Underground Storage Tanks Research Articles

Divergent dual C-H isotopic fractionation pattern during anaerobic biodegradation of toluene within Aromatoleum species under nitrate-reducing conditions

Toluene is a pollutant frequently detected in contaminated groundwater, mostly due to leakage from underground gasoline storage tanks and pipeline ruptures. Multi-element compound-specific isotope analysis provides a framework to understand transformation processes and design efficient remediation strategies. In this study, we enriched an anaerobic bacterial culture derived from a BTEX-contaminated aquifer that couples toluene and phenol oxidation with nitrate reduction and the concomitant production of carbon dioxide and biomass. The 16S rRNA gene amplicon data indicated that the toluene-degrading consortium was dominated by an Aromatoleum population (87 ± 2 % relative abundance), and metagenome sequencing confirmed that the genome of this Aromatoleum sp. encoded glycyl-radical enzyme benzylsuccinate synthase (BssABC) and phenylphospate synthase (PpsA1BC) homologous genes involved in the first step of toluene and phenol transformation, respectively. Carbon and hydrogen isotopic fractionation were εbulk, C = - 3.5 ± 0.6 ‰ and εrp, H = - 85 ± 11 ‰, respectively, leading to a dual C-H isotope slope of ΛH/C = 26 ± 2. This value fits with a previously reported value for a consortium dominated by an Azoarcus species (ΛH/C = 19 ± 5) but differs from that reported for Aromatoleum aromaticum (ΛH/C = 14 ± 1), both of which grow with toluene under nitrate-reducing conditions. Overall, this suggests the existence of different BssABC enzymes with different mechanistic motifs even within the same Aromatoleum genus.

Mitigation of ammonia and methane emissions with manure amendments during storage of cattle slurry.

This study aimed at assessing the efficacy of manure amendments in abating ammonia (NH3) and methane (CH4) emissions during storage. Two experiments were carried out. Experiment 1 was conducted using 20 L of slurry for 98 days. Treatments were: aluminium sulphate (alum), lactogypsum, zeolite, actiglene, ammonium thiosulphate, biochar, dairy processing waste, Digest-IT and control (without amendment). Experiment 2 was conducted using 660 L of slurry in underground storage tanks for 77 days. Treatments were: sulphuric acid, gypsum, biochar and control (without amendment). NH3 measurements for experiment 1 and experiment 2 were conducted using the photoacoustic gas monitor and dynamic chamber techniques, respectively. CH4 was measured using the static chamber technique in both experiments. The effect of amendments on slurry composition was determined at the end of the experiments. Experiment 1 showed a significant reduction in NH3 emissions in the alum (82%), lactogypsum (46%) and zeolite (32%) treatments relative to the control (100.3% total ammoniacal nitrogen (TAN)). CH4 was reduced significantly in the alum (87%), ammonium thiosulphate (64%) and lactogypsum (67%) relative to the control (291.9 g m-2). Experiment 2 showed a significant reduction (32%) in NH3 emissions in the sulphuric acid relative to the control (4.4% TAN). CH4 was reduced significantly in the sulphuric acid (46%), gypsum (39%) and biochar (15%) treatments relative to the control (291.9 g m-2). In general, amendments altered slurry composition such as dry matter, volatile solids, carbon and nitrogen contents at the end of storage. Lactogypsum, alum and sulphuric acid were effective in abating both NH3 and CH4 emissions and can contribute to improving air quality.

Field performance of 15 rain gardens in different cities in Taiwan

Rain gardens are widely used for low impact development (LID) or as a nature-based solution (NbS). They help to reduce runoff, mitigate hot temperatures, create habitats for plants and insects, and beautify landscapes. Rain gardens are increasingly being established in urban areas. In Taiwan, the Ministry of Environment (MoE) initiated a rain garden project in Taipei city in 2018, and 15 rain gardens have since been constructed in different cities. These Taiwanese-style rain gardens contain an underground storage tank to collect the filtrated rainwater, which can be used for irrigation. Moreover, the 15 rain gardens are equipped with sensors to monitor temperature, rainfall, and underground water levels. The monitoring data were transmitted with Internet of Things (IoT) technology, enabling the capture and export of real-time values. The water retention, temperature mitigation, water quality, and ecological indices of the rain gardens were quantified using field data. The results from the young rain gardens (1–3 years) showed that nearly 100 % of the rainfall was retained onsite and did not flow out from the rain gardens; however, if the stored water was not used and the tanks were full, the rainwater from subsequent storms could not be stored, and the tanks overflowed. The surface temperatures of the rain garden and nearby impermeable pavement differed by an average of 2–4 °C. This difference exceeded 20 °C in summer at noon. The water in the underground storage tanks had very low levels of SS and BOD, with averages of 1.6 mg/L and 5.6 mg/L, respectively. However, the E. coli concentrations were high, and the average was 6283 CFU/100 mL; therefore, washing or drinking water is not recommended. The ecological indices, i.e., the Shannon and Simpson indices, demonstrated the good flora status of the rain gardens after one year. Although the weather differed by city, the performance of the rain gardens in terms of water retention, temperature mitigation, rainwater harvesting, and providing biological habitats was consistent. However, maintenance influences rain garden performance. If the stored water is not frequently used, the stored volume is reduced, and the stored water quality degrades.

Fluid-Solid-Thermal Coupled Freezing Modeling Test of Soil under the Low-Temperature Condition of LNG Storage Tank

Due to the extensive utilization of liquid nature gas (abbreviated as LNG) resources and a multitude of considerations, LNG storage tanks are gradually transitioning towards smaller footprints and heightened safety standards. Consequently, underground LNG storage tanks are being designed and constructed. However, underground LNG storage tanks release a considerable quantity of cold into the ground under both accidental and normal conditions. The influence of cold results in the ground freezing, which further compromises the safety of the structure. Existing research has neglected to consider the effects of this. This oversight could potentially lead to serious safety accidents. In this work, a complete set of experiments using a novel LNG underground storage tank fluid-solid-thermal coupled cryogenic leakage scale model were conducted for the first time to simulate the effect of the tank on the soil temperature field, stress field, and displacement field and to analyze the development of the three fields and the results of the effect. This research helps the related personnel to better design, construct, and evaluate the LNG underground storage tanks to avoid the catastrophic engineering risks associated with cryogenic leakage and helps to improve the design process of LNG underground storage tanks.

Full‐scale experimental and theoretical investigation on wall stress for underground ecological group tanks with four‐circle tangential connections

SummaryThe storage safety of edible oil is critical for global and Chinese food security. In this study, a practical underground four‐circle tangential group tank with the steel‐plate and concrete structure based on a grain storage warehouse was firstly introduced, and the measured hoop reinforcement stress of the outer tank wall is discussed. Secondly, a numerical model consistent with the practical underground group tank is established from the measured data. The distribution of the hoop reinforcement stress of the outer tank wall under earth pressure is extracted and analyzed thoroughly. Finally, formulas reflecting the properties of the hoop reinforcement stress distribution are presented based on the theoretical analysis, and their accuracy is verified by comparison with the measured data. It could be conducted from the experimental results and theoretical formulas that the outer tank wall is under compressive pressure station generally, and the compressive stress increases with the increasing of the ring angle until reaching a steady state. Moreover, the hoop stress curve follows a disproportional function approximately. The moment at 180° hoop with 1‐m plate belt follows the arc‐tangent function while the moment has a sudden‐change point at 120°, which has minor effect on the reinforcement of this tank wall. Consequently, additional attention should be paid to the effects of this sudden‐change phenomenon on the associated structures in in the process of designing of underground storage tanks.

Microbial community response to hydrocarbon exposure in iron oxide mats: an environmental study.

Hydrocarbon pollution is a widespread issue in both groundwater and surface-water systems; however, research on remediation at the interface of these two systems is limited. This interface is the oxic-anoxic boundary, where hydrocarbon pollutant from contaminated groundwaters flows into surface waters and iron mats are formed by microaerophilic iron-oxidizing bacteria. Iron mats are highly chemically adsorptive and host a diverse community of microbes. To elucidate the effect of hydrocarbon exposure on iron mat geochemistry and microbial community structure and function, we sampled iron mats both upstream and downstream from a leaking underground storage tank. Hydrocarbon-exposed iron mats had significantly higher concentrations of oxidized iron and significantly lower dissolved organic carbon and total dissolved phosphate than unexposed iron mats. A strong negative correlation between dissolved phosphate and benzene was observed in the hydrocarbon-exposed iron mats and water samples. There were positive correlations between iron and other hydrocarbons with benzene in the hydrocarbon-exposed iron mats, which was unique from water samples. The hydrocarbon-exposed iron mats represented two types, flocculent and seep, which had significantly different concentrations of iron, hydrocarbons, and phosphate, indicating that iron mat is also an important context in studies of freshwater mats. Using constrained ordination, we found the best predictors for community structure to be dissolved oxygen, pH, and benzene. Alpha diversity and evenness were significantly lower in hydrocarbon-exposed iron mats than unexposed mats. Using 16S rDNA amplicon sequences, we found evidence of three putative nitrate-reducing iron-oxidizing taxa in microaerophile-dominated iron mats (Azospira, Paracoccus, and Thermomonas). 16S rDNA amplicons also indicated the presence of taxa that are associated with hydrocarbon degradation. Benzene remediation-associated genes were found using metagenomic analysis both in exposed and unexposed iron mats. Furthermore, the results indicated that season (summer vs. spring) exacerbates the negative effect of hydrocarbon exposure on community diversity and evenness and led to the increased abundance of numerous OTUs. This study represents the first of its kind to attempt to understand how contaminant exposure, specifically hydrocarbons, influences the geochemistry and microbial community of freshwater iron mats and further develops our understanding of hydrocarbon remediation at the land-water interface.

Evaluating Environmental Justice and Public Housing in a Data-Rich Era

We examined the spatial concentration of public housing, demographic indicators of low socioeconomic status, and environmental locally unwanted land uses (LULUs) in eight populous U.S. cities. Using the updated EJScreen database and its geographic information systems capabilities, we, as expected, found subsidized housing to be disproportionately colocated in areas with poor and underserved residents. Underground storage tanks and high traffic density were consistently associated with the location of public housing, whereas Superfund sites were located near public housing in only half of the cities in the study. Increasing our understanding of the variables typically used to measure environmental and social justice is important to expand the discussion around a broader set of environmental measures that might be more relevant to the communities that live near them without ignoring the traditional ones that have marked the early legacy of the environmental justice movement.

Underground Storage Tanks: A Review of an Unseen Aging Infrastructure

Underground storage tanks (USTs) are a critical infrastructure for the storage of petroleum and other hazardous substances. As with much of the nationwide infrastructure, USTs are aging beyond their intended lifetime. In 1985, the average age of a UST removed for replacement or closeout was 17 y old; USTs removed today are on average 33 y old. Corrosion in UST systems can lead to tank failure resulting in leaks that can contaminate soil and groundwater and also result in vapor intrusion in nearby buildings. Presently, there are approximately 65,000 leaking USTs in the United States With increased flooding, both inland and coastal, there is greater potential for accelerated corrosion, where there are approximately 33,000 USTs within Federal Emergency Management Agency’s 100 y floodplain. With changes in the fuel supply through the introduction of alternative fuels, unintended consequences to fuel storage and delivery infrastructure have been observed. Biofouling and corrosion can be exacerbated by adding relatively small volumes of alternative fuels. The current standards for monitoring the potential leakage events of USTs are wholly inadequate in terms of predictive capabilities. In this present work, the past, current, and future of UST infrastructure are detailed. The materials used in the construction of the USTs including plastics and steels are reviewed as well as their compatibilities with the current and future fuels. A geospatial database application developed by the Environmental Protection Agency is highlighted for insights into correlations between UST data (e.g., age, type, location, and fuel) and natural disasters (e.g., flooding, fires) to identify potentially vulnerable systems.

Long-Term Performance of Reference Electrodes in Alkaline Radioactive Waste Storage Environments

Accurate measurements of corrosion potential are important for assessing the likelihood of internal localized corrosion and stress corrosion cracking of carbon steel tanks used for storing radioactive wastes. Reference electrodes in underground radioactive waste storage tanks are challenging to deploy, and more difficult to extract and replace frequently due to radiological exposure and disposal constraints. Hence, electrodes that exhibit stable performance over long periods of immersion in these waste environments are desirable. The present study evaluates the stability of reference electrodes used in radioactive waste storage tanks over a much longer period than previously studied. Long-term tests on Ag/AgCl and Hg/HgO reference electrodes were performed in nonradioactive simulants formulated from wastes stored at the Hanford site. Electrode degradation, which was studied by various in situ and ex situ evaluation techniques, was correlated to changes in electrode fill chemistry from waste intrusion via the porous frit junction. An intentional contamination study was performed to better understand and predict contamination effects on electrode potential drift.

Camp Lejeune Marine Cancer Risk Assessment for Exposure to Contaminated Drinking Water From 1955 to 1987

This study utilizes guidance from the United States Environmental Protection Agency (USEPA) and the Agency for Toxic Substances and Disease Registry (ATSDR) to calculate the cancer risk to United States Marines who were exposed to carcinogens in drinking water at Marine Corps Base Camp Lejeune. Camp Lejeune is a 233-square-mile Marine Corps training facility in North Carolina. From 1953 to 1987, nearby dry cleaners, landfills, and underground storage tanks contaminated drinking water systems that served Camp Lejeune (ATSDR, 2017). Some of the most toxic contaminants found in the drinking water modeled by ATSDR include benzene, tetrachloroethylene (PCE), trichloroethylene (TCE), trans-1,2-dichloroethylene (DCE), and vinyl chloride (VC). ATSDR utilized MODFLOW and EPANET modeling software to determine the level of contamination in the three main drinking water systems at Camp Lejeune: Tarawa Terrace, Holcomb Boulevard, and Hadnot Point. This paper presents an application of methodology to quantify cancer risk for the Marines who lived and served at Camp Lejeune from 1953 to 1987 using ATSDR’s health assessment, chemical contaminant modeling, and USEPA methodology. While VC and TCE were found to be the main risk drivers, benzene and PCE also contributed to the cumulative cancer risk. This analysis shows (1) That the cancer risk was greatest during the 1970s and 1980s and (2) that the inhalation exposure pathway had the greatest contribution to overall cancer risk followed by ingestion, with the smallest contribution from dermal absorption.

A study on the materials of smart barrier for selectively blocked TCE and TPH

Many barrier materials are used around industries, construction areas, livestock dump sites, waste landfills, and underground oil storage tanks. In the case of barriers, even if there is no inflow of contaminants, they do not provide selective permeability, develop water barrier properties, and hinder groundwater flow when contaminants encounter groundwater. Recently, contaminated sites that are difficult to resolve with current purification technologies continue to emerge. Pollutants flow into groundwater through the advection and diffusion by leaking. The pollutants introduced in this way cause pollution to the surrounding environment, and various types of severe underground environmental pollution problems occur depending on the type of pollutants leaked. Therefore, using a material that has the property of adsorbing organic contaminants and gelling them is harmless to the environment by penetrating groundwater under normal conditions. It has the property of selectively adsorbing the pollutant and gelling it upon contact with it underground. Therefore, the authors aim to study the applicability of polynorbornene and polyolefin as components of smart barrier materials that make barrier materials impermeable through the adsorption of pollutants, swelling, and coagulation behavior in this study. The components of smart barrier materials include Ottawa sand, organo-bentonite, polynorbornene, and polyolefin. Polynorbornene and polyolefin adsorb only organic pollutants selectively. Before applying polynorbornene and polyolefin to the barrier material, TCLP was performed to evaluate environmental hazards. As a result of heavy metal analysis, it was determined that there was no environmental hazard. The pH results are 7.27 for polynorbornene and 7.31 for polyolefin, indicating that both materials are slightly alkaline. In addition, as a result of testing with TCE (stock solution) and TPH (diesel crude oil) to confirm the swelling effect when in contact with organic pollutants, the efficiency of pollutant adsorption and swelling was found to be high when the ratio of polynorbornene: polyolefin = 6:4. Therefore, when using the material used in this study, it is expected that it can be applied as a component of a smart barrier material that selectively blocks pollutants.

Cathodic protection systems: approaches and open challenges

Cathodic Protection System (CPS) is used on a variety of structures to prevent corrosion in ship hulls, pipelines, and underground storage tanks. Transmission pipelines extend over wide distances that may extend for hundreds of kilometers, the problem of corrosion exists in pipelines transporting liquids such as oil, petroleum or water, as well as in pipelines transporting gases. Corrosion leads to leakage into the surrounding environment, causing pollution. Artificial intelligence (AI) is used in risk management to determine the possibility of corrosion growth rates, considering all the determinants and factors that contribute to corrosion, including alternating currents, soil properties, environmental conditions, and geographical features. According to research, there are two ways to enhance the performance of cathodic protection systems: one is to design cathodic protection in unconventional ways based on different algorithms and methods that show superiority over the traditional method in determining the number and location of anodes, and the other is to continuously monitor the environmental conditions surrounding the structure to be protected, which includes soil and weather. A study will be conducted to determine the most effective factors in protecting the pipelines and other factors to determine the required energy in an efficient method.

Impact Assessment of Petrol Filling Stations on Groundwater Quality in Akure Metropolis, Ondo State

Abstract: The presence of PFSs in urban areas has increased significantly, leading to conflicts with existing land use planning and violations of the minimum environmental safety requirements set by the Department of Petroleum Resources (DPR) and have adverse social and environmental impacts despite their socioeconimic importance. This paper aim to investigate the spatial distribution of petrol filling stations and their impact on groundwater quality in Akure Metropolis of Ondo State. A total of 147 PFSs and 140 water wells were identified and recorded. Laboratory analysis was done purposefully on wells near PFSs that were both 26 years or older and still functional, as older underground storage tanks (USTs) pose a potential threat to groundwater safety. Findings revealed 119 functional filling stations, 28% located within residential area and 68% domiciled in commercial areas, 2% in outskirt of town and 1% in standalone environment. Findings showed all mapped filling stations were found to be within 50m from built up (residential) area, 104 mapped stations within residential and commercial areas violates the DPR standard. Using spatial analysis, it was also found that 116 of the 147 (78.9%) mapped filling stations were within 400m away from the next. 108 of the 147 (73.47%) mapped PFSs violated the standard of distance not less than 15meters from the edge of the road to the nearest pump. The findings also showed that groundwater system is contaminated by PAHs, which comprises; naphthalene.F, pyrene and acenaphthylene.F. Low mean concentrations of PAHs recorded in this study suggest that there is no major compromise in the quality of groundwater due to the operation of PFSs in Akure metropolise Hand-dug Wells in the study area. It is recommended that spatial compliance for siting PFSs should be strictly adhered to in order to avoid disaster that may occur due to the hazard they pose

Health risk analysis of benzene, toluene, ethylbenzene, and xylene (BTEX) in groundwater in Yogyakarta City, Indonesia

Benzene, Toluene, Ethylbenzene, and Xylene (BTEX) are persistent and bio-accumulative compounds that occur in petroleum-based products. Benzene is categorized as a carcinogenic substance while ethylbenzene is potentially carcinogenic. One of the sources of BTEX contamination in the environment is gas stations. The leakage of underground storage tanks (UST) of gas stations is a potential source of groundwater contamination, while in many areas, it is the main source of daily water consumption. The long-term consumption of this BTEX-contaminated groundwater may generate health risks. This paper will present the health risk analysis of the consumption of BTEX-contaminated groundwater taken from dug wells near a gas station in Yogyakarta City which has a history of major leakage. Analysis of BTEX in groundwater samples has been already presented in the previous study. Data for intake calculation was acquired through questionnaires and interviews on water consumption patterns. Risk analysis was conducted for both the carcinogenic effect of benzene and the non-carcinogenic effect for all BTEX compounds. Health risk analysis on BTEX exposure in groundwater resulted in the Hazard Quotient (HQ) value for all compounds which were still less than one, meanwhile, the Excess Cancer Risk (ECR) for benzene was less than 10-4. The result indicates the low health risk associated with the consumption of BTEX-contaminated groundwater in the study area.

Underground storage tank blowout analysis: Stability prediction using an artificial neural network

Most geotechnical stability research is linked to “active” failures, in which soil instability occurs due to soil self-weight and external surcharge applications. In contrast, research on passive failure is not common, as it is predominately caused by external loads that act against the soil self-weight. An earlier active trapdoor stability investigation using the Terzaghi's three stability factor approach was shown to be a feasible method for evaluating cohesive-frictional soil stability. Therefore, this technical note aims to expand “active” trapdoor research to assess drained circular trapdoor passive stability (blowout condition) in cohesive-frictional soil under axisymmetric conditions. Using numerical finite element limit analysis (FELA) simulations, soil cohesion, surcharge, and soil unit weight effects are considered using three stability factors (Fc, Fs, and Fγ), which are all associated with the cover-depth ratio and soil internal friction angle. Both upper-bound (UB) and lower-bound (LB) results are presented in design charts and tables, and the large dataset is further studied using an artificial neural network (ANN) as a predictive model to produce accurate design equations. The proposed passive trapdoor problem under axisymmetric conditions is significant when considering soil blowout stability owing to faulty underground storage tanks or pipelines with high internal pressures.

The toxicity effects of the individual and combined exposure of methyl tert-butyl ether (MTBE) and tire rubber powder (RP) on Nile tilapia fish (Oreochromis niloticus)

Methyl tert-butyl ether (MTBE) is soluble in water and can contaminate water sources when it spills during transportation or leaks from underground storage tanks. Incomplete combustion releases MTBE as exhaust fumes that can be deposited on urban surfaces. Meanwhile, car tires erosion emits of large amounts of rubber dust (RP), easily transported to water bodies. Therefore, this study has the objective of assessing the toxicity of varying concentrations of MTBE (0, 2.5, 5.0 μL L−1) and RP (0, 5.0, 10.0 mg L−1 RP), both individually and in combination, over a period of 28 days on Nile tilapia (Oreochromis niloticus). MTBE and PR decreased fish growth performance. Blood biochemical analytes indicated that MTBE and RP led to increasing Aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), and creatinine phosphokinase (CPK), alkaline phosphatase and gamma-glutamyl transferase (GGT) activities. Alterations related to glucose, triglycerides, cholesterol, and creatinine, plasma contents, were also observed. Increased antioxidant biomarkers, including superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx), glutathione reductase (GR), and malondialdehyde (MDA), was observed. Exposure fish to MTBE and PR changed metabolic profile of muscle tissue. Moreover, results showed that MTBE, its metabolites, and PR could accumulate in the muscle tissue of fish. Results suggest that MTBE and RP can impact fish health, both individually and when combined. The presence of MTBE enhances the toxicity of RP, indicating a synergistic effect. Nevertheless, further studies are needed to understand the impact of toxic compounds on aquatic environments and organisms' health.

DESIGN, INSTALLATION, CAPACITIES AND EXPENSES OF AN INDOOR MULTIPURPOSE MODULAR 2D WAVE FLUME AND CIRCULATING WATER CHANNEL

In this article all the details related to the design, installation process, working capacities and expenses of a modular indoor laboratory flume are presented. The facility is able to work as wave flume or circulating water channel. Flume structure design distributes appropriately the load, to ensure the structural safety of the building. The length of the wave flume depends on the number of these structures, 2.5 m each, which are attached one to each other. Presented cases are 12.5 m and 25 m length. Width is 600 mm and can be filled up to 700 mm water depth. In this work, a multipurpose 50 m3 underground water storage tank is used to feed the flume through three centrifugal pump pressure group equipped with a variable frequency drive. Main structure is made of a welded stainless steel square-tubular frame. Seabed is flat, made from a folded stainless steel 5 mm sheet metal and a sandwich-type assembly system allows the fitting of the lateral glasses to the seabed frame. A fine-tuning regulation system allows a perfect alignment of each of the modules with the adjacent. This manufacturing and assembly strategy avoids undesirable whirls effects. Two types of wave generators have been tested, an in-house developed one for regular waves and an externally manufactured one with added options: irregular waves, and active absorption system of reflected waves. At the end of the flume, a parabolic beach has been installed as wave energy dissipation system. An in-house developed regulation system sets the optimal position of this device. Several dissipation options have been tested: height, slopes and perforated surfaces. A foldable wave generator paddle and a set of pipes and valves, allows working as water channel by recirculating water to the underground storage tank, and therefore, increasing flume research versatility. In the upper part, there have been mounted guides along the whole facility so that different ad-hoc devices can be attached onto it, such as testing models or necessary instrumentation. Among this, we can mention wave gauge module together with resistive wave gauges; digital, ultra-low pressure sensor that is fully conditioned and temperature compensated; CompactRIO controller as data acquisition system (National Instruments, cRIO-9063 model) with an inputs voltage module (National Instruments-9205, C-series). A computer with a Labview program that has been developed specifically for that purpose controls all data recording. In addition, the expenses of the main components are also presented, which demonstrate the cost effective of this indoor laboratories where small scale models can be tested. In this work the design characteristics and operation of the main components of the wave flume, such as the wave-maker, wave absorber, wave probes and data acquisition system are reported in detail together with the full range of wave parameters achievable in any experimental campaign in the Le Méhauté chart. This technical recommendations provides any research group with useful guidelines and details necessary to construct their own domestic wave flume being good value for money and unachievable otherwise.

Using groundwater monitoring wells for rapid application of soil gas radon deficit technique to evaluate residual LNAPL

The application of the 222Radon (Rn) deficit technique using subsurface soil gas probes for the identification and quantification of light non-aqueous phase liquids (LNAPL) has provided positive outcomes in recent years. This study presents an alternative method for applying this technique in the headspace of groundwater monitoring wells. The developed protocol, designed for groundwater monitoring wells with a portion of their screen in the vadose zone, is based on the use of portable equipment that allows rapid measurement of the Rn soil gas activity in the vadose zone close to the water table (i.e., smear zone) where LNAPL is typically expected. The paper first describes the step-by-step procedure to be followed for the application of this method. Then, a preliminary assessment of the potential of the method was carried out at two Italian sites characterized by accidental gasoline and diesel spills into the subsurface from underground storage tanks. Although the number of tests conducted does not allow for definitive conclusions, the results obtained suggest that, from a qualitative point of view, Rn monitoring in the headspace of monitoring wells is a promising, fast, and minimally invasive screening method that could also potentially reduce the costs associated with field data acquisition. This method proves to be suitable for detecting the presence of LNAPL in both the mobile and residual phases with results consistent with the other lines of evidence available at the sites, such as groundwater and soil gas monitoring. Future efforts should be directed toward evaluating the accuracy of this method for a quantitative assessment of residual LNAPL saturations.

Comparison between Air-Exposed and Underground Thermal Energy Storage for Solar Cooling Applications

Solar energy is one of the main alternatives for the decarbonization of the electricity sector and the reduction of the existing energy deficit in some regions of the world. However, one of its main limitations lies in its storage, since this energy source is intermittent. This paper evaluates the potential of an underground thermal energy storage tank supplied by solar thermal collectors to provide hot water for the activation of a single-effect absorption cooling system. A simulator was developed in TRNSYS 17 software. Experimentally on-site measured data of soil temperature were used in order to increase the accuracy of the simulation. The results show that the underground tank reduces thermal energy losses by 27.6% during the entire hot period compared with the air-exposed tank. The electrical energy savings due to the reduction in pumping time during the entire hot period was 639 kWh, which represents 23.6% of the electrical energy consumption of the solar collector pump. It can be concluded that using an underground thermal energy storage tank is a feasible option in areas with high levels of solar radiation, especially in areas where ambient temperature drops significantly during night hours and/or when access to electrical energy is limited.

Statistical Measures of Income and Demographic Inequality from Underground Storage Tanks

Statistical Measures of Income and Demographic Inequality from Underground Storage Tanks