Review on the Evaluation of the Impacts of Wastewater Disposal in Hydraulic Fracturing Industry in the United States

Acute and chronic risk assessment of BTEX in the return water of hydraulic fracturing operations in Marcellus Shale

Environmental pollution caused by human activities is a pressing issue in developed countries. In this context, it is vital to establish methodologies for the early and reliable estimation of the health risks posed by potential pollutants. Flowback and produced water (return water) from shale gas operations can contain toxic compounds, of which BTEX (benzene, toluene, ethylbenzene, and xylenes) are of concern due to their toxicity and frequent presence above regulatory limits. The return water generated by these operations is stored in ponds or tanks before reaching its final destination. Over time, the composition of this water changes, and leaks or inadequate contact can harm the environment and human health. Here we developed a risk assessment framework to evaluate the temporal evolution of chronic and acute BTEX exposure risks caused by accidental return water leakage. We applied the approach to a hydraulic fracturing operation in the Marcellus Shale Formation. Starting with a time series of BTEX concentrations in the return water, our method deploys transport models to assess risk to health. Our approach compares exposure levels with regulatory limits for inhalation, ingestion, and dermal contact. By identifying the risk levels, exposure pathways, and control parameters in the case study for a range of periods after leakage, our study supports the implementation of appropriate risk mitigation strategies. In addition, by examining risk variation under arid, semi-arid, and humid climate scenarios, the study reveals the impact of climate change on soil characteristics and BTEX transport. The development and application of this methodology is an important step in addressing concerns regarding shale gas operations. The approach proposed paves the way for sustainable practices that prioritise the protection of human health and the environment.

Recent progress and future directions of membranes green polymers for oily wastewater treatment

The preparation, modification and application of green polymers such as poly-lactic acid (PLA), chitosan (CS), and cellulose acetate (CA) for oily wastewater treatment is summed up in this review. Due to the low environmental pollution, good chemical resistivity, high hydrophobicity, and good capacity for water-oil emulsion separation of the presented polymers, it then highlights the various membrane production methods and their role in producing effective membranes, with a focus on recent advances in improving membrane properties through the addition of various Nano materials. As a result, the hydrophilic/hydrophobic properties that are critical in the oil separation mechanism are highlighted. Finally, it looks at the predictions and challenges in oil/water separation and recovery. These ideas are discussed with a focus on modern production methods and oil separation proficiency.

Evaluating Preventive Measures for Flooding from Groundwater: A Case Study

Groundwater (GW) flooding mechanisms differ from river flooding, both spatially and temporally, and preventative methods against groundwater flooding must take this into account. Although groundwater flooding caused by a rise of river water seldom occurs, it can occasionally become severe and last for a long time if the river is significantly flooded. In the southwest portion of the research domain, Friedrichshafen, Germany, with a few urban communities, the level of the groundwater table was discovered to be roughly 1 m below the surface. In the study region, it is typical for the bottom level of the foundation of a single-story building to extend up to a depth of about 1.5 m. Therefore, flood mitigation methods are taken into account for the southwest portion of the study region. In this study, FEFLOW is used to explore the preventative methods for groundwater flooding caused by river water increase in urban settings, the spread of contamination, and the strategizing of effective mitigation solutions for flooding. The installation of a pumping well, drainage, and a barrier in the affected area are three different flood control strategies that are taken into consideration for the study area. Pumping well installation, reducing up to 1.5 m of hydraulic head, was found to be the most effective flood control measure locally in a small region. By contrast, removing groundwater by building drainage and barriers was shown to be ineffective for lowering the groundwater table over an extended region, and was significantly more expensive than the installation of wells. Additionally, when river flooding is taken into account, compared to the default scenario where no intake of water from the river is included along the western border of the study area, it was discovered that the spread of pollution (nitrate concentration) is significantly greater.

The Acute Toxicity of Salinity in Onshore Unconventional Gas Waters to Freshwater Invertebrates in Receiving Environments: A Systematic Review

Industries such as unconventional natural gas have seen increased global expansion to meet the increasing energy needs of our increasing global population. Unconventional gas uses hydraulic fracturing that produces significant volumes of produced waters, which can be highly saline and pose a toxic threat to freshwater invertebrates if exposure via discharges, spills, leaks, or runoff were to occur. The primary aim of the present review was to determine the sodium (Na⁺ ) and chloride (Cl^- ) content of these waters as an approximate measure of salinity and how these values compare to the NaCl or synthetic marine salt acute toxicity values of freshwater invertebrate taxa. Shale gas produced waters are much more saline with 78 900 ± 10 200 NaCl mg/L and total dissolved solids (TDS) of 83 200 ± 12 200 mg/L compared to coal bed methane (CBM) produced waters with 4300 ± 1100 NaCl mg/L and TDS of 5900 ± 1300 mg/L and pose a far greater toxicity risk from NaCl to freshwater invertebrates. In addition, the toxicity of other major ions (Ca²⁺ , K⁺ , Mg²⁺ , CO 3 2 - , HCO₃ ^- , and SO 4 2 - ) and their influence on the toxicity of Na⁺ and Cl^- were evaluated. Exposure of untreated and undiluted shale gas produced waters to freshwater invertebrates is likely to result in significant or complete mortality. Shale gas produced waters have higher concentrations of various metals compared with CBM produced waters and are more acidic. We recommend future research to increase the reporting and consistency of water quality parameters, metals, and particularly organics of produced waters to provide a better baseline and help in further investigations. Environ Toxicol Chem 2022;41:2928-2949. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Fenton process for the treatment of wastewater effluent from the edible oil industry

The present study intends to investigate the performance of the Fenton reaction as one of the most efficient (AOPs) in a batch mode for treating wastewater effluent from the edible oil industry, as well as the parameters that influence the reaction, such as pH, hydrogen peroxide (H₂O₂), and ferrous sulfate heptahydrate (FeSO₄.7H₂O) doses at various reaction times. The response surface methodology (RSM) was applied with a central composite design (CCD) for optimizing the responses of pollutant removals. The obtained results indicated that the authenticated response to the chemical oxygen demand (COD) removal was 93.52%, at optimum values of pH, FeSO₄.7H₂O dose, H₂O₂ dose, and reaction time of 3, 1 g/L, 8.38 g/L, and 50 min, respectively. Furthermore, the authenticated response to oil and grease (O&G) removal was 99.8%, at optimum values of pH, FeSO₄.7H₂O dose, H₂O₂ dose, and reaction time of 3, 0.71 g/L, 8.7 g/L, and 37.4 min, respectively. Under these conditions, the residual COD and O&G after Fenton oxidation become 155.4 mg/L and 10 mg/L, respectively.

Investigations on influences of MWCNT composite membranes in oil refineries waste water treatment with Taguchi route

Most of the 'oil refineries' severally pollutes the water resources by depleting their untreated waste water like cooling water, storm water and unsanitary sewage water. These wastewaters are to be treated with high care to protect the human, pebbles, plants, fish and other water animals and from harmful effects. The present study focused to treat the oil refinery wastewater by means of Multi wall carbon nanotube (MWCNT) coated Polyvinylidene Fluoride (PVDF) membrane. The main objectives are: to increases the life of filter, reduce the percolation flux and reduce the formation of antifouling in the filter by using MWCNT composite membrane in it. Different process parameters of the proposed water treatment process, like diameter of MWCNT (15 nm, 20 nm, 25 nm and 30 nm), operating pressure (3 bar, 4 bar, 5 bar and 6 bar), pH value (3, 5, 7 and 9) and temperature (25 °C, 30 °C, 35 °C and 40 °C) temperature. Taguchi statistical technique is employed for designing experiments and for optimizing the process parameters of wastewater treatment process of an oil refinery. The proposed filter for wastewater treatment exhibited appreciable performance in removal rate of Percolation flux, percentage of chemical oxygen demand removal and percentage of total carbolic rejection as 27.2 kg/m²h, 78.51% and 95.33% respectively.

Can a compact biological system be used for real hydraulic fracturing wastewater treatment?

Hydraulic fracturing wastewater (HFW), a byproduct of hydraulic fracturing oil extraction, contains a complex mixture of oil, aldehydes, and benzene compounds. Efficient and eco-friendly HFW treatment means are critical for the oil extraction industry, particularly in developing countries. In this study, two biological processes namely an anaerobic/anoxic/moving bed biofilm reactor (A²-MBBR) and an A²-MBBR with a microfiltration membrane (A²-MFMBBR) were established, and assessed for the real HFW treatment. Removal efficiencies of chemical oxygen demand (COD) and NH₄⁺-N were over 92% and 95%, respectively, in both processes with a hydraulic retention time of 72 h. The majority of organic compounds in both systems identified by GC-MS were degraded in the anaerobic units. In comparison, A²-MFMBBR demonstrated higher removal efficiencies for oil, total suspended solids, and complex compounds. The average relative abundances of refractory compound degrading bacteria were 43.4% and 51.6% in the A²-MBBR and A²-MFMBBR, respectively, which was consistent with the COD and oil removal, and suggested that the MBR could maintain a high diversity of microorganisms and contribute to deep recalcitrant organics degradation. This study sheds light on the potential of using a compact biological process for the real HFW treatment.

The Impact of Climate Change and Soil Classification on Benzene Concentration in Groundwater Due to Surface Spills of Hydraulic Fracturing Fluids

Hydraulic fracturing drilling technology can cause a high risk of surface spill accidents and thus water contamination. Climate change together with the high water demand and rapid increase in industrial and agricultural activities are valued reasons why we should all care about the availability of water resources and protect them from contamination. Hence, the purpose of this study is to estimate the risk associated with a site contaminated with benzene from oil spillage and its potential impact on groundwater. This study focused on investigating the impact of soil variability and water table depth on groundwater contamination. Temperature-dependent parameters, such as soil water content and the diffusion of pollutants, were considered as key input factors for the HYDRUS 1D numerical model to simulate benzene migration through three types of soil (loamy, sandy clay loam, and silt loam) and evaluate its concentration in the water aquifer. The results indicated that an anticipated increase in earth’s average surface temperature by 4 °C due to climate change could lead to a rise in the level of groundwater pollution in the study area by 0.017 mg/L in loamy soil, 0.00046 mg/L in sandy clay loam soil, and 0.00023 mg/L in silt loam soil. It was found that climate change can reduce the amount of benzene absorbed from 10 to 0.07% in loamy soil, 14 to 0.07% in sandy clay loam soil, and 60 to 53% in silt loam soil. The results showed that the soil properties and solute characteristics that depend on the temperature have a major and important role in determining the level of groundwater pollutants.

Industry 4.0 Applications for Medical/Healthcare Services

At present, the whole world is transitioning to the fourth industrial revolution, or Industry 4.0, representing the transition to digital, fully automated environments, and cyber-physical systems. Industry 4.0 comprises many different technologies and innovations, which are being implemented in many different sectors. In this review, we focus on the healthcare or medical domain, where healthcare is being revolutionized. The whole ecosystem is moving towards Healthcare 4.0, through the application of Industry 4.0 methodologies. Many technical and innovative approaches have had an impact on moving the sector towards the 4.0 paradigm. We focus on such technologies, including Internet of Things, Big Data Analytics, blockchain, Cloud Computing, and Artificial Intelligence, implemented in Healthcare 4.0. In this review, we analyze and identify how their applications function, the currently available state-of-the-art technologies, solutions to current challenges, and innovative start-ups that have impacted healthcare, with regards to the Industry 4.0 paradigm.

Evaluation of Galdieria sulphuraria and Chlorella vulgaris for the Bioremediation of Produced Water

Produced water (PW) is the largest waste stream generated by the oil and gas industry. Traditional treatment of PW burdens the industry with significant expenses and environmental issues. Alternatively, microalgal-based bioremediation of PW is often viewed as an ecologically safe and sustainable platform for treating PW. Moreover, the nutrients in PW could support algal growth. However, significant dilution of PW is often required in algal-based systems due to the presence of complex chemical contaminants. In light of these facts, the current work has investigated the potential of cultivating Galdieria sulphuraria and Chlorella vulgaris in PW using multiple dilutions; 0% PW, 5% PW, 10% PW, 20% PW, 50% PW and 100% PW. While both algal strains can grow in PW, the current results indicated that G. sulphuraria has a higher potential of growth in up to 50% PW (total dissolved solids of up to 55 g L−1) with a growth rate of 0.72 ± 0.05 g L−1 d−1 and can achieve a final biomass density of 4.28 ± 0.16 g L−1 in seven days without the need for additional micronutrients. Additionally, the algae showed the potential of removing 99.6 ± 0.2% nitrogen and 74.2 ± 8.5% phosphorus from the PW.

Volume Resistivity of Viton Polymer under Thermal Aging

This study examines the influence of various electrical parameters on the volume resistivity of the Viton fluoroelastomer. The transient current, the temperature dependence of volume resistivity, the voltage dependence of resistivity, and the surface morphology of Viton insulators are investigated for new and aged specimens. An accelerated aging process has been employed in order to simulate the natural aging of insulators in service. A detailed comparison between the new and aged samples is presented. The transient effect, which is a challenge to the resistivity measurement of insulators, has been investigated. The first 60 s of the resistivity measurement test showed a significant influence from the transient effect and should be excluded from the data. The volume resistivity of both new and aged samples decreased when the temperature increased. However, the resistivity of the aged sample was lower than the new one at all tested temperatures. When the temperature increased from 35 to 190 °C, resistivity decreased from 4.77 × 10¹⁰ to 6.99 × 10⁸ Ω-cm for the new sample and from 2.6 × 10¹⁰ to 6.68 × 10⁸ Ω-cm for the aged sample under 500 V. Additionally, the results from this study showed that the volume resistivity is inversely proportional to the applied voltage. Finally, scanning electron microscope (SEM) micrographs/images allowed us to closely examine the surface morphology of new and aged Viton samples. The surface of aged samples has been recognized with higher surface roughness and more significant surface cracks leading to poor performance under high voltage applications.

Meteorological Drivers of Permian Basin Methane Anomalies Derived from TROPOMI

The launch of the TROPOspheric Monitoring Instrument (TROPOMI) on the Sentinel-5 Precursor (S-5P) satellite has revolutionized pollution observations from space. The purpose of this study was to link spatiotemporal variations in TROPOMI methane (CH4) columns to meteorological flow patterns over the Permian Basin, the largest oil and second-largest natural gas producing region in the United States. Over a two-year period (1 December 2018–1 December 2020), the largest average CH4 enhancements were observed near and to the north and west of the primary emission regions. Four case study periods—two with moderate westerly winds associated with passing weather disturbances (8–15 March 2019 and 1 April–10 May 2019) and two other periods dominated by high pressure and low wind speeds (16–23 March 2019 and 24 September–9 October 2020)—were analyzed to better understand meteorological drivers of the variability in CH4. Meteorological observations and analyses combined with TROPOMI observations suggest that weakened transport out of the Basin during low wind speed periods contributes to CH4 enhancements throughout the Basin, while valley and slope flows may explain the observed western expansion of the Permian Basin CH4 anomaly.