Proyecto de Graduación (Licenciatura en Ingeniería Ambiental). Instituto Tecnológico de Costa Rica. Escuela de Química, 2014. | In Costa Rica, despite the fact that nearly a quarter of the population is served by municipal or rural water systems, many of these systems operate in fragile condition. An example is the town of Agujitas in Canton de Osa, where it was decided to generate base information towards the improvement of water supply for human consumption. The conditions of system operation and water quality at the sources were analyzed and assessed. Projections of water needs were also made to set availability scenarios using a methodology based on disaggregated consumption, used in Colombia and another based on the calculation of equivalent houses, recommended by the Costa Rican Institute of Aqueducts and Sewerage (AyA). Additionally, a survey was conducted to the users of the aqueduct and distributed water was analyzed in order to identify the major problems of service and water quality in the system. Numerous conditions of vulnerability that compromise the service itself and population’s health, such as poor infrastructure, discontinuous service and fecal contamination in all sampled points in the distribution network were identified. Water sources (surface type), showed low quality ranges in fecal coliform and turbidity according to a model for the selection of multi-stage filtration (MSF) systems, developed in Colombia, with averages less than 500 MPN/100 mL and 10 NTU respectively, indicating that the purification could be feasible by this type of system. Water availability scenarios showed similar results with both methods and suggest that it could be a shortage of water if measures are not implemented to reduce the irrational consumption; also they suggest the need for further studies such as volumetric audits.

Proyecto de Graduación (Maestría en Gestión de Recursos Naturales y Tecnologías de Producción) Instituto Tecnológico de Costa Rica. Área Académica Agroforestal, 2011. | El presente Proyecto de Graduación, consiste en la evaluación de rendimiento del uso del ácido tricloroisocianúrico en la desinfección del agua del acueducto de Horquetas de Sarapiqui; basados en las normas existentes que regulan la calidad del agua. La revisión bibliográfica, incluye un resumen sobre la importancia del agua; desde el punto de vista de efectos sobre la salud y sus beneficios, al igual que presenta la situación a nivel nacional del agua potable, fuentes de agua, estado del agua para consumo humano en Costa Rica, sistemas de desinfección del agua generalmente utilizados por los entes operadores de acueductos. Por último se realiza una comparación entre los productos más comúnmente utilizados entre los sistemas dosificadores de cloro mediante tabletas. En la metodología se realiza una breve descripción de cómo se realizaron las mediciones del cloro residual, los lugares donde se tomaron las muestras y de cómo se realizó el análisis de los datos recolectados mediante la utilización de fórmulas matemáticas y estadísticas. Al realizar el análisis de los datos recolectados, se pudo determinar que el rendimiento del ácido tricloroisocianúrico en la desinfección del agua es del 99,5% ± 0.5%. Igualmente se pudo comprobar que de acuerdo a la concentración de cloro disponible, es económicamente más rentable el uso del ácido tricloroisocianúrico y un 25% más eficiente que el uso del hipoclorito de calcio. | Instituto Tecnológico de Costa Rica. Área Académica Agroforestal. Programa de Maestría en Gestión de Recursos Naturales y Tecnologías de Producción.

Proyecto de Graduación (Licenciatura en Ingeniería Agrícola) Instituto Tecnológico de Costa Rica, Escuela de Ingeniería Agrícola, 2013. | The conduction line of water and the irrigation system model were designed for the 28 members of the "Sociedad de Usuarios de Agua del Asentamiento Río Guayabo de Turrialba" plots. For this purpose, the conduction aqueduct diameters were determined in order to the system established meets with the needs of flow, pressure and for it reduces the cost. Based in a limited flow of 12 lps an operation scheme was established with 2 groups of 14 valves for a total of 28 valves into the project. In each valve the delivered flow is of 0.84 lps and the pressure is of 30 m.w.c. An irrigated standard plot without slope was defined; this plot was subdivided in 6 modules of 25x25m and other one in 20x25m, it was used an irrigation system by micro sprinkling with a spacing of 5x5m and with pressure regulators to the beginning of every lateral pipe. For the main pipe and secondary pipe, the diameters obtained were of 38 mm and 16 mm for the lateral pipe. The irrigation system´s operation was defined for 7 irrigation turns, one per module; hence each module must operate 1 hour and 40 minutes for 12 hours of total irrigation. The established irrigation frequency is of 2 days. | Se diseñó la línea de conducción de agua y el sistema de riego modelo para las parcelas de 28 productores miembros de La Sociedad de Usuarios de Agua del Asentamiento Río Guayabo de Turrialba. Para ello se determinaron los diámetros del acueducto de conducción procurando que el sistema satisficiera los requerimientos de caudal, presión y reduciendo costos. Debido a que se cuenta con un caudal limitado de 12 l/s se establece un esquema de operación del mismo, conformado por 2 grupos de 14 tomas parcelarias para un total de 28 en el proyecto, en cada toma parcelaria, el caudal entregado es de 0,84 lps y la presión de 30 m.c.a. Se definió una parcela de riego estándar para terreno plano, que se subdividió en seis módulos de 25x25m y uno de 20x25m, utilizando un sistema de riego por microaspersión con un espaciamiento de 5x5m y con reguladores de presión a la entrada de cada lateral. El diámetro obtenido para la tubería principal y múltiple es de 38 mm y para laterales de 16 mm. La operación del sistema de riego se definió para 7 turnos de riego, uno por módulo, de tal forma que cada módulo opera por 1 hora y 40 minutos para una jornada total de 12 horas de riego. La frecuencia de riego establecida es de 2 días. | Sociedad de Usuarios de Agua del Asentamiento Río Guayabo de Turrialba, Servicio Nacional de Aguas Subterráneas, Riego y Avenamiento

Proyecto de Graduación (Licenciatura en Ingeniería en Biotecnología) Instituto Tecnológico de Costa Rica, Escuela de Biología, 2020 | Las cianotoxinas son contaminantes cada vez más frecuentes a nivel mundial en el agua potable procedente de aguas superficiales, debido a que las condiciones del cambio climático pueden aumentar la proliferación de las cianobacterias. La presencia de estas toxinas en el agua potable puede generar diferentes problemas a la salud como: daño hepático y daño a nivel neurológico. En Costa Rica, los análisis de cianobacterias en agua potable se realizan en casos excepcionales como cuando ocurren intoxicaciones masivas, por lo tanto, actualmente son escasos los datos que se tienen sobre las cianobacterias y sus toxinas: En 1994, Peinador aisló tres especies de cianobacterias de la Planta Potabilizadora de Tres Ríos, y en el año 2006 Avendaño y Arguedas encontraron en el agua cruda de la Planta Potabilizadora de Tres Ríos concentraciones superiores a lo establecido en la normativa. En este estudio se analizaron los datos suministrados por el ICE (Instituto Costarricense de Electricidad) sobre el embalse El Llano (fuente de la planta potabilizadora de Cartago) de los parámetros de temperatura, pH, fósforo total y amonio de las épocas entre 2016-2018, para determinar si con las características históricas del embalse, se podrían desarrollar las cianobacterias; además se empleó la técnica de espectrofotometría con el kit comercial Mycrocistest® para determinar la concentración de microcistinas tóxicas en el agua cruda y tratada de la planta potabilizadora de Cartago. Tras el análisis de los datos históricos se encontró que, con las características históricas de los parámetros analizados, si era posible el crecimiento de las cianobacterias y por ende de la producción de toxinas. Al realizar los ensayos, no se detectaron microcistinas (Mcs) en concentraciones iguales o superiores a 0,25 μg/L, lo que podría deberse a algunos factores como la presencia de sedimentos en el embalse, la biodegradación de las Mcs por parte de los microorganismos que crecen en el embalse, el corto tiempo de retención del embalse, entre otros. No obstante, no se descarta en el futuro, la presencia de cianobacterias, ni de cianotoxinas, por lo que se recomienda establecer un monitoreo de vigilancia de las densidades de cianobacterias presentes en el agua cruda de la planta y en caso de detectar densidades importantes, realizar una prueba de toxidad. | Cyanotoxins are an increasingly frequent pollutant worldwide in drinking water from surface waters, as the conditions of climate change can increase the proliferation of cyanobacteria. The presence of these toxins in drinking water can generate different health problems, such as liver damage and neurological damage. In Costa Rica, the analysis of cyanobacteria in drinking water is carried out in exceptional cases such as when massive intoxications occur, therefore, currently there is little data on cyanobacteria and their toxins: In 1994, Peinador isolated three species of cyanobacteria of the Tres Ríos drinking water treatment Plant, and in 2006 Avendaño and Arguedas found in the raw water of the same plant concentrations higher than that established in the regulations. In this study, the data provided by the ICE (Instituto Costarricense de Electricidad) on the El Llano reservoir (source of the Cartago drinking water treatment plant) of the parameters of temperature, pH, total phosphorus and ammonium of the periods between 2016-2018 were analyzed, to determine if with the historical characteristics of the reservoir, cyanobacteria could be developed. In addition, the spectrophotometric technique was used with the commercial Mycrocistest® kit to determine the concentration of toxic microcystins in the raw and treated water of the Cartago drinking water treatment plant. After analyzing the historical data, it was found that with the historical characteristics of the analyzed parameters, there is the possible for the growth of cyanobacteria and therefore the production of toxins. When performing the tests, no microcystins (Mcs) were detected in concentrations equal to or greater than 0.25 μg / L, which could be due to some factors such as the presence of sediments in the reservoir, the biodegradation of the Mcs by the microorganisms that grow in the reservoir, the short retention time of the reservoir, among others. However, the presence of cyanobacteria or cyanotoxins is not ruled out in the future, so it is recommended to establish surveillance monitoring of the densities of cyanobacteria present in the raw water of the plant and in case of detecting significant densities, perform a toxicity test.

Proyecto de Graduación (Licenciatura en Ingeniería Agrícola) Instituto Tecnológico de Costa Rica, Escuela de Ingeniería Agrícola, 2017. | The present report consists in a study to determine the water requirements of some crops grown in the northern part of Cartago. The study area of the project covers 7 districts, 1 in the province of San José and 6 in the province of Cartago. The purpose of this project came from the need to evaluate the calculation techniques to determine the water requirements that rule the development process of the crops in the northern zone of Cartago as a proposal for the concession manual for the Dirección de Agua belonging to (MINAE); to implement the most appropriate calculation technique and demonstrate the benefits in an economic, environmental and social assessment, in an area that presents problems with hydric resources especially in the dry season or when occur climatic issues like El Niño o La Niña. To obtain these assessments at first, we evaluate the current technique what determines the water needs to deliver the endowments in irrigation; for this purpose, la Dirección de Agua uses a combination of the evapotranspiration methodology and the consumptive use by applying the Blaney and Criddle formula, printed in the concession manual of the Dirección de Agua (MINAE), in which unique calculation variable it’s the elevation over sea level where the crop is located. Subsequently the methodology of the manual was compared with other calculation methods to relate its parameters and established results. It was found FAO Penman-Monteith equation to find the evapotranspiration is the most adequate to replace the current calculation technique. The meteorological parameters to find the evapotranspiration in crops with FAO Penman-Monteith method were obtained from meteorological stations near the study area and the model farms, with very reliable historical data up to 30 years, suggested for this equation. The results of the water requirements for some of the crops in the study area were determined using the proposed technique, and it was decided to go to the farms and identify the soil texture and the infiltration rate, elementary data to corroborate that the Irrigation used in these farms does not produce runoff or loss percolation. The results obtained in all the cases for the zone dictated that the methodology used by the Dirección de Agua Manual distribute high concessions compared with the methodology proposed in this report. For example, on a hectare of crops on model farms, up to 10,000 liters of water could be saved and conserved, which could be used for other concessions and generate new income from the economic point of view. From this conclusion would generate awareness in the method of calculation of the endowment, the irrigation systems used and the water resource saving in the area. | El presente informe consiste en un estudio de determinación de los requerimientos de agua de algunos cultivos que se producen en la zona norte de Cartago. El área en estudio del proyecto abarca siete distritos, uno de la provincia de San José y seis de la provincia de Cartago. La finalidad de este proyecto surgió de la necesidad de evaluar las técnicas de cálculo para determinar los requerimientos de agua que rigen en el proceso de desarrollo de los cultivos en la zona norte de Cartago como propuesta para el Manual de Dotaciones para la Dirección de Agua del Ministerio de Ambiente y Energía (MINAE) para implementar la técnica de cálculo más adecuada y demostrar los beneficios de dicha evaluación en materia económica, ambiental y social, en una zona que presenta problemas por falta del recurso hídrico especialmente en la época seca o cuando suceden patrones climáticos de fenómenos como el Niño o la Niña. Para cumplir con los objetivos propuestos, se tomaron y evaluaron cuatro fincas modelo dentro de la zona de estudio y se logró el cálculo idóneo de agua para diferentes cultivos. Primeramente, se evaluó la técnica de cálculo actual que determina las necesidades hídricas para entregar las dotaciones en riego- la Dirección de Agua utiliza una combinación de la metodología de la evapotranspiración y el uso consuntivo aplicando la fórmula de Blaney y Criddle- impresa en el Manual de Dotaciones de la Dirección de Agua del (MINAE), en la cual la única variable de cálculo es la altura en la que el cultivo se encuentra. Posteriormente, la metodología del manual fue comparada con otros métodos de cálculo para confrontar sus parámetros y resultados establecidos para su medición. Se encontró que la ecuación propuesta para hallar la evapotranspiración de los cultivos de FAO Penman-Monteith es la más adecuada para sustituir la técnica de cálculo actual. Los parámetros meteorológicos para hallar la evapotranspiración de los cultivos de FAO Penman-Monteith se obtuvieron de las estaciones meteorologías cercanas a la zona de estudio y a las fincas modelo, con datos históricos muy confiables de hasta 30 años sugeridos para dicha ecuación. Encontrados los resultados de los requerimientos de agua para algunos de los cultivos de la zona en estudio, se visitó las fincas y se e identificó la textura del suelo y la velocidad de infiltración básica, datos necesarios para corroborar que el sistema de riego empleado en dichas fincas no produce escorrentía ni perdida por percolación. Los resultados obtenidos en todos los casos para la zona dictaron que la metodología utilizada por el Manual de Dotaciones de la Dirección de Agua entrega concesiones sobrestimadas comparadas con la metodología propuesta en este informe. Por ejemplo, en una hectárea de cultivos en las fincas modelo se podría ahorrar y conservar hasta 10.000 litros de agua, los cuales pueden ser empleados para otras concesiones y generar desde el punto de vista económico nuevos ingresos. En conclusión, con la aplicación de la propuesta de cálculo de la dotación se generaría conciencia en el método, los sistemas de riego utilizados y en el ahorro del recurso hídrico que ocasionaría en la zona.

Proyecto de Graduación (Licenciatura en Ingeniería Ambiental). Instituto Tecnológico de Costa Rica. Escuela de Química. Carrera de Ingeniería Ambiental. 2015. | In Costa Rica in 2009, concentrations of arsenic were identified in water higher than the allowable limit (10 μg / L) in Guanacaste and San Carlos. Adsorption using natural materials has been successfully used for arsenic removal, especially rich in oxides / hydroxides of iron. Four natural materials from the province of Guanacaste were evaluated as adsorbents arsenic: basalt, biotite, magnetite and pumice. A multi-criteria analysis using Analytic Hierarchy Process and Grey Relational Analysis was performed for ranking materials for their potential use as adsorbents from the economic, technical and environmental point of view. Magnetite and biotite presented the best features, followed by basaltic materiales and pumice respectively. The chemical composition was analyzed by fluorescence and X-ray diffraction, showing varied compositions of iron, aluminum, titanium and silicon. The materials generate alkaline environments in contact with water, exhibit negative zeta potential at pH near 7. The BET surface areas are low: 2,68m2/g, 4,24m2/g, 5,18m2/g y 12,69m2/g for magnetite, pumice, biotite and basalt respectively. Removal evaluation was done with contact times of 10 minutes up to 48 hours, 25 ° C, 125rpm, pH 7 and 200μg/L As (V).The materials are analyzed in particle sizes between 0.1 to 1.18 mm and at concentrations of 1, 5 and 20g/L. Removal increases with time and the amount of material, however, the highest percentage of removal achieved is 74% for magnetite. Adsorption capacities were obtained by adjusting the data to the linear, Langmuir or Freundlich models, giving values below 28μg/g, considered low. Due to the low percentage of removal and adsorption capacity, the materials are not recommended as adsorbents for arsenic, despite being inexpensive, easily accessible and iron compounds. Key words: Arsenic, Water treatment, Adsorption, Natural adsorbents. | Instituto Tecnológico de Costa Rica. Escuela de Química. Carrera de Ingeniería Ambiental.

Proyecto de Graduación (Licenciatura en Ingeniería Ambiental) Instituto Tecnológico de Costa Rica, Escuela de Química, 2014. | Distribution of tanks have been linked in various studies with the effect of storage in water quality related problems concerning the disinfection process by deficiencies in the chlorine time of contact and hydrodynamics, specifically, because poor mixing, short circuit, dead zones mixing and thermal stratification; however, Costa Rica are few or no studies to confirm or refute such scenarios occur in distribution tanks. Therefore it is necessary to begin by assessing the hydrodynamic conditions, the spatiotemporal variation of free chlorine and temperature with appropriate and applicable to different administrative entities of the water supply systems protocols. To contribute this need the present research was conducted in the New Tank in San Ignacio de Acosta, where the hydrodynamic conditions and the spatiotemporal variation of the concentration of chlorine and temperature tank were evaluated. It was necessary to perform the test with instantaneous tracer injection of sodium chloride, the resulting data using four hydrodynamic models were analyzed: analysis of Wolf-Resnick, Trend Curve, Peclet number and Tanks in Series to evaluate the hydrodynamic conditions. With regard to space variation-temporal residual chlorine and the temperature, the study included nine sampling points into the tank through the use of water traps and a suction pump. Also we included two points abroad, one at the inlet and one at the outlet pipe. The set of data obtained for the study of variation space - time were analyzed with analysis of variance and Tukey's test. Moreover, analyzed the operation and maintenance of the tank related the test results with their physical explanation and so generate recommendations that we will improve water quality was performed. It was found that the new tank had percentages of 33% of mixed flow, plug flow 11% and 56% of dead zones in accordance with the method of Wolf- Resnick. It was also confirmed with the four methods aforementioned, the flow reactor was the ideal complete mixing reactor operation more approached the tank , but misses in all this behavior to be three methods the presence of a short circuit. That proceeds of short circuit and deficiency in the mixture was found actual holding time was 498.0 min, 15 min to less theoretical. Added to this the variation of the levels in the tank didn´t exceed 30 %, recording minimum values of 2 m, which together with possibly short circuit causes 56% of dead zones. The input and output configuration allows the presence of short circuit and therefore was recommended relocate one pipeline; regulating flow of income was recommended in conjunction with control levels to prevent foster varying volumes and prevent aging water. Finally, the feasibility of hydrodynamic studies related to water quality in storage tanks by a process applicable to the local context was found. The problem of maintaining high percentages of stored water, It wasn´t taking into account as the configuration of the inlet and outlet of the tank can affect water quality, demonstrating in turn that the storage tank wasn´t the structure is evidenced ideal for efficiently performing the disinfection process, constricted a valuable contribution in terms to risk minimization in water quality in the supply system in San Ignacio de Acosta.

The analysis of a two-phase timber skidding system was carried out in Ticabán town, located in Pococí, Limón, Costa Rica and its main objective was to evaluate two extraction methods: water buffaloes and agricultural tractors. Operation efficiency was determined through a time and motion study and production for each day evaluated was calculated, for this, all log´s volume hauled by the buffaloes and by the agricultural tractor was calculated using Smalian´s formula. A total of 12 working days of timber skidding with buffaloes and 6 with farm tractor were evaluated. The first timber skidding phase carried out with water buffaloes reported an average efficiency of 77,44 % and an average production of 1,73 m3/programmed hour, values that surpass those reported in similar research. In contrast, average efficiency and production reached using the agricultural tractor during the evaluation was 88,10 % and 3,16 m3/programmed hour, respectively. These results suggest that timber extraction techniques in two phases maximizes the advantages of the technologies used in each of them (buffaloes and farm tractor) and minimizes their disadvantages, increasing efficiency and the total production of the operation. | El análisis del sistema de arrastre de madera en dos fases se llevó a cabo en la localidad de Ticabán, ubicada en Pococí, Limón, Costa Rica y tuvo como objetivo principal la evaluación de dos métodos de extracción: búfalos de agua y tractor agrícola. Se determinó la eficiencia de la operación a través de un estudio de tiempos y movimientos y se calculó la producción de cada una de las jornadas evaluadas, para esto se cubicaron todos los fustes arrastrados por el búfalo y por el tractor agrícola utilizando la fórmula de Smalian. Un total de 12 jornadas de arrastre de madera con búfalo y 6 con tractor agrícola fueron evaluadas. Para la primera fase del arrastre realizada con búfalos de agua se obtuvo una eficiencia promedio de 77,44 % y una producción promedio de 1,73 m3/hora programada, datos que superan a los reportados en investigaciones similares. Por otra parte, la eficiencia y la producción promedio alcanzada por el tractor agrícola durante la evaluación del arrastre de madera fue de 88,10 % y 3,16 m3/hora programada, respectivamente. Estos resultados sugieren que la técnica de extracción de madera en dos fases maximiza las ventajas de las tecnologías empleadas en cada una de ellas y minimiza sus desventajas, aumentando la eficiencia y la producción total de la operación.

Proyecto de Graduación (Licenciatura en Ingeniería Ambiental) Instituto Tecnológico de Costa Rica, Escuela de Química, 2014. | The Aqueduct of San Isidro de El Guarco is in need of a immediate intervention due to water shortages during the dry season was presented in the catchments El Cubano, Casa Blanca #1 and Casa Blanca #2, the flow is insufficient to meet the demand during summer. New water sources near the population was proposed to achieve the maximum daily flow of 13 L / s is required over a period of 20 years. During rainy season, the increase of solid color and was in the water storage tank. The causes of the presence of high water turbidity and condition of slow upward flow filter were evaluated. The methodology used to afford data análisis was visits and interviews with the plumber and the manager of the ASADA were scheduled, in order to assess the current situation of the aqueduct; through the database SENARA, which two streams flow more was chosen to ensure the demand for current and future population needs. Each of the structures were measured internally, because there were no plans or the functioning of the chlorination was known and for 12 hours the volume change was measured in the storage tank for the use by users of San Isidro. The main results are that using the headwaters, the topographic profile of the pipe driving was obtained, this to ensure easy installation and lower costs. Also, with the high value of 12.95 NTU turbidity in the water filter in November indicates the status of the filter should be checked and constructing two filters to treat the flow entering the treatment plant. Expanding volume of 197 m3 is required in the storage tank. As finding in the months of December to April a decrease in precipitation is presented, as illustrated in the water balance, indicating a deficit of water in summer. Is recommended that the technical study, to determine whether the construction of a dam is the only technically feasible solution.