Pilot Test Site Research Articles

Long-Term Leaching Behavior and Geochemical Modeling of Cement Solidified Incineration Fly Ash Containing Waste Tires and Wood Biomass

Waste incineration is a widely used treatment method, and sustainable approaches are required to properly recycle large volumes of incineration ash to reduce environmental impacts and landfill space consumption. Studies have focused on the potential of recycling incineration ash as a replacement for natural aggregates in civil engineering applications, such as road construction. However, industrial waste incineration ash, such as waste tire incineration ash, contains hazardous heavy metals, such as lead and zinc that pose potential environmental threats. Moreover, few studies have investigated the leachability of these hazardous metals after long-term natural aging. This study investigates the long-term evolution of leachate chemistry, mineralogical transformation, and heavy metal fixation performance of a recycled roadbed material using ash from industrial waste incineration of waste tires and biomass (SFA). Additionally, field samples from a five-year pilot test site utilizing SFA were also examined. Regulatory leaching tests showed that the concentrations of Cd, Pb, As, T-Cr, and Ni were all below permissible limits even after five years of utilization. Long-term column leaching experiment results indicated that, compared to the total content of the SFA material, the leaching ratios of Pb, T-Cr, Cu, and Zn were 27%, 12%, 5%, and 0.1%, respectively. The SFA pH-stat leaching test results demonstrated that the mass release of the total content of heavy metals was relatively minimal, even under acidic pH conditions (pH < 4). Finally, profiles of pH and major ions in leachate from the column leaching experiment were simulated using HYDRUS HP1, implementing a dual-porosity modeling approach. In conclusion, despite containing hazardous heavy metals, SFA exhibits significantly low leaching rates over a long-term period.

Evaluation and scientific justification of polymer flooding application in the Uzen oilfield

The Uzen field is at the late stage of development, with an average field water cut of over 90% due to a long-term non-shale waterflooding. At the same time, the current oil saturation of the reservoir is estimated as more than 50%, which may provide a promising future for the field. According to world practice, the application of chemical enhanced oil recovery (CEOR) methods can provide high oil recovery, and extend the cost-effective life of the field. Therefore, the application of chemical enhanced oil recovery is particularly relevant considering the current status of the Uzen field. The main method of CEOR is polymer flooding (PF), which has proven its high efficiency over 60 years of application in the industry. The objective of this study is to evaluate and justify the application of the polymer flooding technology to the conditions of the Uzen field. According to this objective, first of all, the world experience of polymer flooding was studied, including the latest large-scale projects in the fields of China, the USA, Canada, India, Oman and other countries. Criteria for the effective application of polymer flooding were developed and screening of the geological and physical characteristics (GPC) of all objects of the field was carried out. In addition, facies maps and the current state of development were analyzed to select a potential pilot test site. A review of the surface facilities, an analysis of the water supply sources and the characteristics of different polymers were carried out to develop a project for the pilot test of the technology. Preliminary hydrodynamic calculations show reduced water cut, increased oil production and an increase of 7% in oil recovery. Feasibility studies prove the profitability of the polymer flooding at oil prices above $55/bbl. This study is the basis for further implementation, adaptation and optimization of polymer flooding

Application of Combined In Situ Chemical Reduction and Enhanced Bioremediation to Accelerate TCE Treatment in Groundwater

Groundwater at trichloroethylene (TCE)-contaminated sites lacks electron donors, which prolongs TCE’s natural attenuation process and delays treatment. Although adding electron donors, such as emulsified oil, accelerates TCE degradation, it also causes the accumulation of hazardous metabolites such as dichloroethylene (DCE) and vinyl chloride (VC). This study combined in situ chemical reduction using organo-iron compounds with enhanced in situ bioremediation using emulsified oil to accelerate TCE removal and minimize the accumulation of DCE and VC in groundwater. A self-made soybean oil emulsion (SOE) was used as the electron donor and was added to liquid ferrous lactate (FL), the chemical reductant. The combined in situ chemical reduction and enhanced in situ bioremediation achieved favorable results in a laboratory microcosm test and in an in situ biological field pilot test. Both tests revealed that SOE+FL accelerated TCE degradation and minimized the accumulation of DCE and VC to a greater extent than SOE alone after 160 days of observation. When FL was added in the microcosm test, the pH value decreased from 6.0 to 5.5; however, during the in situ biological pilot test, the on-site groundwater pH value did not exhibit obvious changes. Given the geology of the in situ pilot test site, the SOE+FL solution that was injected underground continued to be released for at least 90 days, suggesting that the solution’s radius of influence was at least 5 m.

Utilizing off-the-shelf LCA methods to develop a ‘triple bottom line’ auditing tool for global cataract surgical services

Cataract surgery is the most commonly performed medical procedure in the world but there continues to be a large, unmet requirement for more surgery, with cataract still accounting for one third of all global blindness. A great deal of progress has been made in increasing cataract surgical rates or productivity, and associated cost containment. However, there is currently no audit tool which facilitates capture of routine cataract surgical productivity, solid waste, carbon, and cost-related data which could be used for global benchmarking, learning, and improvement. The Eyefficiency tool, discussed here, develops a universal Life Cycle Assessment (LCA) methodology for cataract surgery to identify opportunities for sites to minimize the footprint of cataract surgical services and increase access to cataract surgery for patients worldwide.Here, we describe the LCA approaches tested for use in Eyefficiency, with the goals of creating an easy-to-use, open source tool that is also easy to maintain and update. Given those goals, the development team chose to use a hybrid LCA approach with UK-based process and environmental extended input–output inventories. The carbon results of the Eyefficiency tool are compared to previous studies at two of Eyefficiency's pilot test sites. Though Eyefficiency's carbon calculator may only provide order of magnitude accuracy, it offers cataract surgical providers everywhere in the world an opportunity to benchmark their costs, throughput, waste generation, and carbon emissions. Eyefficiency enables ground level ownership in sustainable pathways for the most common medical procedure worldwide.

Improving Earthquake Resistance of Structures by Injection Consolidation of Earth Foundations

Based on the analysis of the results of field experiments, recommendations were developed on increasing the earthquake resistance of soil foundations of buildings and structures at the Krasnobrodsky coal open-pit mine, providing conditions for an uninterrupted and safe technological process of minerals extraction and transportation. As a result of research carried out at a pilot test site by the method of seismic sounding using the refraction technique, scientific and practical results were obtained. It has been experimentally proved that compacting soils with cement-sand mortar allows us to improve their deformation properties, which leads to an increase in the earthquake resistance of structures. The seismicity of the soil foundation of the enrichment complex of inclined separation was calculated on the basis of the performed simulation of deformation processes in the consolidated foundation of the structure in a critical state. The studies have found out that when weakened soils are compacted under the supports of the galleries of the structure and after the artificial foundation has gained strength, seismicity decreased from 7 to 6 points.

Electric Safety Challenges with a Conductive Electric Road System—Chassis Potential Modeling and Measurement

Conductive Electric Road Systems (ERS) appear as a promising solution for the electrification of transportation, particularly for heavy vehicles and long-distance trips but also for light vehicles. Significant research efforts are currently devoted to the development of conductive ERS systems, with up to four pilot test sites with different technologies in operation only in Sweden. With the help of electric models and experimental measurements on a pilot test track, this article assesses the potential safety challenges associated with one aspect of this technology: the absence of a reliable protective earth connection while the vehicle is connected to the ERS power supply. The results highlight the importance of monitoring the chassis potential at all times and the need of an active safety mechanism to disconnect the vehicle from the ERS supply if a severe fault occurs.

Effect of reducing irreducible water saturation in a near-well region on CO2 injectivity and storage capacity

Fossil fuels currently supply 80% of the world’s energy demands and are primarily responsible for increasing carbon concentration in the atmosphere and the associated climate change. Achieving internationally discussed goals for reducing carbon emission will be either impossible or involve significant costs without implementing the CO2 capture and storage (CCS). The volumetric CO2-storage capacity of a brine aquifer is among the most critical factors for the economically-viable & large-scale geologic CO2-storage projects. The maximum sustainable injection rate or CO2 injectivity is another important criterion that depends on many reservoir properties. Based on previous experimental studies, we hypothesized that if the sweep efficiency of CO2 is improved by using suitable additives, then a higher end-maximum CO2 saturation can be achieved that, in turn, can increase the CO2 injectivity. In this regard, a strategy to enhance the CO2 injectivity was proposed by reducing the irreducible water saturation in a near-well region. In this study, the influence of reducing the irreducible water saturation and thus improving the relative permeability of CO2 on the CO2 injectivity and storage capacity is investigated in depth. A series of numerical simulations involving two test models – a hypothetical horizontal aquifer and a pilot test site in South Korea – were conducted to examine our assumptions with the concentration of surfactants confirmed from the previous experimental study. The results help to ascertain the applicability and effectiveness of the proposed injectivity-enhancing strategy. It was observed that the pre-injection of surfactant solution slows down the well-bottom-hole pressure and increases the total CO2 injection capacity, with the effect deemed proportional to the quantity of surfactant for a hypothetical flat aquifer. However, a nonlinear relationship between the surfactant quantity and the injectivity was found in the case of the pilot test site, which revealed that the surfactant pre-injection influences the migration of CO2-plume and solubility trapping as well.

О ходе апробации примерной адаптированной основной общеобразовательной программы дошкольного образования детей с расстройствами аутистического спектра

The article summarizes the key results of the first four months of approbation of an approximate adapted basic general educational program for preschool education of children with autism spectrum disorders: a description of the contingent of pupils, diagnostic, organizational, methodological and personnel support of organizations, which are pilot test sites.

Development of the First Co2 Storage Pilot Test for Ccs Capacity Building in South Africa – Phase I Experience

The development of carbon dioxide (CO2) storage options in South Africa is a high priority due to the country’s heavy reliance on coal as a primary energy source. The primary goal of the South African Pilot Carbon Storage Project (PCSP) is to carry out a smallscale CO2 injection, storage, and monitoring project that includes injection of 10,000 to 50,000 metric tons (MT) over a 2-year period, with monitoring activities to extend beyond injection. Battelle is providing the Project Technical Advisory Services (PTAS1) for the project, with the Phase I goal of developing the project management framework, identification of pilot test sites within the previously selected sedimentary basin (geologically termed the Zululand Basin), and screening for CO2 storage potential. The comprehensive analysis of all the existing data indicated critical data gaps. The data acquisition plan developed under PTAS1, which will be carried out in PTAS Phase 2 (PTAS2) will fill critical data gaps prior to the selection of a candidate well site for the PCSP.

Monitoring the Complete Life-cycle of a CO2 Storage Reservoir – Demonstration of Applicability of Geoelectrical Imaging

In this paper, the applicability of deep downhole geoelectrical monitoring for detecting CO2 related signatures is evaluated after a nearly ten year period of CO2 storage at the Ketzin pilot site. Deep downhole electrode arrays have been studied as part of a multi-physical monitoring concept at four CO2 pilot test sites worldwide so far. For these sites, it was considered important to implement the geoelectrical method into the measurement program of tracking the CO2 plume. Analyzing the example of the Ketzin site, it can be seen that during all phases of the CO2 storage reservoir development the resistivity measurements and their corresponding tomographic interpretation contribute in a beneficial manner to the measurement, monitoring and verification (MMV) protocol. The most important impact of a permanent electrode array is its potential as tool for estimating reservoir saturations.

Vertical and Horizontal Distribution of Bacterial Communities in Alluvial Groundwater of the Nakdong River Bank

ABSTRACTAs a collaborative effort to characterize a pilot test site for managed aquifer recharge (MAR), vertical and horizontal distributions of microbial communities in the river bank subsurface were investigated to assess the ecological effects after the operation of the MAR using the river water adjacent to the site. Along with a geochemical analysis, barcoded pyrosequencing was performed using the genomic DNAs extracted from the subsurface groundwater/sediment samples retrieved from three multilevel wells among the installed cluster of 14 boreholes. A total of 9 samples from 3 depths (10, 15–25, and 33 m below the ground surface) of each borehole showed higher bacterial abundance and diversity in the shallow (10 m) depths than in the deep (33 m) groundwater. In addition, there was a slight separation of the microbial communities between the depths based on the nonmetric multidimensional scaling analysis of the Yue and Clayton distance and the distance-weighted UniFrac analysis. The phylum Proteobacteria was dominant in all the samples at the sequence abundance of 64.0–97.8% with the total operational taxonomic units of 3375 at the species level, while among the total 288 genera, the genus Pseudomonas and an unclassified genus from Betaproteobacteria were the most abundant across the samples. The community separation between the shallow and the deep groundwater seemed to be correlated with depth differences, supported by differences in the dissolved oxygen (DO) concentration and oxidation-reduction potential (ORP). In the study site, unusually high values of electrical conductivity (EC) were found in the deep groundwater, but those values were unlikely to contribute to the community separation between the shallow and deep groundwater, unlike the DO and ORP values, which were found to influence the community differences.

The Study of Processes of Electrochemical Treatment of Soils at the Pilot Test Site

The techniques of field testing of controlled electrochemical cleaning of soil from oil pollution and the experimental setup are described. The results of engineering-geological surveys of groundmass artificially saturated with petroleum products (used oil, gasoline) are presented. The processes of formation of zones of drying, accumulation of petroleum products in electroosmotic transport, changes in the structure of soil as a result of the phase transformation and dissolution of petroleum products are shown in detail. The phenomenon was established of oil coagulation in the pores of the soil when subjected to electric treatment leading to an increase of particle size of sand and clay components of the soil and contributing to its deactivation. The efficiency of electrochemical treatment of tight sand and clay soils was proved experimentally. Experiments confirmed the effectiveness of the integrated electrophysical control of soil properties changes in the process of treatment, and in combination with the previously established correlation dependencies – the possibility of the average assessment of the contamination factor change.

Prevention of railway trespassing by automatic sound warning—A pilot study

ABSTRACTObjective: The objective of this study was to investigate the effects of a sound warning system on the frequency of trespassing at 2 pilot test sites in Finland.Methods: The effect of automatic prerecorded sound warning on the prevention of railway trespassing was evaluated based on observations at 2 test sites in Finland. At both sites an illegal footpath crossed the railway, and the average daily number of trespassers before implementation of the measures was about 18 at both sites.Results: The results showed that trespassing was reduced at these sites by 18 and 44%, respectively. Because of the lack of proper control sites, it is possible that the real effects of the measure are somewhat smaller.Conclusions: The current study concludes that automatic sound warning may be efficient and cost effective at locations where fencing is not a viable option. However, it is not likely to be a cost-effective panacea for all kinds of sites where trespassing occurs, especially in countries like Finland where trespassing is scattered along the railway network rather than concentrated to a limited number of sites.

Comprehensive Observations of Resident Evolution: A Novel Method for Assessing Procedure-Based Residency Training.

Assessment of surgical skills in the operating room remains a challenge. Increasing documentation requirements of the Accreditation Council for Graduate Medical Education are necessitating mechanisms to document trainee competence without hindering operative turnover. The authors created a comprehensive electronic resource to facilitate plastic surgery training program compliance with changes mandated by Next Accreditation System Milestones and the ACGME. In 2013, the authors implemented the Comprehensive Observations of Resident Evolution, or CORE, a Web-based tool to assess plastic surgery residents. It comprises a rapid electronic assessment of resident operating room performance completed after each surgery; a data dashboard displaying graphical summaries of resident progress by case, Milestone, or current procedural terminology code; and an electronic Milestones tracker (MileMarker), which enables ongoing trainee assessments. From January through October of 2014, 24 residents completed nearly 1300 Operative Entrustability Assessments. Thirty-eight percent of residents reported more immediate feedback regarding operative performance. The assessment demonstrates construct validity, which distinguishes novice residents from experienced residents. Individual case data identify resident-specific operative strengths and weaknesses. Using assessment data, the first two Clinical Competency Committee reviews were 81 percent and 87 percent shorter than Milestones pilot test site reports (average, 11.5 and 8 minutes versus 60 minutes per resident, respectively). Comprehensive Observations of Resident Evolution is capable of capturing operative performance data on all operating room cases by primary current procedural terminology code. It increases immediate attending/trainee feedback and assessment transparency, enables trainee self-monitoring, and informs end-of-rotation reviews, programwide assessments, and tailoring of training to address specific needs. It is a valuable resource for tracking resident progress in real-time while maintaining compliance with evolving ACGME requirements.

Rational regional distribution of sugarcane cultivars in China.

Knowing yield potential and yield stability of sugarcane cultivars is of significance in guiding sugarcane breeding and rationalising regional distribution of sugarcane cultivars. In the present study, a heritability-adjusted genotype main effect plus genotype × environment (HA-GGE) biplot program was used to analyze the cane and sucrose yields of 44 newly released sugarcane cultivars at eight pilot test sites. The cane and sucrose yields of nine cultivars were higher than those of the control cultivar ROC22. From the perspective of cane yield, cultivars FN 40 and YZ 06–407 were well adapted to a wider range of conditions and produced relatively high cane yields in several pilot sites. From the perspective of sucrose yield, cultivars LC 03–1137, FN 38, FN 41, MT 01–77 and LC 05–136 were well adapted to a wide range of conditions and produced relatively high sucrose yields. Based on these results, three high yielding and widely adapted cultivars, namely, FN 39, LC 05–136, and YZ 05–51 were recommended for production in three major Chinese sugarcane planting areas. The results will provide a theoretical basis for recommending the effective use and rational regional distribution of sugarcane cultivars in China.

Using stable carbon isotopes to track potential leakage of carbon dioxide: Example from an enhanced coal bed methane recovery site in West Virginia, USA

Produced natural gas, shallow groundwater, and soil vadose gas samples were collected at the CONSOL Energy Inc. CO2 Sequestration Pilot Test Site in Marshall County, WV to test the feasibility of using carbon isotope signatures to detect potential leakage of CO2. CO2 was injected into the Upper Freeport coal bed at a depth of ∼396m intermittently from September 2009 to December 2013. Water and gas samples were collected over a 12-month period (August 2013–August 2014). The injected CO2 had δ13C values ranging from −12.0‰ to −11.0‰ V-PDB. The average δ13CCO2 values of the soil vadose gas, the groundwater, and the produced CO2 from overlying Pittsburgh coal bed were −25.0‰, −16.6‰ and +22.8‰ V-PDB, respectively. These distinct carbon isotope signatures allow us to use δ13C as a natural tracer to detect any potential leakage from the injected coal bed into the overlying monitored zones. In September 2013, the monitored downstream production well in Upper Freeport showed presence of injected CO2 indicating injected CO2 plume had migrated in the coal bed over the entire study area. However, the carbon isotope values observed in the overlying formations indicate no significant leakage of injected CO2 from the underlying Upper Freeport coal bed.

화강풍화암에 시공된 부분현장타설말뚝의 IGM이론의 적용성

본 연구에서는 IGM 구간에서 주면마찰력을 활용하여 지지력을 확보하기 위해 선단부에만 부분적으로 현장타설말뚝을 시험시공하고 IGM 이론의 적용성을 분석하였다. 시험시공 현장의 지반조사와, 교란여부, 거칠기 상태를 측정하여 IGM 이론 적용을 위한 지반특성을 점성, 비교란, 매끄러운 상태로 분석하였다. 또한, 정재하시험 및 하중전이시험을 통해 허용지지력과 심도별 주면마찰력을 산정한 결과, 주면마찰력은 심도가 깊어질수록, 기준침하량이 클수록 증가하는 것으로 평가되었으며, 심도와 매우 높은 상관성을 보였다. 일축압축강도(<TEX>$q_u$</TEX>)는 점성 IGM에서 가장 중요한 변수이나, 화강풍화암 구간에서 직접 측정이 불가능하므로 정재하시험 및 하중전이시험 결과와 N값을 이용하여 <TEX>$q_u$</TEX>값을 얻을 수 있었다. In this study, partial drilled shafts (Bottom Cast-in-place Concrete pile) were applied to the pilot test site to ensure the bearing capacity; we used the skin friction force in the IGM to analyze the feasibility of the application of IGM theory. The soil characteristics were analyzed in cohesive, non-smear, and smooth conditions for the application of the IGM theory via geotechnical investigation and measurement of the disturbance and surface roughness. Static load and load transfer tests were conducted to calculate the allowable bearing capacity and the skin friction force by depth. The skin friction force increased with increase in the depth and standard settlement, showing a very high correlation. In addition, because the unconfined strength (<TEX>$q_u$</TEX>), which is the most important parameter in the cohesive IGM, cannot be measured in a weathered granite area, the static load and load transfer test results and the N value were used to obtain <TEX>$q_u$</TEX>.

지오셀 보강 친환경성 투수성포장의 현장 적용성 검토

도시화에 따른 포장도로의 증가는 불투수성 면적의 증가를 가져왔다. 자연과 다른 도시 환경은 물순환 시스템의 문제로 나타나며, 이로 인하여 도시형 수해 등과 같은 환경 문제가 발생하고 있다. 본 연구에서는 이러한 문제를 해결하기 위해 친환경형 투수성포장의 현장 적용성을 검토하였다. 투수성포장의 지지력 확보를 위해 지오셀 보강공법을 적용하였으며, 시험포장을 통해 현장 적용성을 평가하였다. 또한, 현장 포장 상태조사를 통하여 공용성능 및 내구성을 분석하였다. FWD 측정결과 지오셀로 보강한 투수성포장은 강우 모사 후에도 밀입도 포장과 유사한 지지력을 확보할 수 있었으며, 또한 투수성포장은 기타 도시환경을 개선 할 수 있는 것으로 나타났다. Increase of paved areas due to urbanism resulted in a rapid increase of impermeable areas. As a result, it caused urban types of frequent floods and water circulation problems. The main objective of the research is to suggest a solution for these typical urban problems. Geocell reinforcement was adopted to improve the bearing capacity in permeable pavements. In this research, a pilot test site was operated to verify the field applications of environment-friendly permeable pavements. In addition, a pavement condition survey was conducted to investigate the performance and durability of the pavements. FWD test results showed that the geocell reinforced permeable pavement was able to get the bearing capacity similar to dense graded pavement. Test results revealed that the environment-friendly permeable concrete pavement could reduce the environmental problems in urban areas.

Atmospheric and soil-gas monitoring for surface leakage at the San Juan Basin CO2 pilot test site at Pump Canyon New Mexico, using perfluorocarbon tracers, CO2 soil-gas flux and soil-gas hydrocarbons

Near-surface monitoring and subsurface characterization activities were undertaken in collaboration with the Southwest Regional Carbon Sequestration Partnership on their San Juan Basin coal-bed methane pilot test site near Navajo City, New Mexico. Nearly 18,407 short tons (1.670×107kg) of CO2 were injected into 3 seams of the Fruitland coal between July 2008 and April 2009. Between September 18 and October 30, 2008, two additions of approximately 20L each of perfluorocarbon (PFC) tracers were mixed with the CO2 at the injection wellhead. PFC tracers in soil-gas and in the atmosphere were monitored over a period of 2 years using a rectangular array of permanent installations. Additional monitors were placed near existing well bores and at other locations of potential leakage identified during the pre-injection site survey. Monitoring was conducted using sorbent containing tubes to collect any released PFC tracer from soil-gas or the atmosphere. Near-surface monitoring activities also included CO2 surface flux and carbon isotopes, soil-gas hydrocarbon levels, and electrical conductivity in the soil. The value of the PFC tracers was demonstrated when a significant leakage event was detected near an offset production well. Subsurface characterization activities, including 3D seismic interpretation and attribute analysis, were conducted to evaluate reservoir integrity and the potential that leakage of injected CO2 might occur. Leakage from the injection reservoir was not detected. PFC tracers made breakthroughs at 2 of 3 offset wells which were not otherwise directly observable in produced gases containing 20–30% CO2. These results have aided reservoir geophysical and simulation investigations to track the underground movement of CO2. 3D seismic analysis provided a possible interpretation for the order of appearance of tracers at production wells.

Multi-phase Equilibrium in a CO2-filled Observation Well at the Ketzin Pilot Site

As part of the Ketzin pilot test site, carbon dioxide (CO2) has been injected into a saline formation around 650 m deep since June 2008. Analysis of measured well temperature and pressure data at two observation wells after the arrival of CO2 has shown that two-phase fluid conditions are prevailing in the upper 400 m of the wells. This significantly hampers the ability to accurately describe the density – and temperature – profile of a well, which is essential to predict the relationship between well-head and reservoir pressure. The pressure and temperature profile depends crucially on the depth of the liquid CO2 free surface, which can be obtained by wrapping a radial temperature simulator in an optimization algorithm that imposes closure of the heat transport at the well scale. Vertical heat transport, necessary for balancing the heat in- and outflow, relies on the upward movement of CO2 vapor bubbles in the liquid-dominated zone and by a descending liquid CO2 film in the upper vapor-dominated zone. A vertical bubble velocity of around 45 mm/s was derived from heat balance and confirmed by camera inspection movie. Temperature and pressure profiles also showed that Ktzi 200 acted as a distillation column: the injected CO2 (with purity >99.9%), picked up water during the residence in the storage horizon. The extremely accurate equation of state for CO2 can accurately predict fluid properties in the two-phase zone and reveals that both light and heavy components in the gas entering the well are not present in the two-phase zone. This, together with an analysis of the thermodynamic behavior of the gas mixture suggests that a distillation process purified CO2, at least in the upper part of the well.