Soil and groundwater at many existing and former industrial areas and disposal sites is contaminated by organic solvent compounds that were released into the environment. Organic solvent compounds are heavier than water. When they are released into the subsurface, they tend to adsorb onto the soils and cause the appearance of LNAPL (light nonaqueous phase liquid) and DNAPL (dense nonaqueous phase liquid) pool. The industrial petroleum hydrocarbons (e.g., methyl tertiary-butyl ether, MTBE and benzene) and chlorinated solvent (e.g., trichloroethylene, TCE) are among the most ubiquitous organic compounds found in subsurface contaminated environment. One cost-effective approach for the remediation of the chlorinated solvent and petroleum products contaminated aquifers is the installation of permeable reactive zones or barriers within aquifers. As contaminated groundwater moves through the emplaced reactive zones, the contaminants are removed, and uncontaminated groundwater emerges from the downgradient side of the reactive zones. The objectives of this study were developed to evaluate the feasibility of applying in-situ chemical oxidation (ISCO) barrier and in-situ slow polycolloid-releasing substrate (SPRS) biobarrier system on the control of petroleum hydrocarbons and chlorinated solvent plume in aquifer. In the ISCO barrier system, it contained oxidant-releasing materials, to release oxidants (e.g., persulfate) contacting with water for oxidating contaminants existed in groundwater. In this study, laboratory-scale fill-and-draw experiments were conducted to determine the compositions ratios of the oxidant-releasing materials and evaluate the persulfate release rates. Results indicate that the average persulfate-releasing rate of 7.26 mg S2O82-/d/g was obtained when the mass ratio of sodium persulfate/cement/sand/water was 1/1.4/0.24/0.7. The column study was conducted to evaluate the efficiency of in situ application of the developed ISCO barrier system on MTBE and benzene oxidation. Results from the column study indicate that approximately 86-92% of MTBE and 95-99% of benzene could be removed during the early persulfate-releasing stage (before 48 pore volumes of groundwater pumping). The removal efficiencies for MTBE and benzene dropped to approximately 40-56% and 85-93%, respectively, during the latter part of the releasing period due to the decreased persulfate-releasing rate. Results reveal that acetone, byproduct of MTBE, was observed and then further oxidized completely. Results suggest that the addition of ferrous ion would activate the persulfate oxidation. However, excess ferrous ion would compete with organic contaminants for persulfate, causing the decrease in contaminant oxidation rates. In the SPRS biobarrier system, the food preparation industry has tremendous experiences in producing stable oil-in-water (W/O, 50/50) emulsions with a uniformly small droplet size. Surfactant mixture (71 mg/L of SL and 72 /L of SG) blending with water could yield a stable and the optimal emulsion was considered the best. The small absolute value of the emulsion zeta potential reduces inter-particle repulsion, causing the emulsion droplets to stick to each other when they collided. Overtime, large masses of flocculated droplets can form which then clog the sediment pores. The results can be used to predict abiotic interactions and distribution of contaminant mass expected after SPRS injection, and thus provides a more accurate estimate of the mass of TCE removed due to enhanced biodegradation. The effect of TCE partitioning to the vegetable oil on contaminant migration rates can be approximated using a retardation factor approach, where 0.28 years through a 3 m barrier. In anaerobic microcosm experiments, result show that SPRS can be fermented to hydrogen and acetate could be used as a substrate to simulate reductive dehalorination. The apparent complete removal of nitrate and sulfate by SPRS addition was likely a major factor that promoted the complete reduction of TCE at later stages of this study. Results from the column experiment indicate that occurrence of anaerobic reductive dechlorination in the biobarrier system can be verified by: (1) the oil: water partition coefficients of dissolved TCE into vegetable oil were be used to predict abiotic interactions and distribution of contaminant mass expected after SPRS injection. (2) The SPRS can ferment to hydrogen and acetate could be used as a substrate to simulate reductive dechlorination. The proposed treatment scheme would be expected to provide a more cost-effective alternative to remediate other petroleum hydrocarbons and chlorinated solvents-contaminated aquifers. Experiments and operational parameters obtained from this study provide an example to design a passive barriers system for in-site remediation.

The objectives of this study are to use phytoremediation ecotechnology to improve the long-term soil pollution contaminated by petroleum and its refined products, and to explore the influence of environmental factors to the effective degradation of TPH.This study is divided into three stages.First, we selected the biofuel crops seeds to test their diesel fuel pollution tolerance.The crops include soybean¡Bsunflower¡Bcanola and corn.This four Taiwanese common energy crops were selected to manually configure three levels of diesel fuel pollution(1000¡B5000¡B10000 mg kg-1)in soil test the seed tolerance experiments.The experimental results in the first stage exhibited that the best energy crop species and non-edible crop(Jatropha),are selected in second phase for contaiminated soil degradation experiment to explore the possible influence of enviromented factors,such as soil moisture¡BpH¡Btotal plate¡Ketc,and to explore the applied fertilizer to increase soil nutrients,whether it will affect the degradation of diesel pollution.Finally, in the third phase, the energy crops were used in the oil-contaminated site to assess their decontamination efficiency. From June 2011 to November 2011, the experimental results shown in the first phase of seed tolerance test, for a period of 30 days showed that the soybean diesel-contaminated soil presented the best tolerance.Although the germination rate was increased with the concentration from 80% to 27%, it showed the best growth conditions.Therefore, in the second phase of test run, the speices of soybean and jatropha were selected prepared with concentrations of 1745¡B6271 and 10072 mg kg-1 dry soil. After 90 day for phytoremediation, soybean group(S) were found that the residual concentrations in soil were measured equal to 524¡B809 and 1913 mg kg-1 dry soil,with the removal rates of 69.97%¡B87.09% and 81.01% respectively.The concentration level of 10000 ppm was found not reach our control standard of 1000 ppm. The soil planted by jatropha(J) showed that residual concentration in soils equial to 303¡B1864 and 4837 mg kg-1 dry soil, with removal rates equal to 82.61%¡B70.27% and 51.98% respectively.Through statistical regression analytical results, the soybean can handle up to a concentration of 5300 mg/kg for diesel, while jatropha can handle up to 2170 mg/kg in this system. Except for the concentration level of 1000 ppm can reach our control standards, the other two groups were found below the control standard. To improve the removal efficieneies, it was suggested that phyto remediation time can be extended.

This study focuses on the Kaohsiung industrial pier sediment survey, assessment and feasibility study of the approach. In this study, field monitoring operations, including the close Salt Water River mouth area of the industrial port (area A), the far Salt Water River mouth area of the industrial port (area B) and for the factories and shipyards at the junction of the terminal area (area C), The sampling of sediments of three core and three surface sediments of area A that used as treating test at laboratory. The survey results show that the industrial pier some heavy metals in the sediment concentration is higher than the quality indicators in the sediment above the limit (ULV), especially copper and zinc. In addition, the concentration of heavy metals of industrial pier area A, B and C of the sediment at least one of them is than current soil control standard. Among them, the frequency of exceeding control standards of copper concentration is the highest, the surface sediments of area A, B and C were about 75%, 42% and 0% respectively, while the core sediments were about 20%, 90% and 15%. These results indicate that the industrial pier sediment required to carry out appropriate pre-treatment to reclamation land to recycling. After investigation, simulation and estimation, the required appropriate treatment sediment in order to landfill volume of industrial pier area A and B (Salt Water River mouth) were approximately 40,000 and 36,400 cubic meters, the total approximately 76,400 cubic meters. Industrial pier is located in the Salt Water River mouth, and therefore withstand the effects of pollutants of the upstream sources flowed in, and than the sediment quality was poor. Sediments were accumulated in the bottom should be removed and sediments at the upstream Salt Water River should be treated too, the remediation and pollution source control for the future to improve the sediment quality is the most important work in Taiwan. In this study, chemical washing and chemical oxidation of the two treatment technology for industrial pier sediment organic pollutants (total petroleum hydrocarbons (TPH) as the target pollutants) to deal with the feasibility test. Sediment to be processed was collected neart the industrial pier, the pH value of approximately 7.1, the moisture content was 43.9%, 20.1% organic matter content, while the particle size composition of mainly fine particles (silt + clay) to about 84.3% handling may be more difficult. The sediments of the TPH concentration of 8,691 mg / kg. Three surfactants Simple Green (SG), Triton X-100 (TX-100) and Tween 80 (TW80) were used at sediment washing test,washing with 60 pv and 5% (v / v) SG could remove 97.3% TPH at the end of the mud; 0.5% (v / v) TX-100 could remove 96.8% TPH; washing with 30 pv, 1% (v / v) TX-100 could remove 94.6% the TPH; washing with 10 pv, 5% (v / v) TX-100 could remove 96.7% TPH; but TW80 leaching ineffective. Oxidation processing, applied 6% H2O2 reaction 180 min, 58.2% of TPH could be removed. Connection of washing and oxidation treatment process, could be removed total of 86% of TPH. The sediment surface morphology before and after treatment were observed by SEM were not significantly different, no surfactant emulsion was left at sediment after treated, this result revealed the connection of washing and oxidation treatment process could remove most of TPH and less harmful to the environment was an available technique.

No description available.

Alternative strategies involving in situ remediation technologies have been developed to assist with property clean up, however, cost-effectiveness and discrepancies in success rates and timeliness continue. The objective of my research was to critically demonstrate the application and usefulness of an in situ remediation technology at a petroleum hydrocarbon impacted site. This project was proposed as part of the research programs: Groundwater Plume Formation and Remediation of Modern Gasoline Fuels in the Subsurface and Enhancing In Situ Bioremediation at Brownfield Sites funded by the Ontario Centres of Excellence for Earth and Environmental Technologies as part of the multiphase project entitled “Enhancing in situ Bioremediation at Brownfield Sites”. This research focused on the demonstration of nitrate-enhanced in situ bioremediation at a decommissioned service station. Petroleum hydrocarbon impacted soil and groundwater is a common occurrence at gasoline distribution facilities, where toxicological effects are known for gasoline constituents of interest such as benzene, toluene, ethylbenzene and total xylenes (BTEX). These chemicals are volatile, readily soluble, and persistent in groundwater. In particular, residual contaminants present in the saturated zone were targeted for remediation as they serve as a long term source of contamination and contribute to mobile vapour phase and dissolved phase plumes. Site investigations characterized the complex hydrogeological conditions and contaminant distribution present in order to effectively design an in situ bioremediation treatment system. The addition of nitrate as a terminal electron acceptor (TEA) to an aquifer enhances in situ biodegradation of petroleum hydrocarbons, by providing the microbes with a sustainable energy source to promote cell maintenance and growth of the microbial population. The remediation strategy involved pulsed injections of remedial solution amended with a conservative bromide (200 mg/L Br-) and reactive nitrate (90 to 265 mg/L NO3-) tracers with the purpose of providing a continuous supply of TEA available to the indigenous microbial populations. Nitrate was selected as an alternative electron acceptor over the thermodynamically favoured O2 because of typical challenges encountered using O2 in bioremediation applications in addition to the existing anaerobic environment. In situ anaerobic degradation of BTEX compound using TEA amendments has been well documented; however benzene is often recalcitrant under denitrification conditions. The results of the Br- tracer breakthrough curves indicate that different preferential flow pathways were established under the transient saturated conditions present at the Site, although the behaviour of the injected remedial slug was generally consistent between the different units and the test solution was ultimately delivered to the target zone. The delivery of the remedial test solution was greatly influenced by the hydrogeological conditions present at the time of injection. The injectate was preferentially transported in the high permeability zone of sandy gravel aquifer Unit 3 under high saturated condition and background hydraulic gradients. However the seasonal decline in groundwater levels and hydraulic gradients resulted in the lower portion of Unit 4 comprised of higher permeable materials being able to transmit the test solution more effectively. Given the variable hydrogeological conditions present at the Site influenced by seasonal effects, the delivery of the remedial solution to target zones containing petroleum hydrocarbons at residual saturation is more effective under reduced saturated conditions. The delivery of TEA amended water to enhance the in situ biodegradation of petroleum contaminants is more effective when the treatment water has an increased residence time in the target remedial zone, attributed to low gradients and groundwater transport velocities at the Site. Longer residence periods enable the indigenous microbes to have increased contact time with the TEA which will be preferentially utilized to degrade the contaminants.   A reducing zone enriched with TEA in the anaerobic aquifer was established following consecutive injections of remedial test solution. A cumulative mass of 4 kg of NO3- was added to the target aquifer during the course of the remedial injections. Evidence demonstrating NO3- utilized as a terminal electron acceptor in the bioremediation of the petroleum-contaminated aquifer include: laboratory microcosm study confirming local indigenous microbial population’s ability to degrade hydrocarbons using NO3- as the TEA in addition to observed decrease in NO3- relative to a conservative Br- tracer and generation of nitrite, an intermediate product in denitrification in the pilot-scale operation. Contaminant mass removal likely occurred as Br- tracer evidence indicates that NO3- was utilized in the study area based on the inference of denitrification rates. Post-injection groundwater sampling indicate declining concentrations of toluene, however long term monitoring is recommended in order to evaluate the success of the remediation activity and assess the potential for rebound. Post-injection soil core results are unable to demonstrate the reduction in individual toluene, let alone BTEXTMB hydrocarbon levels, as a result of insufficient quantities of nitrate delivered to the target zone relative to the significant but heterogeneously distributed residual mass in the subsurface.

abstract: In this work, the vapor transport and aerobic bio-attenuation of compounds from a multi-component petroleum vapor mixture were studied for six idealized lithologies in 1.8-m tall laboratory soil columns. Columns representing different geological settings were prepared using 20-40 mesh sand (medium-grained) and 16-minus mesh crushed granite (fine-grained). The contaminant vapor source was a liquid composed of twelve petroleum hydrocarbons common in weathered gasoline. It was placed in a chamber at the bottom of each column and the vapors diffused upward through the soil to the top where they were swept away with humidified gas. The experiment was conducted in three phases: i) nitrogen sweep gas; ii) air sweep gas; iii) vapor source concentrations decreased by ten times from the original concentrations and under air sweep gas. Oxygen, carbon dioxide and hydrocarbon concentrations were monitored over time. The data allowed determination of times to reach steady conditions, effluent mass emissions and concentration profiles. Times to reach near-steady conditions were consistent with theory and chemical-specific properties. First-order degradation rates were highest for straight-chain alkanes and aromatic hydrocarbons. Normalized effluent mass emissions were lower for lower source concentration and aerobic conditions. At the end of the study, soil core samples were taken every 6 in. Soil moisture content analyses showed that water had redistributed in the soil during the experiment. The soil at the bottom of the columns generally had higher moisture contents than initial values, and soil at the top had lower moisture contents. Profiles of the number of colony forming units of hydrocarbon-utilizing bacteria/g-soil indicated that the highest concentrations of degraders were located at the vertical intervals where maximum degradation activity was suggested by CO2 profiles. Finally, the near-steady conditions of each phase of the study were simulated using a three-dimensional transient numerical model. The model was fit to the Phase I data by adjusting soil properties, and then fit to Phase III data to obtain compound-specific first-order biodegradation rate constants ranging from 0.0 to 5.7x103 d-1. / Dissertation/Thesis / Ph.D. Civil and Environmental Engineering 2012

Esta pesquisa tem por objetivo contemplar as variáveis inerentes aos compostos, mais precisamente hidrocarbonetos totais de petróleo em função de sua disposição no meio ambiente, relacionando o comportamento associado ao seu risco toxicológico e de forma inovativa, verificar a influência de se considerar toda a gama de hidrocarbonetos de petróleo na avaliação de risco, quantificando o erro e incerteza de uma avaliação de risco clássica. O escopo de trabalho contemplou a definição da potenciometria local, definição de contaminantes de interesse, modelagens de transporte e para estes contaminantes e definição do programa de gerenciamento da área em função da inclusão de um modelo de risco toxicológico. A área encontra-se inserida em um pacote sedimentar que confere condutividades hidráulicas entre 10-4 e 10-5 cm/s. O modelo de fluxo é radial, e a velocidade linear de fluxo foi definida entre 0,5 e 8,6 m/ano. Os resultados obtidos nas campanhas sistemáticas de monitoramento indicaram que a grande maioria dos poços apresentou concentrações abaixo dos padrões ambientais. Obteve-se a constatação de contaminação efetiva nas áreas compreendidas pela Oxiteno (OXI) e Petroflex (PTX). As simulações de risco efetuadas somente para os compostos BTEX indicaram valores acima dos limites preconizados pelos órgãos ambientais somente em um cenário hipotético de utilização de água captada em área próxima ao poço PPTX 070 (Petroflex). Os demais cenários apresentam riscos dentro dos limites aceitáveis. A quantificação do risco toxicológico associado a toda a gama de hidrocarbonetos de petróleo apresentou valores mais restritivos do que as avaliações executadas para a mesma amostra quando considerou-se somente os compostos padronizados etilbenzeno, tolueno e xilenos, As variações foram de até duas ordens de grandeza no quociente de risco. A definição de metas de remediação e adoção de um programa de gestão específico deve considerar toda a gama de hidrocarbonetos de petróleo e não somente compostos padronizados. / This research aims to consider all the inherent variables to the compounds due to their disposal in the environment, relating their fate associated to their toxicological risk and verify the influence of considering all the petroleum hydrocarbons range in the risk evaluation, quantifying the uncertainty of a classic risk evaluation. The study scope considered the potenciometric trend of the site, definition of compounds of interest; fate and transport modelling for these compounds and finally the definition of the site management program associated to a model of toxicological risk. The potenciometric map illustrates a radial flow for the groundwater, with hydraulic conductivities ranging from 10-4 to 10-5 cm/s. The lineal flow velocity of groundwater was determined between 0,5 m/year and 8,69 m/year. The results obtained in the systematic monitoring campaigns indicated that the great majority of the wells presented concentrations below the environmental standards. It was verified effective contamination in the areas comprehended by Oxiteno (OXI) and Petroflex (PTX). The risk simulations performed for the BTEX compounds indicated values above the limits accepted by the environmental agencies only for a hypothetical scenery regarding explotation of water nearby the PPTX 070 well area. The other scenaries presented acceptable risk limits. The quantification of the toxicological risk associated to all the petroleum hydrocarbons range presents more restrictive values than the evaluations performed for the same water sample, when it was considered only the standardized compounds ethilbenzene, toluene and xilenes, The variations went up to two greatness orders in the risk quotient. The definition of remediation goals and adoption of a specific management program must consider all the petroleum hydrocarbons range and not only standardized compounds.

Abstract Despite tightened environmental legislation, spillages of petroleum products remain a serious problem worldwide. The environmental impacts of these spillages are always severe and reliable methods for the identification and quantitative determination of petroleum hydrocarbons in environmental samples are therefore needed. Great improvements in the definition and analysis of total petroleum hydrocarbons (TPH) were finally introduced by international organizations for standardization in 2004. This brought some coherence to the determination and, nowadays, most laboratories seem to employ ISO/DIS 16703:2004, ISO 9377-2:2000 and CEN prEN 14039:2004:E draft international standards for analysing TPH in soil. The implementation of these methods, however, usually fails because the reliability of petroleum hydrocarbon determination has proved to be poor. This thesis describes the assessment of measurement uncertainty for TPH determination in soil. Chemometric methods were used to both estimate the main uncertainty sources and identify the most significant factors affecting these uncertainty sources. The method used for the determinations was based on gas chromatography utilizing flame ionization detection (GC-FID). Chemometric methodology applied in estimating measurement uncertainty for TPH determination showed that the measurement uncertainty is in actual fact dominated by the analytical uncertainty. Within the specific concentration range studied, the analytical uncertainty accounted for as much as 68–80% of the measurement uncertainty. The robustness of the analytical method used for petroleum hydrocarbon determination was then studied in more detail. A two-level Plackett-Burman design and a D-optimal design were utilized to assess the main analytical uncertainty sources of the sample treatment and GC determination procedures. It was also found that the matrix-induced systematic error may also significantly reduce the reliability of petroleum hydrocarbon determination. The results showed that strict implementation of the ISO and CEN draft standards is necessary owing to the method dependence of the analyzed parameter. Care should be taken to ensure that the methods used for petroleum hydrocarbon determination are comprehensively validated, and that routine quality control is carried out in order to ensure that the validation conclusions are applicable in the daily work.

The efficacy of BiOWiSHTM-Thai Aqua, a commercially discontinued microbial product, in remediating oil based drill-cutting mud (DCM) was researched in this study. Experimentation was performed directly on DCM and on sand contaminated with oil extracted from DCM. A gas chromatograph-mass spectrometrer and a respirometer were used for analysis of total petroleum hydrocarbons (TPH) and CO2 production respectively. Five experiments were analyzed by TPH extraction and analysis; four experiments were analyzed by respirometric analysis. The specific microcosm conditions tested in the experiments were control, nutrient-only control, and bioaugmentation product. This study concluded that there might be potential for bioaugmentation of TPH using BiOWiSHTM-Thai Aqua. However, a more extensive study including multiple replicates of samples over a longer sampling time period is required to make a conclusion. TPH analysis from the Sand Microcosm Experiment suggested that in seven days, the addition of BiOWiSHTM-Thai Aqua improved TPH removal relative to the control by 89% while the nutrient-only control improved by 58%. Respirometric analysis suggested CO2 respiration of glucose overshadowed CO2 respiration from biodegradation. Thus, major conclusions could not be made from the respirometric analysis.

Natural Attenuation Software (NAS) was developed as a screening tool to estimate remediation timeframes for monitored natural attenuation (MNA) to lower groundwater contaminant concentrations to regulatory limits, and to assist in decision-making on the level of source zone treatment in conjunction with MNA using site-specific remediation objectives. In addition, NAS facilitates the combined use of MNA with engineered remedial actions (ERAs) so that the benefits of each technology can be maximized while minimizing costs of remediation. The primary expected benefit of NAS is to increase regulatory acceptance of MNA, thereby decreasing overall remediation costs. NAS is designed for application to ground-water systems consisting of porous, relatively homogeneous, saturated media, and assumes that groundwater flow is uniform and unidirectional. NAS consists of a combination of analytical and numerical solute transport models implemented in three main interactive modules to provide estimates for: (1) target source concentration required for a plume extent to contract to regulatory limits, (2) time required for NAPL contaminants in the source area to attenuate to a predetermined target source concentration, and (3) time required for a plume extent to contract to regulatory limits after source reduction. Natural attenuation processes that NAS models include advection, dispersion, sorption, non-aqueous phase liquid (NAPL) dissolution, and biodegradation. NAS determines redox zonation, and estimates and applies varied biodegradation rates from one redox zone to the next. Recently, NAS was enhanced to include petroleum hydrocarbons, chlorinated ethenes, chlorinated ethanes, chlorinated methanes, and chlorinated benzenes, or any user-defined contaminants (e.g., heavy metals, radioisotopes), and has included the capability to model co-mingled plumes. To enable comparison of remediation timeframe estimates between MNA and specific ERAs, NAS was modified to incorporate an estimation technique for timeframes associated with pump-and-treat remediation technology for comparison to, or in conjunction with, MNA. NAS also expanded analysis tools for improved performance assessment, as well as the assessment of sustainability of natural attenuation processes over time. A Department of Defense (DoD) Environmental Security Technology Certification Program (ESTCP) demonstration was undertaken to evaluate the capability of the NAS software to provide reasonable estimates of MNA cleanup timeframes in a variety of environments and sites throughout the United States. Overall, results suggest that NAS was satisfactory in meeting performance objectives set forth in the demonstration, and that because NAS is based on sound science, it can serve as an effective tool for decision-making and data analysis at a wide range of contaminated sites and is not limited to a small subset of “simple sites” because of its simplicity. At some sites, NAS-estimated timeframes were crucial for winning regulatory acceptance of MNA, with cost-benefit analyses providing estimates of savings associated with using MNA as a final remediation strategy. / Ph. D.