The Experts below are selected from a list of 10398 Experts worldwide ranked by ideXlab platform
Yale Deng - One of the best experts on this subject based on the ideXlab platform.
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the impact of do and salinity on microbial community in poly butylene succinate denitrification reactors for recirculating Aquaculture System wastewater treatment
AMB Express, 2017Co-Authors: Yale Deng, Yunjie Ruan, Zhangying YeAbstract:The interactions between environmental factors and bacterial community shift in solid-phase denitrification are crucial for optimum operation of a reactor and to achieve maximum treatment efficiency. In this study, Illumina high-throughput sequencing was applied to reveal the effects of different operational conditions on bacterial community distribution of three continuous operated poly(butylene succinate) biological denitrification reactors used for recirculating Aquaculture System (RAS) wastewater treatment. The results indicated that salinity decreased OTU numbers and diversity while dissolved oxygen (DO) had no obvious influence on OTU numbers. Significant microbial community composition differences were observed among and between three denitrification reactors under varied operation conditions. This result was also demonstrated by cluster analysis (CA) and detrended correspondence analysis (DCA). Hierarchical clustering and redundancy analysis (RDA) was performed to test the relationship between environmental factors and bacterial community compositions and result indicated that salinity, DO and hydraulic retention time (HRT) were the three key factors in microbial community formation. Besides, Simplicispira was detected under all operational conditions, which worth drawing more attention for nitrate removal. Moreover, the abundance of nosZ gene and 16S rRNA were analyzed by real-time PCR, which suggested that salinity decreased the proportion of denitrifiers among whole bacterial community while DO had little influence on marine reactors. This study provides an overview of microbial community shift dynamics in solid-phase denitrification reactors when operation parameters changed and proved the feasibility to apply interval aeration for denitrification process based on microbial level, which may shed light on improving the performance of RAS treatment units.
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biological denitrification using poly butylene succinate as carbon source and biofilm carrier for recirculating Aquaculture System effluent treatment
Bioresource Technology, 2015Co-Authors: Yale Deng, Yunjie Ruan, Jiazheng ShenAbstract:Abstract Nitrate removal is essential for the sustainable operation of recirculating Aquaculture System (RAS). This study evaluated the heterotrophic denitrification using poly(butylene succinate) as carbon source and biofilm carrier for RAS wastewater treatment. The effect of varied operational conditions (influent type, salinity and nitrate loading) on reactor performance and microbial community was investigated. The high denitrification rates of 0.53 ± 0.19 kg NO3−-N m−3 d−1 (salinity, 0‰) and 0.66 ± 0.12 kg NO3−-N m−3 d−1 (salinity, 25‰) were achieved, and nitrite concentration was maintained below 1 mg/L. In addition, the existence of salinity exhibited more stable nitrate removal efficiency, but caused adverse effects such as excessive effluent dissolved organic carbon (DOC) and dissimilation nitrate reduce to ammonia (DNRA) activity. The degradation of PBS was further confirmed by SEM and FTIR analysis. Illumina sequencing revealed the abundance and species changes of functional denitrification and degradation microflora which might be the primary cause of varied reactor performance.
Yunjie Ruan - One of the best experts on this subject based on the ideXlab platform.
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the impact of do and salinity on microbial community in poly butylene succinate denitrification reactors for recirculating Aquaculture System wastewater treatment
AMB Express, 2017Co-Authors: Yale Deng, Yunjie Ruan, Zhangying YeAbstract:The interactions between environmental factors and bacterial community shift in solid-phase denitrification are crucial for optimum operation of a reactor and to achieve maximum treatment efficiency. In this study, Illumina high-throughput sequencing was applied to reveal the effects of different operational conditions on bacterial community distribution of three continuous operated poly(butylene succinate) biological denitrification reactors used for recirculating Aquaculture System (RAS) wastewater treatment. The results indicated that salinity decreased OTU numbers and diversity while dissolved oxygen (DO) had no obvious influence on OTU numbers. Significant microbial community composition differences were observed among and between three denitrification reactors under varied operation conditions. This result was also demonstrated by cluster analysis (CA) and detrended correspondence analysis (DCA). Hierarchical clustering and redundancy analysis (RDA) was performed to test the relationship between environmental factors and bacterial community compositions and result indicated that salinity, DO and hydraulic retention time (HRT) were the three key factors in microbial community formation. Besides, Simplicispira was detected under all operational conditions, which worth drawing more attention for nitrate removal. Moreover, the abundance of nosZ gene and 16S rRNA were analyzed by real-time PCR, which suggested that salinity decreased the proportion of denitrifiers among whole bacterial community while DO had little influence on marine reactors. This study provides an overview of microbial community shift dynamics in solid-phase denitrification reactors when operation parameters changed and proved the feasibility to apply interval aeration for denitrification process based on microbial level, which may shed light on improving the performance of RAS treatment units.
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biological denitrification using poly butylene succinate as carbon source and biofilm carrier for recirculating Aquaculture System effluent treatment
Bioresource Technology, 2015Co-Authors: Yale Deng, Yunjie Ruan, Jiazheng ShenAbstract:Abstract Nitrate removal is essential for the sustainable operation of recirculating Aquaculture System (RAS). This study evaluated the heterotrophic denitrification using poly(butylene succinate) as carbon source and biofilm carrier for RAS wastewater treatment. The effect of varied operational conditions (influent type, salinity and nitrate loading) on reactor performance and microbial community was investigated. The high denitrification rates of 0.53 ± 0.19 kg NO3−-N m−3 d−1 (salinity, 0‰) and 0.66 ± 0.12 kg NO3−-N m−3 d−1 (salinity, 25‰) were achieved, and nitrite concentration was maintained below 1 mg/L. In addition, the existence of salinity exhibited more stable nitrate removal efficiency, but caused adverse effects such as excessive effluent dissolved organic carbon (DOC) and dissimilation nitrate reduce to ammonia (DNRA) activity. The degradation of PBS was further confirmed by SEM and FTIR analysis. Illumina sequencing revealed the abundance and species changes of functional denitrification and degradation microflora which might be the primary cause of varied reactor performance.
Steven T Summerfelt - One of the best experts on this subject based on the ideXlab platform.
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optimizing hydraulic retention times in denitrifying woodchip bioreactors treating recirculating Aquaculture System wastewater
Journal of Environmental Quality, 2016Co-Authors: Christine Lepine, Laura E Christianson, Kata L Sharrer, Steven T SummerfeltAbstract:: The performance of wood-based denitrifying bioreactors to treat high-nitrate wastewaters from Aquaculture Systems has not previously been demonstrated. Four pilot-scale woodchip bioreactors (approximately 1:10 scale) were constructed and operated for 268 d to determine the optimal range of design hydraulic retention times (HRTs) for nitrate removal. The bioreactors were operated under HRTs ranging from 6.6 to 55 h with influent nitrate concentrations generally between 20 and 80 mg NO-N L. These combinations resulted in N removal rates >39 g N m d, which is greater than previously reported. These high removal rates were due in large part to the relatively high chemical oxygen demand and warm temperature (∼19°C) of the wastewater. An optimized design HRT may not be the same based on metrics of N removal rate versus N removal efficiency; longer HRTs demonstrated higher removal efficiencies, and shorter HRTs had higher removal rates. When nitrate influent concentrations were approximately 75 mg NO-N L ( = 6 sample events), the shortest HRT (12 h) had the lowest removal efficiency (45%) but a significantly greater removal rate than the two longest HRTs (42 and 55 h), which were N limited. Sulfate reduction was also observed under highly reduced conditions and was exacerbated under prolonged N-limited environments. Balancing the removal rate and removal efficiency for this water chemistry with a design HRT of approximately 24 h would result in a 65% removal efficiency and removal rates of at least 18 g N m d.
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impact of depuration of earthy musty off flavors on fillet quality of atlantic salmon salmo salar cultured in a recirculating Aquaculture System
Aquacultural Engineering, 2012Co-Authors: Gary S Burr, William R Wolters, Kevin K Schrader, Steven T SummerfeltAbstract:Abstract Over the past decade in the United States, there has been increased interest in the establishment and use of land-based, closed-containment Systems [e.g., recirculating Aquaculture System (RAS)] for salmonid culture. These culture Systems have unique challenges compared to net pen culture of salmonids, including maintenance of pumps and filters as well as the potential growth of certain bacteria within the Systems that can render fish off-flavored. The purpose of this study was to determine the impact of implementing a depuration process to purge the “earthy” and “musty” off-flavor compounds geosmin and 2-methylisoborneol (MIB) from Atlantic salmon fillets on fillet quality characteristics (e.g., lipid content, color). During two depuration trials, salmon were depurated without feed in a flow-through tank, a recently “cleaned” RAS System or the originally stocked grow-out tank for up to 20 days. Results from both trials determined that the salmon required depuration in odor-free water for 10–15 days in either a flow-through System or a recently cleaned RAS to obtain the lowest residual levels of geosmin and MIB in the fish flesh. In trial 1, after 20 days, fish had lost significantly more weight (5.8%) compared to day 5 (3.8%). In the second trial, lipid content of the fillet also significantly dropped from 8.2% to 5.1% and moisture content increased from 69.3% to 71.1%. Fillet color quality was not compromised during the 20-day depuration periods. In trial 1, MIB was the main off-flavor compound present in salmon fillets while geosmin was at higher levels than MIB in fish flesh in trial 2. During the second depuration study, three geosmin-producing species of actinomycetes were isolated from the recirculating System and were attributed as the likely sources of geosmin in the salmon fillets. Because fillet color quality was not compromised during the depuration periods used in these studies, the main fillet quality concerns for producers of RAS-cultured salmon are flavor, texture and lipid levels during the pre-harvest purging process.
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membrane biological reactor treatment of a saline backwash flow from a recirculating Aquaculture System
Aquacultural Engineering, 2007Co-Authors: Mark J Sharrer, Drew Ferrier, Joseph A Hankins, Steven T SummerfeltAbstract:A recirculating Aquaculture System (RAS) can minimize water use, allowing fish production in regions where water is scarce and also placing the waterborne wastes into a concentrated and relatively small volume of effluent. The RAS effluent generated during clarifier backwash is usually small in volume (possibly 0.2–0.5% of the total recirculating flow when microscreen filters are used) but contains high levels of concentrated organic solids and nutrients. When a RAS is operated at high salinities for culture of marine species, recovering the saltwater contained in the backwash effluent could allow for its reuse within the RAS and also reduce salt discharge to the environment. Membrane biological reactors (MBRs) combine activated sludge type treatment with membrane filtration. Therefore, in addition to removing biodegradable organics, suspended solids, and nutrients such as nitrogen and phosphorus, MBRs retain high concentrations of microorganisms and, when operated with membrane pore sizes <1 μm, exclude microorganisms from their discharge. In this research, an Enviroquip (Austin, TX) MBR pilot-plant was installed and evaluated over a range of salinities to determine its effectiveness at removing bacteria, turbidity, suspended solids, nitrogen, phosphorus and cBOD5 content from the approximately 22 m3/day concentrated biosolids backwash flow discharged from the RASs at The Conservation Fund Freshwater Institute. The MBR System was managed at a hydraulic retention time of 40.8 h, a solids retention time of 64 ± 8 days, resulting in a Food: Microorganism ratio of 0.029 day−1. Results indicated excellent removal efficiency (%) of TSS (99.65 ± 0.1 to 99.98 ± 0.01) and TVS (99.96 ± 0.01 to 99.99 ± 0.0) at all salinity levels. Similarly, a 3–4 log10 removal of total heterotrophic microbes and total coliform was seen at all treatment conditions. Total nitrogen removal efficiency (%) ranged from 91.8 ± 2.9 to 95.5 ± 0.6 at the treatment levels and was consistent, provided a sufficient acclimation period to each new condition was given. Conversely, total phosphorus removal efficiencies (%) at 0 ppt, 8 ppt, 16 ppt and 32 ppt salinity were 96.1 ± 1.0, 72.7 ± 3.5, 70.4 ± 2.3, and 65.2 ± 5.4, respectively, indicating reduced phosphorus removal at higher salinities.
Maxime Legendre - One of the best experts on this subject based on the ideXlab platform.
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Aquaculture System diversity and sustainable development: fish farms and their representation
Aquatic Living Resources, 2010Co-Authors: Jérôme Lazard, Aurèle Baruthio, Pierre Morissens, Olivier Mikolasek, Syndhia Mathé, Eduardo Chia, Joel Aubin, Olivier Clément, Hélène Rey-valette, Maxime LegendreAbstract:Initiatives for the sustainable development of Aquaculture have so far focused on the production of codes of conduct, of best management practices, of standards etc., most of which have been developed by international organ- isations, the industrial sector and non governmental organisations. They were, to a large extent, produced using a "top down" process and inspired by models from intensive industrial shrimp and sea fish farming (mainly salmon). How- ever, most of global Aquaculture production comes from small- and medium-sized farms, essentially in Asia which con- tributes 92% of the total world Aquaculture production volume. The objective of this article is to define the contours of Systemic typologies that are able to express the sustainability conditions of Aquaculture Systems. The proposed approach builds on surveys of Aquaculture Systems which differ in terms of their biogeographical nature (temperate/tropical and north/south countries) or their farming techniques and their governance Systems. This work is a prerequisite to any attempt at an individualised and comparative evaluation of specific Aquaculture Systems from either global or territorial viewpoints. In order to go beyond the cleavage of a typology based on the differentiation between developed and devel- oping countries, three typologies were produced. These typologies allow for discriminatory variables to be identified such as for example the marketing methods or the pace of innovation: a structural typology, a functional typology and a Systemic typology. Finally, the representations of Aquaculture activity and of its sustainability that producers have of the 4 different types that emerge from the Systemic typology were recorded and analyzed.
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Aquaculture System diversity and sustainable development: fish farms and their representation
Aquatic Living Resources, 2010Co-Authors: Jérôme Lazard, Aurèle Baruthio, Hélène Rey-valette, Pierre Morissens, Olivier Mikolasek, Syndhia Mathé, Eduardo Chia, Joel Aubin, Olivier Clément, Maxime LegendreAbstract:Initiatives for the sustainable development of Aquaculture have so far focused on the production of codes of conduct, of best management practices, of standards etc., most of which have been developed by international organisations, the industrial sector and non governmental organisations. They were, to a large extent, produced using a “top down” process and inspired by models from intensive industrial shrimp and sea fish farming (mainly salmon). However, most of global Aquaculture production comes from small- and medium-sized farms, essentially in Asia which contributes 92% of the total world Aquaculture production volume. The objective of this article is to define the contours of Systemic typologies that are able to express the sustainability conditions of Aquaculture Systems. The proposed approach builds on surveys of Aquaculture Systems which differ in terms of their biogeographical nature (temperate/tropical and north/south countries) or their farming techniques and their governance Systems. This work is a prerequisite to any attempt at an individualised and comparative evaluation of specific Aquaculture Systems from either global or territorial viewpoints. In order to go beyond the cleavage of a typology based on the differentiation between developed and developing countries, three typologies were produced. These typologies allow for discriminatory variables to be identified such as for example the marketing methods or the pace of innovation: a structural typology, a functional typology and a Systemic typology. Finally, the representations of Aquaculture activity and of its sustainability that producers have of the 4 different types that emerge from the Systemic typology were recorded and analyzed. Les initiatives de développement durable de l’Aquaculture ont jusqu’à présent surtout consisté dans la production de codes de conduite, de guides de bonnes pratiques, de standards, etc., élaborés pour la plupart d’entre eux par des organisations internationales, le secteur industriel et des organisations non gouvernementales. Ces documents ont largement été produits selon un processus de type « top down » et principalement inspirés par les modèles issus de l’Aquaculture industrielle intensive de crevettes et de poissons marins (saumon principalement). Cependant, l’essentiel de la production de l’Aquaculture mondiale provient d’exploitations de petite et moyenne taille, en Asie principalement qui contribue pour 92 % au volume total de la production aquacole mondiale. Cette étude vise précisément à définir les contours de typologies globales aptes à rendre compte des conditions de durabilité des systèmes piscicoles. La démarche proposée s’appuie sur des enquêtes réalisées sur des systèmes de production différenciés tant sur les plans de la biogéographie (pays tempérés et tropicaux, du nord et du sud) que des techniques d’élevage mises en œuvre et des modes de gouvernance de ces systèmes. Ce travail constitue le préalable à toute tentative d’évaluation à la fois individualisée et comparative de la durabilité de systèmes aquacoles spécifiques tant sur les plans systémique que territorial. Afin de dépasser le clivage d’une typologie basée sur la différenciation entre pays développés et en développement, trois typologies ont été produites. Elles permettent l’identification de variables discriminantes telles que par exemple le mode de commercialisation de la production ou le rythme des innovations mises en œuvre: une typologie structurelle, une typologie fonctionnelle et une typologie globale. Enfin, les représentations de l’activité piscicole et de la durabilité de celle-ci que se font les producteurs des 4 différents types ressortant de la typologie globale ont été recueillies et analysées.
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Adaptation of Aquaculture System typologies to the requirements of sustainable development
Cahiers Agricultures, 2009Co-Authors: Jérôme Lazard, Aurèle Baruthio, Hélène Rey-valette, Pierre Morissens, Olivier Mikolasek, Syndhia Mathé, Eduardo Chia, Joel Aubin, Olivier Clément, Maxime LegendreAbstract:Le nouveau référentiel du développement durable impose un renouvellement des grilles d’analyse, notamment des facteurs pris en compte dans les typologies des systèmes productifs. À partir de l’exemple de l’Aquaculture, cet article a pour ambition d’analyser la diversité des systèmes aquacoles au regard du développement durable. Différentes typologies sont réalisées en croisant des approches structurelles, fonctionnelles qui tiennent compte des variables relatives aux systèmes de production, de régulation et à l’insertion territoriale des exploitations. Les catégories définies à l’échelle de l’ensemble des cinq terrains représentatifs d’un éventail élargi de systèmes aquacoles permettent de dépasser les typologies locales, en vue d’élaborer une classification générique des systèmes au sens d’une métatypologie qui est ensuite confrontée aux représentations que les exploitants de ces types d’exploitation ont du développement durable.
Jiazheng Shen - One of the best experts on this subject based on the ideXlab platform.
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biological denitrification using poly butylene succinate as carbon source and biofilm carrier for recirculating Aquaculture System effluent treatment
Bioresource Technology, 2015Co-Authors: Yale Deng, Yunjie Ruan, Jiazheng ShenAbstract:Abstract Nitrate removal is essential for the sustainable operation of recirculating Aquaculture System (RAS). This study evaluated the heterotrophic denitrification using poly(butylene succinate) as carbon source and biofilm carrier for RAS wastewater treatment. The effect of varied operational conditions (influent type, salinity and nitrate loading) on reactor performance and microbial community was investigated. The high denitrification rates of 0.53 ± 0.19 kg NO3−-N m−3 d−1 (salinity, 0‰) and 0.66 ± 0.12 kg NO3−-N m−3 d−1 (salinity, 25‰) were achieved, and nitrite concentration was maintained below 1 mg/L. In addition, the existence of salinity exhibited more stable nitrate removal efficiency, but caused adverse effects such as excessive effluent dissolved organic carbon (DOC) and dissimilation nitrate reduce to ammonia (DNRA) activity. The degradation of PBS was further confirmed by SEM and FTIR analysis. Illumina sequencing revealed the abundance and species changes of functional denitrification and degradation microflora which might be the primary cause of varied reactor performance.
