Advances in bioremediation of hydrocarbon-contaminated soil / 生物工程学报

With continuous improvement of people's living standards, great efforts have been paid to environmental protection. Among those environmental issues, soil contamination by petroleum hydrocarbons has received widespread concerns due to the persistence and the degradation difficulty of the pollutants. Among the various remediation technologies, in-situ microbial remediation enhancement technologies have become the current hotspot because of its low cost, environmental friendliness, and in-situ availability. This review summarizes several in-situ microbial remediation technologies such as bioaugmentation, biostimulation, and integrated remediation, as well as their engineering applications, providing references for the selection of in-situ bioremediation technologies in engineering applications. Moreover, this review discusses future research directions in this area.

Advances in bioremediation of polycyclic aromatic hydrocarbons contaminated soil / 生物工程学报

Polycyclic aromatic hydrocarbons (PAHs) are a class of persistent pollutants that are widely distributed in the environment. Due to their stable structure and poor degradability, PAHs exhibit carcinogenic, teratogenic, and mutagenic toxicity to the ecological environment and organisms, thus increasing attentions have been paid to their removals and remediation. Green, safe and economical technologies are widely used in the bioremediation of PAHs-contaminated soil. This article summarizes the present status of PAHs pollution in soil of China from the aspects of origin, migration, fate, and pollution level. Meanwhile, the types of microorganisms and plants capable of degrading PAHs, as well as the underlying mechanisms, are summarized. The features of three major bioremediation technologies, i.e., microbial remediation, phytoremediation, and joint remediation, are compared. Analysis of the interaction mechanisms between plants and microorganisms, selection and cultivation of stress-resistant strains and plants, as well as safety and efficacy evaluation of practical applications, are expected to become future directions in this field.

Assessment of cadmium tolerance and biosorptive potential of Bacillus Cereus GCFSD01 isolated from cadmium contaminated soil / Avaliação da tolerância ao cádmio e do potencial biossorptivo de Bacillus Cereus GCFSD01 isolado de solo contaminado com cádmio

Continuous occurrence of heavy metals is a major cause of environmental pollution due to its toxic effects. At minimum concentrations, these metals are highly reactive and can gather in the food chains and food web, causing major dangers to public health concerns. Soil samples were collected from Paharang drain, Faisalabad. Cadmium tolerant bacteria were isolated and evaluated for their MIC against Cd. The isolated bacterial strain GCFSD01 showed MIC value upto 30 mM/L. The bacterial strain with the highest resistance against Cd was selected for further study. Molecular characterization of bacterial isolate GCFSD01 was performed by 16S rRNA which confirmed it as Bacillus cereus. Optimum growth conditions of bacterial strain were also evaluated. Strain GCFSD01 showed optimum growth at pH 7 and 37 °C temperature. Our result revealed that B. cereus strain GCFSD01 reduced 61.3% Cd after 48 hrs. Multiple metal tolerance and Cd reduction by B. cereus indicate its potential for further use for decontamination of polluted soil.

A ocorrência contínua de metais pesados é uma das principais causas de poluição ambiental devido aos seus efeitos tóxicos. A contaminação por metais pesados representa um grande risco para todas as formas de vida encontradas no meio ambiente. Em concentrações mínimas, esses metais são altamente reativos e podem se acumular nas cadeias alimentares e na cadeia alimentar, causando grandes perigos às preocupações com a saúde pública. Amostras de solo foram coletadas no esgoto de Paharang, Faisalabad. Bactérias tolerantes ao cádmio foram isoladas da amostra coletada pelo método da placa de ágar. As colônias separadas individuais selecionadas foram avaliadas quanto às suas concentrações inibitórias mínimas contra Cd. A cepa bacteriana isolada GCFSD01 apresentou valores de CIM de 30 mM/L. A colônia bacteriana que apresentou maior resistência contra o Cd foi selecionada para identificação. Após seleção da maior colônia bacteriana resistente ao Cd, coloração de Gram e diferentes testes bioquímicos foram realizados para a caracterização da bactéria isolada. A caracterização molecular do isolado bacteriano GCFSD01 foi realizada por PCR 16S rRNA confirmando a presença de Bacillus cereus. Após a identificação molecular, as condições ótimas de crescimento da cepa bacteriana também foram verificadas. A cepa GCFSD01 apresentou crescimento ótimo em pH 7 e temperatura de 37 °C. Nosso resultado revelou que a cepa de B. cereus GCFSD01 reduziu 61,3% de Cd após 48 horas. A tolerância a múltiplos metais e a redução de Cd por B. cereus indicam seu potencial para uso posterior na descontaminação do solo poluído.

Microbiome and imputed metagenome study of crude and refined petroleum-oil-contaminated soils: Potential for hydrocarbon degradation and plant-growth promotion

Microbial community structure of crude petroleum oil (CP)- and refined petroleum oil (RP)-contaminated soil wasinvestigated. The taxonomical and functional diversity of such soils can be a great source of information about microbialcommunity and genes involved in petroleum hydrocarbon (PHC) degradation. In this study, microbial diversity of soilscontaminated by RP from urban biome of Pune, India, and CP from agricultural biome of Gujarat, India, were assessed by16S rRNA amplicon sequencing on Illumina MiSeq platform. Association between the soil microbial community and thephysicochemical parameters were investigated for their potential role. In RP- and CP-contaminated soils, the microbiomeanalysis showed Proteobacteria as most dominant phylum followed by Actinobacteria. Interestingly, Firmicutes were mostprevailing in a CP-contaminated sample while they were least prevailing in RP-contaminated soils. Soil moisture content,total organic carbon and organic nitrogen content influenced the taxa diversity in these soils. Species richness was more inRP as compared to CP soils. Further prediction of metagenome using PICRUSt revealed that the RP and CP soils containmicrobial communities with excellent metabolic potential for PHC degradation. Microbial community contributing to genesessential for soil health improvement and plant growth promotion was also gauged. Our analysis showed promising resultsfor future bioaugmentation assisted phytoremediation (BAP) strategies for treating such soils.

Potentials of Sugarcane Bagasse and Poultry Manure in the Remediation of Spent Motor Oil Contaminated Soil

This study sought to investigate the potential of sugarcane bagasse, poultry manure and their combination in the remediation of spent motor oil contaminated soil. About 1.5 L of spent motor oil was sprinkled on plots measuring 0.5 m x 0.5 m dimension in 12 replicate plots to simulate a major spill. Poultry dung (PD), Sugarcane bagasse (SB) and hybrid of bagasse and Poultry dung (SB - PD) were applied as organic amendments and bulking agents. The amendments were randomly administered twice within two weeks to treatment plots except the control at rate of 24tons/ha. The soil was tilled to enhance aeration and watered twice a week for 56 days. A significant decrease in Total Petroleum Hydrocarbon, TPH of 61, 53, 46 and 23% for PD, SB - PD, SB and Control plots respectively was observed. TOC and TN decreased in all the plots except the control. Soil moisture contents between 21 and 24% while soil pH within the range of 6.9 to 7.5 enhanced biodegradation process. The Total Heterotrophic Bacterial Counts (THBC) varied in all the plots while heavy metals content remained unchanged during the study. The application of these biostimulants gave promising results on hydrocarbons removal from contaminated soil.

Consequence of chromium-tainted soil on physical and biochemical responses of Vigna radiata L.

Mung bean (Vigna radiata L.) is one of the important leguminous plants of India, with shorter growing season. In this work, the intention was to correlate the effects of chromium on physical and biochemical responses of V. radiata L. Mung bean seeds were germinated and grown under controlled treatment, with different concentrations of waste soil mixed with garden soil. Physical parameters such as shoot length, root length, and fresh weight were found highest in control soil and 25% of contaminated soil, whereas 50% and pure contaminated soil showed poor growth stage and poor quality physical parameters. Biochemical parameters such as total chlorophyll content, protein content, and starch content were found highest in control soil and 25% contaminated soil, but these parameters were found to be less in 50% and pure contaminated soil. It was observed that physical and chemical parameters were declining with increasing chromium contamination.

Análise do potencial microbiano de uma biopilha na biorremediação de solos contaminados por hidrocarbonetos de petróleo / Analysis of microbial potential of a biopile in soil bioremediation contaminated by petroleum hydrocarbons

RESUMO A presente pesquisa avaliou o potencial microbiano de uma biopilha na biorremediação de solos contaminados por hidrocarbonetos, montada em uma base de distribuição de combustíveis na região metropolitana de Porto Alegre, Rio Grande do Sul. Desta biopilha, foram avaliadas as concentrações dos hidrocarbonetos totais de petróleo (HTP) e de compostos benzeno, tolueno, etilbenzeno e xilenos (BTEX), em nove pontos, durante quatro etapas de operação e em três profundidades por ponto. De cada coleta, também foram reservadas amostras de solo para realização das análises microbiológicas. A partir dessas amostras, buscou-se identificar fungos e leveduras pela análise de suas estruturas reprodutivas em lâminas de microcultivo, e bactérias pela técnica da Reação em Cadeira da Polimerase (PCR) e sequenciamento do gene que codifica o RNAr 16S. Ainda, avaliou-se a capacidade dos microrganismos isolados em degradar óleo diesel comercial, utilizando o indicador redox 2,6-diclorofenol indofenol (DCPIP). Como resultado deste estudo, observaram-se elevados percentuais de redução nas concentrações de HTP e BTEX na biopilha, como 92 e 100%, respectivamente. Das amostras de solo da biopilha, foram isoladas 101 cepas de microrganismos, das quais foram identificadas 19 cepas de fungos filamentosos, 34 de bactérias e 1 de levedura. Os resultados evidenciaram a capacidade de alguns gêneros de fungos, como Aspergillus, Trichoderma, Penicillium, Cladosporium e Verticillium, e bactérias, como Bacillus spp. e Streptomyces sp., em degradar hidrocarbonetos constituintes do óleo diesel comercial.

ABSTRACT This research evaluated the microbial potential of a biopile in bioremediation of soils contaminated by hydrocarbons, mounted on a fuel distribution base in the metropolitan region of Porto Alegre, Rio Grande do Sul. Of this biopile were evaluated concentrations of total petroleum hydrocarbons (TPH) and benzene compounds, toluene, ethylbenzene and xylenes (BTEX) at nine points, for four stages of operation and a point in three depths. Of each collection were also reserved sampled soil to perform the microbiological testing. From the samples, we sought to identify fungi and yeasts by analyzing their reproductive structures microcultivation blades, and bacteria by the technique of Polymerase Reaction Chair (PCR) and gene sequencing encoding the 16S rRNA. Still, we evaluated the ability of microorganisms to degrade commercial diesel oil, using the redox indicator 2,6-dichlorophenol indophenol (DCPIP). As result of this study, there was a high percentage reduction in the concentration of TPH and BTEX in biopilha as 92 and 100%, respectively. Of soil samples were isolated from biopilha 101 strains of microorganisms, of which 19 were identified strains of filamentous fungi and 34 bacterial yeast. The results showed the ability of some genera of fungi such as Aspergillus, Trichoderma, Penicillium, Cladosporium and Verticillium and bacteria such as Bacillus spp. and Streptomyces sp. to degrade hydrocarbons constituents of commercial diesel oil.

Draft genome sequence of phenol degrading Acinetobacter sp. Strain V2, isolated from oil contaminated soil

Abstract We report here the draft genome sequence of Acinetobacter sp. Strain V2 isolated from the oil contaminated soil collected from ENGEN, Amanzimtoti, South Africa. Degradation of phenolic compounds such as phenol, toluene, aniline etc. at 400 ppm in 24 h and oil degrading capability makes this organism an efficient multifunctional bioremediator. Genome sequencing of Acinetobacter spp. V2 was carried out on Illumina HiSeq 2000 platform (performed by the Beijing Genomics Institute [BGI], Shenzhen, China). The data obtained revealed 643 contigs with genome size of 4.0 Mb and G + C content of 38.59%.

Assessment of cadmium tolerance and biosorptive potential of Bacillus Cereus GCFSD01 isolated from cadmium contaminated soil

Abstract Continuous occurrence of heavy metals is a major cause of environmental pollution due to its toxic effects. At minimum concentrations, these metals are highly reactive and can gather in the food chains and food web, causing major dangers to public health concerns. Soil samples were collected from Paharang drain, Faisalabad. Cadmium tolerant bacteria were isolated and evaluated for their MIC against Cd. The isolated bacterial strain GCFSD01 showed MIC value upto 30 mM/L. The bacterial strain with the highest resistance against Cd was selected for further study. Molecular characterization of bacterial isolate GCFSD01 was performed by 16S rRNA which confirmed it as Bacillus cereus. Optimum growth conditions of bacterial strain were also evaluated. Strain GCFSD01 showed optimum growth at pH 7 and 37 °C temperature. Our result revealed that B. cereus strain GCFSD01 reduced 61.3% Cd after 48 hrs. Multiple metal tolerance and Cd reduction by B. cereus indicate its potential for further use for decontamination of polluted soil.

Resumo A ocorrência contínua de metais pesados é uma das principais causas de poluição ambiental devido aos seus efeitos tóxicos. A contaminação por metais pesados representa um grande risco para todas as formas de vida encontradas no meio ambiente. Em concentrações mínimas, esses metais são altamente reativos e podem se acumular nas cadeias alimentares e na cadeia alimentar, causando grandes perigos às preocupações com a saúde pública. Amostras de solo foram coletadas no esgoto de Paharang, Faisalabad. Bactérias tolerantes ao cádmio foram isoladas da amostra coletada pelo método da placa de ágar. As colônias separadas individuais selecionadas foram avaliadas quanto às suas concentrações inibitórias mínimas contra Cd. A cepa bacteriana isolada GCFSD01 apresentou valores de CIM de 30 mM/L. A colônia bacteriana que apresentou maior resistência contra o Cd foi selecionada para identificação. Após seleção da maior colônia bacteriana resistente ao Cd, coloração de Gram e diferentes testes bioquímicos foram realizados para a caracterização da bactéria isolada. A caracterização molecular do isolado bacteriano GCFSD01 foi realizada por PCR 16S rRNA confirmando a presença de Bacillus cereus. Após a identificação molecular, as condições ótimas de crescimento da cepa bacteriana também foram verificadas. A cepa GCFSD01 apresentou crescimento ótimo em pH 7 e temperatura de 37 °C. Nosso resultado revelou que a cepa de B. cereus GCFSD01 reduziu 61,3% de Cd após 48 horas. A tolerância a múltiplos metais e a redução de Cd por B. cereus indicam seu potencial para uso posterior na descontaminação do solo poluído.

Influence of oil pollution on soil microbial community diversity / 生物工程学报

Bacteria, actinomycetes and fungi are the three major groups of soil microbes. Soil microbes play a critical role in ecological and biodegradation processes in petroleum-contaminated soils. Based on the actual situation, this study took the oil polluted soil around the abandoned oil well in Shehong County, Suining City, Sichuan Province as the test soil. First, we determined the physiochemical properties of the tested soil; then we analyzed the changes of physiochemical properties and the three major microbes in petroleum contaminated soils. The number of the three major microbes in contaminated soils was relatively fewer than uncontaminated samples, and the water content of the soil was in positive correlation with the number of microbes. Also we assessed the soil bacteria community diversity and changes therein in petroleum-contaminated soils using 454 pyrosequencing of 16S rRNA genes. No less than 23 982 valid reads and 6 123 operational taxonomic units (OTUs) were obtained from all 4 studied samples. OTU richness was relatively higher in contaminated soils than uncontaminated samples. Acidobacteria, Actinobacteria, Bacteroidetes, Chloroflexi, Planctomycetes and Proteobacteria were the dominant phyla among all the soil samples. However, the prokaryotes community abundance of phyla was significantly different in the four samples. The most abundant OTUs associated with petroleum-contaminated soil sample were the sequences related to Acidobacteria, Actinobacteria and Proteobacteria, whereas the most abundance sequences with uncontaminated sample were those related to Actinobacteria, Bacteroidetes and Proteobacteria.

Screening, stability and antibacterial potential of rhamnolipids from Pseudomonas sp., isolated from hydrocarbon contaminated soil.

Surfactant plays an important role in industrial application such as oil recovery, lubricants and emulsifier. But chemical surfactants are toxic to human and other small animals. In recent years, biological based surfactants have gained increasing attention due to their ecofriendly in nature. The present study was focused to isolate biosurfactant producing bacteria, their stability and antibacterial ability from hydrocarbon contaminated and uncontaminated soil collected from different locations in Kanchipuram, Tamil Nadu, India. Biosurfactant producing bacteria were screened by following the haemolytic activity, drop collapsing test, emulsion against kerosene and was further confirmed through surface activity. The stability of the biosurfactant was determined by different physic-chemical conditions like pH, temperature and salinity. A total of 37 strains were selected in three different samples based on cultural characters and finally only 7 strains were confirmed as positive for biosurfactant. Among these strain H11 was considered as potential based on emulsification index (44%), surface activity (34.45 x 10-3 nm-1) and surface tension (23.17 x 10-3 nm-1) and was identified as Pseudomonas sp. The emulsification activity was stable at broad range of pH (4-12), temperature (4-120°C) and salt concentration (0-10%). The biosurfactant was further characterized in HPLC and one major peak was observed at a retention time of 2.033. The antibacterial activity of biosurfactant was high against gram positive pathogenic bacteria than gram negative bacteria. The rhamnolipid produced Pseudomonas sp. may be used as a tool to manage the oil pollution and to control the disease causing bacteria.

Electrobiorremeiiación de un suelo con una contaminación antigua de hidrocarburo / Electrobiorremediation of a Soil with an Old Hydrocarbon Contamination

La electrobiorremediación es la técnica híbrida que suma los efectos de la electrorremediación a la degradación bacteriana de diferentes contaminantes. El objetivo de este estudio fue utilizar esta técnica para aumentar la biodisponibilidad de los hidrocarburos presentes en un suelo con contaminación antigua y su eliminación. El experimento duró 63 días y se realizó en una cuba de vidrio con tres compartimentos comunicados por puentes salinos de buffer fosfato que permitieron establecer la diferencia de voltaje y mantener el pH del suelo en valores óptimos para la vida bacteriana. Se determinaron: pH, humedad, hidrocarburos totales del petróleo (TPH) y bacterias. Los resultados mostraron una disminución de los hidrocarburos siendo la región del cátodo la que mejor eliminó los hidrocarburos, con solo el 9,4 % y 5,46 % de los hidrocarburos alcanos y poliaromáticos; en la celda control estos valores fueron del 15,28 y 14,4 % respectivamente, mientras que el centro fue el lugar que menor degradación presentó quedando el 19,49 % y el 17,88 % de los hidrocarburos alcanos y PAH. Concluimos que los resultados de laboratorio indican la posibilidad de incrementar la biodegradación en suelos con tratamientos biológicos previos.

Electrobioremediation (EKB) is a hybrid technique that combines bioremediation with electrokinetics. EKB uses bioremediation to degrade hydrocarbon contaminants and EK to mobilize them. The aim of this study was to use a technique for increasing the bioavailability of the hydrocarbons in soil pollution. The 63-day experiment was conducted in a three compartment glass vial connected by three salt bridges of phosphate buffer that established a voltage difference and maintained soil pH optimum for bacterial life value​​. pH, moisture, total petroleum hydrocarbons (TPH) and bacteria were determined. The results showed a decrease in hydrocarbon, the best results were close to the cathode, where only 9.4 % and 5.46 % of alkanes and polyaromatic hydrocarbons were left. In the control cell these values ​​were 15.28 and 14.4 % respectively, while the center generated less degradation with 19.49 % and 17.88% of alkanes and PAH hydrocarbons left. We conclude that the results from the laboratory study indicated that this technique gives the possibility of increasing biodegradation in soils with previous biological treatments.

Histopathological Effects of Glyphosate and Its Toxicity to the Earthworm Nsukkadrilus mbae.

This study was carried out to investigate the toxicity of Roundup, aglyphosate-containing herbicide to the earthworm Nsukkadrilus mbae and the associated histological changes. One hundred and sixty five earthworms were randomly divided into five groups and exposed to different concentrations of glyphosate (0.0, 13.0, 52.0, 117.0 and 207 mg/Kg soil) for 96 h. The mortality was recorded every 24h and after 96 h, sections of the earthworm from each treatment group were prepared for microscopic examination. There was no mortality in the control group and the survivors in the treatment groups were weak. The percentage mortality was least after 24 h and highest after 96 h and the mortality was significantly different (P = 0.05) in the groups except after 24h. The survival rate was generally concentration and duration dependent. The 96 h LC50 value was 10.4 mg/Kg soil. The observed histopathological changes included rupture of the cuticullar wall, tissue necrosis and prominent vacuolations. The circular and longitudinal muscle layers had altered structural integrity. These histopathological end points could be useful biomonitors of glyphosate toxicities in ecotoxicological studies involving earthworms.

Characterization of pyrene utilizing Bacillus spp. from crude oil contaminated soil

Pyrene, a high molecular weight polycyclic aromatic hydrocarbon (PAH), is a priority pollutant present in soil contaminated with crude oil, coal-tar and complex PAHs. Bacterial consortium CON-3 developed from crude oil contaminated soil of Patiala, Punjab (India) cometabolized 50 µg ml-1 pyrene in the presence of glucose (0.5 %; w/v) at 30 °C, as determined by reverse-phase high performance liquid chromatography (HPLC). Bacillus sp. PK-12, Bacillus sp. PK-13 and Bacillus sp. PK-14 from CON-3, identified by 16S rRNA gene sequence analysis, were able to cometabolize 64 %, 55 % and 53 % of pyrene in 35 days, respectively. With the increase in glucose concentration to 1.0 % (w/v) in growth medium isolates PK-12, PK-13 and PK-14 showed 19 - 46 % uptake of 50 µg ml-1 pyrene in 4 days, respectively. Uptake of pyrene was correlated with growth and biosurfactant activity, which is suggestive of the potential role of members of Bacillus genera in pyrene mobilization and its uptake.

Microbial activity, arbuscular mycorrhizal fungi and inoculation of woody plants in lead contaminated soil

The goals of this study were to evaluate the microbial activity, arbuscular mycorrhizal fungi and inoculation of woody plants (Caesalpinia ferrea, Mimosa tenuiflora and Erythrina velutina) in lead contaminated soil from the semi-arid region of northeastern of Brazil (Belo Jardim, Pernambuco). Dilutions were prepared by adding lead contaminated soil (270 mg Kg-1) to uncontaminated soil (37 mg Pb Kg soil-1) in the proportions of 7.5 percent, 15 percent, and 30 percent (v:v). The increase of lead contamination in the soil negatively influenced the amount of carbon in the microbial biomass of the samples from both the dry and rainy seasons and the metabolic quotient only differed between the collection seasons in the 30 percent contaminated soil. The average value of the acid phosphatase activity in the dry season was 2.3 times higher than observed during the rainy season. There was no significant difference in the number of glomerospores observed between soils and periods studied. The most probable number of infective propagules was reduced for both seasons due to the excess lead in soil. The mycorrhizal colonization rate was reduced for the three plant species assayed. The inoculation with arbuscular mycorrhizal fungi benefited the growth of Erythrina velutina in lead contaminated soil.

Bioconversion of petroleum hydrocarbons in soil using apple filter cake / Bioconversão de hidrocarbonetos de petróleo no solo pelo uso de bagaço de maçã

The aim of this study was to investigate the feasibility of using apple filter cake, a fruit-processing waste to enhance the bioremediation of petroleum contaminated soil. A rotating barrel system was used to study the bioconversion of the xenobiotic compound by natural occurring microbial population. The soil had been accidentally polluted with a total petroleum hydrocarbon concentration of 41,000 ppm. Although this global value was maintained during the process, microbial intervention was evidenced through transformation of the petroleum fractions. Thus, fractions that represent a risk for the environment (GRO, Gasoline Range Organics i.e., C6 to C10-12; DRO, Diesel Range Organics i.e., C8-12 to C24-26 and RRO, Residual Range Organics i.e., C25 to C35) were significantly reduced, from 2.95 percent to 1.39 percent. On the contrary, heavier weight fraction from C35 plus other organics increased in value from 1.15 percent to 3.00 percent. The noticeable diminution of low molecular weight hydrocarbons content and hence environmental risk by the process plus the improvement of the physical characteristics of the soil, are promising results with regard to future application at large scale.

O objetivo deste estudo foi investigara viabilidade de aplicação de bagaço de maçã, um resíduo do processamento de frutas, para melhorar a biorremediação de solo contaminado com petróleo. Para estudar a bioconversão de compostos xenobióticos pela população microbiana naturalmente presente empregou-se um sistema de barril rotativo. O solo havia sido acidentalmente contaminado com um total de hidrocarbonetos de petróleo na concentração de 41.000 ppm. Embora esse valor tenha se mantido durante o processo, a intervenção microbiana ficou evidenciada através da transformação de frações do petróleo. Assim, as frações de risco para o meio ambiente (GRO, Gasoline Range Organics, i.e., C6 a C10-12; DRO, Diesel Ramge Organics, i.e. C8-12 a C24-26 e RRO, Residual Range Organics, i.e. C25 a C35) foram significativamente reduzidas de 2,95 por cento para 1,39 por cento. Por outro lado, frações mais pesadas, acima de C35, e outros compostos orgânicos aumentaram de 1,15 por cento para 3,00 por cento. A diminuição notável do conteúdo de hidrocarbonetos de baixo peso molecular e conseqüentemente do risco ambiental por esse processo, além da melhoria das características físicas do solo, são resultados promissores para uma futura aplicação em grande escala.

Análises do comportamento físico de um solo contaminado por borra oleosa ácida e encapsulado com cimento Portland / Analyses of physical behavior of a soil contaminated by acidic oily sludge and encapsulated with cement Portland

Este trabalho tem como objetivo aplicar a técnica de encapsulamento em um solo contaminado com crescentes quantidades do resíduo industrial borra oleosa ácida, utilizando como agente encapsulante o cimento Portland CP-V ARI. A aplicação da técnica de encapsulamento consistiu na realização de estudos pós-tratamento, analisando fisicamente o solo contaminado através de ensaios de resistência à compressão simples e durabilidade. Os resultados apontam que quanto maior a quantidade de borra oleosa ácida presente no solo encapsulado, menor a resistência à compressão simples e maior a perda de massa.

The objective of this study is applying the encapsulation technique in soil contaminated with increasing amounts of acidic oily sludge industrial residues, using Portland cement CP-V ARI as the encapsulating agent. The application of the encapsulation technique consisted in the accomplishment of post-treatment studies, analyzing the contaminated soil physically through unconfined compressive strength and durability tests. The results showed that an increasing amount of acidic oily sludge in the encapsulated soil ends up lowering the unconfined compressive strength as well as increasing the mass loss.