摘要:

In this study, it was attempted to identify organic compounds in an industrial wastewater originating from processing of oil/water mixtures and spent oils. For this purpose, samples of oil reclaiming wastewater were extracted with dichloromethane. By gas chromatography/mass spectrometry (GC/MS), organic wastewater constituents had been detected and tentatively identified or at least characterized which belonged to the following groups: hydrocarbons, alcohols, ethers, phenols, ketones, carboxylic acids, esters, nitrogen‐containing heterocycles, and a few others. But the detected organics represented only about 2 % of TOC, which was about 5000 mg/1. Alcohols/ethers (mainly surfactants containing several ethoxy groups) were predominant among the gas chromatographically detectable substances. In all investigated samples l‐(2‐butoxyethoxy)‐ethanol, 2‐[2‐(2‐butoxyethoxy)‐ethoxy]‐ethanol, pentaoxanonadecanol ( or a homologue ) and 2‐phenoxyethanol were the main representatives of the identified organics. Alkanes were very low in samples treated by precipitation and could also be removed by short time contact with activated sludge Other groups of organics (except alcohols/ethers and N‐heterocycles) were reduced by biosorption too. In terms of TOC about 6 % of the organics were removed by biosorption.

ISSN:1093-4529    

DOI:10.1080/10934520009376981

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The goal of this research was to determine the potential of the fungal sterol ergosterol as an indicator of fungal biomass and to determine the growth response of the transformed strain ofT. virens(GvT6) to added substrate and changes in temperature. Experiments in liquid culture and agar plates containing a rich medium of glucose, yeast extract, and casein (GYEC), or a soil extract medium supplemented with maltose (SE) showed that the ergosterol content of GvT6 was greatest when grown on GYEC agar plates (14.02 mg/g dry biomass). For both media, plate cultures produced higher specific ergosterol values than liquid cultures. Changes in specific ergosterol values over time were generally not significant. A value of 5.41 mg ergosterol / g dry biomass, determined for SE plate cultures, was used to convert ergosterol values to biomass values in growth experiments in soil bioreactors.

ISSN:1093-4529    

DOI:10.1080/10934520009376982

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Large temporal and spatial variations in chlorophyll concentration found in estuarine and coastal waters have been attributed to a diverse set of physical, chemical and biological factors. The Keelung River has the largest tidal excursion and the most serious pollution problem among the three tributaries of the Tanshui River system in northern Taiwan. It receives extremely high anthropogenic nutrient loadings from municipal and industrial discharges with little or no treatment. The observed data show very high nutrient concentrations in the river, with total nitrogen of order of several milligrams per liter and total phosphorus of 1 mg/1. However, the summer chlorophyll ‘a’ concentrations are generally less than 10 μg/1. A time‐dependent, laterally averaged, two‐dimensional hydrodynamic and water quality model (HEM‐2DT) was applied to the tidal reach of the Tanshui River estuarine system to simulate the phytoplankton dynamics, nutrient cycling and dissolved oxygen distribution. The numerical model was calibrated and verified with observed chlorophyll ‘a’ and nutrient distributions in the Keelung River, and then used to investigate the various factors regulating chlorophyll ‘a’ distributions in that river. The sensitivity analyses include water‐column light extinction, nutrient reduction, freshwater discharge, boundary condition and effect of salinity distribution. The result reveals that light availability is the predominant limiting factor of phytoplankton growth, while nutrient concentrations are not limiting. The reduction of nutrient N and P loadings have no effect on chlorophyll ‘a’ concentration in the Keelung River.

ISSN:1093-4529    

DOI:10.1080/10934520009376983

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

This study analyzes how solution pH and ionic strength influence the sorption of polycyclic aromatic hydrocarbons (PAHs) onto humic acids (HA) coated aluminum oxide. A series of batch experiments were performed to obtain the apparent sorption coefficient(Kp)for systems with different humic acid concentrations, pH values, ionic strengths, andKowvalues of the sorbate. According to those results, the value ofKpincreases as the ionic strength or hydrophobicity of the PAHs increases, or as the pH value decreases. In addition, the fluorescence quenching method was used to measure the HA‐PAHs binding constantKdom, allowing the estimation ofKpby an overall mechanistic sorption model (OMS model). In most cases, these two approaches display the same trends and have similar results, thereby confirming the feasibility of applying this model to the aqueous chemistry of the third‐phase effect and analyzing the environmental system.

ISSN:1093-4529    

DOI:10.1080/10934520009376984

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The purpose of this study was to analyse, in healthy volunteers exposed to noise of high intensity, any changes in certain hormonal parameters that might be related to psychological and behavioural effects. The parameters studied were cortisol (CORT), dehydroepiandrosterone‐sulphate (DHEA‐S), prolactin (PRL), growth hormone (GH), insulin (IRI). Some subjective spontaneously expressed parameters, such as feeling cold, feeling sleepy, being bothered by noise and feeling uneasy, feeling nausea, were also taken into consideration. A significant reduction of cortisol compared to the base values was noted both during exposure to noise and at the end of the stimulus. The DHEA‐S values increased compared to the base values during administration of the noise and after exposure had finished. After the end of the noise stimulus, prolactin showed a reduction compared to pre‐ and post‐exposure values. Compared to the basic values, GH diminished both during and after exposure to noise. Insulinaemia showed a significant increase of the value during exposure to noise, both compared with basal levels and with the values noted after exposure. The data obtained from the investigation carried out showed an influence on the human organism of acoustic stress that manifests itself through a complex multi‐endocrine response. This suggests that noise affected the endocrine system that might be related to psychological and behavioural effects.

ISSN:1093-4529    

DOI:10.1080/10934520009376985

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Numerous pollution control agencies around the world are attempting to implement smoke opacity tests in efforts to lower ambient fine particulate matter levels. However, this approach is valid only if lower smoke opacity levels do result in lower mass emissions rates and lower number count of particulate matter emissions. This paper is limited to measurements of mass emission rates of particulate matter and smoke opacity. Particle size distributions and concentrations are not discussed. In this study in‐use emissions were measured from eighteen transit buses powered by electronic controlled six‐cylinder, turbo‐charged, after‐cooled engines. Eleven of these were fueled with diesel no. 1 while the remaining were running on bio‐diesel. Vehicle exhaust smoke opacity measurements were made using the Snap‐Acceleration Test procedure using a partial flow smoke meter, Bosch RTT 100 Diesel Smoke Opacimeter. Raw smoke opacity data was analyzed using the running half‐second average and the second order Bessel filter. In most cases the half‐second average gave a higher peak value than the Bessel filter. The smoke opacity data was compared with the mass emission rates of total particulate matter that were obtained during transient testing of these vehicles on the West Virginia University Transportable Heavy‐duty Vehicle Testing Laboratory. The vehicles were operated over the Central Business District cycle on the chassis‐dynamometer based laboratory. While smoke opacity and mass emission rates of particulate matter from heavy‐duty vehicles do exhibit a trend, there is no correlation between these two measurements.

ISSN:1093-4529    

DOI:10.1080/10934520009376986

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Biofilms are believed to significantly influence the accumulation, transport and transformation of heavy metals. A system of bacterium‐ex opolysacchride (EPS)‐kaolinite (BEK) was used as a simulation of biofilm‐coated particle to discern the interaction of biofilms with Cu (II) and Pb (II). The adsorption for single metal ions and in the presence of two metals was interpreted using Freundlich isotherms. The distribution coefficients (Ka) of single ions were 270 for Cu2+and 435 for Pb2+, indicating Pb (II) has a higher affinity for biofilms than Cu (II). Where both metals were present, Kavalues were 413 for Cu2+and 3.09xl04for Pb2+, showing that the two metals competed for biofilm binding sites, with the adsorption of Pb (II) being favored. Metal adsorption was influenced by pH. Adsorption capacity increased with the elevated pH to maximums of 161.80±29.30 μg/g cell (dry weight) for Cu (II) at pH 5.0 and 112.30±26.74 ng/g cell for Pb (II) at pH 4.0. With the further increase of pH, the adsorption capacity decreased owing to the hydrolysis of metals ions and the detachment of EPS. Where both metals were present, an initial increase of metal adsorption with time was observed. Afterwards, the adsorption of Cu2+and Pb2+decreased from the individual maximums to 7603±970 μg/kg cell, 2240±310 μg/kg cell, respectively, suggesting that the metals seemed to be excluded from the biofilms because of their toxicity.

ISSN:1093-4529    

DOI:10.1080/10934520009376987

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The sludge waste obtained from metal plating industries has been converted into a low‐cost sorbent material. The thermally treated activated electroplating sludge is characterized, as well as its use for the removal of metal ions. The effect of contact time, the pH, the sorbate concentrations, the mixture of metal ions and the temperature on the sorption of lead, copper, zinc and nickel were studied in batch experiments. Kinetic studies were undertaken in order to make clear the mechanism of the process. The sorption on electroplating sludge follows both Langmuir and Freundlich's models. The degree of removal of metal ions was found to be dependent on the final pH of the contact solutions. The percentage of the sorbed metal ions rapidly rises at pH above 4.2–5.5. Some experiments were also carried out for chemical regeneration of the exhausted electroplating sludge. The order of preference of sorption of meal ions in a single and in a multicomponent system has been established.

ISSN:1093-4529    

DOI:10.1080/10934520009376988

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Saponins were determined as oleanolic acid in refined sugar and sugar juices from beet sugar refining processes by differential‐pulse cathodic stripping voltammetry (DPCSV) at the hanging mercury drop electrode (HMDE) after acidic hydrolysis of the saponin. Measurements were performed on diluted samples at the mg/1 level without further pretreatment. The optimised procedure allowed the determination of saponin at the mg/kg level. The DPCSV method showed a precision and accuracy adequate for the determination of low levels of saponin in sugar and sugar juices. The perfonnance of the procedure is compared with the HPLC method currently in use in many sugar refineries.

ISSN:1093-4529    

DOI:10.1080/10934520009376989

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Effects of chromium resistant strains ofPseudomonad,Scr 1 and Scr 2 on the germination of seeds and growth of the common blackgramPhaseolus mungogrowing under chromium stress have been evaluated. Scr 1 and Scr 2 were isolated from chromium rich wastewaters and rhizosphere ofEuphorbia hirta,employing standard methods. Rate of germination and growth ofP. mungoexposed to different concentrations of chromium with and without inoculation of Scr 1 and Scr 2 were observed. In the absence of bacterial inoculation chromium had adverse effects on all the parameters studied.P.mungoinoculated with Scr 1 and Scr 2 exhibited varying responses to chromium stress. These responses have been computed and discussed in the light available literature.

ISSN:1093-4529    

DOI:10.1080/10934520009376990

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor