Life-cycle greenhouse gas emissions of shale gas, natural gas, coal, and petroleum

The technologies and practices that have enabled the recent boom in shale gas production have also brought attention to the environmental impacts of its use. It has been debated whether the fugitive methane emissions during natural gas production and transmission outweigh the lower carbon dioxide emissions during combustion when compared to coal and petroleum. Using the current state of knowledge of methane emissions from shale gas, conventional natural gas, coal, and petroleum, we estimated up-to-date life-cycle greenhouse gas emissions. In addition, we developed distribution functions for key parameters in each pathway to examine uncertainty and identify data gaps such as methane emissions from shale gas well completions and conventional natural gas liquid unloadings that need to be further addressed. Our base case results show that shale gas life-cycle emissions are 6% lower than conventional natural gas, 23% lower than gasoline, and 33% lower than coal. However, the range in values for shale and conventional gas overlap, so there is a statistical uncertainty whether shale gas emissions are indeed lower than conventional gas. Moreover, this life-cycle analysis, among other work in this area, provides insight on critical stages that the natural gas industry and government agencies can work together on to reduce the greenhouse gas footprint of natural gas.     

Geochemical and strontium isotope characterization of produced waters from Marcellus Shale natural gas extraction

Extraction of natural gas by hydraulic fracturing of the Middle Devonian Marcellus Shale, a major gas-bearing unit in the Appalachian Basin, results in significant quantities of produced water containing high total dissolved solids (TDS). We carried out a strontium (Sr) isotope investigation to determine the utility of Sr isotopes in identifying and quantifying the interaction of Marcellus Formation produced waters with other waters in the Appalachian Basin in the event of an accidental release, and to provide information about the source of the dissolved solids. Strontium isotopic ratios of Marcellus produced waters collected over a geographic range of ~375 km from southwestern to northeastern Pennsylvania define a relatively narrow set of values (ε(Sr)(SW) = +13.8 to +41.6, where ε(Sr) (SW) is the deviation of the (87)Sr/(86)Sr ratio from that of seawater in parts per 10(4)); this isotopic range falls above that of Middle Devonian seawater, and is distinct from most western Pennsylvania acid mine drainage and Upper Devonian Venango Group oil and gas brines. The uniformity of the isotope ratios suggests a basin-wide source of dissolved solids with a component that is more radiogenic than seawater. Mixing models indicate that Sr isotope ratios can be used to sensitively differentiate between Marcellus Formation produced water and other potential sources of TDS into ground or surface waters.     

Life cycle carbon footprint of shale gas: review of evidence and implications

The recent increase in the production of natural gas from shale deposits has significantly changed energy outlooks in both the US and world. Shale gas may have important climate benefits if it displaces more carbon-intensive oil or coal, but recent attention has discussed the potential for upstream methane emissions to counteract this reduced combustion greenhouse gas emissions. We examine six recent studies to produce a Monte Carlo uncertainty analysis of the carbon footprint of both shale and conventional natural gas production. The results show that the most likely upstream carbon footprints of these types of natural gas production are largely similar, with overlapping 95% uncertainty ranges of 11.0-21.0 g CO(2)e/MJ(LHV) for shale gas and 12.4-19.5 g CO(2)e/MJ(LHV) for conventional gas. However, because this upstream footprint represents less than 25% of the total carbon footprint of gas, the efficiency of producing heat, electricity, transportation services, or other function is of equal or greater importance when identifying emission reduction opportunities. Better data are needed to reduce the uncertainty in natural gas's carbon footprint, but understanding system-level climate impacts of shale gas, through shifts in national and global energy markets, may be more important and requires more detailed energy and economic systems assessments.     

天然矿泉水溶解性总固体与电导率的相关性探讨

溶解性总固体的测定受环境和人为操作影响较大,平行性、稳定性差,而电导率的检测既方便又快捷,重现性、稳定性好,若二者相关性关系显著,可通过测定电导率,按一定的比例推算天然矿泉水中溶解性总固体的含量。经监控、分析崂山矿泉水的源水,二者线性关系较为显著,其比值为0.84。     

Accumulation of arsenic in drinking water distribution systems

The tendency for iron solid surfaces to adsorb arsenic is well-known and has become the basis for several drinking water treatment approaches that remove arsenic. It is reasonable to assume that iron-based solids, such as corrosion deposits present in drinking water distribution systems, have similar adsorptive properties and could therefore concentrate arsenic and potentially re-release it into the distribution system. The arsenic composition of solids collected from drinking water distribution systems (pipe sections and hydrant flush solids), where the waters had measurable amounts of arsenic in their treated water, were determined. The elemental composition and mineralogy of 67 solid samples collected from 15 drinking water utilities located in Ohio (7), Michigan (7), and Indiana (1) were also determined. The arsenic content of these solids ranged from 10 to 13 650 microg of As/g of solid (as high as 1.37 wt %), and the major element of most solids was iron. Significant amounts of arsenic were even found in solids from systems that were exposed to relatively low concentrations of arsenic (<10 microg/L) in the water.     

Predicting pore water EPA-34 PAH concentrations and toxicity in pyrogenic-impacted sediments using pyrene content

Sediment and freely dissolved pore water concentrations of the U.S. Environmental Protection Agency's list of 34 alkyl and parent PAHs (EPA-34) were measured in 335 sediment samples from 19 different sites impacted by manufactured gas plants, aluminum smelters and other pyrogenic sources. The total EPA-34 freely dissolved pore water concentration, C(pw,EPA-34), expressed as toxic units (TU) is currently considered one of the most accurate measures to assess risk at such sites; however, it is very seldom measured. With this data set, we address how accurately C(pw,EPA-34) can be estimated using limited 16 parent PAH data (EPA-16) commonly available for such sites. An exhaustive statistical analysis of the obtained data validated earlier observations that PAHs with more than 3 rings are present in similar relative abundances and their partitioning behavior typically follows Raoult's law and models developed for coal tar. As a result, sediment and freely dissolved pore water concentrations of pyrene and other 3- and 4-ring PAHs exhibit good log-log correlations (r2 > 0.8) to most individual EPA-34 PAHs and also to C(pw,EPA-34). Correlations improve further by including the ratio of high to low molecular weight PAHs, as 2-ring PAHs exhibit the most variability in terms of their relative abundance. The most practical result of the current work is that log C(pw,EPA-34) estimated by the recommended pyrene-based estimation techniques was similarly well correlated to % survival of the benthic amphipods Hyalella azteca and Leptocheirus plumulosus as directly measured log C(pw,EPA-34) values (n = 211). Incorporation of the presented C(pw,EPA-34) estimation techniques could substantially improve risk assessments and guidelines for sediments impacted by pyrogenic residues, especially when limited data are available, without requiring any extra data or measurement costs.     

Thermophilic anaerobic digestion to increase the net energy balance of corn grain ethanol

U.S. production of fuel ethanol from corn grain has increased considerably over the last 10 years. Intense debate regarding the true environmental impact of the overall production process has been ongoing. The present study evaluated the utilization of thin stillage (a major byproduct of the dry-mill corn grain-to-ethanol process) in laboratory-scale thermophilic anaerobic sequencing batch reactors for conversion to methane. We found that augmentation of cobalt as a growth factor to the thermophilic anaerobic digestion process is required. After reaching sustainable operating performances, the methane potential in the reactors was 0.254 L CH4/g total chemical oxygen demand (TCOD) fed. Together with a reduction in the mass of solids that needs drying, methane generation translates to a 51% reduction of natural gas consumption at a conventional dry mill, which improves the net energy balance ratio from 1.26 to 1.70. At the design hydraulic retention time of 10 days, the digesters achieved TCOD, biodegradable COD, volatile solids, and total solids removal efficiencies of 90%, 75%, 89%, and 81%, respectively. We also found that struvite precipitation occurred in the thermophilic digesters during the course of the study, resulting in possibilities for nutrient recovery.     

Ion Chromatographic Determination of Free Cyanide in Different Classes of Bottled Natural Mineral Water Consumed in Turkey

An ion chromatographic method for the quantitative determination of free cyanide in bottled natural mineral waters were measured in terms of selectivity, linearity, the limit of detection, limit of quantification, repeatability, precision, and accuracy. Chromatographic separation of free cyanide ions was accomplished with an anion-exchange column and detected by pulsed amperometric detection with a silver working electrode. The method was found to be selective, linear (r² = 0.999) at a concentration range of 0.5 to 134 μg L^?1, precise, and accurate. Recovery values of free cyanide in all classes of natural mineral water varied from 65.9 ± 1.6 to 95.2 ± 0.7 at different spiking levels (5–70 μg L^?1). Parameters (total dissolved solids, mineral interferences, and added sodium hydroxide) affecting the recovery values were studied in this project. The limit of detection and limit of quantification were found to be 0.295 and 0.983 μg L^?1, respectively. The proposed method was applied to 27 different brands of commercially available bottled natural mineral water products sold in Turkish markets. These natural mineral waters were classified as: (i) very low mineral concentration, (ii) low mineral concentration, (iii) intermediate mineral concentration, and (iv) high mineral concentration based on their total dissolved solids contents according to European Union Directive (Directive 80/777/EEC). Levels of free cyanide residues in the samples ranged from > limit of detection to 6.12 μg L^?1. The highest average concentration of free cyanide residues was found in the class of “high mineral concentration waters.” However, the determined free cyanide values in all of the tested natural mineral water samples were found to be within the limits of European Union legislation.     

Measuring temporal variability in pore-fluid chemistry to assess gas hydrate stability: development of a continuous pore-fluid array

A specialized pore-fluid array (PFA) sampler was designed to collect and store pore fluids to monitor temporal changes of ions and gases in gas hydrate bearing sediments. We tested the hypothesis that pore-fluid chemistry records hydrate formation or decomposition events and reflects local seismic activity. The PFA is a seafloor probe that consists of an interchangeable instrument package that houses OsmoSamplers, long-term pore-fluid samplers, a specialized low-dead volume fluid coupler, and eight sample ports along a 10 m sediment probe shaft. The PFA was deployed at Mississippi Canyon 118, a Gulf of Mexico hydrate site. A 170 day record was acquired from the overlying water and 1.3 m below seafloor (mbsf). Fluids were measured for dissolved chloride, sulfate, and methane concentrations and dissolved inorganic carbon and methane stable carbon and deuterium isotope ratios. Chloride and sulfate did not change significantly over time, suggesting the absence of gas hydrate formation or decomposition events. Over the temporal record, methane concentrations averaged 4 mM at 1.3 mbsf, and methane was thermogenic in origin (delta13C-CH4 = -32.4 +/- 3.4 per thousand). The timing of an anomalous 14 mM methane spike coincided with a nearby earthquake (Mw = 5.8), consistent with the hypothesis that pore-fluid chemistry reflects seismic events.     

Enhancing activated carbon adsorption of 2-methylisoborneol: methane and steam treatments

This research investigated methods for tailoring a commercial, lignite-based granular activated carbon (GAC) to enhance its adsorption of 2-methylisoborneol (MIB) from natural water. Tailoring efforts focused on heat treatments in gas environments comprising steam and/or methane, since these gases can alter GAC pore structure and surface chemistry. Heat treatments that combined methane and steam enhanced MIB adsorption considerably, causing a 4-fold improvement (over untreated GAC) in fixed-bed adsorption performance relative to initial MIB breakthrough. These favorable effects, observed in rapid small-scale column tests, occurred following simultaneous and separate (sequential) applications of methane and steam. Moderately low temperature steam treatments also improved MIB uptake in fixed-bed adsorption tests but to a lesser extent (approximately 1.5-fold). In contrast, methane treatments alone, at various temperatures, led to significant carbon deposition within the GAC pore structure. As a result, total pore volume was reduced and MIB adsorption performance declined.     

DESIGN AND SELECTION OF PROCESSING CONDITIONS OF A PILOT SCALE CONTACTOR FOR CONTINUOUS OSMOTIC DEHYDRATION OF CARROTS

A pilot-scale belt type osmotic contactor was designed and installed in a continuous osmotic dehydration process to obtain maximum water removal from fruits and vegetables with a minimum contact time. The carrot was chosen as a representative vegetable and a ternary mixture of sucrose/sodium chloride/water with total solids concentration of about 50 to 55% was chosen for the osmotic solution. The experimental results showed that the optimum condition was found to require a 44% sucrose/7% sodium chloride aqueous solution with 16 min of contact time which gave a water loss of 26% and a highest ratio of water loss over solids gain (about 9) among different treatments. It is concluded that the continuous type of contactor can have potential applications in the food industry.     

废纸浆水中溶解物在线分析

介绍了废纸浆水中溶解物的来源及其对抄纸的影响,同时介绍了浆水中溶解物的在线分析方法及其用于管理的方针.     

Unexpected arsenic compounds in low-rank coals

Nine low-rank coal samples from three different coal basins (Velenje and Trbovlje basins, Slovenia, and Sokolov basin, Czech Republic) were analyzed for their elemental composition and the presence of arsenic compounds. Total arsenic concentrations in the samples were 1.59-5.77 microg g(-1) with one exception, 142 microg g(-1) for a sample from the Sokolov basin. A methanol/water mixture (1:1) extracted 15.1 - 38.7% of the total arsenic from Velenje basin samples but only 2.2-7.1% from Sokolov and Trbovlje basin samples. Extracts from the Velenje basin samples contained mainly the tetramethylarsonium ion (0.14 - 0.92 microg g(-1)) with considerable amounts of arsenate (0.15 - 0.85 microg g(-1)) and monomethyl arsonic acid 0.04 - 0.27 microg g(-1)). In methanol/water extracts from samples from the Sokolov and Trbovlje basins inorganic arsenic (arsenate) prevailed (0.26 - 37.1 microg g(-1)), but at least trace amounts of organic arsenic compounds were found as well. It is likely that biogeochemical degradation of organic material is related to the unexpected organoarsenic compounds found in low-rank coals. However, it should also not be ruled out that abiogenic synthesis could have taken place in the carbon-rich environment under the harsh conditions present (elevated temperature and pressure).     

Ultrafiltration of pickling bath brine

If the pickling process is finished (after some days or weeks) pickling bath brine (brine) from a meat processing plant consists mainly beside water of sodium chloride, sodium nitrite, proteins and low molecular nitrogen-substances. The raw protein content and the dissolved solids are dependent on the brine age. Usually the brine is discharged to the waste water. That means an increasing of COD (Chemical Oxygen Demand) and of mineral content of the effluent. Membrane processes have been applied to waste water treatment in the food processing industry as an integral part of an effluent processing system for effluent cleaning simultaneously with recovering valuable constituents. First experiments in the field of ultrafiltration (UF) of brine were described by Goldberg [2]. The aim of our experiments was to concentrate and separate the brine proteins and to regenerate the brine by ultrafiltration.     

溶出固形物对软米硬度和黏弹性的影响

以粳米和糯米为对照,研究了溶出固形物对软米硬度和黏弹性的影响.分析发现软米溶出固形物质量分数为11.85％,显著高于粳米和糯米(P<0.05),与弹性显著正相关(P<0.05);与粳米和糯米相比,软米中的固形物直支链淀粉比最低,利于形成连续凝胶网结构.此外,软米溶出淀粉侧链中聚合度为6～12的短链A链比例最高,赋予其较好的黏弹性.质构和流变分析结果表明:除溶出固形物后,软米的硬度显著增加,黏硬比和弹性显著降低.扫描电子显微镜结果表明:除溶出固形物后米粒表面粗糙、凹凸不平,有明显的孔洞;软米表面所形成的渔网状孔洞状结构能够对饭粒起到支撑作用,使得整个饭粒弹性更好.溶出固形物含量、组成、分子结构及其在米饭表面分布的差异是软米较低硬度和较好黏弹性优势产生的主要原因.     

FACTORS AFFECTING THE ULTRAVIOLET INACTIVATION OF ESCHERICHIA COLI K12 IN APPLE JUICE AND A MODEL SYSTEM*

Ultraviolet (UV) light has been used successfully for years to sterilize water and was recently approved as an acceptable irradiation treatment for the processing of juice. Although there is considerable information on the efficacy of UV processing in the treatment of water, limited data are available on its efficacy in fluid food systems. The objectives of this work were to determine the effects of apple‐juice properties on the UV inactivation of Escherichia coli K12 and the interdependence of intensity and time on the efficacy of UV light. Results showed that absorbance (A) and suspended solids (SS) affected UV inactivation, while pH and dissolved solids did not. Concerning the interdependence of intensity and time, intensity levels can only be changed without sacrificing effectiveness at a limited range of intensity and dose levels. This means that the range of the intensity level of the actual UV reactor must be considered in process‐parameter determination.     

阴离子垃圾对新闻纸性能的影响及减轻影响的措施

本文论述了新闻纸纸料中阴离子垃圾的来源及对新闻纸性能的影响，以及减轻阴离子垃圾对新闻纸影响的措施，新闻纸纸料中的阴离了垃圾主要来源于机械浆的漂白，其主要成分可分为两大类，即溶解物质和胶体物质，这两类物质对新闻纸性能的影响不同，胶体物质对抗张强度影响最大，而溶解物质对耐破指数，松厚度及透气度影响最大，另外，不同纸料对相同成分的白水的敏感性不同，机械浆用过氧化氢漂白后，经济浆设备脱水或酸处理有效地降低阴离子垃圾。     

Stoichiometry of coagulation revisited

The roles of particles and natural organic matter (NOM) in determining coagulant (alum) doses in potable water treatment were investigated at two pH conditions (6 and 7). The concentrations of NOM and colloidal silica particles in raw water were systematically varied separately and in combination, and the impacts of these two classes of contaminants on the minimum effective alum doses were investigated using observations of turbidity and dissolved organic carbon (DOC) in laboratory jar tests. At both pHs, coagulant requirements for the removal of these contaminants by sedimentation and filtration were dominated by the DOC concentration in the raw water. The presence of low NOM concentrations (0.75-1.5 mg of C/L) decreased the minimum effective alum dose dramatically for waters low in silica particles, possibly by promoting the precipitation of aluminum hydroxide and/or Al-NOM solids, whose removal would otherwise be limited by low collision opportunities. Strong stoichiometric relationships were observed between DOC and coagulant demand at both pHs regardless of silica particle concentration. Silica contributed to coagulant demand only at very high particle concentrations.     

Survival and growth of Pseudomonas aeruginosa in natural mineral water: a 5-year study

A 5-year study was carried out on the growth curve of two strains of P. aeruginosa inoculated at a density of 10(2) cfu/ml into samples of natural mineral water with different levels of dissolved solids (TDS at 180 degrees C: 72.5 and 382 mg/l) and low organic content (TOC: 0.17 and 0.35 mg/l). The resulting growth curves were similar for both strains, with only slight differences depending on the different amounts of dissolved solids in the water. After 4-5 days counts were increased by 3 log units. This level was maintained until 70-100 days from inoculation, after which a slow decrease began, culminating in the death of one of the strains after 5 years. No difference in recovery was observed between the method using direct inoculation on Cetrimide Agar and the resuscitation technique (preincubation in Tryptone Soya Agar followed by inoculation on Cetrimide Agar) in the exponential phase of the growth curve. During the stationary and death phases, however, the enrichment technique gave statistically slightly higher counts than the selective technique, indicating the presence of damaged P. aeruginosa cells. The use of a resuscitation step when using Cetrimide Agar to assess bottled water quality is recommended.     

Solubility of carbon dioxide in a seafood model product with fish oil

The solubility of carbon dioxide (CO₂) in a seafood model product with various amounts of salmon oil was investigated. Differential scanning calorimetry analysis of the salmon oil gave an onset temperature for crystallization at ?14.75 ± 0.74 °C, showing that the oil was in liquid state in the temperature range used in this experiment (1–8 °C). Solubility of CO₂ in salmon oil in liquid state was similar to water, with the same temperature dependency as water. Increased storage temperature decreased the amount of dissolved CO₂ and increased the headspace CO₂ and headspace gas volume. Headspace gas composition at equilibrium was linearly (R ² = 0.979) related to the composition of the packaging gas, while increasing CO₂ in the packaging gas increased the headspace gas volume and the amount of dissolved CO₂ in the product. When designing modified gas-packaging regimes for products with marine fat, sum of fat and water can be used to estimate the amount of dissolved CO₂ in the product.