Littérature scientifique sur le sujet « Environmetal remediation »

Environmetal context.The mobility of toxic arsenic compounds in the environment can be controlled by the solubility of certain minerals. To predict and model the fate and behaviour of these contaminants, the solubility and related thermodynamic properties of the lead and arsenic mineral mimetite were determined. The data obtained in this study will be used to optimise and increase the effectiveness of remediation procedures that are already applied to contaminated sites. Abstract.The solubility of the synthesised mimetite was measured in a series of dissolution experiments at 5–55°C and at pH values between 2.00 and 2.75. The solubility product logKSP for the reaction Pb5(AsO4)3Cl ↔ 5Pb2+ + 3AsO43– + Cl– at 25°C is –76.35 ± 1.01. The free energy of formation ΔGf,2980 calculated from this measured solubility product equals –2634.3 ± 5.9 kJ mol–1. The temperature dependence of the logKSP is non-linear, indicating that the enthalpy of the reaction depends on the temperature. The enthalpy of the formation of mimetite ΔHf0, is –2965.9 ± 4.7 kJ mol–1, the entropy, ΔS0, is 39.5 J mol–1 K–1, and the heat capacity, ΔCp,f0 is –6172 ± 105 J mol–1 K–1. Hydrochemical modelling indicates that regardless of the composition of the background solution, Pb5(AsO4)3Cl is most stable at neutral to weakly alkaline pH.

Nanotechnology has been widely used in many fields including in soil and groundwater remediation. Nanoremediation has emerged as an effective, rapid, and efficient technology for soil and groundwater contaminated with petroleum pollutants and heavy metals. This review provides an overview of the application of nanomaterials for environmental cleanup, such as soil and groundwater remediation. Four types of nanomaterials, namely nanoscale zero-valent iron (nZVI), carbon nanotubes (CNTs), and metallic and magnetic nanoparticles (MNPs), are presented and discussed. In addition, the potential environmental risks of the nanomaterial application in soil remediation are highlighted. Moreover, this review provides insight into the combination of nanoremediation with other remediation technologies. The study demonstrates that nZVI had been widely studied for high-efficiency environmental remediation due to its high reactivity and excellent contaminant immobilization capability. CNTs have received more attention for remediation of organic and inorganic contaminants because of their unique adsorption characteristics. Environmental remediations using metal and MNPs are also favorable due to their facile magnetic separation and unique metal-ion adsorption. The modified nZVI showed less toxicity towards soil bacteria than bare nZVI; thus, modifying or coating nZVI could reduce its ecotoxicity. The combination of nanoremediation with other remediation technology is shown to be a valuable soil remediation technique as the synergetic effects may increase the sustainability of the applied process towards green technology for soil remediation.

Extensive mining of rare earth deposits has caused severe soil erosion, resulting in the degradation of plant–soil systems and the reduction in microbial diversity. Combined ecological remediation technology is the key method of vegetation reconstruction and ecological restoration in abandoned tailings. In this study, the effects of different cover crops–biochar–organic fertilizer and biochar–organic fertilizer treatments on soil fungal communities in rare earth tailings soil were analysed using high-throughput sequencing technology. Linear discriminant analysis effect size (LEfSe) was used to analyse saprophytic, mycorrhizal, and potential pathogenic fungi in soils after different combined remediations. Moreover, the effects of soil environmental factors on fungal community species’ composition were analysed by redundancy analysis (RDA) and variance partitioning analysis (VPA) after different combined remediations. LEfSe indicated a risk of citrus pathogenicity by Diaporthaceae indicator fungi after biochar–organic fertilizer combined treatment. RDA and VPA revealed that pH was the main environmental factor affecting the fungal community in the different combined remediation treatments. Additionally, the Paspalum wettsteinii cover crops–biochar–organic fertilizer and biochar–livestock manure treatments were more conducive to arbuscular mycorrhizal fungi recruitment. We also clarified the fungal community composition structure, soil environmental factors, and fungal community relationships in rare earth tailings soil after different combined remediation treatments.

The choice between remediation alternatives for contaminated sites is complicated by different elements, e.g., the occurrence of multiple contaminants, the extent of the contamination, or the urban location, complicate the choice between remediation alternatives. This paper addresses this challenging choice by analyzing a case study of an extensive soil and groundwater contamination by a dry-cleaning company. For remediating this site, two alternatives were proposed. The first remediation alternative combines several techniques with in-situ chemical oxidization being the most important one. Due to the potential negative impact of this alternative on local residents a second remediation alternative was drawn up, in which the focus lies on the use of stimulated biological degradation. A Life Cycle Assessment (LCA) was performed on both alternatives and showed that the second alternative had a lower environmental impact. The inclusion of monetized LCA results in the calculation of a social Cost-Benefit Analysis (CBA) provided a more extensive view of the secondary environmental costs and benefits of the remediation alternatives. The results of the social CBA allow to conclude that both alternatives are not socially desirable, the chemical alternative however is socially less disadvantageous than the more natural remediation alternative.

Environmental Pollution is becoming a global challenge in both developing and the developed countries, pollutants discharge from oil and gas industries and or agricultural practices continue effecting the health of human and other animal in an ecosystem in one way or the other. This necessitated the development of a techniques to clean up of the polluted environment. Remediation of pollutants relies mainly on using varioustechniques like physical, chemical and or biological methods for the removal of contaminants from different environmental media be it soil, water, and or air. These techniques have their own limitations as the toxicity of the degrading agents, time consuming and the fate of the environment after remediation matters a lot. Therefore, nanotechnology is gaining interest in remediating pollutions as nanoparticles are relatively cost effective, sensitive and selective and can be used as sensors to monitor toxins, organic contaminants and heavy metals in land, water and or air. The enhanced properties and effectiveness of nanotechnology-based materials makes them suitable for nano remediation. This review provides an overview of the nanomaterials: Organic based nanomaterials (Dendrimers), inorganic (TiO2, nZVI), carbon-based (Carbon nanotubes, (CNTs)), and composite-based materials) used in environmental remediation. These nanomaterials were reported to remediate different contaminants in theenvironment such as heavy metals, pathogens, pesticides, dyes, chlorinated organic compounds, and polycyclic aromatic hydrocarbons. Keywords: Nanotechnology, nanoparticles, Nano remediation, pollutions and environments.

Electrokinetic remediation has, in recent years, shown great potential in remediating polluted environments. The technology can efficiently remove heavy metals, chlorophenols, polychlorinated biphenyls, phenols, trichloroethane, benzene, toluene, ethylbenzene, and xylene (BTEX) compounds and entire petroleum hydrocarbons. Electrokinetic remediation makes use of electrolysis, electroosmosis, electrophoresis, diffusion, and electromigration as the five fundamental processes in achieving decontamination of polluted environments. These five processes depend on pH swings, voltage, electrodes, and electrolytes used in the electrochemical system. To apply this technology at the field scale, it is necessary to pursue the design of effective processes with low environmental impact to meet global sustainability standards. It is, therefore, imperative to understand the roles of the fundamental processes and their interactions in achieving effective and sustainable electrokinetic remediation in order to identify cleaner alternative solutions. This paper presents an overview of different processes involved in electrokinetic remediation with a focus on the effect of pH, electrodes, surfactants, and electrolytes that are applied in the remediation of contaminated soil and how these can be combined with cleaner technologies or alternative additives to achieve sustainable electrokinetic remediation. The electrokinetic phenomenon is described, followed by an evaluation of the impact of pH, surfactants, voltage, electrodes, and electrolytes in achieving effective and sustainable remediation.

With the acceleration of the process of agricultural modernization, many pesticides (insecticides, fungicides, and herbicides) are applied to the field and finally brought into the soils, causing serious damage to the environment. The problem of pesticide pollution has become increasingly prominent. This has highlighted the urgent need for effective and efficient remediation treatment technology for pesticide-contaminated soils. Biochar has a high specific surface area, high porosity, and strong adsorption capacity, making it a soil amendment agent and carbon fixation agent that can improve soil health and enhance adsorption capacity for pesticides to remediate contaminated soils. Recently, efforts have been made to enhance the physicochemical and adsorption properties of biochar by preparing modified biochar, and it has been developed to expand the application of biochar. Specifically, the following aspects were reviewed and discussed: (i) source and modification methods of biochar for pesticide remediation; (ii) the effect of biochar on the environmental fate of remediating pesticides; (iii) the effect of biochar on pesticide-contaminated soils; and (iv) potential problems for the large-scale promotion and application of biochar remediation of pesticides. In conclusion, this review may serve as a reference and guide for pesticide remediation, hence reducing the environmental concerns associated with pesticides in soil.

The purpose of this paper is to provide examples of strategies and procedures for remediation of buildings affected by toxic moulds. Four case studies are included in the paper. Moisture and inadequate ventilation are the keys to proliferation of toxic moulds and dispersion of spores in air. Prevention should always be the main objectives for any environmental management plan or service maintenance of a building. The management and remediation plan should include an adequate control of moisture, damp and ventilation in the building. The most effective strategy for remediating mould problems is by source control, preventing or limiting the generation of moulds, and the other is to remove the sources. There should be a detailed study to identify the sources of mould problems. The remediation could involve mothballing of a building to rectify defects including leaks and removal of damp materials; venting of underfloor or wall cavities and to improve the general airflow in the building. Remediation may involve vacuuming to remove spores in air and mould from surfaces. Other techniques include heat treatment, steam cleaning, biocides treatment, fumigation and UV treatment.

Due to the increasing pollution by petroleum hydrocarbons (PHs), it is an important task to develop eco-friendly and highly efficient methods for remediating petroleum-contaminated soils. In this study, bioremediation technology was applied to remediate PHs contaminated soils, and the bacterial community structure and physicochemical characteristics of the soil treated using different bioremediation regimens were analyzed. Compared with the control condition (S0), the PHs removal efficiency of biostimulation (S2) and bioaugmentation (S3) was increased significantly. Combined biostimulation with bioaugmentation (S4) had the highest PHs removal efficiency, up to 60.14 ± 4.12%. Among all the selected remediation strategies (S1–S4, S1: soil moisture content: 25–30%), the bacterial alpha-diversity was higher than in S0. The genera Acinetobacter, Escherichia-Shigella, Bacteroides, Microbacterium, and Parabacteroides were found to greatly contribute to PHs’ degradation. In the group S4, the PH-degraders and soil enzyme activity were higher than in the other remediation regimens, and these indices gradually decreased in the mid-to-later periods of all remediation tests. Additionally, the abundance of alkB and nah genes was increased by improving the environmental condition of the microorganism communities. Redundancy analysis (RDA) revealed that the total nitrogen (TN) and total phosphorus (TP) had a positive correlation with total PHs degradation. This study offers insights into the microbial community response to environmental factors during bioremediation, which shows a promoting effect in enhancing the efficiency of PHs remediation.

Photoactive semiconductors are a hot topic of research due to their applications in environmental remediation, photovoltaics, smart devices, light-activated synthesis and self-cleaning surfaces. Among them, oxide semiconductors play a main role thanks to their wide availability, stability, ease of preparation and tunable surface properties. In this context, my Ph.D. focused on the application of oxide semiconductors for three main purposes: pollutant remediation, photocatalytic synthesis of hybrid materials, and smart systems for the controlled release of active substances. Alongside this main research project, I developed two original hands-on activities based on oxide systems for public engagement. Oxide semiconductors for environmental remediation. Photocatalysis is an advanced oxidation process that can achieve the complete degradation of contaminants without the addition of reagents. However, its real-life application has been hindered by several limitations, such as the use of nanosized powder, costs of light irradiation, possible accumulation of toxic reaction intermediates and the sensitivity to complex water matrices. During my Ph.D., I investigated the deposition of photocatalyst powder on macroscopic devices based on aluminum plates for air purification. Aluminum is a cheap and technologically-relevant substrate, but its application as substrate for photocatalyst immobilization has been hampered by adhesion issues and metal ion diffusion within the photocatalytic layer that increases recombination of photogenerated carriers. Thus, I investigated the use of silica interlayers to promote adhesion, efficiency and reusability of TiO2 films on aluminum plates. Films were prepared from stable titania sols and deposited on aluminum substrates with different surface morphology and with silica interlayers of different thickness. The study of the coating structure, morphology, optical properties, adhesion and hardness showed that the nature of the substrate and its surface roughness determined the optimal number of silica interlayers. When the silica interlayer was too thin, moderate cracking was still observed, whereas a too thick silica interlayer led to peeling off of the film. The use of rougher surfaces, as in the case of sand-papered aluminum, required a higher number of silica layers to promote a more homogeneous surface where the titania coating could effectively adhere. However, the addition of a thicker silica layer did not erase the effect of the sand-paper pre-treatment on surface roughness. Films on sand-papered substrates showed promoted photocatalytic activity with respect to the smoother counterparts, possibly due to their larger exposed contact area. The prepared films exhibited excellent light-induced superhydrophilicity and self-cleaning properties towards fouling agents (alkylsilanes). Photocatalytic degradation tests were carried out using both a model volatile organic compound (ethanol) and NOx. The silica interlayer proved crucial to promote the film robustness, effectively increasing the mechanical stability and reusability when a thicker interlayer was adopted on sand-papered aluminum plates. In order to cut the costs associated with lamp irradiation, the visible-light promotion of large band gap photocatalysts is a widely investigated approach. In this regard, I studied the modification of TiO2 with Sn and N species aiming to improve the photocatalyst visible-light absorption for the solar-light photocatalityc degradation of emerging pollutants. Three different synthetic routes were investigated: a bulk synthesis, where Ti and Sn precursors were both added in the sol-gel synthesis, a seeded procedure, where pre-formed SnO2 crystals were added to TiO2 synthesis, and a mechanical mixture, where the oxides were mixed together then calcined. Marked differences were observed in the final composites’ structural, morphological and optical properties, leading to notable changes in the photocatalytic performance. Interestingly, bulk and seeded samples showed notable photochromic properties under UV light, which varied based on the doping level: this is the first time photochromic effects have been observed in Sn-promoted TiO2. These findings can be related to the different nature of the defects introduced in the oxide lattices depending on the synthetic route, which reflect in the photocatalytic performances of the modified semiconductors. The photocatalytic degradation of wastewater pollutants in complex matrices requires a close scrutiny of the generated byproducts to avoid possible accumulation of intermediates even more toxic than the parent compound. In this respect, I determined that the degradation of tetracycline, a widely used antibiotic, by a benchmark TiO2 sample, despite the fast pollutant disappearance, leads to poor mineralization and byproduct accumulation, especially in the presence of common electrolytes, such as HCO3-. Conversely, the use of commercial ZnO samples with the same surface area resulted in a faster tetracycline degradation kinetics and a much higher mineralization degree compared to TiO2 in all the investigated water matrices. These results can be attributed to different photo-degradation pathways followed by the two oxides, as shown by tests with radical scavengers and by-product analyses. While TiO2 degradation pathways are strongly dependent on both hydroxyl radicals and holes, ZnO mineralization activity is mostly related to holes, which limits the interference of •OH-scavenger species such as bicarbonates. Photo-induced synthesis of oxide-polyaniline composites for environmental remediation. To date, photocatalysis remains a comparatively slower and costlier wastewater treatment compared to adsorption. For this reason, during my Ph.D I also investigated new generation adsorbents characterized by easier regeneration and ability to perform a controlled release of the adsorbed species to be further treated or reused. To this aim, I investigated polyaniline (PANI) composites prepared via an innovative photocatalytically-induced synthesis. PANI materials have been recently adopted as sorbents for environmental remediation due to their stability, redox properties and acid-base characteristics. However, PANI traditional oxidative synthesis (here labeled as PANI-aniline) adopts noxious and toxic reagents (aniline and (NH4)2S2O8) and leads to carcinogenic by-products and large amounts of waste. The alternative photocatalytic approach I developed is a two-step synthesis starting from aniline dimer (N-(4-aminophenyl)aniline) and exploiting TiO2 photocatalyst to initiate the oligomerization, and a greener oxidant (H2O2) in the polymerization step. The resulting PANI-TiO2 nanocomposites showed very different structural, morphological and surface properties with respect to PANI-aniline, resulting in fast and efficient removal of water pollutants. To better understand the reaction pathway and tailor the material properties, the relative roles played by TiO2 and H2O2 in the synthetic procedure were investigated in depth. UV-irradiated TiO2 was found to promote PANI crystallinity and polymer-oxide interactions. The amount of added H2O2 has a crucial role on the composite properties by promoting either surface growth of PANI chains or polymerization in the liquid bulk. High H2O2 amounts seem to promote a homogenous polymer formation mechanism, leading to nanocomposites with high PANI content and thermal stability, but low crystallinity degree and surface area. Low H2O2 quantities give rise to highly porous, large surface area nanocomposites with good crystallinity but low PANI content. The latter samples exhibited the best performance in pollutant sorption tests, achieving a fast and complete removal of dyes and heavy metals also in the presence of electrolytes. These samples also showed reusability in consecutive stress tests and could be regenerated simply by treatment with alkaline aqueous solution at room temperature. The next step was to investigate the role of the nature and morphological features of the semiconductor: commercial TiO2 photocatalysts with either 50 m2g-1 (labeled TiO2-P25) and 12 m2g-1 (TiO2-Kronos) were compared with WO3 either lab-synthesized (3.5 m2g-1, named WO3-Synt) or commercial (6.1 m2g-1, WO3-Comm). The composites showed a nanorod / nano-wire morphology: the length of the polymeric rods and the embedding of the oxide particles within the polymer network strongly depended on the nature and morphology of the photocatalyst. Furthermore, while > 80% total dye removal capacity was observed for all samples (with the exception of PANI-WO3-Comm), notable differences were observed in terms of released tests. In particular, PANI-oxide composites consistently showed dye-release capacities far higher than PANI-aniline. The ease of desorption opened the door to the facile regeneration of the adsorbent and to the adsorbate recovery for its recycle in a circular economy perspective. Therefore, I investigated an adsorption-photocatalysis coupled system which exploited the reversibility of the pollutant removal process. In particular, after consecutive dye adsorption cycles, the contaminant was released by the PANI-oxide adsorbent and subsequently mineralized by a ZnO driven photocatalytic process. The nature of the adsorption process was deeply investigated and selectivity tests with cationic and anionic dye mixtures proved the preferential adsorption of PANI-oxide adsorbents towards anionic dyes. In the end, the promising and reversible adsorption capability of PANI composites prompted me to investigate their possible application in CO2 capture systems. Thus I have worked on reviewing the literature works on the topic, comparing the performances of different PANI materials towards CO2 removal. Smart systems based on light-responsive oxides. The intrinsic characteristics of semiconductor oxides, such as their photocatalytic and surface properties, can be exploited in the design of smart systems for the controlled release of unstable active substances, such as essential oils. Among them, cinnamaldehyde (CIN) is a low-cost natural compound endowed with antibacterial, anti-cancer, antifungal, and anti-inflammatory properties. However, CIN has poor water solubility, high volatility and very poor stability in environmental conditions, undergoing degradation when exposed to heat, light or even oxygen. These issues hinder CIN applicability, thus smart systems able to store this active substance and to safely release it at will, are of extreme interest for the scientific community. In this context, during my Ph.D. I developed oxide-based hybrid systems for the release of CIN catalyzed by acidic pH. The smart system was obtained by a grafting method based on amino-silane linkers and imine chemistry: (3-aminopropyl)triethoxysilane (APTES) was adopted for the functionalization of the oxide surface. The terminal amine group of the silane (-NH2) was used for a condensation reaction with the aldehydic group of CIN (-HC=O), yielding an imine bond (-HC=N-) between APTES and CIN and a loading of ca. 5 molecules/nm2, determined with CHN and TG analyses. The covalent grafting of cinnamaldehyde, showed by FTIR spectra, preserved the molecule stability, simplifying storage. Release tests were performed at pH values between 5.0 and 7.4: thanks to the pH-sensitivity of imine bonds, a fast CIN release was observed at pH 5.0. The grafting procedure was also performed on a porous semiconductor film, demonstrating the versatility of this method. Exploiting the oxide photoactivity, the fouled film was regenerated upon 1h UV irradiation, opening the door to reusable devices for CIN controlled release. Besides the conventional approach of loading bioactive compounds on solid drug carriers, smart systems based on particle-stabilized emulsions (i.e., Pickering emulsions) are receiving increasing attention from the scientific community. In this regard, during my last year of Ph.D. I investigated oil-in-water Pickering emulsions prepared with food-grade vegetable oils and stabilized with bare ZnO particles. FTIR studies highlighted that, during emulsification, ZnO particles undergo an in situ functionalization by fatty acids present in the vegetable oil. This procedure gives rise to very stable and homogeneous emulsions (mean droplet size ca. 1 μm). Confocal microscopy images demonstrated the high stability of the system towards long time storage (more than 9 months), temperature variations, mechanical stress and increased ionic strength. ZnO-Pickering emulsions were loaded with CIN in the oil phase, in order to store the active molecule and release it at will by the application of five different stimuli. In particular, thanks to the semiconductor and amphoteric properties of ZnO, the developed smart system was able to release CIN by switching to a water-in-oil Pickering emulsion when subjected to acidification, UV and solar light irradiation, CO2 bubbling and the addition of bi/trivalent cations. This is the first report of an emulsion system responsive to five different stimuli. Depending on the type of stimulus, either a burst release or a controlled release over the course of several hours could be achieved. The emulsion switching can be attributed to the oxide surface charge: when ZnO is negatively or slightly positively charged, the oil-in-water emulsion is stable, while, when the oxide surface has high positive charge, the oil droplets’ intrinsic negative charge is neutralized and coalescence phenomena occur. A more positive ZnO surface charge can be achieved through the addition of acidic species (such as H+ and H2CO3 via CO2 bubbling), multivalent cations, which give specific adsorption on ZnO surface, and through light irradiation, which activates the photocatalyst and generates acidic species. The starting oil-in-water emulsion could be reobtained by basification, N2 bubbling and storage in the dark. The ZnO Pickering emulsions were able to safely store and release CIN molecules, which did not undergo any degradation neither during storage, nor after release in water solution. In the end, I have contributed to a work on near infrared (NIR)-emitting GdVO4:Nd systems. This composite material proved promising for bioimaging applications, thus, I exploited my experience oxide synthesis to investigate the role of the synthetic procedure on the material properties and NIR-emitting activity. Moreover, test on GdVO4:Nd functionalization with silane molecules (octylsilane and APTES) were carried out. The modification of the material surface with organic compounds can led to a possible increase in the material biocompatibility, as well as to the possible grafting of active molecules, such as cinnamaldehyde, for application in theragnostic. Chemistry dissemination activities. During my PhD, I was involved in chemistry dissemination activities in the framework of the “Piano Lauree Scientifiche, PLS”. In this context, I helped to develop two laboratory activities for high school teachers and students. The first one, aimed at teaching the basic concepts of surface science, focused on the preparation of superhydrophobic coatings based on films of surface functionalized oxide particles. The film’s superhydrophobicity was tested for different applications (anti-stain, self-cleaning, liquid transportation) and compared with model hydrophobic, hydrophilic, and superhydrophilic surfaces. The second activity mimicked the chemistry of stained glass, introducing basic concepts of redox reactions, chemistry of color, and plasmonic nanoparticles. Stained glass colors were copied through the deposition, on glass slides, of silica coatings colored by metal ions and nanoparticles. A silica sol was used as matrix to embed metal ions, which were reduced in situ by thermal treatment on a hot plate. The formation of metal nanoparticles by this procedure induces plasmonic colors in the glass coating, thus “mimicking” the ancient procedure of stained-glass fabrication. These works led to two publications on the Journal of Chemical Education.

The growing interest in environmental protection has led to the development of emerging biotechnologies for environmental remediation also introducing the biorefinery concept. This work mainly aimed to evaluate the applicability of innovative biotechnologies for environmental remediation and bioenergy production, throught fermentative processes. The investigated biotechnologies for waste and wastewater treatment and for the valorisation of specific feedstocks and energy recovery, were mainly focused on four research lines. 1. Biotechnology for textile wastewater treatment and water reuse that involving anaerobic and aerobic processes in combination with membrane technologies. Combinations of different treatments were also implemented for water reuse in a textile company. 2. Biotechnology for the treatment of solid waste and leachate in landfill and for biogas production. Landfill operated as Bioreactor with recirculation of the generated leachate was proposed for organic matter biostabilisation and for ammonia removal from leachate by favouring the Anammox process. 3. An innovative two-stage anaerobic process for effective codigestion of waste from the dairy industry, as cheese whey and dairy manure, was studied by combining conventional fermentative processes with a simplified system design for enhancing biomethanisation. 4) The valorisation of the glycerol waste as surplus by-product of the biodiesel industry was investigated via microbial conversion to value-added chemicals, as 1,3-propanediol. The investigated fermentative processes have been successfully implemented and reached high yields of the produced bio-chemical. The studied biotechnological systems proved to be feasible for environmental remediation and bioenergy and chemicals production.

The growing interest in environmental protection has led to the development of emerging biotechnologies for environmental remediation also introducing the biorefinery concept. This work mainly aimed to evaluate the applicability of innovative biotechnologies for environmental remediation and bioenergy production, throught fermentative processes. The investigated biotechnologies for waste and wastewater treatment and for the valorisation of specific feedstocks and energy recovery, were mainly focused on four research lines. 1. Biotechnology for textile wastewater treatment and water reuse that involving anaerobic and aerobic processes in combination with membrane technologies. Combinations of different treatments were also implemented for water reuse in a textile company. 2. Biotechnology for the treatment of solid waste and leachate in landfill and for biogas production. Landfill operated as Bioreactor with recirculation of the generated leachate was proposed for organic matter biostabilisation and for ammonia removal from leachate by favouring the Anammox process. 3. An innovative two-stage anaerobic process for effective codigestion of waste from the dairy industry, as cheese whey and dairy manure, was studied by combining conventional fermentative processes with a simplified system design for enhancing biomethanisation. 4) The valorisation of the glycerol waste as surplus by-product of the biodiesel industry was investigated via microbial conversion to value-added chemicals, as 1,3-propanediol. The investigated fermentative processes have been successfully implemented and reached high yields of the produced bio-chemical. The studied biotechnological systems proved to be feasible for environmental remediation and bioenergy and chemicals production.

Esta tesis doctoral se ha centrado en la preparación de fotocatalizadores nanoestructurados basados en TiO2 modificados con metales de transición o carbón activado para su aplicación en reacciones de interés medioambiental, concretamente, en la eliminación de tres contaminantes: ácido acético y diurón, en fase acuosa, y propeno en fase gas. Se ha estudiado la influencia de las propiedades fisicoquímicas (porosidad, cristalinidad, composición química, propiedades electrónicas) de cada material en su actividad fotocatalítica.

Nella tesi l'inquinamento del suolo viene affrontato a diversi livelli, con l'obiettivo di prevenire, comprendere o risolvere specifici eventi di contaminazione. Lo studio si è concentrato su due classi principali di xenobiotici: elementi potenzialmente tossici e pesticidi. Sono stati discussi sette progetti di ricerca per indagare tre questioni principali: i) Applicazione di tecniche di biorisanamento contro la contaminazione da Ni in una cava in disuso (Capitoli 1 e 2), ii) Cinetica ed ecotossicità dei pesticidi in diversi substrati (Capitoli 3, 4 e 5), iii) Monitoraggio ed ecotossicità del rame in suoli di vigneti (Capitoli 6 e 7). Nel primo caso (i), la novità sta nell'applicare tecniche ecosostenibili per risolvere un reale caso di inquinamento; i principali risultati mostrano che minerali come bentonite e zeolite ed il fitorisanamento immobilizzano il metallo, contenendo così la deriva. Per quanto riguarda i pesticidi (ii), dopo una review riguardo l'impatto di dosi sub-letali di agrofarmaci sul biota del suolo agricolo, sono stati condotti due studi per valutare l'adsorbimento e la degradazione di tre pesticidi e gli effetti ecotossicologici di due insetticidi, uno naturale e uno sintetico, sui lombrichi e sui microorganismi del suolo. Lo studio suggerisce dinamiche diverse a seconda dei formulati e del substrato e può contribuire alla gestione sostenibile delle sostanze chimiche nell'ambiente: l'apporto al suolo di rifiuti organici economici riduce l'impatto dei pesticidi nell'ecosistema. I lombrichi aiutano la degradazione del bioinsetticida e la comunità microbica può adattarsi e cambiare in funzione del tempo e in base alla presenza di Eisenia fetida. Gli effetti del chlorpyrifos sui lombrichi si manifestano precocemente a livello genotossico e sulla loro crescita e a lungo termine, anche sull'attività riproduttiva. Infine, il tema del rame (iii) è stato affrontato inizialmente, monitorando due vigneti a conduzione biologica. Quindi sono stati condotti test ecotossicologici sui lombrichi. I danni precoci al loro DNA sono stati valutati con dosi sub-letali su suolo naturale. Il progetto sperimentale originale è stato ri-proposto per rilevare i cambiamenti della comunità batterica nel suolo e nell'intestino del lombrico. Inoltre, sono stati condotti test di riproduzione e di evitamento. I risultati hanno mostrato un'elevata capacità dei lombrichi di evitare il suolo contaminato dal rame già a basse concentrazioni e hanno mostrato effetti negativi dose-dipendenti sugli output riproduttivi. Nonostante ciò, questi anellidi sembrano recuperare il danno genotossico a concentrazioni intermedie di rame nel suolo, non bioaccumulano il metallo e riportano danni irreversibili oltre una certa soglia. Ad oggi sono in corso le analisi delle modifiche al microbioma intestinale del lombrico e del suolo.
In the thesis, soil pollution is addressed at different levels to prevent, understand, or resolve specific contamination events. The study focused on two main classes of xenobiotics: potentially toxic elements and pesticides. Seven research projects were discussed to investigate three main issues: i) Application of bioremediation techniques against Ni contamination in a disused quarry (Chapters 1 and 2), ii) Kinetics and ecotoxicity of pesticides in different substrates (Chapters 3, 4 and 5), iii) Monitoring and ecotoxicity of copper in vineyard soils (Chapters 6 and 7). In the first case (i), the novelty lies in applying eco-sustainable techniques to solve a real pollution case; the main results show that minerals such as bentonite and zeolite and phytoremediation immobilize the metal, thus containing the drift. Regarding pesticides (ii), after reviewing the impact of sub-lethal doses of pesticides on agricultural soil biota, two studies were conducted to evaluate the adsorption and degradation of three pesticides and the ecotoxicological effects of two insecticides, natural and one synthetic, on earthworms and soil microorganisms. The study suggests different dynamics depending on the formulations and the substrate and can contribute to the sustainable management of chemicals in the environment: the supply of cheap organic waste to the soil reduces the impact of pesticides on the ecosystem. Earthworms aid in the degradation of the bioinsecticide, and the microbial community can adapt and change over time and based on the presence of Eisenia fetida. The effects of chlorpyrifos on earthworms manifest early at the genotoxic level and on their growth. In the long term, it affects reproductive activity. Finally, the issue of copper (iii) was initially addressed by monitoring two organically run vineyards. Then ecotoxicological tests were conducted on earthworms. Early damage to their DNA was evaluated with sub-lethal doses on natural soil. The original experimental design was re-proposed to detect bacterial community changes in earthworm soil and gut. In addition, breeding and avoidance tests were conducted. The results showed a high ability of earthworms to avoid copper-contaminated soil already at low concentrations and showed dose-dependent adverse effects on reproductive outputs. Despite this, these annelids seem to recover the genotoxic damage at intermediate concentrations of copper in the soil, do not bioaccumulate the metal and report irreversible damage beyond a certain threshold. To date, analyses of changes in the intestinal microbiome of the earthworm and soil are underway.

Thesis (M.S. in Management)--Naval Postgraduate School, June 2000.
Thesis advisor(s), Lamm, David V. ; Smith, David A. "June 2000." Includes bibliographical references (p. 165-168). Also available online.

Membrane process including microfiltration (MF), ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO) have provided numerous successful applications ranging from drinking water purification, wastewater treatment, to material recovery. The addition of functional moiety in the membranes pores allows such membranes to be used in challenging areas including tunable separations, toxic metal capture, and catalysis. In this work, polyvinylidene fluoride (PVDF) MF membrane was functionalized with temperature responsive (poly(N-isopropylacrylamide), PNIPAAm) and pH responsive (polyacrylic acid, PAA) polymers. It’s revealed that the permeation of various molecules (water, salt and dextran) through the membrane can be thermally or pH controlled. The introduction of PAA as a polyelectrolyte offers an excellent platform for the immobilization of metal nanoparticles (NPs) applied for degradation of toxic chlorinated organics with significantly increased longevity and stability. The advantage of using temperature and pH responsive polymers/hydrogels also includes the high reactivity and effectiveness in dechlorination. Further advancement on the PVDF functionalization involved the alkaline treatment to create partially defluorinated membrane (Def-PVDF) with conjugated double bounds allowing for the covalent attachment of different polymers. The PAA-Def-PVDF membrane shows pH responsive behavior on both the hydraulic permeability and solute retention. The sponge-like PVDF (SPVDF) membranes by phase inversion were developed through casting PVDF solution on polyester backing. The SPVDF membrane was demonstrated to have 4 times more surface area than commercial PVDF MF membrane, allowing for enhanced nanoparticles loading for chloro-organics degradation. The advanced functionalization method and process were also validated to be able to be scaled-up through the evaluation of full-scale functionalized membrane provided by Ultura Inc. California, USA. Nanofiltration (NF) between UF and RO presents selectivity controlled by both steric and electrostatic repulsions, which are widely used to reject charged species, particularly multivalent ions. In this work, selective permeation of CaCl2 and high sucrose retention are obtained through the modification of nanofiltration membranes with lower charge compared to commercial nanofiltration membrane. The membrane module also shows high stability with constant water permeability in a long-term (two months) test. Extended Nernst-Planck equation were further used to evaluate the experimental results and it fits well.

Exide Technologies finally closed its secondary lead-battery recycling plant on March 12, 2015. The community of primarily Hispanics around the facility had to fight many years to have the polluting facility shut down. Because government agencies, whose job is to protect citizens from polluters, were not regulating the facility properly, residents are not sure if they can trust the agencies to carry out remediation effectively and efficiently either. In this paper I explore the environmental justice issues associated with environmental remediation and what community members can do to make sure that their neighborhood is cleaned up properly. Through interviews with government agencies and environmental activists heavily involved in this case, I discovered that the main environmental justice issue in remediation is increased exposure to toxins. I argue that strong community activism and involvement are necessary for remediation to happen properly, and explore some tools that can be used in this process.

The Savannah River Site (SRS) Figure 1 is a 310-square-mile United States Department of Energy nuclear facility located along the Savannah River near Aiken, South Carolina. During operations, which started in 1951, hazardous substances (chemicals and radionuclides) were released to the environment. The releases occurred as a result of inadvertent spills and waste disposal in unlined pits and basins which was common practice before environmental regulations existed. The hazardous substances have migrated to the vadose zone and groundwater in many areas of the SRS, resulting in 515 waste units that are required by environmental regulations, to undergo characterization and, if needed, remediation. In the initial years of the SRS environmental cleanup program (early 1990s), the focus was to use common technologies (such as pump and treat, air stripping, excavation and removal) that actively and tangibly removed contamination. Exclusive use of these technologies required continued and significant funding while often failing to meet acceptable clean-up goals and objectives. Recognizing that a more cost-effective approach was needed, SRS implemented new and complementary remediation methods focused on active and passive technologies targeted to solve specific remediation problems. Today, SRS uses technologies such as chemical / pH-adjusting injection, phytoremediation, underground cutoff walls, dynamic underground stripping, soil fracturing, microbial degradation, baroballs, electrical resistance heating, soil vapor extraction, and microblowers to more effectively treat contamination at lower costs. Additionally, SRS’s remediation approach cost effectively maximizes cleanup as SRS works proactively with multiple regulatory agencies. Using GIS, video, animation, and graphics, SRS is able to provide an accurate depiction of the evolution of SRS groundwater and vadose zone cleanup activities to convince stakeholders and regulators of the effectiveness of various cleanup technologies. Remediating large, complex groundwater plumes using state of-the art technologies and approaches is a hallmark of years of experience and progress. Environmental restoration at SRS continues to be a challenging and dynamic process as new cleanup technologies and approaches are adopted.

In France, the nuclear industry has developed a substantial program for decommissioning plants and nuclear installations, and for remediating and rehabilitating industrial sites. The Commission for the Establishment of Analysis Methods (CETAMA) is a unit of the French Alternative Energies and Atomic Energy Commission (CEA) whose main objective is to improve the quality of analysis and measurement results in the nuclear field. Analysis is the primary tool for monitoring the spread of nuclear material. This document shows that sampling, in close relation with measurement techniques, is a factor of potential gain and risk reduction for site remediation, decommissioning, and rehabilitation projects.

A major focus of Department of Energy’s (DOE’s) environmental management mission at the Hanford site involves characterizing and remediating contaminated soil and groundwater; stabilizing contaminated soil; remediating disposal sites; decontaminating and decommissioning structures, and demolishing former plutonium production process buildings, nuclear reactors, and separation plants; maintaining inactive waste sites; transitioning facilities into the surveillance and maintenance program; and mitigating effects to biological and cultural resources from site development and environmental cleanup and restoration activities. For example, a total of 470,914 metric tons of contaminated soil from 100 Areas remediation activities were disposed at the Environmental Restoration Disposal Facility (ERDF) during 2004 [5]. The Applied Research Center (ARC) at Florida International University (FIU) is supporting the Hanford’s site remediation program by analyzing the effectiveness of several soil stabilizers (fixatives) for contamination control during excavation activities. The study is focusing on determining the effects of varying soil conditions, temperature, humidity and wind velocity on the effectiveness of the candidate stabilizers. The test matrix consists of a soil penetration-depth study, wind tunnel experiments for determination of threshold velocity, and temperature and moisture-controlled drying/curing experiments. These three set of experiments are designed to verify performance metrics, as well as provide insight into what fundamental forces are altered by the use of the stabilizer. This paper only presents the preliminary results obtained during wind tunnel experiments using dry Hanford soil samples (with 2.7% moisture by weight). These dry soil samples were exposed to varying wind speeds from 2.22 m/sec to 8.88 m/sec. Furthermore, airborne particulate data was collected for the dry Hanford soil experiments using an aerosol analyzer instrument.