Biobutanol production from apple pomace: The importance of pretreatment methods on the fermentability of lignocellulosic agro-food wastes

This document is a pre-print version of the manuscript that was subsequently peer-reviewed and accepted for publication by the journal Applied Microbiology and Biotechnology (Vol. 101, pages 8041-8052, year 2017). The final publication is available at Springer via http://dx.doi.org/10.1007/s00253-017-8522-z

Uptake and Detoxification of Organic Micropollutants by Macrophytes in Constructed Wetlands

Pollution by organic micropollutants (OMPs) is recognized worldwide as an emerging environmental problem. Since conventional wastewater treatment processes are generally ineffective for most of these pollutants, alternative/complementary technologies need to be considered with the aim of more efficiently addressing this problem. Constructed wetlands is a promising technology that uses plants and microorganisms to remove OMPs from wastewaters. As result of their sedentary nature, plants have evolved diverse abilities for dealing with toxic compounds present in their environment. They, therefore, possess a variety of pollutant attenuation mechanisms that makes their use in wastewater treatment more feasible than physical and chemical processes. This chapter presents an overview of OMPs’ fate inside plants, following their uptake, and discusses the main factors influencing their uptake and translocation within plants. The various phases of the metabolic transformations of organic pollutants inside plants, which have the aim of modifying the xenobiotics in order to make them less toxic to the plants, are also described in this chapter. Finally, a brief account is given on the response of antioxidant defense systems of plants which are triggered by abiotic stress conditions that may result from long-term exposure of plants to OMPs

The Role of Macrophytes in the Removal of Organic Micropollutants by Constructed Wetlands

The contamination of aquatic environments with organic micropollutants (OMPs) resulting from human activities is becoming a widespread, serious environmental issue. The problem is mainly rooted in a general inefficiency of conventional wastewater treatment plants to deal with this type of pollutants, which causes treated wastewaters to still contain significant amounts of OMPs as they are discharged into the receiving water bodies. Among various technologies that have been developed and evaluated for removal of OMPs from wastewaters, constructed wetland systems (CWS) are generally seen as a cost-effective option. Aquatic macrophytes are a fundamental component of CWS, possessing a vast potential for removal, transformation/degradation of a variety of OMPs. This chapter presents a review focusing on the role of macrophytes in CWS targeted for OMPs removal, detailing the several types of physical, chemical and biological processes that may be responsible for their role in removing these pollutants from wastewater, how these processes are affected by several conditions and characterizing the situations where each type of process may be more relevant. Furthermore, the types of interactions that potentially occur between plants and the other components of CWS, and how important these interactions may be for the system's performance are briefly presented

Bioelectrochemical enhancement of methane production from exhausted vine shoot fermentation broth by integration of MEC with anaerobic digestion

[ES] A microbial electrolysis cell integrated in an anaerobic digestion system (MEC-AD) is an efficient configuration to produce methane from an exhausted vine shoot fermentation broth (EVS). The cell worked in a single-chamber two-electrode configuration at an applied potential of 1 V with a feeding ratio of 30/70 (30% EVS to 70% synthetic medium). In addition, an identical cell operated in an open circuit was used as a control reactor. Experimental results showed similar behavior in terms of carbon removal (70–76%), while the specific averaged methane production from cycle 7 was more stable and higher in the connected cell (MECAD) compared with the unpolarized one (OCAD) accounting for 403.7 ± 33.6 L CH4·kg VS−1 and 121.3 ± 49.7 L CH4·kg VS−1, respectively. In addition, electrochemical impedance spectroscopy revealed that the electrical capacitance of the bioanode in MECAD was twice the capacitance shown by OCAD. The bacterial community in both cells was similar but a clear adaptation of Methanosarcina Archaea was exhibited in MECAD, which could explain the increased yields in CH4 production. In summary, the results reported here confirm the advantages of integrating MEC-AD for the treatment of real organic liquid waste instead of traditional AD treatment.SIPublicación en abierto financiada por el Consorcio de Bibliotecas Universitarias de Castilla y León (BUCLE), con cargo al Programa Operativo 2014ES16RFOP009 FEDER 2014-2020 DE CASTILLA Y LEÓN, Actuación:20007-CL - Apoyo Consorcio BUCL

Potential effects of rainwater-borne H2O2 on competitive degradation of herbicides and in the presence of humic acid

In a previous piece of work, we reported some preliminary experimental results showing that hydrogen peroxide at a concentration range frequently encountered in rainwater could lead to degradation of three common herbicides (diuron, butachlor and glyphosate). However, the work was limited to the observation on the effects of Fenton process on the individual herbicides. In field conditions, different types of herbicides along with other organic molecules may occur concurrently. It is unclear how different herbicides and various organic molecules compete for the available hydroxyl radical. In this study, further microcosm experiments were conducted to observe the changes in the herbicides in the scenarios where multiple herbicides or humic acid are present. The results show that humic acid impeded hydroxyl radical-driven degradation of the diuron and butachlor. However, humic acid had no significant effects on reducing glyphosate removal rate. Glyphosate could compete strongly with the humic acid for the available hydroxyl radical in the reaction systems. The reactivity of glyphosate with hydroxyl radical was much higher than those of diuron and butachlor due possibly to its relatively simpler chemical structure, as compared to either diuron or butachlor. Butachlor degradation was much weaker in the combined diuron and butachlor system than in the combined glyphosate and butachlor system. In the glyphosate-butachlor system, the opposite was observed. The findings have moved another step forward to understanding the potential role of rainwater-borne H2O2 in degrading herbicides in open water environments

Impacts of design configuration and plants on the functionality of the microbial community of mesocosm-scale constructed wetlands treating ibuprofen

Microbial degradation is an important pathway during the removal of pharmaceuticals in constructed wetlands (CWs). However, the effects of CW design, plant presence, and different plant species on the microbial community in CWs have not been fully explored. This study aims to investigate the microbial community metabolic function of different types of CWs used to treat ibuprofen via community-level physiological profiling (CLPP) analysis. We studied the interactions between three CW designs (unsaturated, saturated and aerated) and six types of mesocosms (one unplanted and five planted, with Juncus, Typha, Berula, Phragmites and Iris) treating synthetic wastewater. Results show that the microbial activity and metabolic richness found in the interstitial water and biofilm of the unsaturated designs were lower than those of the saturated and aerated designs. Compared to other CW designs, the aerated mesocosms had the highest microbial activity and metabolic richness in the interstitial water, but similar levels of biofilm microbial activity and metabolic richness to the saturated mesocosms. In all three designs, biofilm microbial metabolic richness was significantly higher (p < .05) than that of interstitial water. Both the interstitial water and biofilm microbial community metabolic function were influenced by CW design, plant presence and species, but design had a greater influence than plants. Moreover, canonical correlation analysis indicated that biofilm microbial communities in the three designs played a key role in ibuprofen degradation. The important factors identified as influencing ibuprofen removal were microbial AWCD (average well color development), microbial metabolic richness, and the utilization of amino acids and amine/amides. The enzymes associated with co-metabolism of l-arginine, l-phenyloalanine and putrescine may be linked to ibuprofen transformations. These results provide useful information for optimizing the operational parameters of CWs to improve ibuprofen removal

Removal of the pesticide tebuconazole in constructed wetlands: design comparison, influencing factors and modelling

Constructed wetlands (CWs) are a promising technology to treat pesticide contaminated water, but its implementation is impeded by lack of data to optimize designs and operating factors. Unsaturated and saturated CW designs were used to compare the removal of triazole pesticide, tebuconazole, in unplanted mesocosms and mesocosms planted with five different plant species: Typha latifolia, Phragmites australis, Iris pseudacorus, Juncus effusus and Berula erecta. Tebuconazole removal efficiencies were significantly higher in unsaturated CWs than saturated CWs, showing for the first time the potential of unsaturated CWs to treat tebuconazole contaminated water. An artificial neural network model was demonstrated to provide more accurate predictions of tebuconazole removal than the traditional linear regression model. Also, tebuconazole removal could be fitted an area-based first order kinetics model in both CW designs. The removal rate constants were consistently higher in unsaturated CWs (range of 2.6–10.9 cm d−1) than in saturated CWs (range of 1.7–7.9 cm d−1) and higher in planted CWs (range of 3.1–10.9 cm d−1) than in unplanted CWs (range of 1.7–2.6 cm d−1) for both designs. The low levels of sorption of tebuconazole to the substrate (0.7–2.1%) and plant phytoaccumulation (2.5–12.1%) indicate that the major removal pathways were biodegradation and metabolization inside the plants after plant uptake. The main factors influencing tebuconazole removal in the studied systems were system design, hydraulic loading rate and plant presence. Moreover, tebuconazole removal was positively correlated to dissolved oxygen and all nutrients removal

Pharmaceuticals and personal care products (PPCPs) in the environment and their removal from wastewater through constructed wetlands

Pharmaceuticals and personal care products are emerging organic contaminants that are continuously introduced into the environment due to their regular and widespread consumption by human beings. Their sources and fate in the aquatic environment are multiple and depend on the particular compound. Conventional wastewater treatment plants constitute the major source of these contaminants in the environment due to their incomplete removal by unspecific treatment methods. While advanced treatment technologies are available to treat these substances, their use is oftentimes not economically justified under the current concept of wastewater treatment. In this context, constructed wetlands represent an appropriate low-cost, energy-efficient, and easy-to-operate technology to treat wastewater, which are able to achieve a very high removal of these substances due to the vast number of biotic and abiotic processes that occur within these units, especially when different wetland types are used.Postprint (published version

Destruction of chemical warfare surrogates using a portable atmospheric pressure plasma jet

Today’s reality is connected with mitigation of threats from the new chemical and biological warfare agents. A novel investigation of cold plasmas in contact with liquids presented in this paper demonstrated that the chemically reactive environment produced by atmospheric pressure plasma jet (APPJ) is potentially capable of rapid destruction of chemical warfare agents in a broad spectrum. The decontamination of three different chemical warfare agent surrogates dissolved in liquid is investigated by using an easily transportable APPJ. The jet is powered by a kHz signal source connected to a low-voltage DC source and with He as working gas. The detailed investigation of electrical properties is performed for various plasmas at different distances from the sample. The measurements of plasma properties in situ are supported by the optical spectrometry measurements, whereas the high performance liquid chromatography measurements before and after the treatment of aqueous solutions of Malathion, Fenitrothion and Dimethyl Methylphosphonate. These solutions are used to evaluate destruction and its efficiency for specific neural agent simulants. The particular removal rates are found to be from 56% up to 96% during 10 min treatment. The data obtained provide basis to evaluate APPJ’s efficiency at different operating conditions. The presented results are promising and could be improved with different operating conditions and optimization of the decontamination process