PRESAS DE AYAGAURES Y GAMBUESA [Material gráfico]

Copia digital. Madrid : Ministerio de Educación, Cultura y Deporte, 201

Conversion of chemical scrubbers to biotrickling filters for VOCs and H2S treatment at low contact times

The purpose of this work was to evaluate the technical and economical feasibility of converting three chemical scrubbers in series to biotrickling filters (BTFs) for the simultaneous removal of H2S and volatile organic compounds (VOCs). The conversion of the full-scale scrubbers was based on previous conversion protocols. Conversion mainly required replacing the original carrier material and recycle pumps as well as modifying the controls and operation of the reactors. Complete removal of H2S and VOCs on a routine basis was reached at neutral pH in a longer period of time compared to previous conversions reported. Biotrickling filters operated at a gas contact time of about 1.4 s per reactor and at pH controlled between 6.5 and 6.8. Inlet average concentrations below 10 ppmv of H2S and below 5 ppmv for VOCs were often completely removed. The first and second bioreactors played a primary role in H2S removal. Year-round operation of the biotrickling filters proved the ability of the system to handle progressive load increases of H2S and VOCs. However, fast, sudden load changes often lead to reduced removal efficiencies. Odor analyses showed average removal efficiencies above 80 %. Gas chromatography-mass spectrometry of selected samples showed that outlet odor concentration was due to limited removal of VOCs. The conversion showed was economically viable taking into account the theoretical consumption of chemicals needed for the absorption and oxidation of both H2S and VOCs.Peer ReviewedPostprint (published version

CFD modeling of a fixed-bed biofilm reactor coupling hydrodynamics and biokinetics

Peer ReviewedPostprint (author's final draft

A review: biological technologies for nitrogen monoxide abatement

David Cubides is a fellow of Eurecat's “Vicente López” PhD grant program. This work was financially supported by the Catalan government through the funding grant ACCIÓ-Eurecat (Project PRIV 2020/21-AIRECAT). The authors acknowledge the Spanish Government, through project RTI 2018-099362-B-C21 MINECO/FEDER, EU, for the financial support provided to perform this research.Peer ReviewedPostprint (published version

Study of immobilized biomass reactors for sulfate reducing activity characterization and improvement

Immobilization of non-granular sludge is an auspicious option for sulfate reducing activity improvement. In this study, PVA-biomass granules and alginate-biomass granules were tested for mechanical stability, adsorption capacity and sulfate reduction. Moreover, two configurations of reactors, a Continuous Stirred Tank Reactor (CSRT) and a Column Reactor (CR) were operated, evaluating sulfate and glycerol consumption H2S production in order to improve sulfate-reduction process within SONOVA process. The CR presented a stable sulfate reducing activity, higher production of H2S and low wash out comparing to CSTR.Peer ReviewedPostprint (published version

Biofilm dynamics characterization using a novel DO-MEA sensor: mass transport and biokinetics

Biodegradation process modeling is an essential tool for the optimization of biotechnologies related to gaseous pollutant treatment. In these technologies, the predominant role of biofilm, particularly under conditions of no mass transfer limitations, results in a need to determine what processes are occurring within the same. By measuring the interior of the biofilms, an increased knowledge of mass transport and biodegradation processes may be attained. This information is useful in order to develop more reliable models that take biofilm heterogeneity into account. In this study, a new methodology, based on a novel dissolved oxygen (DO) and mass transport microelectronic array (MEA) sensor, is presented in order to characterize a biofilm. Utilizing the MEA sensor, designed to obtain DO and diffusivity profiles with a single measurement, it was possible to obtain distributions of oxygen diffusivity and biokinetic parameters along a biofilm grown in a flat plate bioreactor (FPB). The results obtained for oxygen diffusivity, estimated from oxygenation profiles and direct measurements, revealed that changes in its distribution were reduced when increasing the liquid flow rate. It was also possible to observe the effect of biofilm heterogeneity through biokinetic parameters, estimated using the DO profiles. Biokinetic parameters, including maximum specific growth rate, the Monod half-saturation coefficient of oxygen, and the maintenance coefficient for oxygen which showed a marked variation across the biofilm, suggest that a tool that considers the heterogeneity of biofilms is essential for the optimization of biotechnologies.Peer ReviewedPostprint (published version

Técnicas avanzadas en el estudio de bioprocesos para el tratamiento de aire y olores

Peer ReviewedPostprint (published version

Optimization of SO2 and NOx sequential wet absorption in a two-stage bioscrubber for elemental sulfur valorisation

Removal of SO2 and NOX from flue gases has become an important issue in air pollution control. A two-stage bioscrubber based on a sequential wet absorption of SO2 and NOx followed by a two-stage biological process has been proposed in order to valorise SO2 and NOx by elemental sulphur production. Biological process characterization established a maximum sulfate loading rate (5 kg S·m-3·d-1) and an optimal COD/S ratio (5.4 g O2·g S-1) in order to maximize elemental sulfur production and to avoid biological process limitations. Absorption of SO2 and NOx species is highly dependent on the absorption effluents compositions. In this sense, the success of the two-stage bioscrubber process lies in an optimal sequential transfer of pollutants to the liquid. Differences in the solubility of pollutants enable the individual absorption of pollutants in two in-series scrubbers operated under different pH and residence time conditions. In addition, the use of secondary effluents from the reduction-oxidation biological process as absorbent was demonstrated as a key parameter to improve the efficiency and reduce operating costs.Peer ReviewedPostprint (published version

An inkjet-printed amperometric H2S sensor for environmental applications

Peer ReviewedPostprint (published version

Effect of biomass density on oxygen diffusivity measured inside biofilms with a MEA Sensor

The optimization of biofiltration technologies can be addressed improving the knowledge of the process taking place within biofilms, mainly biokinetics and mass transport. Biokinetics are usually defined using different methodologies, such as respirometric and titrimetric tests. Mass transport within biofilms is usually described as diffusion through a homogeneous phase, despite it is accepted that biofilms are very heterogeneous. Thus, a quantitative understanding of how biofilm structure is linked to mass transport is essential to develop reliable models. For this purpose different works have collected the results of various diffusion studies, proposing correlations between biofilm density and mass transport. However the reliability of these correlations, widely used in modeling works, is under suspect because data used in their construction are highly dependent on the experimental conditions where they were obtained. The goal of this paper was to experimentally quantify the effective diffusivity inside biofilms, using a specific microsensor, as function of biomass density, for a specific microbial population and substrate. In addition, biofilm diffusivity was measured at different hydrodynamic conditions. Combining both studies, an equation for the calculation of biofilm diffusivity, considering biomass density and liquid phase velocity, was proposed.Peer ReviewedPostprint (published version