Leaks In Underground Storage Tanks Research Articles

Comparative Study of Injection Systems in Vapor Phase in the Remediation of Soils Contaminated by Diesel

Gasoline and diesel leaks in underground storage tanks contaminate soils with petroleum hydrocarbons. Various techniques using surfactants have been proposed to remedy this type of contamination. This study presents the application of different systems containing surfactants in vapor phase. It compares the removal efficiencies of diesel contaminated soils using vapor injection systems: surfactant water solutions, micro-emulsions, and nano-emulsions. The surfactant used in the experiments was ethoxylated alcohol UNTL-90 in aqueous solution, in nano-emulsion, and micro-emulsion systems. Among the systems investigated, the nano-emulsion showed the highest removal efficiency (88%), being environmentally friendly and technically feasible with a system that has a lower content of active matter.

Numerical Simulation and Influencing Factors Analysis of the Leakage and infiltration diffusion for Fuel Underground Storage Tank

Mass and heat transfer processes of three fuels commonly used (Liquefied Petroleum Gas (LPG), gasoline, diesel oil) flow dispersing in underground environment for the leak at different zones of underground storage tank (UST) were studied. On the basis of the mass and heat transfer process analysis and employing the three-dimensional multiphase mixture flow model, the migration processes of LPG, gasoline, diesel oil in tank pond for UST leak were simulated. The velocity, density, concentration, pressure, temperature fields can be obtained. From the simulation results, the detailed analysis were performed to investigate the characteristics of the three fuels infiltration flow processes and the effects of various influencing factors on infiltration flow such as storage pressure, fuel composition, leak position of tank, position of outlet, gravity, viscous force, etc.

Hybrid Technologies for the Remediation of Diesel Fuel Polluted Soil

AbstractDiesel fuel may be released into soil due to anthropogenic activities, such as accidental spills or leaks in underground storage tanks or pipelines. Since diesel fuel is mainly composed of hydrophobic organic compounds, it has low water solubility. Therefore, treating contaminated areas with conventional techniques is difficult. In this study, electrokinetic treatment of soil contaminated with diesel fuel was carried out. Two different hybrid approaches to pollutant removal were tested. A surfactant was used as a processing fluid during electrokinetic treatment to increase desorption and the solubility of diesel fuel. Additionally, a hybrid technology combining a Fenton reaction and electrokinetic remediation (EK‐Fenton) was tested in an attempt to generate favorable in situ degradation of pollutants. The efficiency of each treatment was determined based on diesel fuel removal. After 30 days of treatment, the highest removal of diesel fuel was found to be achieved with the EK‐Fenton process.

Bayesian credible intervals for monitoring liquid blending rates

We consider the problem of constructing confidence interval s (CIs) for the blending coefficient of different liquid, suc h as the blended underground storage tank (UST) leak data for compliance. For this problem, confidence intervals based on F ieller's Method have been proposed. This method utilizes a blending coefficient estimator which is a ratio of two correlated norma l random variables. However, this method assumes normally distributed random errors in the UST leak model and therefore may be inappropriate for the UST leak data which typically have heavy-tailed empirical distributions. In this paper we develo p a Bayesian approach assuming non-normal random errors with the Power Exponential Distribution (PED). A real-data example using Cary blended site data is given to illustrate both the Fieller's C Is and the Bayesian credible intervals. Monte Carlo simulations are conducted to compare the coverage probability and average width of CIs for both methods. For data with heavy-tailed distributions, the simulations show that both Fieller's an d Bayesian intervals perform adequately in terms of coverage. However, Bayesian intervals perform better in terms of yielding CIs with shorter expected width.

Using statistical models to detect leaks in underground storage tanks

Using statistical models to detect leaks in underground storage tanks

Using statistical models to detect leaks in underground storage tanks

In modern service stations, intermediate grades of gasoline are formed by blending different volumes of unleaded and super unleaded gasolines stored in underground storage tanks. The volumes displaced from these coupled tanks can be modeled in a two-dimensional model as a function of the volumes dispensed through the flow meters located at the pumps (or positive flow displacement meters). The intercepts in these models represent the sizes of leaks in the respective underground storage tanks. Inferences on the vector of intercepts are discussed based on a regression model, a measurement-error model and a sequential model. In the last model, bivariate control charts are used to monitor the leak status of the tanks. Copyright © 2000 John Wiley & Sons, Ltd.

Electrical Impedance Tomography

t. This paper surveys some of the work our group has done in electrical impedance tomography.

Detection of Leaks in Underground Storage Tanks Using Electrical Resistance Methods

Two field experiments were performed to evaluate the performance of electrical resistance tomography (ERT) as a leak detection method under metal underground storage tanks (UST). This document provides a summary of field experiment results performed under a 15 m diameter steel tank mockup located at the Hanford Reservation, Washington, and of supporting numerical simulations. Two different leak events were created. About 3800 liters of saline solution were first released along a portion of the tank's edge and another 1900 liters were later released near the tank's center. The release rate averaged about 26 liters/hour for the leak on the tank's side and about 3.0 liters/hour for the center leak. Two‐ and three‐dimensional tomographs were calculated using data collected before, during and after each spill. The tomographs mapped the spatial and temporal evolution of resistivity changes caused by the leak; as the solution penetrated the soil, readily detectable resistivity decreases were observed and used to...

Capture Zone Theory in the Recovery of a Free Product Plume Resulting from an Underground Storage Tank Leak: ABSTRACT

Capture zone theory has been used to recover a combined free product and dissolved hydrocarbon plume from the subsurface resulting from an underground storage tank leak in an urban area. Results of hydrostratigraphic mapping demonstrate that product lost into the subsurface was trapped in sand and gravel materials in a meander bend associated with a glacial outwash channel. Approximately 20,000 gal of gasoline and diesel fuel were lost to the subsurface. The vertical and horizontal extent of the free-product plume was mapped based on the observed oil saturated thickness in soil samples. The mapping indicated that the plume was wedge shaped, with a maximum thickness of free product in soil of 3.5 ft. Hydraulic data from pump tests and slug tests indicate that product migrated into permeable sediments associated with a member bend. Low-permeability silt and clay materials surrounding the meander bend acted as a barrier preventing migration of the plume off-site. The ARMOS model and the CAPZONE model were used to determine the optimum location of product recovery wells and to evaluate the effect of boundary conditions on the safe yield of the outwash channel so that hydrocarbon recovery could be optimized over time.

Laboratory Demonstration of Hydrocarbon Migration in the Vadose Zone: Effectiveness of the U‐Tube Design for Underground Storage Tank Leak Detection Monitoring

AbstractThe experimental results derived from a laboratory model of gasoline migration from a simulated leaking underground storage tank (UST) demonstrate that the direction of migration through the simulated fill material is essentially straight down. Consequently, the U‐tube design for leak detection monitoring of USTs has limited utility because that design relies on the assumption that the path of migration of the leaked fluids will follow the surface of the tank to the bottom and be intercepted by the U‐tube below.

Evaluation of volumetric leak detection methods used in underground storage tanks

In the spring and summer of 1987, the United States Environmental Protection Agency (EPA) evaluated the performance of 25 commercially available volumetric test methods for the detection of small leaks in underground storage tanks containing gasoline. Performance was estimated by means of an experimentally validated performance simulation. The simulation used (1) experimentally validated models of the important sources of ambient noise that control the performance of these methods, (2) a large database of product-temperature changes that result from the delivery of product at a temperature different from that of the product in the tank, and (3) a mathematical model of each test method to estimate the performance of that method. A major objective of this program was to quantify experimentally the major sources of ambient noise. This paper describes the results of these experiments and presents performance estimates for generic testing methods, which are typical of the methods evaluated, to illustrate the effect of these sources of ambient noise on performance. The experiments were performed at the EPA Risk Reduction Engineering Laboratory's Underground Storage Tank Test Apparatus in Edison, New Jersey.

4709577 System for continuously monitoring for leaks in underground storage tanks : Glenn M Thompson assigned to Tracer Research Corporation

4709577 System for continuously monitoring for leaks in underground storage tanks : Glenn M Thompson assigned to Tracer Research Corporation

System for continuously monitoring for leaks in underground storage tanks : Glenn M Thompson assigned to Tracer Research Corporation

System for continuously monitoring for leaks in underground storage tanks : Glenn M Thompson assigned to Tracer Research Corporation

UNDERGROUND STORAGE TANK CORRECTIVE ACTION TECHNOLOGIES

ABSTRACT Of the estimated 1.4 million underground petroleum and chemical storage tanks in the United States, between 100,000 and 400,000 may leak. The average cleanup cost is estimated by industry sources at $70,000, but corrective action may cost more than $1 million if water supplies are affected. Leaks can occur for several reasons, the most common of which is corrosion of the tank or associated piping systems. To detect leaks, a tank monitoring program can use any of four methods: (1) volumetric (quantitative) leak testing; (2) qualitative leak testing; (3) inventory controls; and (4) environmental effects monitoring, in which wells outside the tank are tested. Response to an underground storage tank leak takes two forms: the initial response to control immediate impacts, and permanent corrective measures. To be effective, the initial response technologies should be in place within hours of the discovered release. Such action usually consists of removing any remaining product in the tank and minimizing immediate risk to public health and the environment. Permanent corrective action focuses on site characterization and assessment to determine the need for further action, on calculation of transport rates, on assessment of the hazard to the environment and public, and on collection of data for selecting and designing further corrective actions.