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Mercury (Hg) cannot be degraded. Therefore only two principal processes are available for the treatment of Hg-contaminated soil: (1) the separation of Hg from the soil or (2) the stabilisation of Hg within the soil. Prior to selecting a suitable treatment technique, it is necessary to have an understanding of Hg behaviour in contaminated soil, i.e., distribution in particle size fractions, dissolution at different pH and in the presence of chlorides, and mobilisation using various extractants. The thesis aims to evaluate the potential for applying soil washing to decontaminate the Hg-contaminated soil. The Hg contamination originated from inappropriate waste disposal, chlor-alkali process and harbour activities, and the soil was also polluted by other trace elements, i.e., Zn, Cu and Pb, etc. The soil was fractionated from fine to coarse particles to study the effectiveness of physical separation. A pH-static titration ranging from pH 3 to 11 was performed to assess the mobility of Hg in response to pH changes. The chloride influence on Hg mobilisation was studied using an HCl solution of different concentrations as the leachant. Batch leaching tests were used to evaluate Hg solubility in water, and extraction efficiency by various extractants. The extractants derived from wastes were acidogenic leachates generated from biodegradable wastes, and alkaline leachates produced from fly/bottom ashes. The studied soil consisted of dominant coarse-grained fractions, which is usually suitable for particle size separation. However, dry sieving has been shown to be insufficient to separate clean from contaminated soil fractions although the Hg concentrations decreased with increasing particle sizes. The reasons are likely to be: (i) the physical attachment of fines to coarse particles; (ii) the strong chemical bond of soil organic matter (OM) and minerals for Hg. Distilled water could barely mobilise the Hg from the soil, most likely due to firm chemical bonding between the soil and Hg. Despite the fact that enhanced Hg dissolution was observed at pH 5 and 11 in this study, soil washing by pH adjustment was insufficient for Hg removal. The introduction of chlorides did not facilitate the Hg mobilisation either. Retention of Hg in the soil by OM seemed to be predominant over Hg mobilisation by chlorides. Chemical extraction by leachates from wastes as well as EDTA solution and NaOH solutions showed that neither alkaline nor acidic leachates could facilitate Hg removal from the soil. Mercury was firmly bound in the soil matrix and no more than 1.5% of the total Hg could be removed by any of the tested extractants. Future research should therefore focus on the development of Hg immobilisation techniques.

No description available.

Two weathered, petroleum contaminated soils were studied to determine if weathered products are amenable to bioremediation and to determine which TPH (total petroleum hydrocarbon) fractions were degrading during particular time frames under different remediation alternatives. Delineation of fractional degradation patterns results in inferences regarding the efficacy of different treatment methods on various petroleum products. A sandy loam and a clay soil were both studied to determine if soil matrix affects the degradation patterns. The experimental matrix included sacrificial static microcosms, soil columns and aerated slurry reactors. Both soils were evaluated under all bioreactor configurations using both a nutrient amended water and a water lacking nutrients. Controls were also used to evaluate abiotic losses. Biodegradation rates generally followed a biphasic pattern, initially rapid then followed by a slow or stagnant period. Degradation rates increased from static microcosms to soil columns to slurry reactors. The slow phase was controlled by the presence of recalcitrant compounds which decreased in number and concentrations from static microcosms to columns to slurry reactors, and generally with nutrient addition. Nutrient addition enhanced degradation for all sandy soil treatments, but only slurry reactor treatment for the clay soil. The entire TPH spectrum was broken down into five minute parcels based on GC elution time. The compounds that eluted quickest generally were the easiest to degrade. The fraction that effectively covered the TPH components in gasoline was well removed under all treatment modes. All nutrient amended studies resulted in rapid essentially complete removal of the light fractions within two weeks. The fraction encompassing the middle distillates such as diesel fuel and jet fuel was degraded under all treatment methods, however only the slurry reactors resulted in final TPH levels that would have met regulatory limits. Fractions that eluted after 15 minutes were not effectively degraded by the static microcosms or the soil columns for either soil, eliminating in situ bioremediation as a viable treatment alternative for crude oil, fuel oil and gas oil contamination, at concentrations present in this study. Persistence of recalcitrant compounds was the major factor leading to the poor biodegradation observed in the static microcosms and soil columns. Fractional degradation was highly dependent on the initial concentration of the fraction. Generally, fractions present in the largest concentrations degraded fastest. / Master of Science

This research identifies the well components, operation factors, and the soil and hydrogeological parameters that influence the recovery of Light-Non-Aqueous-Phase-Liquids (LNAPL) in an heterogeneous environment using pumping wells. The purpose of this research is to improve the analysis of sites contaminated by LNAPLs to efficiently recover the feasible amounts of LNAPL in the sites. The focus is on heterogeneous soil environments. The model adapted to analyze the recovery of LNAPL from the contaminated sites was improved to account for a high degree of vertical heterogeneity, including the vertical variation of one or several of the soil properties within the same layer. This research also studies the optimization of the recovery of LNAPL for the system of wells both at the level of one well and a system of wells. The developed model and method are applied to a real site. Thus, the model’s ability to estimate the performance of a system of recovery wells is evaluated using real soil data and performance measurements. This research constitutes a robust background regarding the design, operation, analysis, and optimization of a system of recovery wells in a heterogeneous soil environment. / text

The rapid urbanization and industrialization has led to an increase of disposal petroleum hydrocarbons (PHC) and trace elements (TE) into the environment. These pollutants are considered as the most toxic contaminants in the world due to their persistence in the environment, and the long range of toxicological effects for living beings. Recent concerns regarding the environmental contamination have initiated the development of several remediation technologies, including physical, chemical, and biological approaches. In this thesis, gentle soil remediation options (GRO) were investigated at different scales for the reclamation of PHC and TE co-contaminated soil. In the first part of this thesis, laboratory experiments were performed to characterize PHC and TE contaminated soil as well as the indigenous microorganisms (bacteria and fungi) present inside these contaminated soil. It was found that the studied aged contaminated soil had a negative effect on earthworm’s development and L. sativum biomass. Moreover, a high respiration of microorganisms attributed to the transformation/ mineralization of organic matter or/and organic pollutants was observed. This presence of viable microorganisms suggested an adaptation of microorganisms to the contaminant. Further results showed that the long-term exposure of soil microorganisms to high PHC concentration and the type of isolation culture media did not influence the ability of isolates to effectively degrade PHC. However, phylogenic affiliation had a strong on PHC biodegradation. In the second part of this thesis, preliminary studies in greenhouse were assessed to investigate the ability of M. sativa assisted by compost in the greenhouse aided-phytoremediation of PHC and TE. It was found that compost incorporation into the soil promoted PHC degradation, M. sativa growth and survival, and phytoextraction of TE. Residual risk assessment after the phytoremediation trial also showed a positive effect of compost amendment on plant growth and earthworm development. Pilot scale ecopile experiment carried out in the third part of this thesis allow a reduction of up to 80% of PHC and 20% of metals after 17 months. This research demonstrated that M. sativa and H. annus were suitable for phytodegradation of PHC and phytoextraction of TE.  Results from this thesis are helpful for further full-scale phytoremediation studies.

Submitted by Angela Maria de Oliveira (amolivei@uepg.br) on 2017-12-20T16:30:11Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) DANIELA TIDRE DE SOUZA.pdf: 1569807 bytes, checksum: a2dd69bd5899839f2401407661d74e73 (MD5) / Made available in DSpace on 2017-12-20T16:30:11Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) DANIELA TIDRE DE SOUZA.pdf: 1569807 bytes, checksum: a2dd69bd5899839f2401407661d74e73 (MD5) Previous issue date: 2017-10-24 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A contaminação dos solos pelo derramamento de gasolina é um grande problema ambiental, principalmente devido aos hidrocarbonetos constituintes da gasolina como o benzeno, tolueno e xilenos. Desta forma, estudos de técnicas modernas de remediação de áreas contaminadas são de grande importância. Os Processos Oxidativos Avançados (POAs) são muito aplicados na remediação de áreas contaminadas com hidrocarbonetos, dentre estas, destaca-se o processo tipo-Fenton, esse processo consiste basicamente da decomposição do peróxido de hidrogênio catalisado por íons Fe3+, onde também pode ser catalisado pelas formas minerais de ferro presente no solo. Em decorrência disso, este trabalho teve como objetivo avaliar e comparar a eficiência do processo tipo-Fenton com adição de Fe3+ e utilizando o ferro mineral, assim como, avaliar o efeito da presença de etanol na gasolina durante o tratamento e a fitotoxicidade. Para as determinações utilizou-se cromatografia gasosa acoplada ao sistema de headspace, onde também houve uma extração prévia associando a adição de cloreto de sódio, vortex e ultrassom, apresentando índices de recuperação entre 79,25% a 108,41% para o benzeno. A determinação dos BTX via CG-headspace mostrou-se um método confiável uma vez que na faixa linear estudada (0,05 a 80 mg Kg-1) apresentou boa linearidade com R2=0,9989 para o benzeno e a precisão avaliada ficou entre 0,87 e 3,18%. Os resultados obtidos dos estudos de degradação mostraram que os processos foram eficientes na remoção dos BTX. Para as reações com adição de ferro (Fe3+) a redução dos BTX foi maior que 93 ± 0,08% e 91 ± 0,24% para as gasolinas com e sem etanol, respectivamente após 120 minutos de reação. E para as reações utilizando apenas o ferro mineral, a remoção foi maior que 89 ± 0,78% e 67 ± 0,49% com etanol e sem etanol. Evidenciando a eficiência dos óxidos de ferro presentes nessa amostra de solo. Apesar da elevada eficiência na remoção dos BTX, os ensaios de fitotoxicidade realizados após o tratamento com sementes de Lactuca sativa mostraram aumento na fitotoxicidade. Os resultados mostraram que após o tratamento e independente do processo utilizado não ocorreu germinação das sementes. Desta forma, os resultados indicam que subprodutos formados durante a degradação, apresentam maior toxicidade frente ao bioindicador Lactuca sativa. Desta forma, embora os processos de remediação utilizados neste estudo mostrarem ser eficientes na remoção dos BTX (remoção > 67%), o tempo do tratamento de 120 minutos não é o suficiente para remover a fitotoxicidade. / The contamination of soils by gasoline spills is a biggest environmental problem, mainly due to the hydrocarbons that derived from gasoline such as benzene, toluene and xylene. In this way, studies of modern remediation techniques of contaminated areas are important. The Advanced Oxidative Processes (AOPs) have are widely employed in remediation of areas contaminated by hydrocarbons, among the Fenton-type process, which has been used quite frequently in soil remediation. This process basically consists of the decomposition of hydrogen peroxide catalyzed by Fe3+ ions, and this process can also be catalyzed by the mineral forms of iron present in the soil. As a result, this work had as objective to evaluate and compare the efficiency of the Fenton-type process with addition of Fe3+ and using the mineral iron. As well as evaluating the effect of the presence of ethanol in gasoline during treatment and the phytotoxicity. For the determinations, gas chromatography coupled to the headspace system was used, where there was also a previous extraction associating the addition of sodium chloride, vortex and ultrasound, presenting recovery rates between 79,25% and 108,41% for benzene. The determination of BTX through CG-headspace proved to be a reliable method since in the studied linear range (0,05 to 80 mg Kg-1) showed good linearity with R2= 0.9989 for benzene and the precision evaluated was between 0,87 and 3,18%. The results obtained from the degradation studies showed that the processes were efficient in the removal of BTX. The obtained results showed that the processes were efficient in the removal of BTX. For reactions with iron addition (Fe3+) the reduction of BTX was greater than 93 ± 0,08% and 91 ± 0,24% for gasolines with and without ethanol, respectively after 120 minutes of reaction. And for reactions using only mineral iron, the removal was greater than 89 ± 0.78% and 67 ± 0.49% with ethanol and without ethanol, respectively. Evidence for the efficiency of iron oxides present in this soil sample. Despite the high efficiency of BTX removal, the phytotoxicity tests performed after treatment with Lactuca sativa seeds showed an increase in phytotoxicity. The results showed that after the treatment and regardless of the process used no germination of seeds occurred. Thus, the results indicate that by-products formed during degradation, present higher toxicity to the bioindicator Lactuca sativa. Thus, although the remediation processes used in this study prove to be efficient in removing BTX (removal> 67%), the treatment time of 120 minutes is not enough to remove phytotoxicity.

Bibliography: leaves 166-180. Determines the effect of chromium on the soil microbial community and its activity, the biotic-abiotic mechanisms involved in chromium oxidation, and phytostabilization of chromium using plants and organic amendment in tannery-waste contaminated soil.