A hybrid constructed wetland for organic-material and nutrient removal from sewage: Process performance and multi-kinetic models

© 2018 Elsevier Ltd A pilot-scale hybrid constructed wetland with vertical flow and horizontal flow in series was constructed and used to investigate organic material and nutrient removal rate constants for wastewater treatment and establish a practical predictive model for use. For this purpose, the performance of multiple parameters was statistically evaluated during the process and predictive models were suggested. The measurement of the kinetic rate constant was based on the use of the first-order derivation and Monod kinetic derivation (Monod) paired with a plug flow reactor (PFR) and a continuously stirred tank reactor (CSTR). Both the Lindeman, Merenda, and Gold (LMG) analysis and Bayesian model averaging (BMA) method were employed for identifying the relative importance of variables and their optimal multiple regression (MR). The results showed that the first-order–PFR (M2) model did not fit the data (P > 0.05, and R2 0.5). The pollutant removal rates in the case of M1 were 0.19 m/d (CODCr) and those for M3 were 25.2 g/m2∙d for CODCr and 2.63 g/m2∙d for NH4-N. By applying a multi-variable linear regression method, the optimal empirical models were established for predicting the final effluent concentration of five days' biochemical oxygen demand (BOD5) and NH4-N. In general, the hydraulic loading rate was considered an important variable having a high value of relative importance, which appeared in all the optimal predictive models

Enhanced efficiency for better wastewater sludge hydrolysis conversion through ultrasonic hydrolytic pretreatment

© 2016 Taiwan Institute of Chemical Engineers The major requirements for accelerating the process of anaerobic digestion and energy production are breaking the structure of waste activated sludge (WAS), and transforming it into a soluble form suitable for biodegradation. This work investigated and analysed a novel bench-scale ultrasonic system for WAS disruption and hydrolysis using ultrasonic homogenization. Different commercial sonoreactors were used at low frequencies under a variety of operating conditions (intensity, density, power, sonication time, and total suspended solids) to evaluate the effects of the equipment on sludge hydrolysis and to generate new insights into the empirical models and mechanisms applicable to the real-world processing of wastewater sludge. A relationship was established between the operating parameters and the experimental data. Results indicated an increase in sonication time or ultrasonic intensity correlated with improved sludge hydrolysis rates, sludge temperature, and reduction rate of volatile solids (33.51%). It also emerged that ultrasonication could effectively accelerate WAS hydrolysis to achieve disintegration within 5–10 min, depending on the ultrasonic intensity. This study also determined multiple alternative parameters to increase the efficiency of sludge treatment and organic matter reduction, and establish the practicality of applying ultrasonics to wastewater sludge pretreatment

Adsorption mechanism of hexavalent chromium onto layered double hydroxides-based adsorbents: A systematic in-depth review

© 2019 Elsevier B.V. An attempt has been made in this review to provide some insights into the possible adsorption mechanisms of hexavalent chromium onto layered double hydroxides-based adsorbents by critically examining the past and present literature. Layered double hydroxides (LDH) nanomaterials are typical dual-electronic adsorbents because they exhibit positively charged external surfaces and abundant interlayer anions. A high positive zeta potential value indicates that LDH has a high affinity to Cr(VI) anions in solution through electrostatic attraction. The host interlayer anions (i.e., Cl−, NO3−, SO42−, and CO32−) provide a high anion exchange capacity (53–520 meq/100 g) which is expected to have an excellent exchangeable capacity to Cr(VI) oxyanions in water. Regarding the adsorption-coupled reduction mechanism, when Cr(VI) anions make contact with the electron-donor groups in the LDH, they are partly reduced to Cr(III) cations. The reduced Cr(III) cations are then adsorbed by LDH via numerous interactions, such as isomorphic substitution and complexation. Nonetheless, the adsorption-coupled reduction mechanism is greatly dependent on: (1) the nature of divalent and trivalent salts utilized in LDH preparation, and the types of interlayer anions (i.e., guest intercalated organic anions), and (3) the adsorption experiment conditions. The low Brunauer–Emmett–Teller specific surface area of LDH (1.80–179 m2/g) suggests that pore filling played an insignificant role in Cr(VI) adsorption. The Langmuir maximum adsorption capacity of LDH (Qomax) toward Cr(VI) was significantly affected by the natures of used inorganic salts and synthetic methods of LDH. The Qomax values range from 16.3 mg/g to 726 mg/g. Almost all adsorption processes of Cr(VI) by LDH-based adsorbent occur spontaneously (ΔG° 0) and increase the randomness (ΔS° >0) in the system. Thus, LDH has much potential as a promising material that can effectively remove anion pollutants, especially Cr(VI) anions in industrial wastewater

Implementation of Web-Based Respondent-Driven Sampling among Men who Have Sex with Men in Vietnam

Objective: Lack of representative data about hidden groups, like men who have sex with men (MSM), hinders an evidence-based response to the HIV epidemics. Respondent-driven sampling (RDS) was developed to overcome sampling challenges in studies of populations like MSM for which sampling frames are absent. Internet-based RDS (webRDS) can potentially circumvent limitations of the original RDS method. We aimed to implement and evaluate webRDS among a hidden population. Methods and Design: This cross-sectional study took place 18 February to 12 April, 2011 among MSM in Vietnam. Inclusion criteria were men, aged 18 and above, who had ever had sex with another man and were living in Vietnam. Participants were invited by an MSM friend, logged in, and answered a survey. Participants could recruit up to four MSM friends. We evaluated the system by its success in generating sustained recruitment and the degree to which the sample compositions stabilized with increasing sample size. Results: Twenty starting participants generated 676 participants over 24 recruitment waves. Analyses did not show evidence of bias due to ineligible participation. Estimated mean age was 22 year and 82% came from the two large metropolitan areas. 32 out of 63 provinces were represented. The median number of sexual partners during the last six months was two. The sample composition stabilized well for 16 out of 17 variables. Conclusion: Results indicate that webRDS could be implemented at a low cost among Internet-using MSM in Vietnam. WebRDS may be a promising method for sampling of Internet-using MSM and other hidden groups. Key words: Respondent-driven sampling, Online sampling, Men who have sex with men, Vietnam, Sexual risk behavio

Acute lyme infection presenting with amyopathic dermatomyositis and rapidly fatal interstitial pulmonary fibrosis: a case report

<p>Abstract</p> <p>Introduction</p> <p>Dermatomyositis has been described in the setting of lyme infection in only nine previous case reports. Although lyme disease is known to induce typical clinical findings that are observed in various collagen vascular diseases, to our knowledge, we believe that our case is the first presentation of acute lyme disease associated with amyopathic dermatomyositis, which was then followed by severe and fatal interstitial pulmonary fibrosis only two months later.</p> <p>Case presentation</p> <p>We present a case of a 64-year-old African-American man with multiple medical problems who was diagnosed with acute lyme infection after presenting with the pathognomonic rash and confirmatory serology. In spite of appropriate antimicrobial therapy for lyme infection, he developed unexpected amyopathic dermatomyositis and then interstitial lung disease.</p> <p>Conclusions</p> <p>This case illustrates a potential for lyme disease to produce clinical syndromes that may be indistinguishable from primary connective tissue diseases. An atypical and sequential presentation (dermatomyositis and interstitial lung disease) of a common disease (lyme infection) is discussed. This case illustrates that in patients who are diagnosed with lyme infection who subsequently develop atypical muscular, respiratory or other systemic complaints, the possibility of severe rheumatological and pulmonary complications should be considered.</p

Оценивание финансово-экономической безопасности предприятий молокоперерабатывающей отрасли

The essence of the concept “financial and economic security of the enterprise” is covered. Methodological approaches to the enterprise financial and economic security evaluation are considered, enabling the method of index numberrating score of the enterprise financial and economic security to be found. Dynamics of milk anddairy production in Ukraine has been studied. Ukrainian regions leading in liquid processed milk production have been identified. Dynamics of milk and dairy production per man has been analyzed which allowed to find out the annual increase in demand per man. Integrated index of the dairy enterprise financial and economic security has been evaluated. As a result, the ways to increase the managerial efficiency of financial and economic security of the following enterprises:PJSC "Dubnomoloko", PJSC "Kupyans'ki milk canning plant", PJSC the "Yagotyns'ki creamery", PJSC the "Pervomais'ki milk canning plant" are offered.У статті розкрито сутність поняття фінансово-економічної безпеки підприємства. Розглянуто методичні підходи щодо оцінювання фінансово-економічної безпеки підприємства, що дозволило виявити підхід рейтингової оцінки показника фінансово-економічної безпеки підприємства. Досліджено динаміку виробництва молока та молочних продуктів України. Виявити області України, які є лідерами з виробництва молока рідкого обробленого. Проаналізовано динаміку виробництва молока та молочних продуктів на одну особу, що дозволило встановити щорічне зростання попиту на одну особу. Визначено підприємства молокопереробної галузі. Проведено оцінку інтегрального показника фінансово-економічної безпеки підприємств молокопереробної галузі. За результатами оцінки запропоновано шляхи підвищення ефективності управління фінансово-економічної безпеки таких підприємств, як: ПАТ «Дубномолоко», ПАТ «Куп’янський молочноконсервний комбінат», ПАТ «Яготинський маслозавод», ПАТ «Первомайський молочноконсервний комбінат».В статье раскрыто сущность понятия финансово-экономическая безопасность предприятия. Рассмотрено методические подходы относительно оценивания финансово-экономической безопасности предприятия, что позволило выявить поход рейтинговой оценки показателя финансово-экономической безопасности предприятия. Исследовано динамику производства молока и молочных продуктов Украины. Выявлены области Украины, которые являются лидерами по производству молока жидкого обработанного. Проанализировано динамику производства молока и молочных продуктов на одного человека, что позволило установить ежегодный рост спроса на одного человека. Определены предприятия молокоперерабатывающей отрасли. Проведена оценка интегрального показателя финансово-экономической безопасности предприятий молокоперерабатывающей отрасли. По результатам оценки предложены пути повышения эффективности управления финансово-экономической безопасности таких предприятий, как: ПАО «Дубномолоко», ПАО «Купянский молочноконсервный комбинат», ПАО «Яготинский маслозавод», ПАО «Первомайский молочноконсервный комбинат»

B-fields and Dust in Interstellar Filaments Using Dust Polarization (BALLAD-POL). I. The Massive Filament G11.11–0.12 Observed by SOFIA/HAWC+

We report the first measurement of polarized thermal dust emission toward the entire infrared dark cloud G11.11−0.12 taken by the polarimeter SOFIA/HAWC+ at 214 μm. The obtained magnetic fields (B-fields) from the polarized emission of the early-stage and massive filament tend to be perpendicular to its spine. We produce a map of B-field strengths for the center region of the filament. The strengths vary in the range of 100–600 μG and are strongest along the filament's spine. The central region is sub-Alfvénic and mostly subcritical, meaning that B-fields dominate over turbulence and are strong enough to resist gravitational collapse. The alignment and properties of dust grains in the filament are studied using radiative torque (RAT) theory. We find the decrease of polarization degree P with emission intensity I, i.e., depolarization effect, of the form P∝ I−α ∼ 0.8–0.9, implying a significant loss of grain alignment in the filament's spine. The depolarization can be explained by the decrease in RAT alignment efficiency toward the denser regions with weaker radiation field, which cannot be explained by B-field tangling. We study the effect of the enhanced magnetic relaxation by embedded iron inclusions on RAT alignment and find that the high polarization fraction P ∼ 20%–30% in the outer layer of the filament is potential evidence for the magnetically enhanced RAT alignment mechanism. This is the first time this effect is evaluated in a filament. Based on the polarization fraction and RAT alignment theory, we also find evidence for grain growth in the filament

X-ray emission from the Sombrero galaxy: discrete sources

We present a study of discrete X-ray sources in and around the bulge-dominated, massive Sa galaxy, Sombrero (M104), based on new and archival Chandra observations with a total exposure of ~200 ks. With a detection limit of L_X = 1E37 erg/s and a field of view covering a galactocentric radius of ~30 kpc (11.5 arcminute), 383 sources are detected. Cross-correlation with Spitler et al.'s catalogue of Sombrero globular clusters (GCs) identified from HST/ACS observations reveals 41 X-rays sources in GCs, presumably low-mass X-ray binaries (LMXBs). We quantify the differential luminosity functions (LFs) for both the detected GC and field LMXBs, whose power-low indices (~1.1 for the GC-LF and ~1.6 for field-LF) are consistent with previous studies for elliptical galaxies. With precise sky positions of the GCs without a detected X-ray source, we further quantify, through a fluctuation analysis, the GC LF at fainter luminosities down to 1E35 erg/s. The derived index rules out a faint-end slope flatter than 1.1 at a 2 sigma significance, contrary to recent findings in several elliptical galaxies and the bulge of M31. On the other hand, the 2-6 keV unresolved emission places a tight constraint on the field LF, implying a flattened index of ~1.0 below 1E37 erg/s. We also detect 101 sources in the halo of Sombrero. The presence of these sources cannot be interpreted as galactic LMXBs whose spatial distribution empirically follows the starlight. Their number is also higher than the expected number of cosmic AGNs (52+/-11 [1 sigma]) whose surface density is constrained by deep X-ray surveys. We suggest that either the cosmic X-ray background is unusually high in the direction of Sombrero, or a distinct population of X-ray sources is present in the halo of Sombrero.Comment: 11 figures, 5 tables, ApJ in pres

Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV

The performance of muon reconstruction, identification, and triggering in CMS has been studied using 40 inverse picobarns of data collected in pp collisions at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection criteria covering a wide range of physics analysis needs have been examined. For all considered selections, the efficiency to reconstruct and identify a muon with a transverse momentum pT larger than a few GeV is above 95% over the whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4, while the probability to misidentify a hadron as a muon is well below 1%. The efficiency to trigger on single muons with pT above a few GeV is higher than 90% over the full eta range, and typically substantially better. The overall momentum scale is measured to a precision of 0.2% with muons from Z decays. The transverse momentum resolution varies from 1% to 6% depending on pseudorapidity for muons with pT below 100 GeV and, using cosmic rays, it is shown to be better than 10% in the central region up to pT = 1 TeV. Observed distributions of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO