Recuperación de amoniaco mediante membranas semipermeables a partir de residuos ganaderos

En este trabajo se desarrolla una investigación novedosa mediante el uso de membranas semipermeables que actuará como captoras del gas amoniaco que generan los residuos ganaderos líquidos. Queremos validar este tipo de sistemas que ya han sido referenciados y desarrollados por diferentes investigadores, especialmente USDA y el grupo de Matías Vanotti, establecer su eficiencia en diferentes condiciones y variables. El objetivo de este estudio es captar N-amoniacal procedente de purines mediante membranas semipermeables de politetrafluoroetileno expandido, microporosas e hidrófobas que permiten el intercambio gaseoso del NH3 para ser capturado por disolución ácida H2SO4 1N. Con el fin de mejorar el proceso y para aumentar el pH del purín se utilizó flujo de aire a baja velocidad (0,24Laire Lmateria-1min-1) para que en presencia de alcalinidad de bicarbonatos se desarrolle la reacción 3+ ⟶ −+2. Este trabajo incluye una serie de estudios consecutivos que permiten profundizar en el objetivo propuesto. Se ha realizado un estudio inicial de validación de las membranas usando disoluciones patrón (NO3-NH4) en diferentes concentraciones (1000 ppm, 2000 ppm, 3000 ppm, 4000 ppm) junto con una concentración fija de 4,82 g/L de NaHCO3 necesaria para provocar el aumento de pH; en segundo lugar se estudia un sistema más complejo incluyendo ácido húmico en concentraciones de 3000 ppm, 4500 ppm y 6000 ppm para simular presencia de materia orgánica similar a la existente en los purines. En el siguiente experimento se trabaja con un flujo residual real como son los lixiviados procedentes de vertedero de residuos sólidos urbanos. Finalmente se ensaya la recuperación de amoniaco a partir de purines de cerdo en dos ensayos, uno de ellos los purines diluidos en relación 1:3 y el otro, los purines se diluyeron en relación 1:5. De forma resumida en los diferentes experimentos se han obtenido recuperaciones de amoniaco significativas mediante el uso del sistema propuesto: en concreto, la recuperación de amonio en disolución patrón fue del 90% para la concentración de 2000 ppm en un plazo de 95 horas; para el trabajo con ácidos húmicos se recuperó casi el 100% para la concentración de 3000 ppm en 72 horas y no apareció ningún efecto provocado por la presencia de materia orgánica. En el ensayo con lixiviado de vertedero la recuperación de NH4 fue del 45% en 48 horas. En los purines se obtuvieron dos resultados, la recuperación de NH4 para disolución 1:3 fue del 76% en 95 horas y la recuperación en purín con relación 1:5 fue del 94% en 95 horasThis scientific work develops a novel research using semipermeable membranes which act as captors of ammonia gas generated in livestock liquids waste. We validate these systems that have already been referenced and developed by different researchers, especially USDA and Mattias Vanotti’s group, establish efficiency under different conditions and variables. The objective of this study is to capture N-ammonia from swine manure by semipermeable membranes of expanded polytetrafluoroethayle, microporous and hydrohbic allowing exchange of NH3 gas to be capture by acid solution H2SO4 1N, to increase slurry’s pH, airflow at low speed was used (0,24Lair Lmanure-1min-1), that in the presence of bicarbonate alkalinity the reaction is developed 3+ ⟶ −+2. This work includes a series of consecutive studies to deepen in the proposed objective. There has been carry out an initial validation study membranes using pattern dissolution (NO3-NH4) in different concentrations (1000 ppm, 2000 ppm, 3000 ppm, 4000 ppm) with a fixed concentration of 4.82 g/L NaHCO3 necessary to cause pH increased; secondly a more complex system was studied, including humic acid at concentrations of 3000 ppm, 4500 ppm and 6000 ppm to simulate the presence of organic matter similar to that existing in the slurry. The next experiment was carried out with a real waste stream such as landfill leachate from municipal solid waste. Finally the recovery of ammonia is tested from pig manure in two trials, one slurry diluted 1: 3 and the other, and slurry were diluted 1: 5. Summarizing, they were obtained in the different experiments significant ammonia recoveries using the proposed system: in particular, the recovery of ammonia in pattern dissolution was 90% for the 2000 ppm concentration within 95 hours; the work with humic acid recovered almost 100% for the concentration of 3000 ppm in 72 hours and did not appear any effect caused by the presence of organic matter. In the test with landfill leachate NH4 recovery was 45% in 48 hours. In the two studies with pig slurry the following results were obtained, NH4 recovery for dissolution 1:3 was 76% in 95 hours and the recovery of NH4 in slurry diluted with 1:5 ratio was 94% 95 hour

Nitrogen recovery from wastewater using gas-permeable membranes: Impact of inorganic carbon content and natural organic matter

Gas-permeable membranes coupled with low-rate aeration is useful to recover ammonia (NH4+) from livestock effluents. In this study, the role of inorganic carbon (bicarbonate, HCO3−) to enhance the N recovery process was evaluated using synthetic effluents with various NH4+ to HCO3− molar ratios of 0.5, 1.0, 1.5 and 2.0. The study also evaluated the effect of increased organic matter on the NH4+ recovery using humic acids (3000–6000 mg L−1), and the N recovery from high-strength swine manure. The release of hydroxide from the HCO3− with aeration increased the wastewater pH and promoted gaseous ammonia formation and membrane uptake. At the same time, the recovery of gaseous ammonia (NH3) through the membrane acidified the wastewater. Therefore, an abundant inorganic carbon supply in balance with the NH4+ is needed for a successful operation of the technology. NH4+ removal efficiencies >96% were obtained with NH4+ to HCO3− ratios ≤1. However, higher molar ratios inhibited the N recovery process resulting in lower efficiencies (<65%). Fortunately, most swine manures contain ample supply of endogenous inorganic carbon and the process can be used to more economically recover the ammonia using the natural inorganic carbon instead of expensive alkali chemicals. In 4 days, the recovered NH4+ from swine manure contained 48,000 mg L−1. Finally, it was found the process was not inhibited by the increasing levels of organic matter in the wastewater evaluated.Co-financed by the Ministry of Economy & Competitiveness of Spain and the European Regional Development Fund (ERDF, “Una manera de hacer Europa”) (Project AGL2013-41612-R). Cooperation with USDA-ARS Project 6082-13630-001-00D “Improvement of Soil Management Practices and Manure Treatment/Handling Systems of the Southern Coastal Plains” is acknowledged

Hydrophobic membranes for ammonia recovery from digestates in microbial electrolysis cells: Assessment of different configurations

The combination of hydrophobic membranes and microbial electrolysis cells (MEC) was assessed in two different configurations in order to recover ammonia from anaerobically digested pig slurry. Polytetrafluorethylene (PTFE) hydrophobic membranes were inserted both in an H-type three-chamber cell (MEC-H) and a two-chamber sandwich configuration MEC (MEC-S), both fitted with a cationic exchange membrane (CEM) dividing the anode and cathode compartments. The use of electrochemical techniques such as electrochemical impedance spectroscopy was applied to monitor the increase of the biofilm on the anode, related to the decrease of the charge transfer resistance. When operated in the higher organic loading rate (28 ± 5 kg COD m−3 d−1) the current density produced in the MEC-H was 1.40 ± 0.71 A m−2, compared to 0.61 ± 0.28 A m−2 in the MEC-S. The flux of ammonium through the CEM in the MEC-H was of 3.4 ± 1.2 g N m−2 h−1. Regarding the recovery of ammonia through the hydrophobic membrane, the flux of ammonia was of 1.5 and 0.7 g N m−2 h−1 in the MEC-H and MEC-S, respectively, mainly governed by the pH value and the ammonia concentration of the catholyte. The combination of MEC with hydrophobic membranes reveals as a suitable technology for the recovery of ammonia and treatment of high strength wastewater such as livestock.info:eu-repo/semantics/acceptedVersio