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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Enhancing Aquaculture Sustainability Through Water Reuse and Biological Treatment

Kuhn, David Dwight 30 April 2008 (has links)
Overfishing of natural fisheries is a global issue that is becoming more urgent as the human population increases exponentially. According to the Food and Agriculture Organization of the United Nations, over 70% of the world's seafood species are fully exploited or depleted. This high demand for seafood protein is not going away; and, in fact, an astonishing one out of five people in this world depend on this source of protein. Traditional aquaculture practices use pond and flow-through systems which are often responsible for discharging pollutants into the environment. Furthermore, aquacultural feeds often contain high levels of fish protein, so the demand on wild fisheries is not completely eased. Even though traditional aquaculture has these drawbacks, there is a significant movement towards more sustainable practices. For example, implementing recirculating aquaculture systems (RAS) maximizes the reuse of culture water which decreases water demand and minimizes the levels of pollutants being discharged to the environment. And, alternative proteins (e.g., soy bean) are replacing the fish and seafood proteins in aquaculture diets. Accordingly, the research described in this dissertation focused on maximizing the reuse of freshwater fish effluent to culture marine shrimp. More specifically, by using suspended-growth biological reactors to treat a tilapia effluent waste stream and to generate microbial flocs that could be used to support shrimp culture. This RAS technology will decrease water consumption by increasing the amount of recycled water and will also improve effluent water quality. The biomass generated in the bioreactors could be used to feed shrimp with an alternative source of protein. Treating fish effluent to be reused to culture shrimp while producing this alternative feed, could significantly decrease operational costs and make these operations more sustainable. Understanding which ions are critical for the survival and normal growth of marine shrimp in freshwater effluents is essential. It is also very important to understand how to convert an effluent's organic matter into food for shrimp. Results from studies revealed that the marine shrimp, Litopenaeus vannamei, can be raised in freshwater effluent when supplemented with specific ions and wet microbial flocs fed directly to shrimp can enhance growth in shrimp fed a restricted ration of commercial feed. The treatability of the tilapia effluent using suspended-growth, biological reactors and nutritional analysis of the generated biomass were also reported. Carbon supplementation enhanced reactor performance and microbial floc generation. These microbial flocs also proved to be a superior feed ingredient when dried and incorporated into a pellet feed. / Ph. D.
2

Utilização de efluente de piscicultura na irrigação De pimentão cultivado com fosfato natural e Esterco bovino / Use of fish effluent to irrigate bell pepper plants cultivated with natural phosphate and cow manure

Lima, Cybelle Barbosa de 06 February 2007 (has links)
Made available in DSpace on 2016-08-12T19:15:29Z (GMT). No. of bitstreams: 1 Cybelle Barbosa e Lima.pdf: 447436 bytes, checksum: 5ec6e3f3a7fc0eba45c6355f0d31dd8f (MD5) Previous issue date: 2007-02-06 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The fish effluent discharge in the environment may causing soil and water pollution resulting in environment impacts. One alternative to solve the problem of fish effluent discharge is their use to irrigate plants. The use of fish effluent to irrigate plants can be also one alternative to solve the problem of water scarcity in arid and semi-arid regions, making the system more sustainable and bringing incomes to the producer. Since the fish effluent is rich in microorganisms, organic mater and nutrients, as phosphorus and nitrogen, the effluent may function as a fertigation for the plants. The objective of this experiment was to evaluate the use of fish effluent to irrigate bell pepper, fertilized with cow manure andnatural phosphate to determine the advantage of this integration in a semi-arid region. A randomized complete block design, with two replications within of each block, in a split plot the scheme was used. To the plots were assigned two types of water (well water and fish effluent) and to the subplots, treatments of a 2X2 factorial arrangement, resulting from the combination of two levels of phosphate (with and without natural phosphate) with two levels of organic matter (with and without cow manure). The total experiment area was 768 m2. Each experimental unit consisted of four rows with a total area of 16 m2. The harvest area of the experimental unit was 6 m2, constituted for two central rows. In each row final part disregarded 0,50m. The cro management practices were performed according to the region recommended techniques for bell pepper plants. The following characteristics were evaluated: number of flowers per plant, number of fruits per plant, relationship fruit and flower, fruit number, fruit weight, fruit mean weight and productivity. The cow manure or natural phosphate fertilization, as well as the bell pepper plants irrigation with fish effluent irrigation, not provided significant increase in the number of flowers and fruits for plant. The natural phosphate fertilization and the bell pepper plants irrigation with fish effluent reduced the fruits productivity. Did not observe any significant interaction between water types and the natural phosphate or cow manure fertilization in the number of flowers or fruits for plants and bell pepper productivity / A descarga de efluentes de piscicultura no meio ambiente pode causar a poluição do solo e de mananciais, gerando impactos ambientais. Uma alternativa que vem surgindo para resolver o problema da eliminação desses efluentes é a sua utilização na irrigação de hortaliças. A reutilização dessas águas pode ser também uma alternativa para resolver o problema da escassez de água para irrigação em regiões semi-áridas, tornando o sistema mais sustentável e complementando a renda do produtor. O fato do efluente ser rico em matéria orgânica e nutrientes, como nitrogênio e fósforo, além de microorganismos que podem ser transferidos para o solo, possibilita que a irrigação com essas águas funcione como uma fertirrigação para as plantas. Este trabalho teve como objetivo estudar o efeito da irrigação com efluente de piscicultura na cultura do pimentão adubado com fosfato natural e esterco bovino, visando determinar as vantagens dessa integração nas condições do semi-árido nordestino. O experimento foi delineado em parcela subdivididas em blocos casualizados completos com duas repetições por bloco. Nas parcelas foram designados os tipos de água (água de poço e efluente de piscicultura) e nas subparcelas os tratamentos do fatorial 2x2, resultante da combinação de dois níveis de fósforo (com e sem fosfato natural) com dois níveis de matéria orgânica (com e sem esterco bovino). A área total do experimento foi de 768 m2. Cada unidade experimental foi constituída de quatro fileiras, com uma área total de 16 m2. A área útil desta unidade experimental foi de 6 m2, constituída das duas fileiras centrais, se desprezando 0,5 m da cabeceira de cada fileira. O plantio e condução do experimento foram feitos de acordo com as práticas culturais em uso na região. As características avaliadas foram: a) flores/planta; b) frutos/planta; c) relação fruto/flor (%); d) produtividade; e) número de frutos; f) peso dos frutos; e g) peso médio de fruto. A adubação com esterco ou fosfato, bem como a irrigação de plantas de pimentão com efluente de piscicultura, não proporcionaram aumento significativo no número de flores e de frutos por planta. A adubação com fosfato natural e a irrigação de plantas de pimentão com efluente, reduziram a produtividade de frutos. Não se observou qualquer interação significativa entre os tipos de água e a adubação tanto com fosfato como com esterco no número de flores ou frutos por plantas e na produtividade de pimentão
3

Utilização de efluente de piscicultura na irrigação De pimentão cultivado com fosfato natural e Esterco bovino / Use of fish effluent to irrigate bell pepper plants cultivated with natural phosphate and cow manure

Lima, Cybelle Barbosa de 06 February 2007 (has links)
Made available in DSpace on 2016-08-12T19:18:48Z (GMT). No. of bitstreams: 1 Cybelle Barbosa e Lima.pdf: 447436 bytes, checksum: 5ec6e3f3a7fc0eba45c6355f0d31dd8f (MD5) Previous issue date: 2007-02-06 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The fish effluent discharge in the environment may causing soil and water pollution resulting in environment impacts. One alternative to solve the problem of fish effluent discharge is their use to irrigate plants. The use of fish effluent to irrigate plants can be also one alternative to solve the problem of water scarcity in arid and semi-arid regions, making the system more sustainable and bringing incomes to the producer. Since the fish effluent is rich in microorganisms, organic mater and nutrients, as phosphorus and nitrogen, the effluent may function as a fertigation for the plants. The objective of this experiment was to evaluate the use of fish effluent to irrigate bell pepper, fertilized with cow manure andnatural phosphate to determine the advantage of this integration in a semi-arid region. A randomized complete block design, with two replications within of each block, in a split plot the scheme was used. To the plots were assigned two types of water (well water and fish effluent) and to the subplots, treatments of a 2X2 factorial arrangement, resulting from the combination of two levels of phosphate (with and without natural phosphate) with two levels of organic matter (with and without cow manure). The total experiment area was 768 m2. Each experimental unit consisted of four rows with a total area of 16 m2. The harvest area of the experimental unit was 6 m2, constituted for two central rows. In each row final part disregarded 0,50m. The cro management practices were performed according to the region recommended techniques for bell pepper plants. The following characteristics were evaluated: number of flowers per plant, number of fruits per plant, relationship fruit and flower, fruit number, fruit weight, fruit mean weight and productivity. The cow manure or natural phosphate fertilization, as well as the bell pepper plants irrigation with fish effluent irrigation, not provided significant increase in the number of flowers and fruits for plant. The natural phosphate fertilization and the bell pepper plants irrigation with fish effluent reduced the fruits productivity. Did not observe any significant interaction between water types and the natural phosphate or cow manure fertilization in the number of flowers or fruits for plants and bell pepper productivity / A descarga de efluentes de piscicultura no meio ambiente pode causar a poluição do solo e de mananciais, gerando impactos ambientais. Uma alternativa que vem surgindo para resolver o problema da eliminação desses efluentes é a sua utilização na irrigação de hortaliças. A reutilização dessas águas pode ser também uma alternativa para resolver o problema da escassez de água para irrigação em regiões semi-áridas, tornando o sistema mais sustentável e complementando a renda do produtor. O fato do efluente ser rico em matéria orgânica e nutrientes, como nitrogênio e fósforo, além de microorganismos que podem ser transferidos para o solo, possibilita que a irrigação com essas águas funcione como uma fertirrigação para as plantas. Este trabalho teve como objetivo estudar o efeito da irrigação com efluente de piscicultura na cultura do pimentão adubado com fosfato natural e esterco bovino, visando determinar as vantagens dessa integração nas condições do semi-árido nordestino. O experimento foi delineado em parcela subdivididas em blocos casualizados completos com duas repetições por bloco. Nas parcelas foram designados os tipos de água (água de poço e efluente de piscicultura) e nas subparcelas os tratamentos do fatorial 2x2, resultante da combinação de dois níveis de fósforo (com e sem fosfato natural) com dois níveis de matéria orgânica (com e sem esterco bovino). A área total do experimento foi de 768 m2. Cada unidade experimental foi constituída de quatro fileiras, com uma área total de 16 m2. A área útil desta unidade experimental foi de 6 m2, constituída das duas fileiras centrais, se desprezando 0,5 m da cabeceira de cada fileira. O plantio e condução do experimento foram feitos de acordo com as práticas culturais em uso na região. As características avaliadas foram: a) flores/planta; b) frutos/planta; c) relação fruto/flor (%); d) produtividade; e) número de frutos; f) peso dos frutos; e g) peso médio de fruto. A adubação com esterco ou fosfato, bem como a irrigação de plantas de pimentão com efluente de piscicultura, não proporcionaram aumento significativo no número de flores e de frutos por planta. A adubação com fosfato natural e a irrigação de plantas de pimentão com efluente, reduziram a produtividade de frutos. Não se observou qualquer interação significativa entre os tipos de água e a adubação tanto com fosfato como com esterco no número de flores ou frutos por plantas e na produtividade de pimentão

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