering the outlined results, it was concluded that the recirculating aquaculture system, built with simple and low cost national material, was successful with respect to fish cultivation, water use reduction, and effluent residue load discharges when compared with the conventional aquaculture technique. Despite the required refinements of the tested prototype, especially regarding scale and economic viability in different scenarios, it offers subsidies to the advance of the recirculating aquaculture technology at the national level.

The results of an experimental rearing of peled under different oxygen regimes are presented in this work. Four variants were tested in three repetitions (hypoxia 55-65 %, normoxia 85-95 %, permanent hyperoxia 145-155 % and alternate hyperoxia 145-155 % during the day and 85-95 % overnight). Also the oxygen consumption of fish with weight from 4.5 to 20 g at temperatures of 15, 19 and 23 °C was measured.

O intenso desenvolvimento da aquacultura tem sido acompanhado de um aumento nos impactos ambientais causados por esta atividade. As descargas de efluentes da aquacultura em ecossistemas aquáticos são uma fonte de deterioração da qualidade ambiental e podem causar eutrofização. O presente trabalho investigou e avaliou o desempenho de um sistema de tratamento e recirculação de efluentes de aquacultura em relação à sua eficiência em manter e restaurar os parâmetros de qualidade da água em níveis adequados ao ciclo produtivo, considerando as implicações desta técnica na conservação dos recursos hídricos. O experimento foi conduzido em dois sistemas funcionando paralelamente, simulando situações com e sem tratamento e recirculação de efluentes. Os sistemas aquícolas, em escala experimental, foram compostos pelos tanques e pelas unidades de tratamento e recirculação. Os tanques de cultivo foram povoados com juvenis de tilápia-do-Nilo (Oreochromis niloticus). Os sistemas sem recirculação e com recirculação receberam, respectivamente, 65 indivíduos (biomassa total inicial = 477g) e 64 indivíduos (biomassa total inicial = 491g). O sistema de tratamento e recirculação de efluentes foi composto por um filtro biológico de leito flutuante granular (floating beads biofilter) e duas colunas de aeração, com diferentes meios de preenchimento. Ao longo dos seis meses de experimento foram medidos os principais parâmetros de qualidade da água para a aquacultura e para a estimativa do funcionamento e desempenho do sistema de tratamento e recirculação de efluentes. O desempenho zootécnico obtido nos tanques foi também avaliado e comparado. Análise de variância (ANOVA) foi utilizada para comparar os dados. Na comparação entre a água de cultivo dos tanques, os seguintes parâmetros apresentaram um valor mais elevado (p<0,05) para o sistema com recirculação: nitrato, carbono orgânico total, fosfato, cloreto, sulfato e condutividade. A água de cultivo do tanque sem recirculação apresentou maiores valores de nitrogênio amoniacal, sólidos suspensos e turbidez (p<0,05). As duas colunas de aeração usadas no experimento não apresentaram diferenças significativa entre si (p>0,05), apresentando uma eficiência de aeração de 67%. O sistema com recirculação foi caracterizado por um uso semanal de água significativamente menor (p<0,05), utilizando apenas 36% do volume de água que foi necessário para o tanque sem recirculação. Indícios de nitrificação foram identificados em ambos os sistemas, porém este processo apresentou uma importância maior sobre a qualidade da água no sistema com recirculação e filtro biológico. O sistema com recirculação produziu efluentes (através da retrolavagem do filtro) mais concentrados (p<0,05) em relação a nitrato, alcalinidade, carbono orgânico total, fosfato, sólidos suspensos e dissolvidos, cloreto, sulfato, condutividade. Em relação à carga de resíduos lançada ao ambiente, o sistema sem recirculação obteve valores maiores (p<0,05) de nitrogênio amoniacal, nitrato, carbono orgânico total, fosfato, sólidos suspensos, sólidos dissolvidos, fluoreto, cloreto e sulfato. Para os demais parâmetros, não houve diferenças significativas quanto à carga de resíduo do efluente produzido (p>0,05). Não houve diferenças significativas entre os dois sistemas comparados (p>0,05) quanto ao ganho de peso das tilápias durante o período de avaliação do desempenho zootécnico. A partir da biomassa total de peixes produzida nos dois tanques durante todo o período experimental calculou-se que o sistema sem recirculação fez uso de 4053 litros de água para cada kg (L/kg) de peixe produzido e o sistema com recirculação usou 1129 L/kg. O sistema de aquacultura com recirculação estudado, construído a partir de materiais nacionais e de baixo custo, obteve êxito como forma de criação de peixes, oferecendo uma significativa redução no volume de água usado e na carga de alguns resíduos em seus efluentes, quando comparado a técnicas convencionais de aquacultura. Apesar de haver significativas necessidades de aprimoramento do protótipo usado e de estudos complementares em relação ao assunto tendo em vista a realidade brasileira, principalmente contemplando a sua viabilidade econômica em diferentes cenários, o experimento conduzido oferece subsídios para o desenvolvimento da tecnologia de aquacultura com recirculação em âmbito nacional. / The active aquaculture growth that has been observed over the last few decades has been accompanied by important environmental impacts. One main concern is the discharge of aquaculture effluents in aquatic systems. Since these effluents contain nutrients, their discharge can contribute to the eutrophication of the receiving water bodies. The present work describes an investigation in which the aquaculture effluent was treated and recycled back to the system. The treatment process was evaluated with respect to its capability to remove contaminants and restore water quality to levels that were adequate to the fishing productive cycle. Such a system can contribute to the conservation of water resources by saving water and discarding fewer pollutants. The experiment was conducted in two pilot systems working in parallel, simulating fish culture processes with and without effluent treatment and recycling. The culture tanks were populated with Nile tilapia (Oreochromis niloticus). The systems with and without recirculation were populated with 65 (initial total biomass = 477g) and 64 (initial total biomass = 491g) individuals, respectively. The effluent treatment and recirculation system were composed by a floating bead biofilter and two natural aeration columns, each filled with different media. The experiment was conducted along six months, during which the systems were monitored for water quality parameters and zootechnical performance. Analysis of variance (ANOVA) was used to compare data collected in the culture tanks. The following parameters presented a higher value (p<0.05) in the recirculation system: nitrate, total organic carbon, phosphate, chloride, sulfate and conductivity. Culture water without recirculation presented higher values for total ammonia nitrogen, suspended solids and turbidity (p<0.05). The two aeration columns used in the experiment had about 67% aeration efficiency. Water use in the recirculation system was significantly lower (p<0.05) than the system without recycling, using just 36% of the water needed by the latter. Nitrification occurred in both systems, but had greater importance in the process with recycling and biological filtration. Filter backwashing from the recirculating system produced effluent that was more concentrated (p<0.05) than the system without recycling with respect to nitrate, alkalinity, total organic carbon, phosphate, suspended and dissolved solids, chloride, sulfate and conductivity. On the contrary, the residue loads discharged from the system without recirculation were higher (p<0.05) for total ammonia nitrogen, nitrate, total organic carbon, phosphate, suspended and dissolved solids, fluoride, chloride and sulfate. For the remaining parameters, no significant difference in the residue loads of the two systems was observed (p>0.05). One important observation was that no significant difference occurred between the two systems (p>0.05) regarding tilapia weight gains in the experimental period. Based on the fish biomass growth and water use measured on both systems, it was calculated that the system without recirculation used 4053 liters of water per each kg of produced fish. On the other hand, the system with recirculation used 1129 liters per kg. Considering the outlined results, it was concluded that the recirculating aquaculture system, built with simple and low cost national material, was successful with respect to fish cultivation, water use reduction, and effluent residue load discharges when compared with the conventional aquaculture technique. Despite the required refinements of the tested prototype, especially regarding scale and economic viability in different scenarios, it offers subsidies to the advance of the recirculating aquaculture technology at the national level.

Made available in DSpace on 2014-06-11T19:30:23Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-08-22Bitstream added on 2014-06-13T20:20:51Z : No. of bitstreams: 1 maigualenriquez_ya_me_ilha.pdf: 1515184 bytes, checksum: 854b45266358b64c6017c5058af88c81 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Sistemas de Recirculação para Aquicultura (SRA) possibilitam um meio alternativo de produção de peixes para áreas com limitada disponibilidade de água. Estes sistemas de cultivo intensivo de peixes oferecem potencial de produção em pequena escala assim como em grande escala, devido a recuperação de efluentes e a reutilização da água, produzindo volumes relativamente pequenos de resíduos líquidos e sólidos. O objetivo deste estudo foi determinar a eficácia do tratamento de águas residuárias em relação à remoção de Nitrogênio Amoniacal Total (NAT), Sólidos Totais (ST), Sólidos Suspensos Totais (SST), Demanda Química de Oxigênio (DQO) e Demanda Bioquímica de Oxigênio (DBO5), Nitrogênio total (NT) e Fósforo Total (FT). Para tanto, foram introduzidos Tilápia do Nilo (Oreochromis niloticus), com 0,323kg de peso médio inicial e 17 kg m-3 de densidade de armazenamento inicial no SRA experimental. O SRA era composto de 03 tanques de plástico com capacidade de 0,20 m3, Decantador de Coluna (DC), o reator de leito fluidizado aeróbio com circulação em tubos concêntricos (BAS-CT), tendo como meio de suporte a areia de diâmetro efetivo (D10) = 0,29 mm e na sequência reator de transferência de oxigênio e remoção de CO2. A eficiência na remoção do NAT no reator BAS-CT no período de aclimatação e de estabilização foi 31,0% e 35,2%, respectivamente. A remoção de ST e SST foi de 44,44% e 71,71%, respectivamente. A eficiência alcançada de remoção no SRA da DQO foi de 64,90% e de 48,01% para DBO5. Os valores médios de remoção do NT e FT no SRA foram de 25,02% e 41,05%, respectivamente. Estes resultados indicaram que o tratamento de águas residuárias de aquicultura proposto neste estudo através do BAS-CT associado ao DC tem evitado elevadas concentrações e acumulação de poluentes dentro do SRA / Recirculating aquaculture systems (RAS) offer an alternative means of fish production for areas that to have limited water and land availability. RAS are a highly intensive fish culture systems and offer potential production units for small and large scale operations. For effluent recovery and treated water reuse, RAS produce relatively small volumes of liquid and solids wastes. The objective of this study were to determine the efficiency of the wastewater treatment with recommended to removal of Total Ammonia Nitrogen (TAN), Total Solids (TS), Total Suspended Solids (TSS), Chemical Oxygen Demand (COD) and Biochemical Oxygen Demand (BOD5), Total Nitrogen (TN) and Total Phosphorus (TP). In this study was cultivating the Nile Tilapia (Oreochromis niloticus) with 0.323kg initial average weight and 17 kg m-3 initial storage density, cultivated in RAS. The RAS was composed with 03 plastic tanks with capacity of 0.20 m3 in each, column settler (CS), aerobic fluidized bed reactor with concentric tubes circulation (BAS-CT) with sand bed support of effective diameter (D10) of 0.29 mm and oxygen transfer-CO2 removal reactor. NAT removal efficiency was in acclimation and stabilized periods in BAS-CT reactor were 31.0% and 35.2% respectively. TS and TSS removal was 44.44% and 71.71% respectively. In this RAS, the COD removal efficiency reached was 64.90% and 48.01% for BOD5. The average removal in the NT and FT in the RAS were 25.02% and 41.05% respectively. These results indicate that aquaculture wastewater treatment proposed in this study by BAS-CT associated to CS prevents high concentrations and accumulating of pollutants within the SRA

Persteril (Acidum peraceticum) is a trademark used for a disinfectant with peracetic acid as an active ingredient. It is highly effective biocide and has extensive application possibilities with regard to environmental friendliness, it also has the widest range of disinfection efficacy. The practical part took place in the Genetic centre hatchery at the FROV JU in Vodnany. Persteril? was used for Short-time bath followed by rearing roe in the recirculating system and for short-time bath followed by rearing roe in the flow system. Both versions are breeding quite well; Persteril? detects fungal infection of fish roe in comparison with other liquids, as well as it leaves smaller or no residue in the water or out of the water until the evaporation (according to the concentration).