Solid dilutions: a novel sample preparation method for the determination of COD in heterogeneous solid or semi-liquid samples

The method consists on solid dilution with MgSO4 as sample preparation method. Reagents concentration and ratio were optimized to analyze complex substrates (from 5 to 2,500 g COD Kg-1 TS). Comparison with the standard titrimetric method demonstrated much better precision and accuracy, allowing a significant decrease on chemicals consumption and toxic waste generation.Postprint (published version

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. Politetrafluorethilene (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 resistence.This research was funded by the Spanish Ministry of Economy and Competitiveness (INIA project RTA2015-00079-C02-01). The support of the CERCA Program and of the Consolidated Research Group TERRA (ref. 2017 SGR 1290), both from the Generalitat de Catalunya, is also acknowledgedPostprint (updated version

Different approaches to assess the environmental performance of a cow manure biogas plant

In intensive livestock production areas, farmers must apply manure management systems to comply with governmental regulations. Biogas plants, as a source of renewable energy, have the potential to reduce environmental impacts comparing with other manure management practices. Nevertheless, manure processing at biogas plants also incurs in non-desired gas emissions that should be considered. At present, available emission calculation methods cover partially emissions produced at a biogas plant, with the subsequent difficulty in the preparation of life cycle inventories. The objective of this study is to characterise gaseous emissions: ammonia (NH3-N), methane (CH4), nitrous oxide (N2Oindirect, and N2Odirect) and hydrogen sulphide (H2S) from the anaerobic co-digestion of cow manure by using different approaches for preparing gaseous emission inventories, and to compare the different methodologies used. The chosen scenario for the study is a biogas plant located next to a dairy farm in the North of Catalonia, Spain. Emissions were calculated by two methods: field measurements and estimation, following international guidelines. International Panel on Climate Change (IPCC) guidelines were adapted to estimate emissions for the specific situation according to Tier 1, Tier 2 and Tier 3 approaches. Total air emissions at the biogas plant were calculated from the emissions produced at the three main manure storage facilities on the plant: influent storage, liquid fraction storage, and the solid fraction storage of the digestate. Results showed that most of the emissions were produced in the liquid fraction storage. Comparing measured emissions with estimated emissions, NH3, CH4, N2Oindirect and H2S total emission results were in the same order of magnitude for both methodologies, while, N2Odirect total measured emissions were one order of magnitude higher than the estimates. A Monte Carlo analysis was carried out to examine the uncertainties of emissions determined from experimental data, providing probability distribution functions. Four emission inventories were developed with the different methodologies used. Estimation methods proved to be a useful tool to determine emissions when field sampling is not possible. Nevertheless, it was not possible to establish which methodology is more reliable. Therefore, more measurements at different biogas plants should be evaluated to validate the methodologies more precisely.Postprint (author's final draft

Development of indicators to evaluate manure processing technologies. Anaerobic digestion and composting of cow manure plant as case study

Postprint (published version

Evaluation of manure management systems in Europe

The gross value of the agricultural goods in 2014 amounted up to 370 billion Euros. Almost 50% of all agricultural production is provided by livestock farming.Postprint (published version

Tecnologías limpias para la reducción de contaminantes y la recuperación de solutos de fuentes hidrominerales mediante resinas de intercambio iónico

A la portada: Unitat de Química AnalíticaDescripció del recurs: el 18-08-2008Consultable des del TDXTítol obtingut de la portada digitalitzadaLa memoria recoge una serie de procesos de intercambio iónico para el tratamiento de fuentes hidrominerales, tanto en lo que se refiere a procesos de producción como a la reducción de contaminantes. Los procesos se realizan bien sustituyendo los reactivos químicos por variables físicas como puede ser la temperatura, o bien recirculando los reactivos químicos empleados de modo que se evite su vertido al medio ambiente. Este tipo de procesos se han aplicado al tratamiento de dos muestras diferentes: el agua de mar y las aguas ácidas de mina. En primer lugar se ha desarrollado un proceso para la concentración y separación de calcio y magnesio del agua de mar utilizando la técnica de intercambio iónico a temperatura dual. A continuación se ha aplicado la misma técnica para la concentración selectiva de metales de aguas ácidas de mina. Por otro lado se ha desarrollado la nueva técnica de partición por intercambio iónico en tandem (TIEF) para la separación de mezclas metálicas multicomponentes. Finalmente se ha desarrollado un tratamiento integral de las aguas ácidas de mina que consiste en la precipitación selectiva del hierro, la conversión de contaminantes en fertilizantes y la recuperación de los metales

Tecnologías limpias para la reducción de contaminantes y la recuperación de solutos de fuentes hidrominerales mediante resinas de intercambio iónico

La memoria recoge una serie de procesos de intercambio iónico para el tratamiento de fuentes hidrominerales, tanto en lo que se refiere a procesos de producción como a la reducción de contaminantes. Los procesos se realizan bien sustituyendo los reactivos químicos por variables físicas como puede ser la temperatura, o bien recirculando los reactivos químicos empleados de modo que se evite su vertido al medio ambiente. Este tipo de procesos se han aplicado al tratamiento de dos muestras diferentes: el agua de mar y las aguas ácidas de mina. En primer lugar se ha desarrollado un proceso para la concentración y separación de calcio y magnesio del agua de mar utilizando la técnica de intercambio iónico a temperatura dual. A continuación se ha aplicado la misma técnica para la concentración selectiva de metales de aguas ácidas de mina. Por otro lado se ha desarrollado la nueva técnica de partición por intercambio iónico en tandem (TIEF) para la separación de mezclas metálicas multicomponentes. Finalmente se ha desarrollado un tratamiento integral de las aguas ácidas de mina que consiste en la precipitación selectiva del hierro, la conversión de contaminantes en fertilizantes y la recuperación de los metales

Numerical methods with particular reference to nonlinear problems

SIGLEAvailable from British Library Document Supply Centre- DSC:D34425/81 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Solid dilutions: a novel sample preparation method for the determination of COD in heterogeneous solid or semi-liquid samples

The method consists on solid dilution with MgSO4 as sample preparation method. Reagents concentration and ratio were optimized to analyze complex substrates (from 5 to 2,500 g COD Kg-1 TS). Comparison with the standard titrimetric method demonstrated much better precision and accuracy, allowing a significant decrease on chemicals consumption and toxic waste generation

Determination of chemical oxygen demand in heterogeneous solid or semisolid samples using a novel method combining solid dilutions as a preparation step followed by optimized closed reflux and colorimetric measurement

This paper reports the development of an innovative sample preparation method for the determination of the chemical oxygen demand (COD) in heterogeneous solid or semisolid samples, with high suspended solids and COD concentrations, using an optimized closed re flux colorimetric method