High Hydrocarbon Content Research Articles

Assessment of a complete truck operating under dual-mode dual-fuel combustion in real life applications: Performance and emissions analysis

The dual-mode dual-fuel (DMDF) strategy has been demonstrated to be a potential combustion mode to cover all the engine map with low-to-moderate NOx and soot emissions and high efficiency simultaneously. This can be accomplished by modifying the injection strategy to promote a fully premixed or a dual-fuel diffusive combustion depending on the operating conditions. The main limitation of the DMDF are the high concentrations of unburned hydrocarbons and carbon monoxide coupled with low exhaust temperatures, which can be a challenge for the stock diesel oxidation catalyst (DOC). Moreover, the use of a diffusive combustion combined with high EGR rates to avoid mechanical issues at high load enhances the soot formation, which can compromise the final soot levels in a homologation cycle. To evaluate these aspects, this work studies the performance and emissions of a DMDF truck concept along a WHVC and different in-service conformity cycles through vehicle systems simulations. For both types of cycles, five payloads were tested (0%, 25%, 50%, 75% and 100%) to evaluate the impact of this parameter on the operating points distribution inside the DMDF map. The first results show that the DMDF concept provides engine-out NOx levels below the EUVI regulation at normative payload (50%) with similar fuel consumption than the conventional diesel truck. On the other hand, the engine-out HC and CO emissions exceed their respective limits in all the cases, while the engine-out soot emissions only reach the EUVI levels up to 25% payload. By this reason, the stock DOC and diesel particulate filter from the conventional diesel truck were modelled and fitted to the DMDF truck model. The results evidenced that the use of these two ATS allows to achieve the EUVI limits in terms of tailpipe HC, CO and soot independently on the cycle and payload analyzed. Moreover, considering the tailpipe emissions values achieved with ATS at 50% payload, it can be inferred that both devices could be downsized for the DMDF application as compared to the conventional ATS for diesel applications.

A gas hydrate site with bi-verging folding in the outer wedge offshore SW Taiwan: Results from kinematic structural modeling and finite strain analysis

Understanding the structural evolution of complex convergent plate boundaries could contribute to linking the anticipated fluid production and transportation at depth to the measured amounts of fluid stored in hydrate methane. To better understand fluid behavior within a complex convergent boundary, we propose an evolution model for a set of doubly plunging, oppositely-verging structures referred to as Ridge A and the Four-Way Closure Ridge (FWCR), located offshore southwestern Taiwan. The structures exhibit 1) initial deformation along a decollement forming a seaward (westward)-verging detachment fold, followed by 2) a landward (eastward)-verging fault propagation fold (trishear) about 8 km west of the detachment fold, and 3) a westward-verging low-angle thrusting modifying the previous structures. Furthermore, finite strain analyses based on the kinematic model suggest high pore space reduction between the detachment and fault propagation folds. The volume of methane possibly expelled during the pore space reduction is not enough to explain the high hydrocarbon concentration necessary for hydrate formation. Kinematic modeling along with finite strain analyses support the possibility of deep sourced fluid migration along such bi-vergent structures at this hydrate-rich site.

Fatty acid benzyl esters asbio‐basedplasticizers insilica‐filled solution‐polymerized styrene‐butadienerubber/butadiene rubber composites

AbstractBio‐oil based plasticizers have gained great attention in rubber industry as alternatives of petro‐based plasticizers with high content of polycyclic aromatic hydrocarbons. In this work, five fatty acid benzyl esters were synthesized by the esterification of fatty acids (lauric acid, myristic acid, palmitic acid, stearic acid, and oleic acid, which are obtained after hydrolysis of some vegetable oils) with benzyl alcohol. They were further applied as plasticizers in silica‐filled solution‐polymerized styrene‐butadiene rubber/butadiene rubber (SSBR/BR) composites in order to study the structure‐property relationship, compared with treated distillate aromatic extract (TDAE) as standard. The composites were studied for their processability, curing, static, and dynamic mechanical properties by developing through compatibility between bio‐plasticizers and polymer matrix. The results show that benzyl laurate with suitable hydrocarbon chain length and benzyl oleate with a carbon‐carbon double bond have comparatively improved performance compared to TDAE in the silica‐filled SSBR/BR composites.

Статистика Getis-Ord Gi* при обработке многолетних данных содержания углеводородов в бассейне реки Большой Балык

Balyk river basin for the period 2006–2017 using ArcGIS Pro statistical analysis tools are presented in this article. The information basis of the research is the local environment monitoring data of license areas of Ugra, Khanty-Mansiysk Autonomous Okrug, RF. The research was implemented in two stages. At the first stage, pollution hot spots were revealed basing on the calculation of local Getis-Ord Gi* index for each year. The calculation was made taking into account the mutual location of sampling points and value of the neighborhood. At the second stage hot spots genesis for 12 years was analyzed via modelling space-and-time cube. Clustering time series of hydrocarbons average annual concentration according to the Getis-Ord Gi* indicator made it possible to determine the places of one-off pollution, most likely associated with oil spills, and to track pollutants transportation along the current. The location of the increasing river ecosystem pollution was also determined. The obtained results enable bringing out basic zones of permanent high hydrocarbon concentrations and places of periodic discharges into the river basin.

Pollution characteristics of aromatic hydrocarbons in the groundwater of China

Much of the world's groundwater supply has been contaminated by aromatic hydrocarbons originating from anthropogenic sources. To study the occurrence and distribution characteristics of aromatic hydrocarbons in groundwater, 24 aromatic hydrocarbon compounds were selected: Five BTEX compounds (benzene, toluene, ethylbenzene, o-xylene, m-xylene, and p-xylene), 10 alkyl-substituted benzene, and 9 halogenated aromatics. These aromatic hydrocarbons were then analyzed from 355 samples collected from across China. Results indicated that aromatic hydrocarbons were detected in 59 out of 355 samples. Of the selected aromatic hydrocarbons, BTEX compounds were detected with high frequency and at low concentrations; comparatively, halogenated aromatics were detected with low frequency and at high concentrations. The aromatic hydrocarbon characteristics found in both karst and pore groundwater samples were then determined using their respective hydrogeological conditions and corresponding human activities. In karst groundwater, BTEX compounds were the most frequently detected aromatic hydrocarbon. The high detection frequencies of aromatic hydrocarbons were caused by their rapid migration, owing to the developed conduit system in the sampled karst area. The low concentrations of aromatic hydrocarbons in karst groundwater samples were caused by low-intensity human activity along with special hydrogeological conditions with higher redox potential and the unique compositions of aromatic hydrocarbons. Alkyl-substituted aromatics and halogenated aromatics were detected at higher concentrations in pore groundwater, owing to high-intensity human activity. Aromatic hydrocarbon pollution was gradually decreased along piedmont-alluvial plain-coast line, owing to a decrease in aquifer vulnerability. These were positively correlated with the size of the aquifer's particles. Samples with a high accumulative concentration of these aromatic hydrocarbons tended to occur in pore groundwater with a high concentration of either SO42− or Cl−.

Dysbiosis in the Gut Microbiota of Soil Fauna Explains the Toxicity of Tire Tread Particles.

Tread particles (TPs) from vehicle tires are widely distributed in soil ecosystems; therefore, there is an urgent need to evaluate their effects on soil biota. In the present study, the soil worm Enchytraeus crypticus was incubated for 21 days in soil microcosms containing increasing concentrations of TPs (0, 0.0048%, 0.024%, 0.12%, 0.6%, and 3% of dry soil weight). High concentrations of zinc (Zn, 9407.4 mg kg-1) and polycyclic aromatic hydrocarbons (PAHs, 46.8 mg kg-1) were detected in the TPs, which resulted in their increased concentrations in soils amended with TPs. We demonstrated that TPs had an adverse effect on the survival (decreased by more than 25%) and reproduction (decreased by more than 50%) of the soil worms. Moreover, TP exposure disturbed the microbiota of the worm guts and surrounding soil. In addition, a covariation between bacterial and fungal communities was observed in the worm guts after exposure to TPs. Further analysis showed that TP exposure caused an enrichment of microbial genera associated with opportunistic pathogenesis in the worm guts. The combined results from this study indicate that TPs might threaten the terrestrial ecosystem by affecting soil fauna and their gut microbiota.

Isolation and characterization of Botryococcus braunii from a freshwater environment in Tenggarong, Kutai Kartanegara, Indonesia

Abstract. Nugroho RA, Subagyono DJN, Arung ET. 2020. Isolation and characterization of Botryococcus braunii from a freshwater environment in Tenggarong, Kutai Kartanegara, Indonesia. Biodiversitas 21: 2331-2336. The use of microalgae as an alternative source of oil has gained much attention in recent years. The present study was conducted to isolate and characterize microalgae Botryococcus braunii from a freshwater environment, located in Tenggarong, Kutai Kartanegara, East Kalimantan, Indonesia. B. braunii were cultured and determined their growth in terms of biomass yield and the presence of lipid globules by red Nile staining. Dry biomass, phosphate, and protein content of cultured B. braunii were measured at 3 days of intervals for 24 days. Biomass yield, hydrocarbon, carotenoid, and chlorophyll content were determined at the pH range of 6, 6.5, 7, 7.5, and 8 and various CO2 concentrations. The result showed that B. braunii collected from freshwater in Tenggarong can produce lipid globules. The highest growth of B. braunii was reached at day 15, while the optimal phosphate content was on the 12th day, and the protein was relatively stable during culture. The optimal weight of B. braunii biomass was reached at pH 7 and 4% CO2 and the highest hydrocarbon content was obtained at pH 8 and 4% CO2. The highest chlorophyll and carotenoid contents were obtained 4% CO2. In conclusion, B. braunii collected from Tenggarong was successfully cultured and able to produce lipid globules. The optimal conditions for its growth and production of hydrocarbon, phosphate, protein, chlorophyll, and carotenoid were at pH of 7-8 and 4% CO2.

Removal Efficiencies of Constructed Wetland Planted with Phragmites and Vetiver in Treating Synthetic Wastewater Contaminated with High Concentration of PAHs

This study aimed to evaluate the capability of horizontal subsurface flow constructed wetlands (HSFCWs) in treating contaminated wastewater with a high concentration of polycyclic aromatic hydrocarbons (PAHs) (Phenanthrene, Pyrene, and Benzo[a]Pyrene), using two plants, namely Phragmites and Vetiver. The investigated parameters were (1) PAHs uptake by the plants, (2) PAHs removal efficiencies, (3) accumulated PAHs in the soil of CWs, (4) shoot/root concentration factor, (5) translocation factor, and (6) PAHs correlation to lipid contains in the plants. During the treatment period, the results showed that the highest concentration of Phenanthrene in the shoot and the root systems of Phragmites, was 229.3 and 192 μg/g; Pyrene was 69.1 and 59.2 µg/g; and Benzo[a]Pyrene 25.1 and 20.2 µg/g, respectively. Meanwhile, in the Vetiver shoot and root systems were Phenanthrene 87.5 and 64.1 µg/g; Pyrene 63.2 and 42.1 µg/g; and Benzo[a]Pyrene 21.3 and 27.3 µg/g, respectively. The removal rates of Phenanthrene, Pyrene, and Benzo[a]Pyrene (PAHs compounds) by the CW planted with Phragmites were found to be 83%, 71%, and 81%, respectively, while the removal rates by CW planted with Vetiver were found to be 67%, 66%, and 73%, respectively. Moreover, the removal rates by unplanted CW were found to be 62%, 58%, and 55%, respectively. The results indicated that the HSFCW planted with Phragmites has an effective pathway to remove high concentrations of PAHs.

Acrylamide impairs ovarian function by promoting apoptosis and affecting reproductive hormone release, steroidogenesis and autophagy-related genes: An in vivo study.

Acrylamide (ACR) toxicity is quite common due to its widespread use in industry and due to the Maillard browning reaction that occurs in foods containing high concentrations of hydrocarbons subjected to high temperatures. This study aimed to elucidate the female reproductive toxicity of ACR in vivo. Fifty-day-old Wistar-Albino female rats were treated with different dosages of ACR (2.5, 10, and 50mg/kg/day). After treatment, the animals were sacrificed, and serum and ovary samples were collected for histological examination, hormone analysis, TUNEL analysis, and RT-PCR studies. We found that ACR acts by significantly reducing ovarian weight and serum progesterone and estradiol concentrations. In addition, ACR treatment led to pyknotic, heterochromatic characteristics and nuclear fragmentation, as evidenced by hematoxylin staining. The TUNEL assay revealed that granulosa cells were affected after the oral administration of ACR, leading to the apoptosis of follicles at different stages of growth. Compared with the control condition, high doses of ACR (50mg/kg/day) significantly induced the overexpression of INSL3, CYP17a, IGF1, ESR1, ESR2, ATG5, ATG12 and LC3 in the ovary. Moreover, LC3 mRNA levels significantly increased with increasing doses of ACR (2.5, 10 and 50mg/kg/day), suggesting that ACR treatment induced autophagy. In conclusion, ACR induced ovarian dysfunction by affecting steroid hormone release, increasing apoptosis and mRNA levels of autophagy-related genes. The eventual correlation between apoptotic granulosa cell death and autophagy needs to be further explored.

Evaluation of glass waste formed containing NORM

In oil and gas production, crude oil is an important ingredient in the manufacture industry. The sludge from the oil is semi-solid waste and classified as a low-level waste that consists of a mixture of oil, sediment and, water containing radioactive element (Naturally Occurring Radioactive Materials (NORM); and high hydrocarbon concentration. It is categorized and considered as hazardous waste that required careful handling and treatment before disposal. Vitrification process was carried out in this study to immobilize the sludge containing radioactive waste. The objectives in this study is to optimize waste loading and to evaluate the glass waste formed after vitrification process. It is found that 20 wt% of oil sludge at 1200°C is the best optimize waste loading in the experiment because the glass waste formed are completely homogeneous phase.

Preliminary Study on the Differences in Hydrocarbons Between Phosphine-Susceptible and -Resistant Strains of Rhyzopertha dominica (Fabricius) and Tribolium castaneum (Herbst) Using Direct Immersion Solid-Phase Microextraction Coupled with GC-MS.

Phosphine resistance is a worldwide issue threatening the grain industry. The cuticles of insects are covered with a layer of lipids, which protect insect bodies from the harmful effects of pesticides. The main components of the cuticular lipids are hydrocarbon compounds. In this research, phosphine-resistant and -susceptible strains of two main stored-grain insects, T. castaneum and R. dominica, were tested to determine the possible role of their cuticular hydrocarbons in phosphine resistance. Direct immersion solid-phase microextraction followed by gas chromatography-mass spectrometry (GC-MS) was applied to extract and analyze the cuticular hydrocarbons. The results showed significant differences between the resistant and susceptible strains regarding the cuticular hydrocarbons that were investigated. The resistant insects of both species contained higher amounts than the susceptible insects for the majority of the hydrocarbons, sixteen from cuticular extraction and nineteen from the homogenized body extraction for T. castaneum and eighteen from cuticular extraction and twenty-one from the homogenized body extraction for R. dominica. 3-methylnonacosane and 2-methylheptacosane had the highest significant difference between the susceptible and resistant strains of T. castaneum from the cuticle and the homogenized body, respectively. Unknown5 from the cuticle and 3-methylhentriacontane from the homogenized body recorded the highest significant differences in R. dominica. The higher hydrocarbon content is a key factor in eliminating phosphine from entering resistant insect bodies, acting as a barrier between insects and the surrounding phosphine environment.

Adsorbed and free hydrocarbons in unconventional shale reservoir: A new insight from NMR T1-T2 maps

Abstract Characterizing free and adsorbed hydrocarbon is crucial for the resources assessment and mobility evaluation of shale oil plays. The complex feature of hydrogen-bearing components in shale reservoirs requires new analytical methods to study the occurrences of different states of hydrocarbons. In this study, forty core samples from five shale oil research wells in the Jiyang Depression of China were analyzed using various analytical tools including nuclear magnetic resonance (NMR) T1-T2 mapping, Leco total organic carbon (TOC) analysis, routine and special programmed Rock-Eval pyrolysis, solvent extraction and fractionation, as well as mercury injection capillary pressure (MICP) experiments. Additional experiments were conducted on a powdered shale for NMR T1-T2 maps under four states: as-received, after being dried at 110 °C, after special programmed pyrolysis to 350 °C, and after solvent extraction. The results showed that residual water signals in the NMR T1-T2 map disappeared after being dried at 110 °C. Free oil signals decreased dramatically when the sample was thermally treated to 350 °C, while adsorbed oil signals decreased sharply after solvent extraction. A good accordance was observed between the organic hydrogen T2 spectra and three modes of Rock-Eval pyrograms, representing free hydrocarbons, adsorbed hydrocarbons, and hydrocarbons from kerogen/bitumen decomposition. A positive correlation was also found between the intensity of NMR T1-T2 map signals and the free and adsorbed hydrocarbon contents from geochemical analysis. T2 cut-off values of adsorbed hydrocarbons and free hydrocarbons were determined to be 0.2 ms and 1 ms, respectively. Core samples with a high oil saturation index, porosity, and relative content of hydrocarbons display a low T1/T2 ratio indicative of a high shale oil mobility. As a complementary method to the Rock-Eval analysis, NMR T1-T2 mapping is a non-destructive technique for the characterization of adsorbed and free hydrocarbons at the core scale with limited sample preparation. The results of this study are helpful for NMR characterization of shale reservoirs.

Biodegradation of slop oil by endophytic Bacillus cereus EN18 coupled with lipase from Rhizomucor miehei (Palatase®)

Removal of slop oil, a by-product of oil refining, also obtained in cleaning up of oil tanks and filters is a difficult issue. High content of hydrocarbons (C3–C40) and other organic compounds makes this waste difficult to eliminate from the environment. The purpose of this investigation was to combine bacterial degradation by endophytic Bacillus cereus EN18 with biotransformation performed using lipase enzyme preparation (Palatase®) to remove recalcitrant compounds present in slop oil from the environment. Endophytic B. cereus EN18 was able to biodegrade up to 40% of slop oil while supplementation with lipase improved the efficiency of contamination removal in about one third. Also the use of lipase enzyme preparation resulted in higher microbial activity of B. cereus EN18 bacterial strain, as well as higher concentration of fatty acids in the culture medium, which indicates higher degradation efficiency. Obtained results suggest that lipase preparation from Rhizomucor miehei (Palatase®) may be a useful agent to improve microbial degradation of recalcitrant pollutants, like slop oil in water environments. GC and spectrometric analysis revealed that hydrocarbons from slop oil were effectively degraded while using both microbial degradation and lipase catalysis.

Outdoor open pond batch production of green microalga Botryococcus braunii for high hydrocarbon production: enhanced production with salinity

The aim of this work was to enhance the biodiesel quality and hydrocarbon content of green microalga B. braunii strain KMITL 2 cultivated outdoor under several salinity conditions in a batch production. The enhancement would be such that the microalgal biodiesel qualities met or exceeded the current standard so that it would be a good raw material for biodiesel production. The microalga production was in 300 L open oval ponds, among various salinity levels tested (0–20 ppt), 5 ppt was the best for hydrocarbon production, yielding 54.2 ± 0.9% hydrocarbon content and 5.1 ± 0.4 g L−1 biomass. As the microalga production was scaled up by cultivation in 3,675 L open raceway pond under the 5 ppt condition, the microalga yielded a bit higher hydrocarbon content (58.8 ± 2.9%) but much lower biomass (2.5 ± 0.5 g L−1). The production in both oval and raceway ponds yielded a nearly identical biodiesel property (61.06–67.42 cetane number) which exceeded the value specified in international standards. Therefore, it was concluded that B. braunii strain KMITL 2 can be batch cultivated in an open pond at optimum salinity to yield sufficient hydrocarbon and biomass for biodiesel production.

Comparison of the quality of beef jerky processed by traditional and modern drying methods from different districts in Inner Mongolia

The influence of drying methods on the quality of beef jerky from Inner Mongolia was discussed. Beef jerky processed by traditional natural freeze-drying from Huhhot (HT) and Bayan Nur (BT) was tough, chewy, red and lustrous, while that processed by modern hot air drying from Huhhot (HM) and Bayan Nur (BM) was cohesive, hard, brown and dark, as observed by the moisture content (MC), shear force and colour. HT and BT had high free fatty acid (FFA) contents. And HM and BM had high free amino acid (FAA) contents. HT and BT had high hydrocarbon, aldehyde and ketone contents, while HM and BM had high nitrogen-containing compound contents. The higher hydrocarbon, acid and ester contents were observed in BT and BM, and higher nitrogen-containing compound contents were observed in HT and HM. The traditional method was related to a typical green grassy, fatty, meaty and sweet odour. The modern method increased nitrogen-containing compound contents, generating a roasted beef odour.

Green diesel production from palm fatty acid distillate over SBA-15-supported nickel, cobalt, and nickel/cobalt catalysts

The utilization of non-edible and low-cost feedstock in bioenergy research is getting more attention in recent decades. Catalytic deoxygenation of fatty acids from waste oil feedstocks is a promising route to produce diesel-like hydrocarbons. Here we report the conversion of palm fatty acid distillate (PFAD), a low-value side product of physical refining of crude palm oil, into green diesel using a solventless and hydrogen-free deoxygenation (DO) reaction using catalytic deoxygenation over solid acid catalysts (Co/SBA-15, Ni/SBA-15, and Ni–Co/SBA-15) with total metal loadings of 5 wt%. Metal precursors (Ni, Co, Ni–Co) were doped on the mesostructured catalyst supporter, SBA-15 by wet impregnation. The catalysts were characterized by nitrogen adsorption-desorption isotherm analysis, X-ray diffraction, X-ray fluorescence, infrared spectroscopy, and high-resolution transmission electron microscopy with elemental mapping. The DO reaction was carried out in a semi-batch reactor with a catalyst loading of 10 wt% at 350 °C for 3 h. The use of both Ni/SBA-15 and Ni–Co/SBA-15 afforded products with high contents of liquid hydrocarbons (C8–C17) with yields of 85.8% and 88.1%, respectively, and selectivity for diesel-range hydrocarbons (C13–C17) above 85% were achieved. Cobalt seems to have a larger particle size, then associates with the carbon formation and introduces coke formation. It blocks some pores and deactivates the active sites of the catalyst, thus reducing the catalytic activity.

Advanced Bioreactor Treatments of Hydrocarbon-Containing Wastewater

This review discusses bioreactor-based methods for industrial hydrocarbon-containing wastewater treatment using different (e.g., stirred-tank, membrane, packed-bed and fluidized-bed) constructions. Aerobic, anaerobic and hybrid bioreactors are becoming increasingly popular in the field of oily wastewater treatment, while high concentrations of petroleum hydrocarbons usually require physico-chemical pre-treatments. Most efficient bioreactor techniques employ immobilized cultures of hydrocarbon-oxidizing microorganisms, either defined consortia or mixed natural populations. Some advantages of fluidized-bed bioreactors over other types of reactors are shown, such as large biofilm–liquid interfacial area, high immobilized biomass concentration and improved mass transfer characteristics. Several limitations, including low nutrient content and the presence of heavy metals or toxicants, as well as fouling and contamination with nuisance microorganisms, can be overcome using effective inocula and advanced bioreactor designs. The examples of laboratory studies and few successful pilot/full-scale applications are given relating to the biotreatment of oilfield wastewater, fuel-contaminated water and refinery effluents.

A Versatile Capacitive Sensing Platform for the Assessment of the Composition in Gas Mixtures.

The energy market is facing a major transition, in which natural gas and renewable gasses will play an important role. However, changing gas sources and compositions will force the gas transporters, gas engine manufacturers, and gas grid operators to monitor the gas quality in a more intensive way. This leads to the need for lower cost, smaller, and easy to install gas quality sensors. A new approach is proposed in this study that is based on the chemical interactions of the various gas components and responsive layers applied to an array of capacitive interdigitated electrodes. For Liquid Natural Gas (LNG), containing a relative high concentration of higher hydrocarbons, an array of ten capacitive chips is proposed, that is sufficient to calculate the full composition, and can be used to calculate energy parameters, such as Wobbe Index, Calorific Value, and Methane Number. A first prototype was realized that was small enough to be inserted in low and medium pressure gas pipes and LNG engine fuel lines. Adding the pressure and temperature data to the chip readings enables the determination of the concentrations of the various alkanes, hydrogen, nitrogen, and carbon dioxide, including small fluctuations in water vapor pressure. The sensitivity and selectivity of the new sensor is compared to a compact analyzer employing tunable filter infrared spectrometry.

Microbial community dynamics and functional responses that contribute to tolerance of high concentrations of petroleum hydrocarbon

AbstractBACKGROUNDIt is a common problem that high‐concentration petroleum hydrocarbon (hc‐PH) is difficult to degrade and remove using biological methods.RESULTSIn this study, when the concentrations of petroleum hydrocarbon (PH) were increased from 972.4 ± 40.3 to 6953.8 ± 294.3 mg L−1, all degradation rates of PH by activated sludge (AS) were beyond 79%. However, the degradation rate of hc‐PH (from 9958.3 ± 401.6 to 19 953.3 ± 896.5 mg L−1) by AS was significantly lower than that of low‐concentration petroleum hydrocarbon (lc‐PH) (from 972.4 ± 40.3 to 6953.8 ± 294.3 mg L−1). Meanwhile, the heterotrophic microorganism number and bacterial community diversity in the hc‐PH environment were lower than those in the lc‐PH environment. Sequencing results of the bacterial community showed that the dominant bacterial community of AS was stable and composed by the genera Pseudomonas, Acinetobacter and Burkholderia‐Paraburkholderia in the hc‐PH condition. Moreover, aimed to enhance the tolerance to hc‐PH stress, the relative abundances of microbial community functions of environmental adaptation, membrane transport, replication and repair were increased. However, the digestive system, circulatory system and endocrine system of the microbial community were significantly disturbed by hc‐PH, which eventually caused the degradation rate of PH by AS to decrease significantly.CONCLUSIONThus the decrease of microbial community diversity and tolerance ability can be regarded as the main limiting factors to enhance the degradation rate of hc‐PH by microorganisms. © 2019 Society of Chemical Industry

Chemical composition and distribution of the headspace volatiles in commercial culinary herbs and spices: Chemometric approach

Fast determination of the volatile components of widely used culinary herbs and spices, without prior preparation of the sample, using headspace sampling (HS) and GC?MS/FID analysis, is presented. Generally, monoterpenes were the dominant class in HS volatiles (HSV): monoterpene hydrocarbons in dill, celery, parsnip and parsley, and oxygenated monoterpenes in coriander, bay laurel and rosemary. The HSV of ginger and clove samples differed from the others due to their high content of sesquiterpene hydrocarbons and phenylpropanoids, respectively. The most extreme case of limited distribution was related to the samples of garlic-HSV comprised organosulfur compounds and none of the above mentioned classes. Furthermore, the HSV data were processed via principal component analysis, making visible the variability and tendency between the investigated samples. Lastly, the research provides insights in many HS profiles of culinary herbs and spices, giving relative representation of volatiles as well as differences and deviation in terms of HSV content.