Ammonia is a nuisance gas in many swine barns. The overall objective of this research project was to model ammonia formation and transmission processes in a grower-finisher swine barn, by first modelling the ammonia production and emission from urine puddles on the floor surface and the ammonia emission from the slurry pit, and then incorporating these emission rates in a dynamic model that separates the room and slurry pit headspace as two separate, but linked, control volumes. A series of studies were conducted to gather more information about the processes affecting the ammonia emission rate from the floor surface and the slurry that were later included in the overall room model developed. The model was then used to investigate ammonia reducing techniques and technologies based on the understanding of ammonia production and transmission incorporated in the model. The first step in modelling the ammonia emission rate from the floor surface was to determine the frequency of urinations by grower-finisher pigs. Male and female pigs were observed three times during their finishing phase to determine their urination frequency over the course of a day. The average measured urination frequency was 0.62 ± 0.11 urinations pig-1 h-1. A sinusoidal dromedary model was developed to describe the daily variation in urination frequency for male and female pigs between 51 and 78 kg.<p>In order for the deposited urinations on the floor surface to emit ammonia, the urea in the urine must first be converted to ammonia and the urease enzyme catalyzes this reaction. Two methods, a fixed-time-point method using the indophenol assay for ammonium-nitrogen analysis and a continuous method using the coupled enzyme assay, were used to measure enzyme activity at the floor surface of a swine barn and were compared to reported urease activity levels in the literature. Using both methods, there appeared to be an ammonia-producing site on the floor surface or within the collected samples that made accurate measurements of urease activity impossible. A review of urease activity levels in the literature from dairy-cow houses suggest that urease activity will be lowest following floor-cleaning and increase quickly following fouling of the floor surface. Based on the literature review, a urease activity value of 5 g NH¬3 m-2 h-1 was suggested for use in ammonia emission modelling of fouled floor surfaces in swine barns until better measurements become available. <p>The ammonia emissions from 36 simulated urine puddles under a variety of temperature, air velocity and initial urea concentration conditions were measured in a bench-scale experimental set-up. The measurements were used to calibrate and validate a dynamic, mechanistic, urine puddle emission model that considered the processes of evaporation, urea conversion, change in liquid concentration and puddle pH in order to simulate the amount of ammonia emitted from a puddle. Based on the correlation coefficients (R) between measured and simulated values for water volume (R=0.99), total ammoniacal nitrogen concentration (R=0.90), and total emission (R=1.00), along with five other statistical tests for each simulated variable, the model was deemed accurate. The measurements and simulations in this experiment showed the impact of puddle pH, urease activity and changing environmental conditions on the average puddle emission rate. Puddle emission continued to occur as long as there was still water.<p> The impact of different slurry compositions on the ammonia emission rate from slurry pits was tested in another bench-scale experimental set-up with emission chambers. The emission chamber concentration data collected was used to calibrate and validate a developed slurry emission model. The collected slurry samples were concentrated mixtures of urine and feces from individually-housed animals fed different diets. An empirical equation was developed to express the amount of total ammoniacal nitrogen in the slurry that was in the form of ammonia (f) and thus volatile to the surroundings. Based on the empirical equation, the simulated value of f was between 0.03 and 0.08 and did not show the sensitivity to slurry pH that has been reported by other authors. The slurry emission model with the empirical equation for f was validated with ammonia emission measurements from eight different slurry samples and simulated hourly concentration measurements within 17% and five-day average concentration measurements within 3%. Further testing was recommended to ensure the model developed for concentrated manure in this study was applicable to the more dilute slurry found in swine barns. <p>Using the information gained in the previous experiments, a mechanistic model describing the dynamic ammonia concentration in the room and in the slurry channel headspace of grower-finisher swine barns, as well as the ammonia emitted to the surrounding environment was developed. Data was collected from two grower-finisher rooms to use as input data to the model and for calibration and validation purposes. The model calibration procedure determined that the amount of emissions originating from the slurry for the simulated room conditions was generally less than 5% of the total room emissions, the air exchange rate through the slatted floor was approximately 4% of the room ventilation rate, and that in the first two weeks of animal activity in a room the urease activity at the floor surface will increase. The model was validated using separate data from that used in the calibration process. The model simulated hourly room concentration levels within 2.2 ppm and 3-day average concentration levels within 1.6 ppm. The model simulations were more accurate for one room that was fed a typical grower-finisher diet compared to another room fed an experimental diet with lower protein content and sugar-beet pulp inclusion. <p>The dynamic model was tested for its sensitivity to various input factors in terms of the floor emission rate, slurry emission rate and total emission rate. An interesting aspect of the simulations was that increases in either floor or surface emission rate were compensated to a small extent by decreases in the other emission rate as a result of a reduced concentration gradient for mass transfer. The ammonia emission rate from the floor was most sensitive to changes in urease activity, fouled floor area and puddle area. The ammonia emission rate from slurry was most sensitive to changes in slurry pH. The impact of input variables on the total emission rate was dependant on the simulated proportion of the total ammonia emission coming from either the floor surface or slurry channel. Three ammonia reduction techniques were tested and evaluated on their impact to the total ammonia emission rate from a room compared to a given set of control conditions.<p>The work in this thesis highlighted the importance of ammonia emission from the floor surface. The proportion of ammonia originating from the slurry and from the floor surface respectively will vary on the specific conditions within the barn, and will impact the effect of any ammonia mitigation technique that is investigated or used.

La carencia de servicios básicos como agua potable, para zonas como Cajamarquilla, es un problema social que se debe solucionar. Ante esta situación existen proyectos para dotar de servicios de agua a la zona, que por la geografía que presentan se utilizarán reservorios apoyados en los cerros aledaños. El procedimiento de diseño de un reservorio circular de concreto para la zona, servirá como guía para futuros proyectos. Siendo el objetivo de la investigación proponer criterios y un método adecuado para diseñar la estructura de un reservorio de concreto armado que cumplan con los parámetros de la propuesta de norma E030 2014 para la zona de Cajamarquilla, dada la poca información que existe de estos a pesar de ser de uso muy común en nuestro país. El tipo de la investigación es cualitativo, correlacional y de diseño experimental puro, con el fin de obtener resultados certeros para el diseño de reservorio. Finalmente, el método a usar es el que propone la norma del ACI 350-06, basándose en masas impulsivas y convectivas, del modelo de Housner, para el análisis estático mientras que para análisis el dinámico se utilizó el software Sap2000, por el método de elementos finitos y aplicando el espectro de diseño de la norma ACI 350 adecuándose a la norma peruana, como también para el diseño estructural de los elementos del tanque. La distorsión hallada es de 0.001 y que las cortantes basales estáticas y dinámicas son similares estando en un rango de 90%, por lo que se cumplen con los parámetros de la nueva propuesta de norma E030 2014. The lack of basic services such as water, to areas like Cajamarquilla, is a social problem to be solve. In this situation there are plans to provide water services to the area, by geography reservoirs that have supported in the surrounding hills are used. The process of designing a concrete circular reservoir area will serve as a guide for future projects. As the aim of the research propose criteria and an appropriate method to design the structure of a reinforced concrete reservoir that meet the parameters of the proposed rule for the 2014 E030 Cajamarquilla area, given the little information that exists in spite of these It is very commonly used in our country. The type of research is qualitative, pure correlational and experimental design, in order to obtain accurate results reservoir design. Finally, the method used is the standard proposed by the ACI 350-06, based on impulsive and convective mass Housner model for static analysis while for the Sap2000 dynamic analysis software used by the method of and applying the finite element design spectrum ACI 350 standard adapting to the Peruvian standard, as well as for the structural design of the elements of the tank. The distortion founded that the cutting 0.001y static and dynamic baseline are like being in a range of 90%, so that meet the parameters of the new E030 2014 proposed rule.

En la presente tesis se ha desarrollado la evaluación estructural de cinco reservorios circulares del tipo apoyado, construidos entre los años 1977 y 1997, ubicados en zonas de alto riesgo sísmico en Lima Metropolitana y ubicados en suelos medianamente rígidos, con el objetivo de evidenciar si estas estructuras continúan conservando un diseño sísmico adecuado en base a los requerimientos sísmicos actuales, y por ende si serán capaces de resistir un evento sísmico severo y continuar con el servicio. Para poder modelar y determinar la respuesta de los se reservorios se empleó el modelo equivalente de Housner, obteniendo así la masa impulsiva y convectiva, modelado en el programa SAP2000 con ayuda de las normas ACI 350.3-06 y E.030. En cuanto a la determinación de las fuerzas resistentes, para poder realizar la evaluación estructural correspondiente, se utilizó la norma peruana E.060-2009 Concreto Armado, con la cual se obtuvo dichas fuerzas y se realizaron las verificaciones estructurales. Con respecto a los resultados de las verificaciones realizadas, se observó que los reservorios en estudio no mantienen un diseño estructural adecuado en cuanto a las solicitaciones sísmicas actuales. Estas deficiencias se plasman en déficit de refuerzo horizontal por corte en muros, cuantía mínima vertical por corte en muros, refuerzo en la base del muro por momento tangencial, armadura requerida en la viga collarín, y refuerzo en el extremo de la cúpula por tracción radial; por lo que estas estructuras, ante la presencia de un evento sísmico severo, se encuentran expuestas a presentar fallas estructurales. / In the present thesis has been carried out the structural assessment of five round ground concrete tanks, built between 1977 and 1997, and located in high seismic risk areas in Lima Metropolitana in moderately rigid soils, with the objective of demonstrating if these structures still preserve an adequate structural design base on the current standards and consequently, if they will be able to withstand a severe seismic event and, hence, continue with their service. In order to model and determine the response of the tanks, the Housner’s rigid equivalent model was used, obtaining this way the impulsive and convective masses, which were modeled in the software SAP2000 with the ACI 350.3-06 standard and the E.030 Peruvian standard. Regarding on the determination of the resistant forces, in order to carry out the corresponding structural evaluation, the Peruvian standard “Concreto Armado E.060” was utilized. With regard to the results of the verifications carried out, it was observed that the reservoirs under study do not maintain an adequate structural design in terms of the current seismic solicitations. These deficiencies are reflected in horizontal reinforcement deficit by shear force on the walls, minimum amount of vertical rebar by shear on the walls, reinforcement in the base of the wall by tangential bending moment, rebar required in the beam by radial tensile force, and rebar in the end of the dome by radial traction; so these structures, in the presence of a severe seismic event, are exposed to structural failures. / Tesis