INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCE AND TECHNOLOGY (IJEST)
Year:2015 | Volume:12 | Issue:7|Papers Count:30

The purpose of this study was to assess selected potentially toxic elements and persistent organic pollutants concentrations in the Shahid Rajaei Dam reservoir as well as their accumulation in barbel and Leuciscus cephalus fish species. The concentration of arsenic, mercury, nickel, chromium and cadmium in all water samples is less than WHO drinking water standard. Chromium shows a higher concentration than WHO standard in both fish species, while nickel and mercury content in barbel fish is higher than WHO standard. The result of principle component analyses indicates an increased elemental concentration due to application of phosphorus fertilizers in the agricultural lands, especially paddy field, ending up to the Tajan River and Shahid Rajaei Dam reservoir. Ni, Co, Mn, Pb and Cr display a quasi-independent behavior within the groups (PC1, PC2 and PC3) reflecting contribution of both geogenic and anthropogenic sources. The concentrations of persistent organic pollutants in all water samples, except M-5 sample, are less than WHO and EPA drinking water standards, while persistent organic pollutants (detected in both fish species) indicate higher contents than those of EPA standard values. Based on carcinogenic health risk value, maximum allowable fish consumption for arsenic is two meals per month. The result of noncarcinogenic health risk of mercury indicates one and three meals consumption per month for barbel and L. cephalusfishes, respectively. The calculation of maximum allowable fish consumption based on carcinogenic health for dieldrin, ∑HCH, heptachlor epoxide, ∑DDT and ∑PCBs reveals monthly meals limitation of both fish species grown in Shahid Rajaei Dam.

Epidemiological studies have shown that 70-90% of all cancers are caused due to the chemicals present in environment. Exogenous exposure to carcinogens and their interaction with genetic sequences and endogenous factors, like exposures to products of metabolism which lead to acute stress, disruption of hormones and inflammation of tissues, are triggering factors. Due to relatively small risk of cancer following immediate exposure, the precise quantification of the burden of human cancer attributed to environmental exposure remains ambiguous, thereby leading to an assumption that a causal relationship is relatively large. Research suggests that 90-95% of all cancers have their roots in the environmental effects on the DNA leading to genetic defects, whereas only 5-10% can be attributed to inherited genetic defects. The hypothesis of the present review is that response of the cells to the environmental stimulants could be an evolutionary process of adaptation of the DNA. Carcinogenesis is considered as a process of adaptation of mammalian cells to sustained stress environment (SSE) by means of epigenetic alteration (EA) of the genome, mutations which arise due to EA and finally, natural selection of originated mutant cells evading apoptosis. Process of adaptation to SSE involves the emergence of senescent epigenetically reprogrammed cells with specific cancer-related EA in the genome.

Previous research suggested that Ricinus communis may be used for soil remediation and oil production. However, the quality of the oil and bioproducts under polluted conditions need to be tested to be assured of their potential use in biofuel production with environmentally friendly bioproducts (cake, seed coats and biomass). Oil characteristics and metal concentrations in oil, cake (de-oiled seeds) and seed coats, as well as the shoot carbon content were analyzed. The oil contents of palmitic and oleic acids from plants growing in polluted mine tailings were comparable to those for plants grown under non-polluted conditions. Linoleic acid content was significantly higher in oil of plants from mine tailings, which enriches the fuel properties. Cadmium and lead were mainly concentrated in the seed coat, whereas copper in the cake. Castor bean oil had low concentrations of cadmium, lead, zinc, nickel, manganese and copper-free. Cake and seed coats can be useful for soil fertilization applications since the metal concentrations are below safety regulations. The biomass carbon was around 43%, which suggests it may be used for biogas production. These properties make castor bean valuable for its oil and bioproducts even when growing at metal-polluted sites. However, agronomic optimization is needed in order to produce higher plant productivity.

A technology of obtaining nitrogen-enriched activated carbons from coniferous tree sawdust by direct activation of the precursor and physical activation with CO2 is described. The effect of activation time, pyrolysis temperature as well as modification with urea on the textural parameters, acid-base character of the surface and sorption properties of activated carbons has been tested. The resulting carbons were characterised by low-temperature nitrogen sorption and determination of the number of surface oxygen groups. The sorption properties of the materials obtained were characterised by nitrogen dioxide adsorption in dry and wet conditions. The final products were nitrogen-enriched microporous activated carbons of medium-developed surface, showing very diverse nitrogen content and acidic–basic character of the surface. The results obtained in our study have proved that through suitable choice of the activation and modification procedure of coniferous tree sawdust, activated carbons can be produced with high capacity towards nitrogen dioxide adsorption, reaching to 69 and 46 mg NO2/g in dry and wet conditions, respectively. The results of our study have also shown that the adsorption ability of carbonaceous adsorbents depends both on the method of preparation as well as on the textural parameters and acid–base properties of the adsorbents surface.

The presence of pharmaceuticals and endocrine-disrupting chemicals (EDCs) in wastewater treatment plant effluents is an issue of great concern due to the negative effects that these compounds may have on human health and ecosystems. The present study aims to assess the capacity of two aquatic plants (Lemna sp. and Spirogyra sp.), commonly found in polishing ponds, for removing six pharmaceutical compounds (diclofenac, acetaminophen, ibuprofen, carbamazepine, clofibric acid, and propranolol), two EDCs (17a-ethinylestradiol and bisphenol A), and one stimulant (caffeine) under laboratory-scale conditions. Planted and unplanted reactors fed with secondary-treated wastewater or ultrapure water in both covered and uncovered conditions were studied. The highest removal efficiencies, which ranged from 31 to 100%, were achieved in uncovered planted systems containing secondary-treated wastewater after 20 days of incubation. The results demonstrated that non-charged compounds with a log Kow between 2 and 4 were affected by the presence of vegetation, probably due to their plant uptake, whereas negatively charged compounds were not. This highlights that the presence of plants in polishing ponds plays an important role in the removal of pharmaceuticals and EDCs.

Biodegradation of crude oil hydrocarbon by microorganisms in seawater is generally slow because of the harsh environmental condition due to high salinity. The aim of this study was to compare sawdust (SD) and oil palm empty fruit bunch wastes as suitable carrier material to immobilise hydrocarbon-degrading bacterial consortium culture to accelerate and improve crude oil degradation in seawater. The consortium culture was found able to tolerate salinity up to 3%, where the degradation of crude oil was not inhibited (p>0.05). In artificial seawater, suspension of bacterial consortium culture was able to degrade 83.3±3.00% of crude oil within 8 weeks, which indicated the possibility of using consortium culture in seawater. When tested in seawater, suspension of consortium culture managed to degrade 47.7±1.53% of crude oil in 8 weeks. In order to improve the performance of consortium culture, immobilisation of consortium culture onto SD and oil palm empty fruit bunch was successfully undertaken when formation of biofilm layers was observed under scanning electron microscope. Immobilising consortium culture onto oil palm empty fruit bunch and SD was shown to increase crude oil biodegradation to 68.7±4.04 and 62.3±5.51% in 8 weeks, respectively. This study demonstrated immobilisation of consortium culture onto SD and oil palm empty fruit bunch can be utilised as ready-to-use seeds to improve and accelerate crude oil biodegradation in seawater.

Polyurethane composite adsorbent polymeric material was prepared and investigated for selected solid-phase extraction for metal ions, prior to its determination by inductively coupled plasma optical emission spectrometry. The surface characterisation was done using Fourier transform infrared spectroscopy. The separation and preconcentration conditions of the analytes investigated includes influence of pH, sample loading flow rate, elution flow rate, type and concentration of eluents. The optimum pH for the highest efficient recoveries for all metal ions, which ranged from 70 to 85%, is pH 7. The metal ions were quantitatively eluted with 5 mL of 2 mol/L HNO3. Common coexisting ions did not interfere with the separation. The percentage recovery of the metal ions ranged between 70 and 89%, while the results for the limit of detection and limit of quantification ranged from 0.249 to 0.256 and 0.831 to 0.855, respectively. The experimental tests showed good preconcentration results of trace levels of metal ions using synthesised polyurethane polymer adsorbent composite.

In this study, an interval fuzzy-robust two-stage stochastic-robust programming (IFRTSRP) model is developed for water resources management under uncertainty. The developed IFRTSRP model incorporates two-stage stochastic programming (TSP), fuzzy robust programming (FRP), interval linear programming (ILP), and stochastic robust optimization (SRO) within a general optimization framework. The IFRTSRP model can not only deal with uncertainties presented as probability distributions, fuzzy membership functions, discrete interval numbers, and their combinations, but also provide an effective linkage between the pre-regulated water resources management policies and the associated economic implications. The IFRTSRP model can also enhance the robustness for the optimization process by delimiting the uncertain decision space through dimensional enlargement of the original fuzzy constraints. Moreover, the IFRTSRP model can evaluate the trade-offs between system economy and stability by incorporating the variability measures on penalty costs into the objective function. The IFRTSRP model is applied to a hypothetical case study of water resources management. The results indicate that reasonable solutions would be generated under different levels of λ and/or ω (non-negative weight coefficients); moreover, a higher net system benefit would correspond to lower system stability and higher system failure risk. Thus, the modeling results can be used for generating decision alternatives and thus help the managers to identify desired water allocation policies based on the reasonable consideration of system economy, system stability, and system failure risk.

Ferula orientalis L. stalks were used as an agricultural solid biomass waste for preparation of activated carbon with zinc chloride activation using slow pyrolysis in a fixed-bed reactor. The chemical characteristics of the activated carbon obtained at 550oC were identified by elemental, fourier transform infrared spectroscopy, Brunauer-Emmett-Teller, scanning electron microscopy analyses and found to have a surface area of 1,476 m2/g. The ability of the activated carbon to adsorb methylene blue and crystal violet from aqueous solutions has been investigated. Adsorption studies were performed at different initial dye concentrations (200-800 ppm), contact time (0.5-90 min) and temperature (25-45oC). Adsorption data were modeled with Langmuir, Freundlich and Temkin adsorption isotherms. Equilibrium data of the adsorption processes showed that adsorption of methylene blue is fitted to the Langmuir and crystal violet to the Freundlich isotherm. Pseudo-first-order, pseudo-second-order and Elovich kinetic models were used to analyze the kinetic data obtained at different initial dye concentrations. The adsorption kinetic data were very well described by the pseudo-second-order model. The calculated thermodynamic parameters such as change in free energy, enthalpy and entropy showed that adsorptions of both dyes onto activated carbon were spontaneous and endothermic under the experimental conditions.

This study deals with anaerobic biotreatments of sediments contaminated with toxic metals carried out in slurry reactor. The sediment samples used for the investigation came from two Italian ports, and they were mainly contaminated with inorganic compounds (zinc, nickel and chromium). The treatments were aimed at assessing the responses of the autochthonous microbial community in relation to the geochemistry of the sediments (mainly organic carbon bioavailability) and the addition of organic and inorganic substrates. It was observed that the bio-available carbon in the sediments can greatly influence microbial growth but without a significant effect on metal mobilization. By contrast, the supply of inorganic nutrients to the sediments did not have a major effect on microbial growth although important changes in metal mobility were observed. Our results provide new insights on the effects of anaerobic biotreatments on changes in metal partitioning in contaminated sediments, highlighting that, under certain conditions, an increase of metals in the more mobile fractions can occur.

In the present work, different methods were tested to evaluate the adsorption and desorption of metalaxyl in two acid soils with different organic carbon and clay contents. The three methods (batch, stirred flow chamber and column) that were examined produced similar findings when the two soils were compared: (a) the metalaxyl adsorption capacity was higher in the soil with higher organic matter and clay content, and (b) the soil with the lower organic matter and clay contents provided higher adsorption rate constants. In the two soils tested, the metalaxyl adsorbed in the soil was highly reversible. When only one soil was considered, the different methods yielded different results. The metalaxyl adsorption and its rate were higher with the stirred flow chamber than in the column experiments, and in the column experiments, the total metalaxyl adsorption and the rate of adsorption were higher than in the batch experiments. The percentages of metalaxyl desorbed from the soil were similar in the stirred flow chamber and column experiments, but in the batch experiments, the percentages were significantly lower. In the stirred flow chamber experiments, the desorption processes were faster than the adsorption processes, while in the column experiments, the adsorption and desorption processes exhibited similar rates.

The removal of four pharmaceutically active compounds, i.e., anti-inflammatory painkiller diclofenac (DCF), lipid-regulating agent clofibric acid (CFA), epilepsy drugs carbamazepine (CBM), and broad-spectrum anti-bacterial agent triclosan (TCS), present in sewage sludge was investigated using anaerobic digestion processes in the mesophilic and thermophilic modes. Sludge retention times (SRTs) were set at 10, 15, and 20 days, respectively, for the mesophilic mode and 7, 15, and 20 days, respectively, for the thermophilic mode. The effective isolation and purification pre-treatment to extract the target compounds from the sewage sludge samples were firstly established, followed by gas chromatography-mass spectrometer analysis to identify and quantify them. The removal efficiencies of the target compounds could be raised to a certain extent with the increase on SRTs, especially under the mesophilic condition. The removal of CFA and TCS under thermophilic condition hardly varied when the SRTs were above 15 days. All the compounds could be partly removed from the sewage sludge under the two temperature conditions, particularly TCS that was reduced by about 74%. Besides, CFA, firstly reported in this study, could be reduced by maximal 65%. On the whole, the thermophilic mode was more conducive to the removal of CBM and TCS, but did not have a noticeable effect on the removal of CFA. Furthermore, DCF could be better removed in the mesophilic mode. In addition, NH3-N accumulation in this measured range might positively affect the removal of the selected compounds, particularly in the mesophilic mode.

In this paper, a new material based on zeolite has been investigated in an attempt to explore the possibility of using it as an efficient adsorbent of copper (II) from industrial wastewater. This composite material is composed of volcanic tuff (containing 83% zeolite) and cellulose in a 4 to 1 ratio. The performances of the new adsorbent composite have been examined against those of a common adsorbent, the zeolitic volcanic tuff. The adsorption studies were carried out in a batch process at room temperature, and the effect of various parameters (i.e., initial concentration, contact time, adsorbent dosage and pH) was tested. The experimental data have been modeled with Langmuir, Freundlich and Temkin isotherms. The results correspond to Langmuir model showing a monolayer adsorption with a maximum adsorption capacity of 12.74 mg g-1 at 25oC. The copper adsorption onto zeolitic composite was well described by a pseudo-second order kinetic model. The experimental results indicate a superior adsorption of copper (II) onto the new adsorbent when compared against the common zeolite.

In this study, applicability of successive-station prediction models, as a practical alternative to streamflow prediction in poor rain gauge catchments, has been investigated using monthly streamflow records of two successive stations on Çoruh River, Turkey. For this goal, at the first stage, based on eight different successive-station prediction scenarios, feed-forward back-propagation (FFBP) neural network algorithm has been applied as a brute search tool to find out the best scenario for the river. Then, two other artificial neural network (ANN) techniques, namely generalized regression neural network (GRNN) and radial basis function (RBF) algorithms, were used to generate two new ANN models for the selected scenario. Ultimately, a comparative performance study between the different algorithms has been performed using Nash-Sutcliffe efficiency, squared correlation coefficient, and root-mean-square error measures. The results indicated a promising role of successive-station methodology in monthly streamflow prediction. Performance analysis showed that only 1-month-lagged record of both stations was satisfactory to achieve accurate models with high-efficiency value. It is also found that the RBF network resulted in higher performance than FFBP and GRNN in our study domain.

In the present study, isopropyl alcohol containing wastewater generated from silicon solar cell manufacture was sequentially treated with sequencing batch biofilm reactor and sequencing batch reactor. Sequencing batch biofilm reactor could remove 90 % of isopropyl alcohol from wastewater efficiently as the chemical oxygen demand lower than 1,200 mg L-1. However, 1,600 mg L-1 of chemical oxygen demand damaged the biofilm. The operation mode was changed to sequencing batch reactor on day 30, and sequencing batch reactor showed a greater ability to remove isopropyl alcohol. When the influent chemical oxygen demand was 1,600 mg L-1, the reactors achieved stable removal efficiencies of >95 % for chemical oxygen demand, and the effluent chemical oxygen demand was lower than 100 mg L-1. Denaturing gradient gel electrophoresis analysis showed an increase in bacteria diversity as the operation mode was switched from sequencing batch biofilm reactor to sequencing batch reactor, which might increase the stability of flocs in sequencing batch reactor. Though 13 bands were sequenced from the denaturing gradient gel electrophoresis and a phylogenetic analysis was conducted based on these sequences, it is difficult to analyze the function of these predominant strains in the reactors. Two models were constructed for interpreting the structure of biofilm in sequencing batch biofilm reactor and flocs in sequencing batch reactor, respectively. Higher efficient transfer rate of dissolved oxygen in flocs was proposed as the main reason for the higher isopropyl alcohol removal ability in sequencing batch reactor.

In the present study, a batch system was used to investigate the adsorption of chromium (VI) ions from an aqueous solution by graphene nanosheets. Graphene is decorated with functional groups containing oxygen such as epoxy and hydroxyl on the basal plane. The large negative charge density available on graphene causes effective adsorption of chromium (VI) ions from aqueous solutions. The adsorption capacity and rate of chromium (VI) ions at different temperatures, adsorbent dosages, initial concentrations, and contact times were evaluated. The kinetic study illustrated that the adsorption of chromium (VI) ions onto graphene obeys the pseudo-second-order model with activation energy of 21.91 kJ mol-1. The chromium (VI) ions adsorption was well explained using Dubinin-Radushkevich isotherm model. The values of standard enthalpy, entropy, and Gibbs free energy changes at 25°C were calculated as 686.07 kJ mol-1, 2.38 kJ mol-1K-1, and -22.43 kJ mol-1, respectively. In this work, graphene was prepared via a green method. Transmission electron microscopy, Fourier transform-infrared spectroscopy, energy-dispersive X-ray analysis, powder X-ray diffraction, Boehm’s titration, and N2 adsorption-desorption techniques revealed a high-quality few-layer nanosheets of graphene with surface area and inter-planar spacing of 594.7 m2 g-1 and 3.6 Å, respectively.

The aim of this work was to investigate the effect of autochthonous bioaugmentation (ABA) in phenanthrene-contaminated Patagonian soil microcosms, maintained under arid conditions, on phenanthrene elimination and soil microbial community. The polycyclic aromatic hydrocarbon (PAH)-degrading strain Sphingobium sp. 22B previously isolated from the Patagonian soil and selected by its resistance to drying conditions was used as inoculant. The phenanthrene concentration, dehydrogenase activity and denaturing gradient electrophoresis of 16S rRNA gene were monitored during 230 days. The results showed that when the microcosms were maintained at 20% of soil water-holding capacity (WHC), the phenanthrene biodegradation was drastically inhibited and changes in the genetic diversity of soil microbial community were not detected, and neither the ABA nor the biostimulation managed to overcome the inhibitory effects. When the moisture was slightly increased, reached 25% WHC, the ABA showed a significant initial stimulatory effect on phenanthrene biodegradation, demonstrating the potential of ABA in PAH bioremediation process in semiarid Patagonia.

The abundance and predominant groups of bacteria, filamentous fungi and yeasts have been studied by culture-dependent microbiological methods in peat probes obtained in two Latvian balneotherapy spa sites, Kemeri and Baldone. Unsterilized peat samples from both the sites contained 5.7-8.1 log bacterial colony-forming units (CFU) and 3.0-5.3 log fungal CFU per gram of dry peat. Isolated species belonged to Alpha-, Beta-, and Gamma-Proteobacteria, Actinobacteria, Clostridia, Bacilli and Flavobacteria as well as to filamentous fungi and yeasts. The composition of microbial population of the peat from both sites shared just four micro-organism groups (Bacillus mycoides, Burkholderia cepacia, Streptomyces spp. and Trichoderma spp.) within totally 36 groups identified. No pathogenic bacteria or fungi and no faecal pollution indicators were recovered. Decimal reduction doses for micro-organisms in peat samples and radiation sterilization doses of peat for the gamma and electron beam radiation were determined. The highest radiation resistance was observed for B. mycoides and Aureobasidium sp. Gamma-sitosterol was the most abundant hydrophobic organic compound in both peats according to GC-MS data. All the sterilization procedures increased concentration of alkanes, alcohols, and ketones and decreased the amount of fatty acids. Heat sterilization proved to be more preserving for the peat sterols than the radiation sterilization. It is concluded that the heat and radiation sterilization methods induce different changes of the profile of hydrophobic organic compounds of balneological peats, what may lead to different therapeutic effects at their application.

In the present study, the decolorization and degradation of azo dye Direct Orange 16 (DO-16) by a potential bacterial isolate isolated from textile effluent were evaluated. Through 16S rRNA sequence matching, the potential isolate was identified as Micrococcus luteus strain SSN2. The effects of various factors (pH, temperature, salt and dye concentration) on decolorization were investigated. The strain SSN2 had the ability to decolorize DO-16 with 96% efficiency at pH 8, 37oC and 3% NaCl in a short time of 6 h under static conditions. DO-16 decolorization was assessed by UV-Vis spectrophotometer with gradual decrease of dye peak intensity at 430 nm (λmax). Analytical techniques (thin-layer chromatography, Fourier transform infrared spectroscopy and high-performance liquid chromatography) further confirmed that biodegradation of DO-16 was due to reduction of the azo bond. The phytotoxicity assay (with respect to seeds of Vigna mungo andVigna radiata) demonstrated the less toxic nature of the DO-16-degraded products compared to the toxic azo dye.

This study assessed the water quality of Mengkuang Reservoir, Penang, Malaysia, by its trophic status according to a Carlson Modified Trophic Index (CMTSI) and by its biological parameters using Shannon-Wiener diversity index (H′) and saprobic index. The study conducted from August 2005 to July 2006 showed that mean values of CMTSI (nutrients), CMTSI (chlorophyll a) and CMTSI (Secchi depth) were 27.18±8.73, 40.63±7.12 and 41.74±6.38, respectively. The mean values of CMTSI indicated that the reservoir was oligotrophic. Mean value of H′ was 2.15 bits/individual, showing that the water quality based on H′ value was in class III (slightly polluted). Saprobic index value (2.24) also revealed that the reservoir was moderately polluted (class II). The occurrence of Anabaena, Microcystis, Oscillatoria, Nostoc, Dinobryon, Chroococcus, Staurastrum paradoxum and Mallomonas which are indicators of toxic and polluted waters was also recorded. This study therefore showed the importance of phytoplankton composition and community structure as a reliable and important tool to assess the degree of pollution in Mengkuang Reservoir. Long-term assessments of biological and chemical parameters in the reservoir are necessary, and phytoplankton community structure as bioindicator provides unique information about the ecosystem. This information is potentially useful as an early warning sign of deteriorating condition and thus gives insight into the overall ecology of lakes and will assist in the future conservation and management of this lentic ecosystem.

In this study, dyeing, fastness and adsorption isotherm characteristics of madder natural dye on the wool and nylon yarns were investigated. Wool and nylon were first mordanted by aluminum sulfate, dyed with natural dye extracted from madder root, and the rates of dyeing and equilibrium times were determined and compared. Nylon, indeed, showed higher dyeing rate and reached equilibrium at comparatively lower times. Adsorption isotherms were identified to be a Nernst-type substrate. In addition, the affinity (Δmo), free energy (ΔHo) and entropy (ΔSo) of madder on the wool and nylon were calculated. The obtained results from thermodynamic data indicated that with temperature rise, the partition ratio and the standard affinity significantly decreased. The affinity of madder natural dye to the nylon was gradually higher as compared with wool. Wool, indeed, displayed higher negative values for both enthalpy and entropy changes as compared to those values of nylon. The colorimetric and fastness properties of madder natural dye on nylon were overall superior than on wool.

Polyhydroxyalkanoates are biodegradable polymer materials that accumulate in numerous bacteria. The polyhydroxybutyrate is the most common type of polyhydroxyalkanoates, which potentially serves as precursor for bioplastic production. The most extensively studied polyhydroxybutyrate producing bacteria is Cupriavidus necator due to its capability to accumulate large amounts of this biopolymer in simple culture medium. Accumulation of polyhydroxyalkanoates granules in the cytoplasm of C. necator significantly depended on pH, aeration, carbon sources, nitrogen sources, and minerals in the culture medium. In the present study, the effect of both nutritional and physical variables on polyhydroxybutyrate production was investigated in order to optimize these conditions. At first, on the basis of one-factor-at-a-time experiments, fructose and ammonium chloride were found to be the most suitable sources of carbon and nitrogen for biopolymer production. Then the most significant factors affecting granules accumulation were recognized as fructose, agitation speed, KH2PO4, and initial pH using the Plackett-Burman and central composite design. ANOVA analysis showed significant interaction between fructose and agitation speed. After optimization of the medium, compositions for polyhydroxybutyrate production were determined as follows: fructose 35 g/L, KH2PO4 1.75 g/L, MgSO4 7H2O 1.2 g/L, citric acid 1.7 g/L, trace element 10 mL/L, initial pH=7, and agitation speed 175 rpm. Under this optimal culture conditions, the maximum yield of PHB was 7.48 g/L. The present strategies included in this study could be used for PHB production by this bacterium. These results are the highest values of PHB ever obtained from batch culture of C. necator reported so far.

In this paper, the effect of adding nanoparticles on the performance characteristics of diesel engine was investigated. Up to now, several metallic nanoadditives including cerium and aluminum have been applied in this area. However, the possibility of using some other metals or modification in the additive structures as well as improving or changing the basic fluid is among factors manifesting a broad scope of work in this area. For this purpose, the silver nanoparticles were used as additives to the net diesel fuel. The results are indicative of significant alteration in the engine power, oil temperature, and the proportion of the released pollutants. The presence of the metallic nanoparticles inside the combustion chamber augments the heat transfer to fuel and shortens the ignition delay through an acceleration of the burning process. Meanwhile, these particles can aid fuel particles further penetrate in the compressed air during the spraying stage. Having all of these features altogether will improve combustion and hence the unburned carbons and other pollutants will decrease. Based on these observations, the rate of CO and NOx would be reduced significantly up to 20.5 and 13%, respectively, noting that the net diesel and HC would undergo the highest change (up to 28%). The results also indicate a 3% fuel consumption reduction accompanied with 6% improvement in the engine power, utilizing nanoparticles in most cases.

The treatment of distillery effluent was investigated experimentally by various advanced oxidation processes such as Fenton and ozone with different combination of UV and H2O2 system. The effect of operating parameters such as hydrogen peroxide concentration, initial effluent pH and Fe2+ concentration on Fenton system for the percentage color and chemical oxygen demand removal has been studied. The energy per order was also calculated for the advanced oxidation process. The ozone-photo-Fenton system has been observed that 100% color and chemical oxygen demand removal compared with other process studied in the present investigation within 4 h of treatment time. Electrical energy per order has been calculated for all the process and found that ozone-photo-Fenton shows lesser energy consumption of about 0.01 kWh/m3 order1, for the complete color and chemical oxygen demand removal.

In this work, we evaluated the ability of rhizobacteria isolated from a metal-contaminated site to produce plant growth-promoting substances, such as indole-3-acetic acid (IAA), ammonia, hydrogen cyanide, siderophores and extracellular enzymes, to solubilize phosphate and for 1-aminocyclopropane-1-carboxylate (ACC)-deaminase activity, while assessing their capacity to enhance Trifolium repens growth. The rhizobacteria that better performed were used as bioinoculants for plants grown in zinc- and cadmium-spiked soils. Rhizobacteria were inoculated onto white clover seedlings growing in 250 and 500 mg kg-1 of zinc and in 10 and 30 mg kg-1 of cadmium-spiked soils and plant traits determined. The available and exchangeable rhizosphere metal concentrations were analyzed. Twenty rhizobacteria stimulated white clover growth under axenic conditions. Overall, strains Rhodococcus erythropolis EC 34, Achromobacter sp. 1AP2 and Microbacterium sp. 3ZP2 increased clover biomass in the absence and in presence of metals; however, in soils with 250 mg kg-1 of zinc, bacterial inoculation did not enhance plant biomass. Biomass enhancement may be related to the multiple bacterial promoting traits, especially the production of high levels of IAA and siderophores and the activity of ACC-deaminase. To the best of our knowledge, this is the first study reporting the potential of R. erythropolis to increase plant growth in metal-contaminated soils. In general, strains Microbacterium sp. 3ZP2 and Arthrobactersp. EC 10 enhanced the available and exchangeable metal concentrations in rhizosphere showing their potential to improve phytoremediation efficiency. This work clearly indicates that rhizobacteria are promising for the development of bioinoculants useful for phytoremediation of polluted soils.

The nickel-copper alloy (70:30) prepared by metallurgical route is currently employed in marine environments because of its good resistance to corrosion. This alloy forms a thin protective surface layer when exposed to marine atmosphere and thus provides its corrosion resistance. Electrodeposition of nickel–copper alloy from sulphamate acetate-based electrolyte is a new and novel approach and was experimented. The detailed study was performed on the effect of electrolyte composition, current density and pH on the preparation of alloy deposit; the prepared alloy deposit particle size is of 78 nm, and the surface morphology of the alloy deposit was characterized with X-ray diffraction, scanning electron microscopy, EDAX, and atomic force microscope. Nickel-copper alloy deposited from the sulphamate acetate-based electrolyte operated at a temperature of 30oC, with a pH of 6.6 and at 3 A/dm2, produces nickel-copper (70:30) alloy deposit. The corrosion behaviour of this alloy deposit was studied by potentiodynamic polarization method; the corrosion current of nickel is 8.67 mA cm-2 and the nickel-copper alloy is 2.65 mA cm-2.

In this paper, the effects of salicylic acid (SA) algicide carried by cross-linked chitosan on the inhibition of Microcystis flos-aquae and the removal ability of heavy metals Pb and Ni in compound polluted water were studied. The results showed that the algicide had significant inhibitory effects onMicrocystis flos-aquae: when the concentrations were 550 and 700 mg L-1, the inhibition time was up to 13 days or more, and the inhibition rate was as high as 99%. The algicide exhibited strong adsorption capacity to heavy metals Pb and Ni. The adsorption rates of the algicide at concentrations of 400 and 550 mg L-1 on Ni and Pb were 61 and 64.9%, 71.2 and 72.5% at 13 days, respectively. The algicide allows a slow release of SA and long-term inhibition of algae and has better adsorption capacity on heavy metals, thus providing a method for the effective control of eutrophication and combined heavy metal pollution in water.

Decomposition of soil organic matter by microorganisms is a major process governing the carbon balance between soil and atmosphere which needs to be fully understood. Extracellular enzyme activity is often the limiting factor for microbial utilization of soil organic matter. Contrary to expectations, we observed that enzymatic activity rises at increasing temperatures in soils and sediments. Current climatic change will induce the increase of global mean temperatures, frequency of extreme heat events and soil temperatures during the next decades. The relevance of the increase in activity at high temperature is dependent on latitude. At latitudes around and below 40° a significant number of days per year present high temperatures. Results suggest that the hydrolytic activity of microbial extracellular enzymes is currently underestimated mainly at medium and low latitudes where soil temperatures frequently reach high values (often above 40oC). This report contributes to understand (1) the hydrolysis of soil organic matter within a latitude-dependent scenario of global warming and (2) the role of microorganisms in processing soil organic matter and their influence in carbon cycling.

This paper investigated the possibilities of using birch wood chips for fixed-bed downdraft gasification. The preliminary air gasification resulted producer gas with an average composition of 11.5% CO, 5.4% CO2, 5.9% H2, 0.38% CH4 corresponding to a mean lower heating value of about 2 MJ/kg. The approximate size of woodchips used for gasification was around 11.5 mm for a maximum solid throughput of 0.65 kg/h. The obtained equivalence ratio (ratio between actual air fuel ratio and stoichometric air fuel ratio) as a result of air and biomass feed was close to 0.45 which was stable throughout the test. Producer gas left the gasifier at ca. 150oC and was diverted for flaring owing to the level of low energy content. Despite availability, the option for gas to generate heat and electricity via integrated gas engine has not been utilized in the present case and remained for further ongoing research.

Concentrations of Cd, Cu, Pb, Ni, Zn and Cr were estimated using inductively coupled plasma-mass spectrometry in sediment, water, fish and shrimp collected from the Subarnarekha River. Fish species Mystus gulio, Puntius conchonius, Labeo calbasu, Labeo rohita and Labeo bata, while the shrimp species Penaeus indicus, were used for the study. The range of Cd, Cu, Pb, Ni, Zn and Cr in all the samples was found to be 0.004-0.85, 0.75-145.2, 0.03-0.41, 1.25-21.5, 12.4-109.5 and 0.22-11.36 mg kg-1 fresh, respectively. The concentrations of metals in the fish and shrimp exceed the limits of Indian and international standards for food for Cu, Ni, Cd and Zn in some samples. Higher concentrations of the metals were observed in the shrimp as compared to fish samples. The calculated daily intakes of the metals through the consumption of fish and shrimps ranged from 0.30 to 27.0% of the corresponding tolerable limits suggested by the Joint FAO/WHO Expert Committee on Food Additives. The mean target hazard quotient values for the 6 metals were below 1 for all the samples; however, the maximum was more than 1 for shrimp Cu and Cr. The results indicated that the concentration of the metals in shrimps at some locations was alarming and pose an appreciable hazard risk on human health. Potential ecological risk analysis of sediment indicated that most of the sites posed moderate ecological risk with Cd posing a considerable risk at all the sites.