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Water reuse in marine fish aquaculture using different effluent treatment including an High Rate Algal Pond: assessment of seasonal depuration performance and limitation, impact on fish health and quality for human consumption

Goal: Water reuse in marine fish aquaculture using different effluent treatment including an High Rate Algal Pond: assessment of seasonal depuration performance and limitation, impact on fish health and quality for human consumption

Date: 1 May 2000 - 7 November 2003

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Geneviève Deviller
added 2 research items
Regardless of the degree of closure of a recirculation system, effluents are produced and replacement water is needed, which limits the possibility of locating a seawater production system away from the shoreline. At the Palavas Ifremer station, in the south of France, a High Rate Algal Pond (HRAP) was operated during several years to treat the effluent from a recirculating aquaculture system before reusing it. The effect of the HRAP-treated water on the recirculation system and on the fish was investigated and the optimal algae growing conditions were defined. The experiments were carried out in three rearing systems: one flow through, one recirculating and one recirculating with a HRAP. The water flow rate, temperature, pH and salinity conditions were similar in all systems. The effect of reusing the HRAP-treated water is very limited (1) on the functioning of the recirculation system and (2) on fish performance, but it allows a significant reduction of the dissolved inorganic nitrogen and phosphorus concentration in the rearing water. HRAP treatment reduced metal accumulation in muscle and liver of RAS fish, except for chromium and arsenic. All biomarkers presented no significant difference between systems, except for Superoxide Dismutase (SOD) and EROD, which showed a higher concentration in RAS and in both recirculating system respectively. (c) 2005 Elsevier B.V. All rights reserved.
Le développement rapide de l'aquaculture dans le monde rend indispensable la maîtrise de ses rejets. Par rapport aux systèmes traditionnels, les systèmes recyclés permettent de réduire les besoins en eau et le volume des rejets. Toutefois, certains nutriments dissous (nitrates, phosphates) s'y concentrent. Le lagunage à haut rendement algal (LHRA) est une des voies possibles pour éliminer ces nutriments. Au cours de ce travail, trois circuits d'élevage: un recyclé, un recyclé avec LHRA et un ouvert témoin ont été étudiés pendant un an pour évaluer l'effet (1) de la réutilisation de l'effluent épuré sur la survie, la croissance et l'alimentation de bars (2) du système d'élevage sur la santé des poissons à travers l'étude de biomarqueurs et de métaux traces bio-accumulés et (3) les conditions optimales de l'épuration algale. Si on n'observe pas d'effet marqué lié au LHRA sur les paramètres zootechniques, une légère réduction de la croissance et de l'alimentation des poissons en circuit recyclé par rapport au témoin est cependant enregistrée. On mesure une faible induction de l'activité EROD et de la SOD dans le circuit recyclé ainsi qu'une bioaccumulation de nombreux métaux dont les teneurs restent cependant très inférieures à celles recommandées pour la consommation humaine. Le traitement par LHRA supprime l'induction de la SOD et la bioaccumulation de la plupart des métaux dans les poissons du circuit recyclé. La croissance des algues et l'épuration des nutriments associée sont saisonnières et améliorées par de faibles densités algales et de forts renouvellements d'eau dans les bassins. L'étude des capacités photosynthétiques des ulves met en évidence une limitation de la croissance algale par le carbone inorganique dissous dans le LHRA. L'intégration du LHRA semble une voie d'amélioration des performances et de la qualité des poissons issus de systèmes recyclés. Par ailleurs, ce travail propose de nouveaux outils d'investigation de la santé des poissons d'élevage.
Geneviève Deviller
added a research item
World aquaculture is a fast growing activity and the control of its waste becomes a key issue. Compared to traditional systems, recirculating systems allow to reduce replacement water and waste volumes. Nevertheless their effluents are more concentrated in dissolved nutrients (nitrate, phosphate). The high rate algae pond (HRAP) is one of the possible treatment technique to remove those nutrients. During this work, three rearing systems: one recycled, one recycled with HRAP and one open as a standard, were operated for one year to assess the impact of: (1) the reuse of treated effluent on survival, growth and nutrition of sea bass (2) the rearing system on fish health using multibiomarkers and trace metals accumulation responses and (3) best conditions for HRAP treatment. HRAP had no major effect on fish global parameters but growth and nutrition were slightly reduced in recirculating circuits compared to the standard. EROD and SOD activities were slightly induced and several metals accumulated in the fishes of the recirculating system, however their concentration remained far lower than the recommended values for human food. SOD induction and main metal accumulation were suppressed in fish from recirculating circuits where water was treated by HRAP. Algae growth and associated nutrients removal are seasonal and are increased by a low algae density and a high renewal rates in HRAP. The measurement of algae photosynthesis showed an inorganic carbon restriction for algae growth in HRAP. HRAP seems to be an interesting solution to improve fish performances and flesh quality in recirculating systems. In other respects, this work suggests new tools to assess rearing fish health.
Geneviève Deviller
added a research item
Understanding the capabilities of particulate organic matter removal devices is critical to the development of recirculating aquaculture systems (RAS). The size of fish and water flow rates were evaluated as factors determining the distribution of particulate wastes throughout the RAS. Elemental carbon and nitrogen analyses (CHN) were employed in order to characterize particulate matter and to evaluate the performances of solid evacuation devices during the rearing of two sizes of European seabass (Dicentrarchus labrax) at four water flow rates. Carbon mass balances show that the rearing tank stocks/transforms (out of fish growth and respiration) 33–16% of the particulate carbon from ingested feed when small (60–100 g) and big (500–600 g) fish, respectively, are reared. On the other hand, the treatment loop consumes 32% and 14% of particulate carbon that arrives from the same group of sizes. Water flow rates through rearing tanks affect solids evacuation, increasing retention of particles and modifying water quality through a decrease in the hydraulic regimes. Concerning treatment loop of the RAS in this study (2 m3), a minimal hydraulic loading rate (36.94±3.19 cm min−1) is necessary in order to avoid the biofilter clogging by retention of particulate matter, and also to allow a sufficient hydraulic retention time (6.5 min in biofilter and 18.5 in all treatment loop) to enhance a proper nitrification rate and a minimal particulate carbon consumption. Dynamics between dissolved and particle materials depend on the fish reared and the management of treatment devices that comprise the RAS.
Geneviève Deviller
added a project goal
Water reuse in marine fish aquaculture using different effluent treatment including an High Rate Algal Pond: assessment of seasonal depuration performance and limitation, impact on fish health and quality for human consumption
 
Geneviève Deviller
added 3 research items
Le développement rapide de l'aquaculture dans le monde rend indispensable la maîtrise de ses rejets. Par rapport aux systèmes traditionnels, les systèmes recyclés permettent de réduire les besoins en eau et le volume des rejets. Toutefois, certains nutriments dissous (nitrates, phosphates) s'y concentrent. Le lagunage à haut rendement algal (LHRA) est une des voies possibles pour éliminer ces nutriments. Au cours de ce travail, trois circuits d'élevage: un recyclé, un recyclé avec LHRA et un ouvert témoin ont été étudiés pendant un an pour évaluer l'effet (1) de la réutilisation de l'effluent épuré sur la survie, la croissance et l'alimentation de bars (2) du système d'élevage sur la santé des poissons à travers l'étude de biomarqueurs et de métaux traces bio-accumulés et (3) les conditions optimales de l'épuration algale. Si on n'observe pas d'effet marqué lié au LHRA sur les paramètres zootechniques, une légère réduction de la croissance et de l'alimentation des poissons en circuit recyclé par rapport au témoin est cependant enregistrée. On mesure une faible induction de l'activité EROD et de la SOD dans le circuit recyclé ainsi qu'une bioaccumulation de nombreux métaux dont les teneurs restent cependant très inférieures à celles recommandées pour la consommation humaine. Le traitement par LHRA supprime l'induction de la SOD et la bioaccumulation de la plupart des métaux dans les poissons du circuit recyclé. La croissance des algues et l'épuration des nutriments associée sont saisonnières et améliorées par de faibles densités algales et de forts renouvellements d'eau dans les bassins. L'étude des capacités photosynthétiques des ulves met en évidence une limitation de la croissance algale par le carbone inorganique dissous dans le LHRA. L'intégration du LHRA semble une voie d'amélioration des performances et de la qualité des poissons issus de systèmes recyclés. Par ailleurs, ce travail propose de nouveaux outils d'investigation de la santé des poissons d'élevage.
European sea bass were reared in three different systems: one flow-through (FTS), one recirculating (RAS), and one recirculating with a high-rate algae pond (RAS + HRAP). After 1 year of rearing, the final fish weight was 15% lower in the RAS compared to the FTS. The accumulation of a growth-inhibiting substance in the RAS is the main hypothesis explaining this difference. As in environmental risk assessment, fish bioaccumulation markers and biomarkers were used to demonstrate exposure to and effects of the rearing water in the three rearing systems. Thirty fish per system were sacrificed before their condition factor (CF) and liver somatic index (LSI) were calculated. Nine biomarkers, including ethoxyresorufin-O-deethylase (EROD) and superoxide dismutase (SOD), were measured in liver and twelve metals including As, Cd, Cu, Pb, Cr, and Zn, for which there are regulations regarding human consumption, were measured in liver and muscle. In all systems, CF and LSI were not significantly different and no correlation was found with biomarker activity or metal concentration. EROD and SOD activities were significantly increased in RAS. Accumulation of seven and four metals in muscle and liver, respectively, was significantly higher in the RAS relative to FTS. The HRAP prevented metal accumulation except for chromium and arsenic. Eight metal concentrations were significantly higher in liver than in muscle. Concentrations of toxic metals were similar to reported values and below FAO/WHO recommended values for human consumption.
A high-rate algae pond (HRAP) was tested as a second loop of water treatment in a recirculating fish rearing system to reduce water requirements and nutrient discharge levels. Three duplicated groups of sea bass (mean initial body weight 35±11 g) were reared under different system conditions (flow-through system, recirculating system and recirculating system with HRAP) for 1 year. Fish survival rate was higher in the system with HRAP, and their mean body weight was statistically higher (p<0.05) during the month of maximal climatic conditions for algae photosynthesis. After 266 days of experiment, mean fish weight was significantly higher (p<0.05) in the flow-through system than in the recirculating systems. Final fish weight was 15% higher in the flow-through system than in recirculating systems and was related to a higher daily-ingested food. The comparison of mean annual nutrient concentrations in the recirculating systems gives a statistically significant reduction of 25% of nitrogen (p<0.01) and 9% of phosphates (p<0.01) due to the HRAP. Absorption of nitrate form is responsible for nitrogen removal and is related to climatic conditions for algae growth. The phosphate precipitation at high pH (above 8) was not considered. The maximal removal rates were 0.5±0.2 g N m−2 day−1 and 0.03±0.02 g P m−2 day−1 for nitrates and phosphates, respectively, and were obtained during the optimal climatic conditions and the shortest algae harvesting frequency. These results are favourable to complete reuse of the HRAP treated water, all year long, in the recirculating rearing systems. In order to improve nitrate and phosphate removal rates, a periodic harvesting of algae is necessary and a higher water inflow in HRAP should partly make up for inorganic carbon depletion in high nitrate and phosphate effluents.