Common Hydraulic Fracturing Fluid Additives Alter the Structure and Function of Anaerobic Microbial Communities.

The development of unconventional oil and gas (UOG) resources results in the production of large volumes of wastewater containing a complex mixture of hydraulic fracturing chemical additives and components from the formation. The release of these wastewaters into the environment poses potential risks that are poorly understood. Microbial communities in stream sediments form the base of the food chain and may serve as sentinels for changes in stream health. Iron-reducing organisms have been shown to play a role in the biodegradation of a wide range of organic compounds, and so to evaluate their response to UOG wastewater, we enriched anaerobic microbial communities from sediments collected upstream (background) and downstream (impacted) of an UOG wastewater injection disposal facility in the presence of hydraulic fracturing fluid (HFF) additives: guar gum, ethylene glycol, and two biocides, 2,2-dibromo-3-nitrilopropionamide (DBNPA) and bronopol (C3H6BrNO4). Iron reduction was significantly inhibited early in the incubations with the addition of biocides, whereas amendment with guar gum and ethylene glycol stimulated iron reduction relative to levels in the unamended controls. Changes in the microbial community structure were observed across all treatments, indicating the potential for even small amounts of UOG wastewater components to influence natural microbial processes. The microbial community structure differed between enrichments with background and impacted sediments, suggesting that impacted sediments may have been preconditioned by exposure to wastewater. These experiments demonstrated the potential for biocides to significantly decrease iron reduction rates immediately following a spill and demonstrated how microbial communities previously exposed to UOG wastewater may be more resilient to additional spills.IMPORTANCE Organic components of UOG wastewater can alter microbial communities and biogeochemical processes, which could alter the rates of essential natural attenuation processes. These findings provide new insights into microbial responses following a release of UOG wastewaters and are critical for identifying strategies for the remediation and natural attenuation of impacted environments.

Factors affecting on hythane bio-generation via anaerobic digestion of mono-ethylene glycol contaminated wastewater: Inoculum-to-substrate ratio, nitrogen-to-phosphorus ratio and pH.

This study aims to assess the effect of inoculum-to-substrate ratio (ISR) and nitrogen-to-phosphorus balance on hythane production from thermophilic anaerobic decomposition of mono-ethylene glycol (MEG) contaminated wastewater. ISRs ranging from 2.65 to 13.23gVSS/gCOD were employed, whereas the tested N/P ratios varied from 4.6 to 8.5. Maximum methane and hydrogen yields (MY and HY) of 151.86±10.8 and 22.27±1.1mL/gCODinitial were achieved at ISRs of 5.29 and 3.78gVSS/gCOD, respectively. HY increased 1.45-fold by decreasing N/P from 8.5 to 4.6, while MY improved 1.6-fold by increasing N/P from 4.6 to 5.5. Methane production was strongly influenced by initial NH4-N, compared to initial PO4-P. Optimal HY of 47.55mL/gCODinitial was achieved at pH 5.0 and ISR of 3.78gVSS/gCOD using thermal-treated sludge. Three-dimensional regression model was applied for the combined effect of initial MEG, NH4-N and PO4-P on hythane production. Potential economic benefits of hythane production from MEG contaminated wastewater were assessed.

Purification of compounds from Lignum Dalbergia Odorifera using two-dimensional preparative chromatography with Click oligo (ethylene glycol) and C18 column.

Purification of compounds from traditional Chinese medicines (TCMs) is an important task for understanding the chemical composition of TCMs. However, it is difficult to obtain compounds with high enough purity for identification by NMR due to the complexity of TCMs in chemical composition. In this study, a two-dimensional purification method based on a Click oligo (ethylene glycol) column and a C18 column was developed to realize an orthogonal separation in preparative level for purifying compounds efficiently. The first dimensional preparation was performed on a Click oligo (ethylene glycol) column to simplify the sample into the fractions with good separation repeatability. On the first dimension, 7.2 g sample was separated into 11 fractions with a recovery of 86% within 6 h. A C18 column was taken as the second dimension to realize the high-performance separation and rapid preparation from the fractions collected from the first dimension. Eight compounds in fraction 6 and 2 compounds in fraction 8 were isolated and identified after optimizing the separation and collection parameters. This method is a high-efficient and orthogonal preparation method to improve the separation of a complex sample and increase the purity of the compounds, which benefits from the application of novel materials in the preparation and purification.

Selective spectrophotometric determination of periodate based on its reaction with methylene green and its application to indirect determination of ethylene glycol and glycerol.

A rapid, simple, accurate, and highly selective spectrophotometric method is proposed for the determination of periodate in water samples. This method is based on the reaction of methylene green with periodate in the presence of iodide. The decrease in the absorbance of methylene green is used to monitor the reaction spectrophotometrically at 613 nm. Under the optimum conditions, periodate could be determined in the concentration range 0.18-6.0 microg mL(-1). The detection limit for the method is 0.010 microg mL(-1). The influence of various foreign species was studied, and it was found that iodate did not interfere with the determination even in the presence of 200-fold of periodate. The relative standard deviations for six replicate determinations of 0.30, 0.50, 1.0, 1.5, 4.0, and 5.5 microg mL(-1) of periodate were 3.33, 2.0, 1.6, 1.33, 0.50, and 0.55%, respectively. The proposed method was applied to the determination of periodate in water samples and indirect determination of ethylene glycol in antifreeze and glycerol in vegetable oil via malaprade reaction, and satisfactory results were obtained.

Screening method for ethylene glycol and diethylene glycol in glycerin-containing products.

This paper describes a capillary gas chromatographic method with flame ionization detection for the identification/quantification of ethylene glycol (EG) and diethylene glycol (DEG) in glycerin. The validation study shows that the proposed method is specific, sensitive, precise, and accurate. The linear range of the method was 0.013-0.031mg/mL for EG and 0.012-0.030mg/mL for DEG. Wider ranges may be achievable but were not investigated. The limit of detection of EG and DEG were determined as 0.0018% and 0.0036% (w/w) respectively, and at this concentration the signal-to-noise ratios for EG and DEG were approximately 3:1. The method was also used to determine EG and DEG in toothpaste. The results were compared to those obtained by thin-layer chromatography (TLC) and showed greater sensitivity and specificity.