摘要:

AbstractThe treatment of water from eutrophic lakes is disturbed by extensive development of plankton, which is caused by particulate algogenic organic substances and frequently also by dissolved ones. They are released by excretion, diffusion, cell destruction, separation of cell wall substances and metabolic processes in the course of the cellular reproduction in dependence on the physiological state of the algae. At a sufficient dosage of metallic salts as a flocculant, the extracellular organic substance (EOS) may act as an anionic flocculation aid in the concentration range of 1 … 2 mg/1 C. There is decisive the mass ratio: Me (metal as flocculant)/EOS (as TOC). Below a mass ratio Fe : TOC =2 … 3 the EOS disturbs the process of flocculation and filtration. Flocculation and filtration tests are carried out with the centrifugate of the culture liquid of eight algae species in flocculation test apparatus in order to clarify the disturbance of flocculation and filtration. The following essential reaction mechanisms influencing flocculation have been found: complexation of the metal‐ions added as flocculation aids, precipitation reactions, neutralization of the positive charge of the metal hydroxo complexes of the flocculant with formation of surface complexes, increasing of the negative charge concentration and formation of protective colloids. The following counter‐measures may be technically used with success: increasing of the addition of flocculant (Fe : TOC =2 … 3), shifting of the pH‐value below the iso‐electric point, addition of calcium‐ions (1 … 2 mmol/l) and limited application of ozone prio

ISSN:0323-4320    

DOI:10.1002/aheh.19890170302

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

ISSN:0323-4320    

DOI:10.1002/aheh.19890170303

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractA gas‐sensitive electrode for the determination of ammonia was tested on the basis of potentiometry by means of parts of measuring devices from the CMEA region. Samples of water, cattle slurry, pig slurry and silo seepage water in the range of concentrations of 10−5… 10−1mol/1 NH4‐N can be measured. Before measurement the samples have to get pH 11 and have to be diluted, if necessary. A maximum period of time of about eight minutes is required for attaining the potential constancy. The relative standard deviation varies between 0.1 and 4.79%; the rate of retrieval was 99.1% on an average. The results of the potentiometric measurements were equivalent to those of the acidimetric measuring method. The practical advantages consist in a low expenditure of material, energy

ISSN:0323-4320    

DOI:10.1002/aheh.19890170304

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractUltraviolet derivative spectroscopy was used as an analytical tool for the direct and simultaneous determination of aniline and phenol in water. It is shown that the diA/dλivalues are proportional to aniline (i= 2, 4) and phenol (i= 2, 4 and 5) concentrations at 205.3 or 271.6 … 282.8 nm. The performance characteristics are discussed in detail. Thus the best precision resulted in both aniline and phenol for the second derivatives. The accuracy of the methods applied is independent on the derivative order and concentration levels within the dynamic range of 1 to 10 mg · 1−1aniline or phenol respect

ISSN:0323-4320    

DOI:10.1002/aheh.19890170305

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractOn the basis of the measurements in 54 storage reservoirs from 1980 till 1985, the Trophic State Index (TSI) by Walker is tested with respect to its functional relations in terms of the criteria of chlorophyll, o‐phosphate and limit of visibility and applied to storage reservoirs. For this, the statistical relations between the chlorophyll concentration and the reciprocal limit of visibility (a vertical extinction coefficient for the non‐planktogenic share being taken into account) as well as the o‐PO4‐P content during the full overturn in spring are determined and transferred into the index of trophy. The total index is formed as the arithmetic mean of the three indices on the basis of chlorophyll, limit of visibility and o‐PO4‐P. The index of trophy provides a safe description of the trophic state of storage reservoirs, especially the expansion of the mesotrophic and hypertrophic range as against the eutrophic and polytrophic range contributing to the increased sensitivity of the cla

ISSN:0323-4320    

DOI:10.1002/aheh.19890170306

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractThe heavy metal content of river water samples with 12 and 15 mg/l dry matter of seston is increased to 400 … 3900μg/l by the addition of inorganic heavy metal salts, and after three days the distribution of the heavy metals is determined by fractional filtration (8, 3, 1.2, 0.8, 0.65, 0.45 and 0.22 μm pore size). More than 80% of Ni, Co and Mn are found in the fraction8 μm as well as 40 and 25%, resp., in<0.22 μm, Cd, Cr and Zn are found in all fractions, 60 … 80% being in the fraction8 μm. The influence of specific parameters of water quality as pH‐value and seston concentration on the distribution requires further in

ISSN:0323-4320    

DOI:10.1002/aheh.19890170307

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

ISSN:0323-4320    

DOI:10.1002/aheh.19890170308

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractIn search for a suitable and fast analytical method for assessing kinds of activated carbon for water purification there were carried out investigations with hydrogen peroxide. According to their catalytic activity, the various kinds of activated carbon are capable of decomposing hydrogen peroxide to different degrees and at different rates. The released oxygen can be determined volumetrically. The results of investigation obtained on always fresh carbon samples with acid and basic groups were discussed on the basis of the velocity constants of the oxygen development. An assessment of quality would be possible, in principle, but the surface characteristic of the kinds of carbon is considerably superimposed by influences of morphology, so that applying this method is advised against.

ISSN:0323-4320    

DOI:10.1002/aheh.19890170309

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

ISSN:0323-4320    

DOI:10.1002/aheh.19890170310

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractAfter a short introduction into the field of the zeolites the use of the molecular sieve 4 A as builder in the washing process is treated. Structure and ion‐exchange capacity are characterized, the mechanism of the elimination of calcium‐ions is described and the environmental behaviour is examined. Finally, other potential applications of zeolitic ion exchangers are presen

ISSN:0323-4320    

DOI:10.1002/aheh.19890170311

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY