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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.
141

Avaliação de um sistema piloto para tratamento de efluentes de sala de ordenha de bovinocultura / Evaluation of a pilot system treating milking parlor effluent

Silva, Edu Max da, 1954- 30 July 2007 (has links)
Orientador: Denis Miguel Roston / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-08-09T13:06:32Z (GMT). No. of bitstreams: 1 Silva_EduMaxda_M.pdf: 12592705 bytes, checksum: fa560f6bfbe78ace9e89fc4061f0170c (MD5) Previous issue date: 2007 / Resumo: Uma das maiores dificuldades no gerenciamento do confinamento de gado leiteiro é a grande quantidade de dejetos produzidos diariamente numa área reduzida, que pode ser uma ótima opção de fertilizantes ou um enorme potencial poluente, dependendo de como é feita a disposição destes dejetos, um dos principais desafios para criadores e especialistas. No Brasil, o destino dos efluentes brutos dos confinamentos de vacas leiteiras, foi e continua sendo os cursos d¿água usando o ultrapassado método da diluição, como única forma para eliminar os resíduos das instalações e com isso podendo provocar a eutrofização de rios, riachos, lagos e lagoas. Foi implantado um projeto piloto, no Sítio Nossa Senhora da Conceição, com as condições tanto opográficas como climáticas idênticas, para tratar 10% de um efluente similar ao produzido na UEP de bovinocultura leite da EAFI/MG. A ETE piloto era composta por três unidades, sendo uma lagoa anaeróbia, uma lagoa facultativa e um pós-tratamento utilizando um leito cultivado (¿constructed wetland¿). A lagoa anaeróbia não suportou o lançamento do efluente bruto lançado na ETE piloto para tratamento de águas residuárias oriundas da sala de ordenha da bovinocultura leite. Para reduzir a quantidade de sólidos flutuantes na lagoa anaeróbia, a recomendação apresentada foi a construção de um tanque tipo séptico capaz de reter os sólidos flotantes. O leito cultivado foi a unidade da ETE piloto que não aparentou mudanças externas. A ETE piloto registrou uma remoção média dos parâmetros analisados em torno de: fósforo na forma de (P) e (PO4) 80%; amônia (NH3-N) e nitrato (NO3) 88%; DQO 89%, pH médio das amostras analisadas em 6,23; sólidos (ST) e (STV) 67%; turbidez 60%. Em se tratando de resíduos líquidos da produção animal, pode-se afirmar que o resultado é positivo, demonstrando que está opção de sistema de tratamento tem grande potencial de aplicação / Abstract: One of the major concerns in dairy cattle lodging management is the great amount of manureproduced daily in a reduced area, that can be an excellent fertilizer option or an enormous pollutant potential, depending on the disposal procedures. In Brazil, the destination of raw effluent of lodged dairy cattle was in the past and continues nowadays being the water courses using the conventional and condemned method of the dilution, as only form to eliminate the residues of the installations which is one of the reasons for eutrophication of rivers, streams, lakes and ponds. A pilot plant was installed to treat 10% of the effluent produced in the dairy parlor installations of the EAFI/MG. The pilot plant was designed with three units: an anaerobic lagoon followed by a facultative pond and a subsurface constructed wetland. The pilot plant presented the following average removal: phosphorus, 80%; nitrate, 88%; COD, 89%; total solids, 67%; and turbidity, 60%. The pH during the whole operation maintained around the value of 6,2. The study conclued that the system presented a great potential for treatment of dairy parlor effluent / Mestrado / Agua e Solo / Mestre em Engenharia Agrícola
142

DinÃmica da comunidade fitoplanctÃnica em um viveiro de engorda de camarÃo marinho (Litopenaeus vannamei) no estado do Cearà / Dynamics of phytoplankton community in a nursery, fattening of marine shrimp (Litopenaeus vannamei) in the state of CearÃ

Renata Stock Fonseca 04 September 2006 (has links)
Em viveiros de camarÃo, a comunidade fitoplanctÃnica pode apresentar padrÃes de desenvolvimento associados aos fatores biÃticos, abiÃticos e operacionais. O presente estudo objetivou caracterizar as mudanÃas semanais na composiÃÃo e biomassa fitoplanctÃnica em um viveiro de engorda do camarÃo Litopenaeus vannamei. CamarÃes com 1,35  0,63 cm de comprimento corporal foram povoados em um viveiro de 3,3 ha sob densidade de 42,4 indivÃduos/m2. As amostragens de Ãgua foram realizadas no estuÃrio (E), canal de abastecimento (C), no platà (P) e ponto de descarga (D) de Ãgua do viveiro. As amostragens qualitativas do fitoplÃncton foram realizadas atravÃs de arrastos horizontais com rede de 20 &#956;m. Para anÃlise de clorofila a e contagem do nÃmero de organismos fitoplanctÃnicos foram coletadas amostras de sub-superfÃcie. Simultaneamente, foram realizadas anÃlises da temperatura, salinidade, oxigÃnio dissolvido, pH, transparÃncia, profundidade, fosfato, silÃcio reativo, nitrogÃnio amoniacal, nitrito, nitrato e material em suspensÃo da Ãgua. O camarÃo foi despescado apÃs 85 dias de engorda, alcanÃado 11,18 g de peso mÃdio, FCA de 1,85 e sobrevivÃncia de 52,9%. A raÃÃo contribuiu com 92,1 e 95,8% de aportes de nitrogÃnio e fÃsforo no viveiro, com o restante atribuÃdo a fertilizantes quÃmicos. Os valores de matÃria orgÃnica no solo do viveiro apresentaram-se estatisticamente mais elevados em D (31,99  13,66 g/kg) quando comparado à P (4,10  1,56 g/kg; P < 0,05). Contudo, o pH do solo destas estaÃÃes nÃo apresentou diferenÃa estatÃstica significativa (P > 0,05), alcanÃando mÃdia de 7,86  0,40 para P e 7,82  0,65 para D. Enquanto a temperatura da Ãgua foi semelhante para as estaÃÃes de amostragem (P > 0,05), o pH apresentou-se estatisticamente mais elevado para P e D (8,45 e 8,47, respectivamente; P < 0,05). A salinidade oscilou entre 10â (E) e 35â (C, P e D), com nÃveis mais baixos no inÃcio do ciclo. O fosfato dissolvido oscilou entre 0,01 mg/l (C) e 0,24 mg/l (P) e o nitrito entre 0,002 mg/l (C, P e D) e 0,05 mg/l (P). O NitrogÃnio Total Dissolvido nÃo apresentou diferenÃa estatÃstica significativa ao longo do cultivo (P > 0,05), exceto para E. As razÃes de N:P, N:Si e Si:P foram abaixo da razÃo de Redfield em todas as estaÃÃes de amostragem, exceto para Si:P nas estaÃÃes E e C. A clorofila a variou entre 1,63 &#956;g/l (C) a 184,83 &#956;g/l (D). P e D apresentaram aumento progressivo de clorofila a ao longo do cultivo. O padrÃo da sucessÃo fitoplanctÃnica no estuÃrio e canal foi distinto do observado no viveiro, onde foi observada inicialmente a predominÃncia de diatomÃceas seguida por floraÃÃes excessivas de cianofÃceas e euglenofÃceas, intercalado por uma floraÃÃo de dinoflagelados detectado no 22Â. Dia de cultivo. Os aportes elevados de raÃÃo e fertilizantes no viveiro foram os fatores que tiveram maior contribuiÃÃo para o desenvolvimento destas floraÃÃes de microalgas potencialmente nocivas ao camarÃo. Os nutrientes dissolvidos (N-NH3,4, N-NO2 -, N-NO3 -, P-PO4 3- e Si) desempenharam uma maior influÃncia sobre o desenvolvimento do fitoplÃncton no viveiro de cultivo. / In shrimp ponds, the phytoplankton community can exhibit development patterns associated with environmental, operational and biological factors. The present study characterized the weekly phytoplankton composition and biomass changes in a pond over the growth cycle of Litopenaeus vannamei. Shrimp of 1.35  0.63 cm in body length were stocked in a 3.3 ha pond under 42.4 animals/m2. Water sampling took place in the estuary (E), water inlet canal (C), pond plateau (P) and near the pond water drainage outlet (D). Horizontal net sampling was carried out with a 20 &#956;m mesh net for taxonomic identification of phytoplankton. For chlorophyll a and phytoplankton counting samplings were conducted on the water sub-surface. Simultaneously, water analysis was carried out for temperature, salinity, dissolved oxygen, pH, visibility, depth, phosphate, reactive silicate, ammonium nitrogen, nitrate, nitrite and suspended solids. Shrimp were harvested after 85 days of rearing and achieved 11.18 g in body weight, 1.85 FCR and 52.9% survival. Feed contributed with 92.1% and 95.8% of nitrogen and phosphorous inputs into the pond, with the remainder attributed to chemical fertilizers. Pond soil organic matter was statistically higher in D (31.99  13.66 g/kg) when compared to P (4.10  1.56 g/kg; P < 0.05). However, soil pH between these sampling stations did not show statistically significant differences (P > 0.05), achieving a mean of 7.86  0.40 for P and 7.82  0.65 for D. While water temperature showed a similar trend for all sampling stations (P > 0.05), water pH was statistically higher for P and D (8.45 and 8.47, respectively; P < 0.05). Water salinity varied between 10â (E) and 35â (C, P and D), with minimum levels observed in the initial phases of the study. Dissolved phosphate ranged from 0.01 mg/l (C) to 0.24 mg/l (P) and nitrate from 0.002 mg/l (C, P and D) to 0.05 mg/l (P). Total Dissolved Nitrogen showed no statistically significant differences throughout the growth cycle (P > 0.05), except for E. The N:P, N:Si and Si:P molar ratios were below Redfield suggested ratios, except for Si:P in E and C. Chlorophyll a varied between 1.63 &#956;g/l (C) and 184.83 &#956;g/l (D). In P and D, chlorophyll a increased progressively throughout the study period. In the pond, phytoplankton showed an ecological succession different from the E and C. In P and D, diatoms predominated initially, but it was followed by excessive blooms of cyanophytes and euglenophytes. High inputs of feed and fertilizers were the main contributors for these blooms, potentially harmful to shrimp. The dissolved nutrients ((N-NH3,4, N-NO2 -, N-NO3-, P-PO4 3- e Si) carried out a larger influence on the phytoplankton development in the pond.
143

Analysis integrated system of Lake Maraponga environmentalperspective. / AnÃlise integrada do sistema lacustre da Maraponga na perspectiva socioambiental

Nataniel Colares Dias 27 October 2010 (has links)
O presente trabalho teve como objetivo analisar os aspectos socioambientais do sistema lacustre da maraponga e a relaÃÃo estabelecida dos moradores e freqÃentadores do bairro com a lagoa, analisando os aspectos geoambientais e socioeconÃmicos relacionados a capacidade do sistema lacustre da maraponga, bem com as alteraÃÃes fÃsico-quÃmica e bacteriolÃgica da lagoa, para tanto foram identificados os agentes emissores de poluentes que comprometem a qualidade da Ãgua. A Lagoa da Maraponga està localizada no setor Sudoeste da cidade de Fortaleza que faz parte do segmento costeiro do Estado do CearÃ, fazendo parte da micro-bacia de Fortaleza, mais precisamente da bacia fluvial do Rio CocÃ. Este trabalho foi desenvolvido sob a abordagem socioambiental desenvolvida por MendonÃa (2002), cujo objeto de estudo à construÃdo a partir da relaÃÃo entre sociedade e natureza, e como o objeto de estudo està inserido na Ãrea urbana utilizou-se o Sistema Ambiental Urbano S.A.U. que à um mÃtodo que comeÃou a ser desenvolvido por MendonÃa (2004), na busca de uma abordagem dos problemas socioambientais urbanos. Sendo este constituÃdo de trÃs subsistemas o natural, o social e o construÃdo, sendo este constituÃdo de um sistema complexo e aberto. Esse mÃtodo està associado aos princÃpios limnolÃgicos uma vez que trata do estudo das Ãguas continentais, alÃm de possuir uma caracterÃstica interdisciplinar. Para a anÃlise dos fatores socioeconÃmicos foram utilizados os dados estatÃsticos do censo do IBGE de 2000 e entrevistas com os freqÃentadores do parque onde està localizada a lagoa Os dados de indicadores da qualidade da Ãgua da lagoa da Maraponga, que foram utilizados, foram coletados junto a SEMAM/PMF, os parÃmetros fÃsico-quÃmico e bacteriolÃgico das amostras utilizaram como determinaÃÃo padrÃo as especificaÃÃes da ResoluÃÃo CONAMA 357/2005. A partir dos dados coletados foi possÃvel constatar os principais impactos socioambientais e inter-relaÃÃo entre sociedade / This study aims to examine the environmental aspects of the lake system and the relationship of Maraponga of residents and visitors to the neighborhood pond, examining aspects related to socio-economic and geo-environmental capacity of the lake system Maraponga well with the physical and chemical changes Bacteriological and the lagoon, both pair identifying the agents emitters that compromise water quality. Maraponga's Lagoon is located in sout hwest sector of the city of Fortaleza that is part of the coastal segment of the state of Ceara at latitude 3  47'20 .58 "S and longitude 38  34'7 .475" W. It is part of the micro-watershed of Fortaleza, specifically the Rio Coco river basin and is conne cted to other watersheds in the city. This work will be developed under the social environmental approach developed by Mendonca (2002). The object of study of social and environmental geography is constructed from the relationship between society and nature, and as the object of study is inserted in the urban area, we used the Urban Environmental System SAU a method that was first developed by Mendonca (2004), in search of an approach to urban social and environmental problems. This being composed of three subsystems that natural, social and built, and the UAA consists of a complex system and open. This method is associated limnological principles as regards the study of inland waters, also has an interdisciplinary character. For the analysis of socioeconomic factors were used for statistical data from the IBGE census of 2000 and interviews with patrons of the park is located where the pond data quality indicators Maraponga of pond water , which were used were collected from SEMAM / PMF, the physico-chemicaland bacteriological samples used to determine the standard specifications of Resolution 357/2005. From the data collected, we determined the major environmental impacts and inter - relationship between society nature, which made proposals for better use of that water resource.
144

Estudo da comunidade fitoplanctônica da lagoa facultativa do módulo III da estação de tratamento de esgotos Mangabeira (João Pessoa - PB) / Assessment of the phytoplanktonic community at the facultative pond of the module III of waste water plants of Mangabeira (João Pessoa - PB)

Maribel Santos Roque de Oliveira 04 February 2010 (has links)
As lagoas facultativas mantêm uma biota característica, decorrente de sua área superficial, que permite grande disponibilidade de energia luminosa para a coluna de água e promove o estabelecimento da comunidade fitoplanctônica. A presença dos nutrientes na forma assimilável aos microorganismos autotróficos induz a síntese de biomassa, a qual provoca a supersaturação de oxigênio dissolvido, que se constitui como substrato necessário ao desenvolvimento de bactérias heterotróficas, responsáveis pela degradação aeróbia da matéria orgânica nas camadas superiores da lagoa. Este estudo teve como objetivo principal a caracterização da estrutura da comunidade fitoplanctônica em termo de diversidade de espécies, densidade abundância relativa e dominância na lagoa facultativa do módulo III da estação de tratamento de esgotos de mangabeira, na cidade de João Pessoa - PB. As amostragens foram realizadas em escala semanal e sazonal, com coletas entre 8 e 9 horas da manhã, no período de junho/2008 a fevereiro/2009, as regiões afluente e efluente. As alterações no comportamento sazonal das variáveis físicas, químicas e biológicas, assim como das climatológicas, foram analisadas através da ferramenta estatística multivariada da Análise de Componentes Principais (ACP). Foram identificados 36 taxa nas duas regiões de amostragem e apenas cianobactérias foram predominantes durante o período deste estudo. Contudo, não foi observada variação sazonal na composição da comunidade fitoplanctônica nas duas regiões de amostragem. Embora, algumas espécies foram mais frequentes na região afluente, a densidade total apresentou nítida variação sazonal, com valores entre 2,0 x \'10 POT.4\' e 1,2 x \'10 POT.5\' ind/mL. A cianobactéria Planktothrix agardhii, a qual pode produzir a hepatotoxina microcistina, foi a espécie que mais contribuiu para a densidade, assim como para o biovolume. / Facultative ponds keep a characteristic biota, as a result of its superficial area, wich permits high availability of solar energy to the water column favoring the establishment of the phytoplanktonik community. The presence of available nutrients to the autotrophic microorganisms leads to the synthesis of biomass cellular into the pond and it causes the oversaturation dissolved oxygen, which is necessary to the development of heterotrophic bacteria, responsible for aerobic stabilization of organic material at the upper layer of the pond. The main goal of this study was to caracterize the structure of phytoplanktonic community in relation to different species, biomass, relative abundance and dominance at the facultative pond of the module III of waste water plants of Mangabeira (João Pessoa - PB). Samples were taken in seasonal and weekly scale, with collects between 8 a.m to 9 a.m, in the period of June, 2008 to February, 2009, at the regions of inflow and outflow of effluents. Alterations in seasonal behavior of the physical, chemical and biological variables, as well as climatic, were analyzed through statistics multivariate tool of the principal component of analysis (PCA). It was identified 36 taxa on the facultative pond and only the cyanobacteria were predominant during the period of this study. However, it was not observed temporal variation in the composition of phytoplanktonic community at two collected regions. Although, it was noticed that some species were more frequent at the region of inflow than at the outflow. It was also observed that the high total phytoplanktonic density shows a clear seasonal variation, with values between 2.0 x \'10 POT.4\' and 1,2 x \'10 POT.5\' ind/mL. The cyanobacteria Planktothrix agardhii, which may produce hepatotoxic microcystins, was the species that more contributed for the density as well as the biovolume.
145

The development of methods to assess the ecological integrity of Perennial Pans

Ferreira, Martin 30 May 2012 (has links)
Ph.D. / Wetlands play an integral role in the hydrological cycle and biodiversity. Despite this, wetlands have been neglected in terms of research and monitoring in South Africa. This lack of research has become even more insufficient when it comes to endorheic wetlands. Endorheic wetlands in South Africa are known as pans. Pans are isolated depressions that for through wind erosion are generally shallow and lack an integrated drainage. Water gain is depended on rainfall and surface runoff and water loss is largely due to evaporation. Pans can be either ephemeral in nature or can remain inundated for long periods of time. There are close to 5000 pans in the study area of the Mpumalanga province of South Africa. An estimated 40% of these pans are perennial in nature. The little information on the ecology of pans is all focussed on those systems that are ephemeral. The lack of knowledge is, however, not restricted to the ecology of perennial pans but also the management tools available for these ecosystems. Whereas a variety of methods are available to determine the quantity and quality of water needed to sustain riverine systems (and wetlands connected to rivers), there are no such methods for pans. Especially important is the lack in standardised methods to assess the ecological integrity of perennial pans. This is important as perennial pan ecosystems are increasingly under threat from an increase in coal mining and agricultural activities in Mpumalanga. Coal mining activities have increased in the study area due to both an increase in energy demands and the ease of mining coal deposits in the study area. The lack in standardised methods could be as a direct result of the lack in knowledge of the ecology of the perennial pans. The aim of this study was thus to develop standardised methods for assessing the ecological integrity of perennial pans in Mpumalanga by studying the ecology of the pans. The study thus uses a fundamental approach to reach certain applied goals. To achieve the aim, a total of nine pans were included in the study of which seven were surveyed seasonally for two years and two were sampled on a single occasion. Five of these pans were located in the Mpumalanga Lake District (MLD) and were in a relatively pristine condition. The other four pans were impacted either by agricultural activities, mining activities or both. During these surveys, various components of the ecosystem were studied. These components included the spatial and temporal variations in the abiotic components like the physico-chemical characteristics, habitat quality and quantity, and the sediment characteristics. It also included the spatial and temporal variations in the vegetation communities surrounding the pans and the aquatic invertebrate communities within the pans. The aquatic invertebrate communities were assessed based on a taxonomic approach (diversity) and functional approach (biological traits).
146

L'évaporation dans le bilan hydrologique des étangs du Centre-Ouest de la France (Brenne et Limousin) / Evaporation in water balance of ponds in the French Midwest (Brenne and Limousin)

Aldomany, Mohammad 12 September 2017 (has links)
L’effacement des plans d’eau (petits ou grands) du continuum hydrographique est le nouveau dogme français lié à l’interprétation de la Directive Cadre européenne sur l'Eau (DCE-2000) dans la Loi sur l’Eau et les Milieux Aquatiques (LEMA-2006). En effet, cette stratégie se base sur des idées ne reposant sur aucune mesure exacte de l’influence des plans d’eau, supposée néfaste, sur la quantité d’eau s’écoulant dans les réseaux hydrographiques aval. Face à ce paradoxe notable entre réglementation appliquée et absence de mesures directes de l'évaporation des étangs de France métropolitaine, il apparaît un double besoin, tant en géographie fondamentale qu’en recherche appliquée, pour une étude détaillée sur l'évaporation et le bilan hydrologique des étangs.Sur le plan méthodologique, cette étude montre que le bac flottant en plastique transparent est l’outil le plus à même de mesurer l'évaporation des étangs. Sur le plan conceptuel, le travail intensif de terrain a conduit à établir une nouvelle formule empirique ''Aldomany'' qui peut fournir des estimations fiables de l'évaporation des plans d'eau peu profonds à l'échelle annuelle, mensuelle et journalière en utilisant seulement des données météorologiques facilement accessibles. Dans une optique de gestion, cette étude montre que la perte en eau provoquée par un étang s’apparente à celle d’une chênaie de même superficie et que les propos à charge tenus contre les étangs méritent d’être nuancés, les étangs de la Brenne étant bien en partie responsables de l'étiage estival de la Claise, alors que les étangs limousins jouent un rôle plutôt positif en assurant un bon débit estival du réseau hydrographique de cette région. / The erasure of water bodies (large or small) of the hydrographic continuum is the new French dogma related to the interpretation of the European Water Framework Directive (WFD-2000) in the Water and Environment Act (LEMA-2006). In fact, this strategy is based on ideas that are not based on any exact measure of the influence of the supposedly harmful water bodies on the amount of water flowing into the downstream hydrographic networks. In view of this remarkable paradox between applied regulation and the absence of direct measurements of the evaporation of metropolitan France's ponds, there appears to be a dual need in both basic geography and applied research for a detailed study on evaporation and the water balance of ponds.Methodologically, this study shows that the evaporation floating pan constructed of transparent plastic is the most suitable tool for measuring the evaporation of ponds. Conceptually, intensive field work has led to the development of a new empirical formula ''Aldomany'' that can provide reliable estimates of the evaporation of shallow water bodies at on an annual, monthly and daily basis using only readily available meteorological data. From a management perspective, this study shows that the loss of water caused by apond is similar to that of an oak has the same area and that the statements against the ponds should bere considered, the ponds of La Brenne being partly responsible for the summer low water of the Claise,while the Limousin's ponds play a rather positive role in ensuring a good summer flow of the hydrographic network of this region.
147

Salinity of irrigation water in the Philippi farming area of the cape flats, Cape Town, South Africa

Aza-Gnandji, Cocou Davis Ruben January 2011 (has links)
Magister Scientiae - MSc / This research investigated the nature, source and the spatial variation of the salinity of the water used for irrigation in the urban farming area of Philippi, which lies in the Cape Flats region of the Cape Town Metropolitan Area, South Africa. The irrigation water is mainly drawn from the Cape Flats aquifer, and pumped into ponds for eventual crop irrigation. Water samples were collected in summer and in winter from fifteen selected sites using standard water sampling procedures. Each site consisted of one borehole and one pond. The samples were routinely analyzed for salinity levels, and concentrations of major and minor ions. From the same boreholes and ponds, water was sampled in summer for isotope analysis to assess effects of evaporation on the water quality and salinity. Descriptive statistics were used to display the variation in range of specific ions in order to compare them with the recommended ranges. Geographical Information Systems analysis described the spatial distribution of the salinity across the study area, and hydrogeochemical analysis characterized the various waters and detected similarities between the water samples in the study area and other waters found in the Cape Flats region. In addition, the US salinity diagram classification of irrigation water developed by Richards (1954) was used to assess the current suitability of groundwater and pond water samples collected during the entire sampling period for irrigation activities. The research indicated that the concentrations of some ions such as chloride, nitrate, potassium and sodium exceeded in places in the study area, the target range values set by the Department of Water Affairs and Forestry (DWAF, 1996) and the Food and Agriculture Organization (Ayers and Westcot, 1985). It revealed that borehole and pond water were mostly brackish across the area regarding their total dissolved salts content, and fresh water was only found in the middle part of the study area. The research found that sea water does not intrude into the aquifer of the study area, and the accumulation of salts in groundwater and soil in the study area is mainly due to the agricultural activities and partially due to the natural movement of water through the geological formation of the Cape Flats region. The conceptual model of the occurrence of the salinization process supported these findings. From this investigation it is understood that the groundwater and pond water in the study area were generally suitable for irrigation purposes but they have to be used with caution as the vegetables are classified as sensitive and moderately sensitive to salt according to DWAF Irrigation water guidelines (1996). The quality of these waters was mainly affected by the land use activities. / South Africa
148

A Net Plankton Survey of a Small Perennial Pond

Legett, Jesse Harrison 08 1900 (has links)
This thesis resulted from an examination of Lake Worth plankton in comparison to plankton found in similar bodies of water throughout the United States.
149

Sediment nutrient dynamics in Fondriest agricultural settling pond

Bezold, Marie Grace 03 June 2021 (has links)
No description available.
150

Posouzení návrhu malé vodní nádrže v obci Mutěnice z hlediska ekonomické stránky / Assessment of design small water reservoir in the village Mutenice in economic terms

Suchánek, Petr January 2018 (has links)
This diploma thesis evaluates a design of a small water reservoir in Mutenice village from an economic point of view. This final work is a follow-up of the bachelor work of the same student, it completes it and improves on previously noticed inaccuracies. There are several aspects elaborated in the theoretical part, such as sellection of material for homogenous dam, safety spilway, accompanying woods in the flooding area of and especialy the evaluation of the commercial advantage of the water reservoir design. There are corrections of the bachelor work in the practical part of this study, based on the comments and lately found facts as well as the economical estimate based on the cost calculation of the construction. Content of the work are also technical drawings illustrating this take on the reservoir design and a detailed bill of material.

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