Search results for "Environmental engineering"
showing 10 items of 2674 documents
Organic chlorine compounds in lake sediments. III. Chlorohydrocarbons, free and chemically bound chlorophenols
1990
Abstract Chlorohydrocarbons and free and chemically bound chlorophenols, catechols and guaiacols were measured from lake sediments in Central Finland. Chlorohydrocarbons occurred at low backround levels except chlorocymenes from pulp mills and PCBs near the city of Aanekoski, where a local leakage occurrs. Free chlorophenols (hexane extractables) were found in all 18 areas studied, but the bound ones (extracted with strong alkali) only in the pulp mill reciepient lakes where they dominated. Preliminary analyses of chemically bound chlorophenols in high molecular fractions of spent bleach liquors and pulp mill effluents indicated that majority of chlorocatechols and guaiacols are bound alrea…
Alkylated dibenzothiophenes in pine needles from pulp and paper mill environment
1998
Abstract Concentrations of alkylated dibenzothiophenes (C n DBTs) in pine needles in a recipient area of the emissions from a pulp and paper mill where also waste combustion was done were measured. The concentrations (ng/g dry weight) of C 1 DBTs were in the range of 2 DBTs in the range of 3 DBTs in the range of 3 DBTs] > [C 2 DBTs] > [C 1 DBTs]. The pulp mill could not be shown to be the source of C 1 C 3 DBTs in the pine needles. Other possible sources are situated in the vicinity of the pulp and paper mill. Long-range transport, either, cannot be excluded as a possible source.
Transport of high molecular mass lignin material in the receiving water system of a mechanical pulp mill
1998
High molecular mass material (HMM) of water samples collected from the receiving water system of a mechanical pulp mill was characterized applying cupric oxide oxidation combined with GC and HPLC analysis of the oxidation products. This qualitative method was used to follow the transport of organic HMM discharged by the mill. The interpretation of results was complicated by degradation reactions of HMM in the water system and the assimilation of HMM produced by the mill to natural humic compounds. The analytical data was subjected to the principal component analysis (PCA) to verify the results obtained.
Importance of ligand speciation in environmental research:A case study
2001
The speciations of EDTA and DTPA in process, waste and river waters are modelled and simulated, specifically to the mode of occurrence in the pulp and paper mill effluents and subsequently in receiving waters. Due to relatively short residence times in bleaching process and waste water treatment and slow exchange kinetics, it is expected that the thermodynamic equilibrium is not necessarily reached. Therefore, the initial speciation plays a key role. As such, the simulations have been extended to the process waters of the pulp and paper industry taking into account estimated average conditions. The results reveal that the main species are; Mn and Ca complexes of EDTA and DTPA in pulp mill p…
Bioaccumulation of dioxins, coplanar PCBs, PCDEs, HxCNs, R-PCNs, R-PCPHs and R-PCBBs in fish from a pulp-mill recipient watercourse
1993
Abstract Pike, perch and lake bream from the river Kymijoki were analyzed by gas chromatography/mass spectrometry (GC/MS) for toxic polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs), hexachlorinated naphthalenes (HxCNs), non-ortho substituted polychlorinated biphenyls (coplanar PCBs) and alkylchloroaromatics of pulp mill origin. In most fish, the only congener of PCDD/PCDFs found was 2,3,7,8-TeCDF (
Synthesis of chlorinated alkylbibenzyls and 9-chlororetene
1995
Abstract The synthesis of chlorinated alkylbibenzyls and 9-chlororetene is described. These compounds were synthesized for use as model compounds in analytical and toxicological characterization. The structures of the synthesized model compounds found to be very similar to those identified in pulp mill effluent and products. The 1H NMR and mass spectral data for the compounds are also reported.
Fate of pulp mill effluent compounds in a finnish watercourse
2013
Chloroorganic chemicals emitted from the pulp and paper mill at nekoski in central Finland were monitored for several years. Concentration time series are used for evaluating the environmental fate and the applicability and validity of an exposure models. Fitted elimination rates of 3,4,5-Tri-, 4,5,6-Tri-, Tetrachloroguaiacol and 2,4,6-Trichlorophenol are approx. 0.22 d(-1), or rather the half-lives are approx. 3 days. The elimination is most likely by biodegradation and transport-controlled. For 2,3,6-trichloro-p-cymene, fate simulations indicate significant volatilization and sedimentation. Good agreement is achieved with a one-dimensional steady-state box model, except for concentrations…
Model compound synthesis for the structure determination of new unknown planar aromatic compounds originating from pulp mill
1991
Abstract Several model compounds have been synthesized for verification of the structures of new unknown planar aromatic compounds (UPACs) observed in high-resolution gas chromatography/low-resolution mass spectrometry analyses of the polychlorodibenzodioxins (PCDDs) and polychlorodibenzofurans (PCDFs) in pulp mill products, effluents, sediments and mussels. The mass spectra of synthetic alkyl polychlorodibenzofurans (C6-PCDFs) were different, but those of alkyl polychlorobibenzyls (C5-PCBBs) were very similar compared to the spectra of UPACs.
Alkyl polychlorobibenzyls and planar aromatic chlorocompounds in pulp mill products, effluents, sludges and exposed biota
1992
Abstract Aromatic chlorocompounds which interfere in GC/MS analysis of dioxins were studied in samples from three different pulp mills and in fish and mussels exposed to pulp mill effluents. The major interfering compounds were chlorinated alkyl bibenzyls (R-PCBBs; R = C5-alkyl; P = 1–4). In pulp mill samples, levels of C5-PCBBs (10–120 ng/l in effluents, 5–33 ng/g in dried sludges) were orders of magnitude higher than the levels of toxic PCDDs and PCDFs. C5-PCBBs bioaccumulated slightly to the recipient fish (0–2 pg/g in fresh muscles) and to incubated mussels (3–26 ng/g in lipid). In mussels, significant levels (19–73 ng/g in lipid) of other than pulp mill originated toxic hepta- and octa…
Method for size optimisation of large wind–hydrogen systems with high penetration on power grids
2013
Wind power generation is growing rapidly in many locations around the world. Power systems are able to absorb large amounts of wind capacity, but operational problems arise when the wind power penetration becomes high. Such factors as voltage dips, frequency variations, low power system stability, low reactive power and power flow imbalances reduce the economic value and represent a barrier to the unlimited development of wind energy. Hydrogen production from wind power that is not matched with hourly electricity demand appears to be an attractive storage option capable of providing a balancing service to the electricity generators and suppliers for mitigation of the negative impacts due to…