Enhanced control of activated sludge process using predetermined set-points

The performance of activated sludge process (ASP) is evaluated by the effluent quality which is determined by five different variables of the treated wastewater such as ammonia, total nitrogen, COD, BOD₅ and TSS. To keep these five variables within the limits as per environmental regulations, nitrate and nitrite concentration (S _NO) in the second anoxic reactor and the dissolved oxygen concentration (S _O) in the last aerobic reactor of the ASP should be maintained at prescribed levels. To do that, a closed-loop control configuration is required and proper set-points for these closed-loop control configurations are needed. In this paper, the optimal values of controller set-points are determined for nitrogen removal in the activated sludge process. Effluent quality limits have been considered to evaluate the optimal set-points for the Indian climatic conditions. Once the optimal set-points are determined, PI controllers are used to control S _NO in the second anoxic reactor and S _O in the last aerobic reactor of the ASP. Further, feed-forward control is incorporated to minimize the effect of disturbances, which enters along with the influent. No case studies of BSM1 model have been reported in the literature for the Indian wastewater. In this work, the dynamic simulation of an activated sludge process is performed using the data collected from the sewage treatment plant, located in India. The results of the simulation showed that feed-forward with PI control strategy, ASP can be efficiently controlled without any effluent violations, when compared to BSM1.     

Anaerobic digester sludge as nutrient source for culturing of microalgae for economic biodiesel production

After decades of ‘living dangerously’, the human kind has paused to think of Mother Nature. Alternate energy sources are being developed as a part of this realization. The use of indigenous sources of nutrients would considerably bring down the cost of production. A mixed consortium of Chlorella vulgaris, Arthrospira platensis, and tap water-originated Scenedesmus dimorphus was cultured using natural seawater, anaerobic digester sludge, and its growth was compared with synthetic commercial media like Zarrouk’s media, NaNO₃ media, and NH₄Cl media. A spectrophotometric method was standardized for regular biomass estimation. The dry biomass of a 15-day pure, batch culture of Arthrospira was found to yield around 600 mg/L in anaerobic digester sludge, whereas the pure batch culture of chlorella’s growth was hindered mainly due to the presence of bacteria and grazers. Regular microscopic observation and biomass monitoring revealed a drastic reduction in grazing activity, with the use of autoclaved AD sludge, resulting in a strong and stable microalgal mixed consortia. The consortia growth in AD sludge was found to be better than with the synthetic media with no cost of nutrient. The mixed consortia yielded a biomass up to 600 mg/L and lipid of 21.18%. The lipid generated from AD sludge had around 95% unsaturates and contained around 5% omega-3 fatty acids. The use of anaerobic digester sludge in a non-sterile condition reduces the total cost of the biodiesel production process as a whole and introduces a decentralized system for waste water treatment as well.     

Use of glycosides extracted from the fique (<Emphasis Type="Italic">Furcraea</Emphasis> sp.) in wastewater treatment for textile industry

The laboratory tests for the use of sapogenic amphiphilic glycosides as a coagulation–flocculation aid are presented in this paper. These amphiphilic glycosides were obtained, through a natural fermentation process, of the juice, of fique (Furcraea sp.) leaves. Decantation allows for the separation of a supernatant denominated “supernatant fique juice” and a decanted fraction denominated “decanted fique juice.” The latter contains most of the sapogenic amphiphilic glycosides and was mixed with the chemical coagulant ferric chloride hexahydrate, at varying doses. Ferric chloride hexahydrate was also used as a control to ascertain the removal efficiency of persistent contaminants from samples of a textile industry effluent. The parameters of interest were typical indicators of water quality such as color, turbidity, chemical oxygen demand, pH and conductivity. The results indicate that the decanted fique juice, when used as a coagulation–flocculation aid, and upon comparison with the chemical coagulant alone, causes an additional color and turbidity reduction of 31 and 17 %, respectively. No significant differences were noted in the chemical oxygen demand values (α = 0.05; P < 0.001). Thus, there is a scope for further research about the commercial feasibility of DFJ as an industrial water treatment agent, which reduces the toxicity of raw fique juice and its detrimental environmental effects.     

Competitive interference during the biodegradation of cresols

Phenol and its methylated derivatives, cresol isomers, are hazardous pollutants that are commonly present in various industrial effluents and known to have detrimental effect on aquatic life as well as human health, due to their toxic and carcinogenic nature. It is essential, therefore, to reduce the concentration of these contaminants in industrial effluent to acceptable levels prior to being discharged into the environment. Bacterial cells of the strain Pseudomonas putida, with excellent biodegradation capabilities and high tolerance of cresols, were extracted and immobilized in polyvinyl alcohol (PVA) gel for cresols biodegradation. The biodegradation was carried out at different operating conditions, in both batch and continuous modes, using a cylindrical spouted bed bioreactor. Factors affecting o-cresol and m-cresol degradation were studied in batch experiments, and the results showed that the immobilized bacteria could tolerate cresols concentration up to 200 mg/l. Moreover, the experiments indicated that the biodegradation rate was highly affected by the operating parameters such as pH and temperature, with optimum ranges of 6–8 for pH and 30–35 °C for temperature. However, the optimum conditions were different for each cresol isomer. The potential of P. putida in degrading binary and ternary mixtures of cresols was also examined in the continuous process and compared with single component biodegradation. The experimental results revealed that the biodegradation of o-cresol was highly inhibited by the presence of p-cresol and m-cresol.     

Efficient removal of Evans blue dye by Zn–Al–NO<Subscript>3</Subscript> layered double hydroxide

Evans blue (EB) dye has been successfully removed from aqueous solution through chemisorption process with synthetic layered double hydroxides (LDH) [Zn_1?x Al _x (OH)₂NO₃·nH₂O, x = 0.2–0.33]. Detailed evaluation of dye adsorption characteristics in aqueous medium has been studied for different layer charged hydroxides. The objective of the study was efficient removal of a dye by LDH and understanding the structure–property relationship of the LDH on its adsorption behaviour. Highest Langmuir monolayer adsorption capacity (Qt) of 113.64 mg g^?1 was observed for highest layer charge x = 0.33, and it is higher than previously reported values for the LDH-EB dye system. Under optimized condition, 99% of EB dye is removed from aqueous solution within 60 min at 313 K. The monotonous increase in Qt value with increasing layer charge is correlated with layer charge density (LCD) and lower particle size of the synthetic LDH. The variation in Qt among different layer charged materials is marginal (3.46–4.17%) with respect to the respective anion exchange capacity (AEC) of LDH NO₃. The limited contribution of AEC surmises the occurrence of surface-only adsorption and absence of intercalation as validated by the XRD analysis. The spontaneity of the EB dye removal increases with increasing temperature and LCD. The chemisorption nature of the adsorption reaction is well supported by the thermodynamics values.     

Laboratory parallel-beam transmission X-ray powder diffraction investigation of the thermal behavior of nitratine NaNO<Subscript>3</Subscript>: spontaneous strain and structure evolution

Present work provides in-situ structural data at a fine temperature scale from RT to the melting point of nitratine, NaNO₃. From the analysis of log e ₃₃ versus log t plots, it is possible to prove that an univocal indication on the R \( \overline{3} \) c (low temperature, LT) → R \( \overline{3} \) m (high temperature, HT) transition mechanism cannot be obtained because of the relevant role played by the arbitrary assumptions required for defining the c ₀ dependence from temperature of the HT phase. This is due to the occurrence of excess thermal expansion for the HT phase. A significantly better fit for an Ising-spin structural model over a non-Ising rigid-body one has been obtained for the LT phase. Moreover, the Ising model led to a smooth variation of the oxygen site x fractional coordinate throughout the transition. The structure of the HT polymorph has been successfully refined considering an oxygen site at x, 0, ½, with 50% occupancy. Such model was the only acceptable one from the crystal chemical point of view as the alternative model (oxygen site at x, y, z with 25% occupancy) led to unrealistically aplanar \( {\text{NO}}_{3}^{ - } \) groups.     

Photosynthetic capability and Fe,Mn, Cu,and Zn contents in two Moraceae species under different phosphorus levels

The strong adaptability of Broussonetia papyrifera (L.) Vent. to low phosphorus (P) conditions can be attributed to the large amount of root-exuded organic acids and the high efficiency of P extraction. However, microelement contents are influenced by low-P stress, and their effects on the photosynthetic capability of B. papyrifera remain unknown. In this study, we investigated the effects of low-P treatment on net photosynthetic rate (P _N); chlorophyll a fluorescence (ChlF) characteristics; and Fe, Mn, Cu, and Zn contents of B. papyrifera and Morus alba L. seedlings. Results show that B. papyrifera exhibited better photosynthetic capability under moderate P deficiency (0.125, 0.063, and 0.031 mmol/L P treatments), whereas the photosynthetic capability of M. alba decreased under moderate and severe P deficiency (0.016 and 0 mmol/L P treatments). Under moderate P deficiency, the decrease in Cu and Zn contents in B. papyrifera was lower than that in M. alba. Under severe P deficiency, a considerable decrease of photosynthetic capability in B. papyrifera and M. alba was associated with low Cu and Zn contents. The P _N of the two Moraceae species exhibited a better correlation with Cu and Zn contents than with Fe or Mn content. P deficiency could not only decrease cyclic photophorylation and photosynthetic efficiency, but could also affect the stability of thylakoid membrane structure and electron transport efficiency by influencing the contents of Cu or Zn, thereby affecting photosynthesis.     

Abundances of carbon,nitrogen, oxygen,and other elements in the atmospheres of the giants 25 Mon and HR 7389

An analysis of high-resolution CCD spectra of the giant 25 Mon, which shows signs of metallicity, and the normal giant HR 7389 is presented. The derived effective temperatures, gravitational accelerations, and microturbulence velocities are T_eff = 6700 K, log g = 3.24, and ξ _t = 3.1 km/s for 25 Mon and T_eff = 6630 K, log g = 3.71, and ξ _t = 2.6 km/s for HR 7389. The abundances (log ε) of nine elements are determined: carbon, nitrogen, oxygen, sodium, silicon, calcium, iron, nickel, and barium. The derived excess carbon abundances are 0.23 dex for 25 Mon and 0.16 dex for HR 7389. 25 Mon displays a modest (0.08 dex) oxygen excess, with the oxygen excess for HR 7389 being somewhat higher (0.15 dex). The nitrogen abundance is probably no lower than the solar value for both stars. The abundances of iron, sodium, calcium (for HR 7389), barium, and nickel exceed the solar values by 0.22–0.40 dex for both stars. The highest excess (0.62 dex) is exhibited by the calcium abundance for 25 Mon. Silicon displays a nearly solar abundance in both stars—small deficits of ?0.03 dex and ?0.07 dex for 25 Mon and HR 7389, respectively. No fundamental differences in the elemental abundances were found in the atmospheres of 25 Mon and HR 7389. Based on their T_eff and log g values, as well as theoretical calculations, A. Claret estimated the masses, radii, luminosities, and ages of 25 Mon (M/M_⊙ = 2.45, log(R/R_⊙) = 0.79, log(L/L_⊙) = 1.85, t = 5.3 × 10⁸ yr) and HR 7389 (M/M_⊙ = 2.36, log(R/R_⊙) = 0.50, log(L/L_⊙) = 1.24, t = 4.6 × 10⁸ yr), and also of the stars 20 Peg (M/M_⊙ = 2.36, log(R/R_⊙) = 0.73, log(L/L_⊙) = 1.79, t = 4.9 × 10⁸ yr) and 30 LMi (M/M_⊙ = 2.47, log(R/R_⊙) = 0.73, log(L/L_⊙) = 1.88, t = 4.8 × 10⁸ yr) studied by the author earlier.     

Adsorption of a cationic dye (methylene blue) by Iranian natural clays from aqueous solutions: equilibrium,kinetic and thermodynamic study

Removal of dyes by low-cost adsorbents is an effective method in wastewater treatment. Iranian natural clays were determined to be effective adsorbents for removal of a basic dye (methylene blue) from aqueous solutions in batch processes. Characterizations of the clays were carried out by X-ray diffraction, Brunauer–Emmett–Teller surface area analysis and field-emission scanning electron microscopy. Effects of the operational parameters such as adsorbent dosage, initial dye concentration, solution pH and temperature were investigated on the adsorption performance. Adsorption isotherms like Langmuir, Freundlich and Temkin were used to analyze the adsorption equilibrium data and Langmuir isotherm was the best fit. Adsorption kinetics was investigated by pseudo-first-order, pseudo-second-order and intraparticle diffusion models and the results showed that the adsorption system conforms well to the pseudo-second-order model. The thermodynamic parameters of adsorption (ΔS°, ΔH° and ΔG°) were obtained and showed that the adsorption processes were exothermic.     

Exploring the diverse potentials of <Emphasis Type="Italic">Planococcus</Emphasis> sp. TRC1 for the deconstruction of recalcitrant kraft lignin

Kraft lignin (KL) is the chief contaminant which is responsible for dark coloration, toxicity and high chemical oxygen demand (COD) of paper pulp mill effluent. The present study investigated the diverse potentials of Planococcus sp. TRC1 in the biodegradation of KL. Preliminary evaluation indicated that the strain was able to grow on broad spectrum of lignin-derived compounds, decolorize lignin-mimicking dyes and catabolize substrates of ligninolytic enzymes. Response surface methodology (RSM) was executed to perform the optimization of different process parameters. The results displayed that Planococcus sp. TRC1 could completely utilize 100 mg L^?1 of KL and 78% of 200 mg L^?1 of KL as sole source of carbon with concurrent reduction in COD and color. The biokinetic details of KL biodegradation showed that the values of \(\mu^{*}\), µ _max, \(q^{*}\) and q _max were 0.018 h^?1, 0.01 h^?1, 0.023 g g^?1 h^?1 and 0.05 g g^?1 h^?1, respectively. UV–visible spectrophotometry, SEM and FTIR indicated the significant alterations in the surface morphology, functional groups and chromophores during the course of biodegradation. XRD revealed the emergence of peak signifying the formation of low molecular weight intermediates after bacterial treatment. Considering the environmental impact, bacterial-treated KL illustrated less phytotoxicity using Vigna radiata seed bioassay. These results suggested that Planococcus sp. TRC1 could be a promising strain for the degradation of KL in an ecofriendly way.     

Principal component analysis for interaction of nitrifiers and wastewater environments at a full-scale activated sludge plant

This study investigated the relationship between wastewater environments and the nitrifiers at a full-scale plant using principal component analysis. Ammonia-oxidizing bacteria and nitrite-oxidizing bacteria were detected by florescent in situ hybridization, polymerase chain reaction, phylogenetic analysis, real-time quantitative polymerase chain reaction. Pyrosequencing was also used in profiling the ammonia monooxygenase locus of ammonia-oxidizing bacteria community. It was found that the dominant ammonia-oxidizing bacteria sequences were related to uncultured ammonia-oxidizing bacterium, uncultured Nitrosomonadaceae bacterium, Nitrosomonas sp., and uncultured bacterium. In addition, Nitrobacter clones were related to uncultured alpha proteobacterium, uncultured bacterium, uncultured Nitrobacter sp., and uncultured Bradyrhizobium sp., whereas Nitrospira clones were similar to uncultured bacterium, Candidatus Nitrospira defluvii, uncultured Nitrospira sp., and uncultured Nitrospirae bacterium. The ammonia-oxidizing bacteria and nitrite-oxidizing bacteria ranged 2.83 × 10⁸–1.33 × 10¹⁰ and 1.25 × 10¹⁰–1.13 × 10¹¹ copies L^?1, respectively, equivalent to nitrite-oxidizing bacteria: ammonia-oxidizing bacteria ratio of 10:1. The first three parts of the principal components analysis accounted for 76.8% of the explained variance. The first principal component (44.4%) designated that ammonia-oxidizing bacteria and Nitrospira were mainly influenced by seasonal variations, followed by chemical oxygen demand concentration and nitrogen species (i.e., ammonia, nitrite, and nitrate). The second principal component (19.1%) showed no information about the nitrifiers’ interaction with environmental factors, whereas Nitrobacter demonstrated a high correlation with ammonia on the third principal component (13.3%). These results revealed that the species of Nitrobacter were less influenced by environmental conditions than ammonia-oxidizing bacteria and Nitrospira spp.     

Abundances of carbon,nitrogen, oxygen,and other elements in the atmospheres of the giants 15 ori and 22 <Emphasis Type="Italic">ɛ</Emphasis> sex

We have used high-resolution spectra to study the giants 15 Ori and 22 ? Sex. The effective temperature T _eff = 7060 K, gravity log g = 3.16, and microturbulence velocity ξ _t = 3.5 km/s were determined for 15 Ori, with T _eff = 7350 K and log g = 3.90 for 22 ? Sex (the microturbulence velocity for 22 ? Sex was assumed to be ξ _t = 2.7 km/s). We estimated the abundances of C, N, O, Na, Si, Ca, Fe, and Ba (N and Ba, for 15 Ori only). The abundances of carbon, iron, and oxygen in 22 ? Sex are higher than the solar values by +0.31 dex, +0.33 dex, and +0.18 dex, respectively, while the calcium abundance is ?0.19 dex below the solar level. For 15 Ori, we find a slight carbon excess (+0.19 dex), a slight nitrogen deficiency (?0.13 dex), and a considerable deficiency of silicon (?0.42 dex). The abundances of the remaining elements in both stars are near-solar. We find no substantial differences between the abundances derived for 15 Ori and 22 ? Sex and the results of earlier studies of giants by both ourselves and Erspamer and North. A comparison of the atmospheric elemental abundances of giants and δ Scuti stars indicates that the abundances of some lighter elements (oxygen, sodium, silicon, and possibly nitrogen) are somewhat lower for δ Scuti stars than for A-F giants. We determined the masses, radii, luminosities, and ages for 15 Ori and 22 ? Sex.     

Stable carbon and oxygen isotope study on benthic foraminifera: Implication for microhabitat preferences and interspecies correlation

Stable isotopes of benthic foraminifera have widely been applied in micropalaeontological research to understand vital effects in foraminifera. Isotopic fractionations are mainly controlled by ontogeny, bottom/pore water chemistry, habitat preference, kinetic effect and respiration. Discontinuous abundance of a species for isotopic analysis has forced us to select multiple species from down-core samples. Thus standardisation factors are required to convert isotopic values of one species with respect to other species. The present study is pursued on isotopic values of different pairs of benthic foraminifera from the Krishna–Godavari basin and Peru offshore to understand habitat-wise isotopic variation and estimation of isotopic correction factors for the paired species (Cibicides wuellerstorfi–Bulimina marginata, Ammonia spp.–Loxostomum amygdalaeformis and Bolivina seminuda–Nonionella auris). Infaunal species (B. marginata, Ammonia spp. and N. auris) show a lighter carbon isotopic excursion with respect to the epifaunal to shallow infaunal forms (C. wuellerstorfi, L. amygdalaeformis and B. seminuda). These lighter \(\updelta ^{13}\) \(\hbox {C}\) values are related to utilisation of \(\hbox {CO}_{2}\) produced by anaerobic remineralisation of organic matter. However, enrichment of \(\updelta ^{18}\) \(\hbox {O}\) for the deeper microhabitat (bearing lower pH and decreased \({\hbox {CO}_{3}}^{2-})\) is only recorded in case of B. marginata. It is reverse in case of N. auris and related to utilisation of respiratory \(\hbox {CO}_{2}\) and internal dissolve inorganic carbon pool. Estimation of interspecies isotopic correction factors for the species pairs (\(\updelta ^{13}\) \(\hbox {C}\) of C. wuellerstorfi–B. marginata, L. amygdalaeformis–Ammonia spp., N. auris–B. seminuda) and \(\updelta ^{18}\) \(\hbox {O}\) of C. wuellerstorfi–B. marginata are statistically reliable and may be used in palaeoecological studies.     

Stability and phase relations of nonstoichiometric clinopyroxenes in the join diopside-Ca-Eskola component at high pressures

The stability of nonstoichiometric clinopyroxenes in the Di-CaEsk join was experimentally studied, and phase diagrams were constructed for this join at pressures of 2.0 and 3.0 GPa. It was found that melting in the diopside part of the join occurs at anomalously low temperatures, and nonstoichiometric clinopyroxene coexists with a phase approaching diopside in composition. Phase relations along the Di-CaEsk join can be described and consistently interpreted only assuming that the diopside phase (α-diopside) is thermodynamically stable. The following phase volumes were observed along the solidus of the join at a pressure of 3.0 GPa: Cpx, αDi+Cpx, αDi+Cpx+Qtz, αDi+Cpx+Grt+Qtz, Cpx+Grt+Qtz, Cpx+Grt+Ky+Qtz, Grt+Ky+Qtz. Melting occurs via the eutectic reaction αDi+Cpx+Grt+Qtz=L at a temperature of about 1200°C in the diopside part of the system and via the eutectic reaction Cpx+Grt+Ky+Qtz=L at a temperature of 1400°C in the calcium-rich part of the system. At a pressure of 2.0 GPa, melting occurs at temperatures of 1200–1300°C via the eutectic reaction αDi+Cpx+ An + Qtz=L. The invariant equilibrium (L, An, Cpx, Grt, αDi, Qtz) lies within the pressure range 2.0–3.0 GPa. Nonstoichiometric clinopyroxenes form complex solid solutions, the compositions of which are not strictly confined to the Di-CaEsk join and depend on temperature, pressure, and phase association. Grossular garnets coexist with nonstoichiometric clinopyroxenes and α-diopside.     

Atmospheric elemental abundances for the components of the multiple system ADS 11061. 41 Draconis

We obtained speckle interferometric and spectroscopic observations of the system 41 Dra during its periastron passage in 2001. The components’ lines are resolved in the spectral interval 3700–9200 Å. The observed wavelength dependence of the brightness difference between the components is used to estimate the B-V indices separately for each of the components: B-V = 0.511 for component a and B-V = 0.502 for component b. We derived improved effective temperatures of the components from their B-V values and hydrogen-line profiles. The observations can be described with the parameters for the components T _eff ^a = 6370 K, log g^a = 4.05 and T _eff ^b = 6410 K, log g^b = 4.20. The iron, carbon, nitrogen, and oxygen abundances in the atmospheres of the components are log N(Fe)^a = 7.55, log N(Fe)^b = 7.60, log N(C)^a = 8.52, log N(C)^b = 8.58, log N(N)^a = 8.05, log N(N)^b = 7.99, log N(O)^a = 8.73, log N(O)^b = 8.76.     

Biosorption optimization and equilibrium isotherm of industrial dye compounds in novel strains of microscopic fungi

The aim of this study was to evaluate the biosorption capacity of selected strains of microscopic fungi. We optimized the biosorption process and used the Freundlich isotherm for three strains: H. haematococca BwIII43, K37 and T. harzianum BsIII33 to describe the biosorption equilibrium of anthraquinone dye, Alizarin Blue Black B (ABBB) and alkali lignin (AL). In optimal conditions (1 g of mycelium biomass, pH = 7.0, 28 °C) for ABBB and AL sorption, the live biomass of H. haematococca BwIII43 was characterized by a higher sorption capacity, amounting to 247.47 and 161.00 mg g^?1, respectively. The highest sorption properties toward anthraquinone dye (K _F = 19.96 mg g^?1) were shown for the biomass of H. haematococca K37. In the presence of alkali lignin, the highest sorption capacity and bond strength exhibited the biomass of H. haematococca BwIII43 (K _F = 28.20 mg g^?1, n = 3.46). Effective decolorization of ABBB and AL by the selected strains of microscopic fungi indicated that the biosorption process additionally enhanced the removal of color compounds from the solution.     

Comparative study of the absorptive potential of raw and activated carbon <Emphasis Type="Italic">Acacia nilotica</Emphasis> for Reactive Black 5 dye

Acacia nilotica was used for the adsorption of Reactive Black 5 (RB5) dye from an aqueous solution. Both the raw and activated (with H₃PO₄) carbon forms of Acacia nilotica (RAN and ANAC, respectively) were used for comparison. Various parameters (including dye concentration, contact time, temperature, and pH) were optimized to obtain the maximum adsorption capacity. RAN and ANAC were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The maximum experimental adsorption capacities for RAN and ANAC were 34.79 and 41.01 mg g^?1, respectively, which agreed with the maximum adsorption capacities predicted by the Langmuir, Freundlich, and Dubinin–Radushkevich equilibrium isotherm models. The adsorption data of ANAC showed a good fit to the isotherm models based on the coefficient of determination (R ²): Langmuir type II (R ² = 0.99) > Freundlich (R ² = 0.9853) > Dubinin–Radushkevich (R ² = 0.9659). This result suggested monolayer adsorption of RB5 dye. The adsorption of RB5 dye followed pseudo-second-order kinetics. The RAN adsorbent reflected an exothermic reaction (enthalpy change, ΔH = ?0.006 kJ mol^?1) and increased randomness (standard entropy change, ΔS = 0.038 kJ mol^?1) at the solid–solution interface. In contrast, ANAC reflected both exothermic [?0.011 kJ mol^?1 (303–313 K)] and endothermic [0.003 kJ mol^?1 (313–323 K)] reactions. However, the ΔS value of ANAC was lower when the RB5 adsorption increased from 313 to 323 K. The negative values for the Gibbs free energy change at all temperatures indicated that the adsorption of RB5 dye onto RAN and ANAC was spontaneous in the forward direction.     

Bioaugmentation for the enhancement of hydrocarbon phytoremediation by rhizobacteria consortium in pilot horizontal subsurface flow constructed wetlands

The development of the bioaugmentation during the phytoremediation of contaminated water with diesel in pilot horizontal subsurface flow constructed wetlands was investigated for 63 days. The objective of this study was to examine the enrichment of rhizobacteria in a pilot-scale system for efficient treatment of total petroleum hydrocarbon (TPH) effluent. A consortium of three rhizobacteria strains (Bacillus aquimaris, Bacillus anthracis and Bacillus cereus), which were able to utilize hydrocarbon compounds as sole carbon sources, was injected into the constructed wetlands (batchwise operation) planted with Scirpus grossus. The TPH removals from water, without or with the addition of rhizobacteria, were found to be 72 and 84%, while from sand was found to be 59 and 77%, for each treatment, respectively. These results showed that the rhizobacteria strains could enhance S. grossus growth by decreasing diesel stress and protecting S. grossus against diesel, with 12 and 18% additional TPH removal from water and sand, respectively. Our results demonstrate that S. grossus is potential to improve the phytoremediation of hydrocarbon contaminants through inoculation with effective rhizobacterial strains.     

Masses of the visual components and black holes in X-ray novae: Effects of proximity of the components

It is shown that the approximation of the complex, tidally distorted shape of a star as a circular disc with local line profiles and a linear limb-darkening law, which is usually applied when deriving equatorial stellar rotation velocities from line profiles, leads to overestimation of the equatorial velocity V _rot sin i and underestimation of the component mass ratio q = M _x /M _v . A formula enabling correction of the effect of these simplifying assumptions on the shape of a star is used to re-determine the mass ratios q and the masses of the black holes M _x and visual components M _v in low-mass X-ray binary systems containing black holes. Taking into account the tidal–rotational distortion of the stellar shape can significantly increase the mass ratios q = M _x /M _v , reducing M _v , while M _x changes only slightly. The resulting distribution of M _v attains its maximum near M _v ? 0.35M _⊙, in disagreement with the results of population synthesis computations realizing standard models for Galactic X-ray novae with black holes. Possible ways to overcome this inconsistency are discussed. The derived distribution of M _x also differs strongly from the mass distribution for massive stars in the Galaxy.     

Atmospheric chemical abundances of the components of the quadruple system ADS 11061. 40 Draconis

As part of our study of the components of the hierarchic quadruple system ADS 11061, we acquired spectroscopic observations of the binary 40 Dra. Echelle spectra showing the separation of the components’ lines were obtained in the spectral range 3700–9200 Å. Effective temperatures and surface gravities were derived for the components from BV photometry and the hydrogen-line profiles. The components of the 40 Dra system have parameters close to T _eff ^a = 6420 K, log g _a = 4.17, T _eff ^b = 6300 K, and log g _b = 4.20. We find the microturbulence velocity in the component atmospheres to be V _t = 2.6 km/s. The abundances of iron, carbon, nitrogen, and oxygen in the atmospheres of both components are estimated to be log N(Fe)^a = 7.50, log N(Fe)^b = 7.46, log N(C)^a = 8.39, log N(C)^b = 8.45, log N(N)^a = 8.12, log(N)^b = 8.15, log N(O)^a = 8.77, log N(O)^b = 8.74.