Orientador: Marcos Franke Pinto / Coorientador: Danielle de Bem Luiz / Coorientador: Elisa Helena Giglio Ponsano / Resumo: O crescimento sustentável da indústria de processamento de tilápia está diretamente relacionado com o uso eficiente de água e com a gestão da qualidade da água devolvida ao meio ambiente. Foi avaliado o uso global de água um uma planta de produção de filé de tilápia, bem como o uso de água em diferentes etapas do processamento. Para isso, foram instalados hidrômetros em 13 pontos do estabelecimento. Em seguida, foram sugeridas ações de minimização visando diminuir o uso de água. O uso global de água foi de 432 m³.dia-1, sendo a etapa de depuração responsável por 40,7% desse volume, seguida das atividades relacionadas com a limpeza (32,3%). As ações de minimização implantadas reduziram 29% do uso de água referente à área limpa do processamento da empresa. Em seguida, foi realizada a caracterização físico-química e microbiológica dos efluentes gerados na indústria para a determinação das suas cargas de poluentes. A indústria, como um todo, gerou um efluente com alta carga de matéria orgânica, sendo as etapas onde há maior contato da água com o pescado e seus resíduos (cabeça, carcaça, carne, pele, sangue e vísceras) as maiores fontes poluidoras. Os parâmetros de DBO, DQO e óleos e graxas apresentaram os valores acima dos limites estabelecidos pela legislação para lançamento em sistemas de esgotamento sanitário ou em corpos hídricos receptores. Isso evidenciou a necessidade de um tratamento prévio do efluente antes do seu descarte. Além disso, foi avaliado o potencial do efluent... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The sustainable growing of the tilapia processing industry is directly related to the efficient use of water and to the management of the quality of water returned to the environment. The global use of water in a tilapia fillet processing plant and the use of water in different processing stages were evaluated. For this, hydrometers were installed at 13 points within the premisses. Additionally, minimization actions were suggested aiming at reducing the water use. It was used 432 m3 .d-1 of water, being the depuration stage responsible for 40.7% of this volume, followed by the general cleaning process of the plant (32.3%). The applied minimization actions reduced in 29% the use of water in the clean area of the processing flow. After this, the physical-chemical and microbiological characterization of the effluents generated by the industry was performed in order to evaluate the pollutant load. The industry, as a whole, produced an effluent with high organic matter load, being the stages in which the water contacts the fish and the solid residues (head, carcass, meat trimmings, skin, blood and viscera) the main pollutant sources. The parameters BOD, COD, oils and greases presented values above the legal limits to dispose in the effluent treatment systems or in the hydric spring. This demonstrated the necessity of a previous treatment of the effluent before it is discarded. Besides that, the potential of the effluent from the depuration stage to be reused for urban purposes and... (Complete abstract click electronic access below) / Doutor

Ninety-eight percent of water taken from the Mississippi River Shallow Alluvial Aquifer, hereafter referred to as “the aquifer” or “MRVA,” is used by the agricultural industry for irrigation. Mississippi Delta agriculture is increasingly using more water from the MRVA and the aquifer has been losing about 300,000 acreeet per year. This research expands on previous work in which a model was developed that simulates the effects of climatic variability, crop acreage changes, and specific irrigation methods on consequent variations in the water volume of the MRVA. This study corrects an identified problem by replacing total growing season precipitation with an irrigation demand driver based on evaporation and crop coefficients and changing the time scale from the entire growing season to a daily resolution. The calculated irrigation demand, as a climatological driver for the model, captures effective precipitation more precisely than the initial growing season precipitation driver. Predictive equations resulting from regression analyses of measured versus calculated irrigation water use showed R2 and correlations of 0.33 and 0.57, 0.77 and 0.88, 0.71 and 0.84, and 0.68 and 0.82 for cotton, corn, soybeans and rice, respectively. Ninetyive percent of the predicted values fall within a range of + or - about 23,000 acreeet, an error of about 10-percent. The study also adds an additional conservation strategy through the use of surface water from onarm reservoirs in lieu of groundwater. Analyses show that climate could provide the entire water need of the plants in 70-percent of the years for corn, 65-percent of the years for soybeans and cotton, and even 5-percent of the years for rice. Storing precipitation in onarm structures is an effective way to reduce reliance of Delta producers on groundwater. If producers adopted, at a minimum, the 97.5:2.5 ratio suggested management practice, this minimal management strategy could potentially conserve 48-percent, 35-percent and 42-percent of groundwater for cotton, corn and soybeans, respectively. Even in extreme drought years such as 2007, cotton, corn and soybeans produced under the 97.5:2.5 management strategy could conserve 32-percent, 46-percent and 38-percent of groundwater, respectively.