Amounts Of Organic Compounds Research Articles

Experimental Study on Thermal Hydrolysis and Dewatering Characteristics of Mechanically Dewatered Sewage Sludge

After mechanical dewatering, sewage sludge has a moisture content of around 80 wt% and further disposal is required. A new sewage sludge semi-drying (dewatering) process is proposed and verified. It combines thermal hydrolysis and subsequent mechanical dewatering, with less energy consumption than traditional thermal drying. Sludge treated using this new process satisfies further disposal requirements (e.g., landfill or autothermal incineration). In the present study, a high-pressure test reactor was used to study the thermal hydrolysis of dewatered sludge. Thermally hydrolyzed sludge was subsequently dewatered by centrifugal sedimentation or by pressure filtration. The amount of organic compounds returning to the water phase was also measured. According to the results from centrifugal settling tests, the optimal thermal hydrolysis treatment temperature was 180°C. The moisture content then dropped to 1.44 kg/kg dry solids (DS; 59 wt%) after dewatering under relative centrifugal force of 9,000 × g from 5.67 kg/kg DS (85 wt%). Pressure filtration further reduced the moisture content of filter cakes to only 0.5 kg/kg DS (33 wt%, hydrolysis temperature 180°C). After thermal hydrolysis, the heating value of sludge (moisture-free basis) was about 80% that of the untreated sludge.

Control of the Morphology of Molybdenum Dioxide Nanoparticles

Synthesis of MoO2 nanoparticles with one‐dimensional (1D) and spherical morphologies in aqueous solutions, through hydrothermal process was investigated. The materials were studied by x‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Infrared spectroscopy (FTIR) and thermal analysis (TG). It was found that the quantity of organic compound influenced the size and shape of the final product. The possible formation mechanism of MoO2 microspheres and nanowires was also discussed. The conductivity of MoO2 nanowires was explained by the presence of two protons types in the material.

TREATMENT OF WASTEWATER FROM MOLASSES-BASED ALCOHOL DISTILLERIES BY UV/O3 OXIDATION PROCESS

The treatment of wastewater from molasses – based alcohol distilleries in Viet Nam is still an unmanageable problem. This kind of wastewater contains high organic components which is difficult to biodegradation. Survey results on molasses – based alcohol distilleries waste water after biological treatment determined that the composition of wastewater also contains a considerable amount of organic compounds with high COD about 1300 - 1800 mg/L. Research results on wastewater after biodegradation in laboratory conditions by using advanced oxidation technologies demonstrated that the UV/ozone oxidation system is more efficient than the Ozone system UV OZONE in which the COD and colour treatment efficiency is higher from 4,2 – 22%. By using modeling method with the 5.0 software mode, this study determined the optimal reaction conditions for the model UV / ozone: pH = 9, O3 concentration = 54 mg/h; UV power = 8W/h. The treatment efficiency can reach 100% and 93% of colour and COD respectively after 120 minutes. The study also demonstrated that the presence of anions such as Cl-, SO42-, HCO3- had a significant impact on the efficiency of the oxidation process.

Studies on polymeric conservation treatments of ceramic tiles with Paraloid B‐72 and two alkoxysilanes

AbstractThe aim of this study was to evaluate the effect of different polymeric protections applied on ceramic tiles on their mechanical and water absorption properties. Three conservation products were used: the acrylic polymer Paraloid B‐72 and two alkoxysilane‐based formulations (tetraethoxysilane (TEOS) and IN2210, a polidimetilsiloxane‐based formulation). The coatings were applied onto handmade tiles manufactured according to a 18th century procedure. Different application procedures (immersion, brushing, and spraying) were tested. The protection effectiveness was assessed through capillary water absorption and four point bending tests. The mineralogical characterization of tiles was undertaken by XRD. The best protective properties of the tiles were achieved by immersion treatments with Paraloid B‐72 based on the protocols followed by the museums restoration departments. Nevertheless, the results of the present work show that the second immersion in Paraloid B‐72 solution, commonly made, can be eliminated, as it does not provide any significant increase in the hydrophobic or mechanical properties of the tiles. As a result, there are obvious economical benefits, as the coating process became less time‐consuming and more environmental friendly, as the amount of organic compounds is reduced. On the other hand, the use of small volumes of Paraloid B‐72 solution applied by brush, or IN2210 sprayed can provide good results, if the only purpose of the treatment is the increase of the hydrophobic properties. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Analyses of passivation films on lithium and lithium alloys by electrochemical quartz crystal microbalance

Abstract Electrochemical quartz crystal microbalance (EQCM) measurements were carried out during electrochemical deposition/dissolution of Li on the Ti and Pt substrate electrodes of AT-cut quartz crystals in a 1 M LiPF 6 in propylene carbonate (PC) and dimethoxyethane (DME) (1:1 in volume) and a 1 M LiPF 6 in ethylene carbonate (EC) and DME (1:1 in volume). The mass change during Li deposition on the Pt substrate was about half that on the Ti substrate because the alloy formation of Li–Pt suppressed passivation reactions of deposited Li. Furthermore, it was also suggested that the amount of organic compounds in passivation films formed in the PC-based electrolyte was larger than that in the EC-based electrolyte due to PC reacting more easily with Li than EC. The EQCM measurement of the passivation film formations during alloying Li with Pb electrodeposited on the Ti substrate was also conducted successfully. The Li–Pb alloy formation occurred under 0.5 V, in which the potential profile was divided into two regions associated with the phase diagram of Li–Pb alloy. The mass change due to passivation film formations increased in accordance with the changes of Li–Pb alloy compositions into Li rich phases, which were thought either to enhance the reactiveness of Li or decrease the diffusiveness of Li in Li–Pb alloy.

Effective of SiO<sub>2</sub> Addition on the Self-Cleaning and Photocatalytic Properties of TiO<sub>2</sub> Films by Sol-Gel Process

Thin films of various composition in the system of TiO2•SiO2 have been fabricated by the sol-gel process using Si(OC2H5) and Ti(OC3H7i)4 as precursors. TiO2•SiO2 films were formed on the glass substrate by spin-coating technique and heated at 500°C for 1 h. The relationship between hydrophilicity, photocatalytic properties and self-cleaning property with SiO2 addition and UV light irradiation were investigated. Photocatalytic activity of TiO2•SiO2 films showed decomposition of ~97% of acetaldehyde in 2 h and a water contact angle of ~10°. TiO2•SiO2 films can have more hydrophilic activity and less photocatalytic activity by increasing of SiO2 addition. XPS measurements revealed that the amount of organic compounds adsorbed on the films decreased with the UV light irradiation and SiO2 addition, because of the increased of both OH group contents in films and decomposed organic contaminants of the films surface.

Attenuated Total Reflectance as an Alternative of Diffuse Reflectance Infrared Detection in the Identification of Compounds Separated by Thin Layer Chromatography

Diffuse Reflectance (DRIFT) and Attenuated Total Reflectance (ATR) are infrared sampling methods, based on the detection of infrared radiation reflected by the sample. They are widely used in surface analysis and are both capable of detecting small amounts of organic compounds. DRIFT is a well known on‐layer method for the identification of analytes, separated on thin layers. In the present work, the possibility of using a diamond ATR unit to collect IR spectra of sample spots was examined.

Carbon source in aerobic denitrification

The objective of this study was to demonstrate denitrification by activated sludge under aerobic conditions. Activated sludge was cultivated in a sequencing batch reactor (SBR) with municipal wastewater enriched by acetate. Poly-β-hydroxybutyrate was accumulated in activated sludge to 0.35 g PHB/g VSS ( f PHB = 0.27 Cmol/Cmol). Microorganisms had the opportunity to preserve reducing power from poly-β-hydroxybutyrate (PHB) stored in microbial cells. Activated sludge, cultivated in such conditions, was used in further experimental series. The duration of each series was 24 h. Two types of synthetic wastewater were used in the presented studies: wastewater without organic compounds, and wastewater with acetate as the main carbon source. Ammonium was the only nitrogen source. Since, ammonium oxidation by activated sludge had to go before denitrification. It was shown that under aerobic, autotrophic conditions, the amount of nitrogen reduced by activated sludge was 4.54 mg N red/l, using intracellular PHB stored in microbial cells, as the only carbon source for denitrification. In wastewater with acetate, the amount of reduced nitrogen due to aerobic denitrification increased to 22.5 mg N red/l. The results indicted that PHB, stored in activated sludge, can be served as electron donor for aerobic denitrification. Denitrification under aerobic conditions using internal substrate is not as effective as in presence of the internal and external carbon sources but during denitrification, supported by endogenous substrates, the amount of organic compounds in wastewater required for the process can be limited.

EFECTO DE LA MATERIA ORGÁNICA Y EL MANEJO SOBRE LA HIDROFOBICIDAD DE SUELOS VOLCÁNICOS

Soil water repellence or hidrofobicity depends on a strong interaction among the mineral and organic soils fractions. The content of organic matter is an determinant factor of water repellence. A positive relationship between the content of organic matter and water repellence can be observed, however, not all organic matter may cause repellence in the soil matrix. More than the amount of organic compounds, the quality characteristics impact the hidrofobicity of soil. It is possible to find two types of repellencies:) natural and induced one. The repellence influence the magnitude of intermolecular electrical forces which act in the interface of solid-liquid-gas. This phenomenon can be evaluated by measuring the contact angle (θ) among these phases. Soil management influence water repellency, but this effect is reduced by intense mechanical labor. Hidrofobicity influence soil hydraulic characteristic, modifying preferential flows. The aim of this study was: i) determine the soil water repellency in three volcanic soils from southern of Chile in combinations with two managements (forest and prairie) and ii) to estimate the buffer capacity by using a hydrophilic compound in the volcanic soils. It was observed different contact angle, attributed to soil characteristics, but with a direct effect of vegetation type which contributed to organic materials top cause repellence in these soils. Soils with similar pedogenetic characteristics show different hydrophobic values for the same vegetation (forest or pastures). Soils humectation capacity depends of the quality of soil organic matter more than SOM total content. Buffer capacity of soils depended of the amount of SOM, and its interaction between mineral soil particles.

Reverse osmosis membrane rejection for ersatz space mission wastewaters

Adequate rejection of a variety of inorganic and organic compounds is necessary if reverse osmosis (RO) and nanofiltration (NF) membranes are to be used for space mission wastewater reuse. Three ersatz space mission wastewaters defined by NASA having different pH (2.6–8.9), conductivities (3980–12,640 μS/cm), and amounts of organic compounds (50–2400 mg/L as carbon) were tested to determine the membrane flux and the solute rejection for five RO and two NF membranes that are commercially available. The results show that the rejection of ions depends upon the solution pH which influences electrostatic repulsion. However, the rejection of dissolved organic carbon (DOC) depends upon the composition of the wastewater. The DOC rejection (80–95%) was the highest for the wastewater containing dextran (molecular weight 15–20 k) compared with the other ersatz wastewaters having detergent and urea as the major carbon sources (31–83%). The wastewater having the greatest conductivity (12,640 μS/cm) and DOC (2400 mg/L) showed a greater flux decline (71–96%) than the other ersatz wastewaters (37–82%) having lower conductivities (3980–6980 μS/cm) and DOC (50–660 mg/L) for the RO and NF membranes. The ratio of solute radius ( r i, s) to effective membrane pore radius ( r p ) was employed to compare ion rejection. For ionic compounds, the rejection is higher than 70% when the r i , s / r p ratio is greater than 0.5 for both the RO and NF membranes with all wastewaters.

Classification of dissolved organic carbon (DOC) in river systems: Influence of catchment characteristics and autochthonous processes

Dissolved organic carbon (DOC) in surface waters is influenced by natural and anthropogenic allochthonous sources in the catchment and by autochthonous production and degradation processes. An objective differentiation procedure, a principal component analysis, has been used to answer the question: Is it possible to classify different water types using only DOC-patterns, and how do seasonal variations influence such a classification? Organic compounds from various sources and river systems were analyzed by means of automated size-exclusion chromatography. Four different DOC fractions (humic substances, polysaccharides, low molecular weight acids and low weight substances) were separated on the basis of their molecular weight characteristics and quantified on the basis of their UV absorbance. Significant differences in the quality and quantity of organic compounds were found. These were related to the character of the catchment area and to autochthonous processes. It was possible to classify peat-influenced ditch waters, peat-influenced surface waters, mineral soil-influenced and anthropogenically-influenced surface waters, and waters from small and large lake–river systems. The characterization of DOC patterns combined with principal component analysis is a powerful tool for analyzing allochthonous and autochthonous DOC sources in surface waters, especially if seasonal variations are taken into account.

Odor Control in Composting Plants: Results from Full-Scale Experiences

The development and spread of mechanical biological treatment (MBT) and composting plants is often hindered by the problems and concerns arising from emission bad odors. Several technologies are now available to process exhausted air originated from these or similar plants. Exhausted air emissions contain a large amount of organic compounds, most of them in very low concentrations. This determines the advantage in using biological abatement systems (biofilters) instead of physical–chemical treatments. This article describes the operative results obtained in two Italian waste treatment plants, one in Albano, near Rome, and the other in the “ex-Maserati area” of Milan, including (i) the analysis of operational parameters as temperature, pH, humidity, loss of pressure of the biofilter affecting the biofiltration efficiency, for both chemical parameters and odorous compound concentration, measured by means of odor panel evaluation technique and (ii) the efficiency of the biofiltration system for several compounds present in air emissions, analyzing organic substances by means of gas chromatography/mass spectrometry. The two plants used similar biofiltration systems except for the material used as biofilter bed. A bioscrubber pretreatment of the air flow coming from the aerobic reactor was tested in the Albano plant for the purpose of reducing the odor concentration of the most impacting flow going to the biofilter.

The classification and the monitoring of the state of mouth riverine and lacustrine ecosystems in lake Baikal based on the composition of local microbiocenoses and their activity

The paper presents the results of the long-term investigation of microbial communities in the technogenically vulnerable mouth riverine and lacustrine ecosystems of Lake Baikal. The structural and functional parameters of the microbial communities were analyzed from the standpoint of developing destructive processes. The analysis showed that the total number of microorganisms (TNM), the number of saprophytic bacteria (NSB), and bacterial production (BP) were greater in the river-mouth water than in the near-mouth lake water. In the offshore direction, TNM and NSB decreased by a factor of 1.5 to 2, and BP decreased by a factor of 4 to 7. Based on TNM, NSB, and BP data, we classified the Lake Baikal rivers with respect to the degree of the impact of human activities on them. The degrading capability of the riverine microbial communities was found to be such that they degrade daily from tenths of a percent to 3.5% of the total amount of organic compounds polluted the river waters.

Densification and aging of ZrO 2 films prepared by sol–gel

The densification of ZrO 2 films prepared by sol–gel synthesis has been investigated by stress measurements, infrared spectroscopy, and spectroscopic ellipsometry after annealing at 150–400°C. It is shown that the tensile stress is limited by viscous flow accompanying the densification, and that the main organic compounds reducing the rate of condensation reactions are acetate groups. The oxidation of these groups at 350°C induces a jump in both the stress and the refractive indices of the films. The effect of film aging in air on the stress has also been studied. The moisture-induced stress change follows a logarithmic time dependence, most likely due to hydration of ZrO 2. The sign of stress change is determined by the amount of organic compounds in the gel.

Environmental Characterization of Metal Finishing Sludges

Metal finishing industries generate effluents with high contents of heavy metal, inorganic anions and minor amounts of organic compounds, which must be treated by specific physicochemical processes leading to complex sludges. The characterization of these wastes is necessary to assess their environmental impact and to establish management. In this work two different methods of characterization, based on the Spanish Regulations and European Economic Community suggestions, have been applied to 32 wastes from 16 metal finishing facilities. The ecotoxicity values, EC50, of the TCLP leachates show a high variability among different metal finishing activities and batches of the same activity, ranging from 1 000 mg l−1 to 1 000 000 mg l−1. Results of chemical characterization of leachates, according to the DIN 38414-S4 leaching procedure show a high concentration of SO4 2−, Cr and Ni. The paper establishes the characterization parameters of sludge wastes from the physicochemical treatment of metal finishing effluents.

Formation of organic compounds in superheated steam drying of bark chips

The formation of organic compounds during steam drying of bark chips in the exhaust steam was investigated as a function of time, with temperature and age of bark chips as independent parameters. The rate of formation strongly depends on temperature. The results suggest that the amount of organic compounds in the exhaust steam can be minimized by drying stored bark at ‘low’ temperature, with a short drying time.

Effect of Organic Ligands on Properties of Alumina-Zirconia Composite Powder by Sol-Gel Method

Alumina-zirconia composite powder were prepared from aluminium iso-propoxide, zirconium n-butoxide and various organic ligands which were 1, 2-ethanediol, 1, 2-propanediol and 1, 3-propanediol. The effect of organic ligands on properties of the alumina-zirconia composite powder was investigated. It was suggested that the amount of organic compounds in the dry gels and the homogeneity of the alumina-zirconia composite powder changed with the species of organic ligand. The specific surface area, the pore volume and the pore size distribution of the alumina-zirconia composite powder depended on the organic ligand, and the pore size of the alumina-zirconia composite powder is distributed from 1 to 4nm in radius. The control of pore size distribution by varying the kind of organic ligands was suggested.

Nonextractive immunoassay analysis of contaminated sediments

A novel testing method determines the amount of organic compounds sorbed to sediments. It is a nonextractive immunoassay which has demonstration data for 2,4-dinitrobenzene sulfonate (a model pollutant for which antibodies are commercially available) sorbed to crushed brick (a model sediment surrogate). the nonextractive immunoassay quantitatively distinguishes between contamination levels. Advantages of the nonextractive immunoassay include small sample size (<1 g), easy adaptation to field testing, and elimination of extraction solvents.

RED RIVER OF THE NORTH BASIN, MINNESOTA, NORTH DAKOTA, AND SOUTH DAKOTA1

RED RIVER OF THE NORTH BASIN, MINNESOTA, NORTH DAKOTA, AND SOUTH DAKOTA¹

Effect of a phosphate solubilizing bacteria on maize growth and root exudation over four levels of labile phosphorus

The influence of inoculation with phosphate-solubilizing bacteria (Enterobacter agglomerans) on maize growth, P uptake and root exudation was studied. Plants were grown in an axenic culture device where P was supplied as soluble phosphate at different contents (0, 5, 15 or 25 ppm) in the nutrient solution and as insoluble rock phosphate added to the culture sand. Experimental device was successfully used to obtain axenic root systems or good establishment of the inoculated strain in the rhizosphere of maize (109 bact. g−1 dry rhizospheric material). Plant growth was promoted by inoculation only for 5 or 15 ppm of soluble P in the nutrient medium without any significant effect on P uptake by the plant, suggesting that the quantities of P released by bacterial rhizospheric activity were very small. Amounts of organic compounds (total C and water-soluble C) exuded were relatively low (3.0 to 6.4% of the total plant biomass) and were reduced by bacterial inoculation when plant growth was largely promoted.