摘要:

AbstractSalmonella, mainlyS. manhattanandS. agona, were detected in about 40 = of the 133 flowing waters which were investigated in the District of Leipzig from June 1988 to June 1989 Possible causes of the occurrence of salmonella were discussed. Within the framework of statistical evaluations, correlation investigations were carried out on findings of chemical and biological examinations and relations found so far were confirmed. The applicability of the standard TGL 6466/01 “quality demands on irrigation water” is critically checked on the basis of the results of investigation; as derived from the result, the necessity of a revision of this TGL is pro

ISSN:0323-4320    

DOI:10.1002/aheh.19910190402

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

摘要:

AbstractTwo subsurface reactors of 1 m3volume, filled with fine gravel or coarse sand, are fed with a medium similar to groundwater having a nitrate concentration of 208 mg/l. The retention time of water in the reactor is 400 d. After 30 months the reactor effluent shows a stationary behaviour of the nitrate concentration. Then, the effluent concentration is 90 or 100 mg/l nitrate. The breakthrough curves of nitrate show four pronounced sections: up to the retention time, increase of nitrate to ca. 40 mg/l, a stationary intermediate phase, a further increase of nitrate to the final stationary phase. The stationary intermediate and final phases show 1st‐order reaction constants of 0.0046 d−1and 0.0019 d−1, respectively, or half‐times of 150 and 330 … 400 d, respectively. The higher reaction constants of the intermediate phase are connected with the bituminous coating of the reactors by the relatively easily degradable organic substance of which reaction is accelerated. With respect to variance analysis the annual minima and maxima of the nitrate turnover show significant differences. This is demonstrated by the temperature dependence of denitr

ISSN:0323-4320    

DOI:10.1002/aheh.19910190403

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

摘要:

AbstractFollowing a general representation of the regression analysis, especially concerning the relations between flow and concentrations of matter and loads, these relations are represented and discussed for the suspended solids, nitrate concentration, chloride content and oxygen concentration for seven sections of the Spree river. There result clear connections to the structure and utilizations of all of the parts of the river basin. Finally, the covering of the total river basin by models of water quality management in the form of regression, self‐purification and eutrophication models‐and their coupling is represen

ISSN:0323-4320    

DOI:10.1002/aheh.19910190404

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

ISSN:0323-4320    

DOI:10.1002/aheh.19910190405

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

摘要:

AbstractAfter an introductory description of the importance of heavy metal ions in the environment and a representation of the etching process of copper‐tin alloys with copper(II)‐chloride, the fundamentals of the electrochemical treatment of the spent etching solutions are stated. Different electrode materials were tested in laboratory experiments with model solutions (0.35 … 0.70 = HCl, 5 g/l Cu2+and 2.5 g/l Sn2+). The best separation of copper and tin was achieved at a current density of 1.25 A/dm2. A proposal for the technological design is made with which a maximum reduction of the sewage loading o

ISSN:0323-4320    

DOI:10.1002/aheh.19910190406

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

ISSN:0323-4320    

DOI:10.1002/aheh.19910190407

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

摘要:

AbstractAfter treatment of the anion exchanger resins from several manufacturers with FeCl3or CuSO4their capacity to take up thiocyanate ions increases by the factor 2 … 3. By regeneration with diluted sulphuric acid or hydrochloric acid after precipitation of the ferric or cupric hydroxide a thiocyanate solution of 10 and 15 g/l, respectively, is obtained, which can be reused. The hydroxides dissolved in acid are used for the treatment of the ion exchanger. The process is proposed for the regenerating of wastewaters containing thiocyanat

ISSN:0323-4320    

DOI:10.1002/aheh.19910190408

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

摘要:

AbstractBy way of introduction the general fundamentals and kinetic setups of the competitive and non‐competitive as well as substrate inhibition of cultures of microorganisms are stated. Investigated on a laboratory scale is the degradation of liquid pig slurry in a 600‐1 stirring fermenter with discontinuous addition (pO2≧=30 = saturation) of methanol as external substrate by a yeast mixed culture ofMetschnikowiaandPichia membranifaceansto utilize the steam‐volatile fatty acids (12 g/l) and ofAcetobacter methanolicusto utilize methanol. A stable fermentation with stable residual concentrations of 235 mg/l fatty acids, 142 mg/l mH4‐N an 100 … 300 mg/l methanol for aperiod of 2400 h can

ISSN:0323-4320    

DOI:10.1002/aheh.19910190409

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

ISSN:0323-4320    

DOI:10.1002/aheh.19910190410

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

摘要:

AbstractThe water quality of an urban pond in the thickly populated area of Varanasi city (5 km apart) was studied and compared with a rural pond in the Banaras Hindu University campus for transparency, conductivity and nutrient richness (Cl−, SO 42−, PO 43−P, NO 3−N, organic carbon, Ca2+, Mg2+, K+, Na+) at three depths (surface, 1.5 m, 3 m) at monthly intervals between February 1982 and February 1983. This was done to assess the effects of urban surroundings of a very ancient city sector on pond water quality in reference to that of a rural pond. The rural pond had a lush growth of 12 macrophytic species, whereas the urban one had only such a growth with many phytoplanktonic species. Transparency was maximum in the winter season and the rural pond water was more transparent, while the electrolytical conductance was maximum in the rainy season, being higher in the urban pond. Electrolytical conductivity was negatively correlated to transparency: urban:EC= 1081.612–6.575T,r2= 0.897,F1,11= 96,P<0.005; rural:EC= 728.981–4.328T,r2= 0.892,F1,11= 91,P<0.005.Chloride and sulphate concentrations were highest in summer months, but the former was much higher in the urban pond while the latter in the rural pond. NO3–N was highest in the rainy season in the rural pond and in early winter in the urban one and showed a definite trend with change in depth. PO4–P also varied with depth and time and it was higher in late summer and the early rainy season in the rural pond and in early winter in the urban pond. But both these nutrients were much higher in the urban pond. The maximum organic carbon concentration was found in the rainy season in the rural pond and in summer months in the urban pond. The variation of organic carbon with depth was distinct. Both summer and winter seasons showed almost similar values of calcium concentration in the rural pond, but in the urban pond it was maximum in summer. Organic carbon and calcium were higher in the urban pond. The magnesium concentration was highest in rainy months in both the ponds, but the periodicity of the minimum differed. The distribution of calcium with depth was not well defined. The highest concentration of potassium was found in the winter season in both the ponds. The sodium concentration in the rural pond was observed maximum in summer and minimum in the rainy season, but in the urban pond the trend was different. The variation of potassium and sodium with depth was not well defined. Magnesium and sodium were also higher in the urban pond but potassium was almost at the same concentration in both the ponds. The effect of urbanisation may be one of the factors which might be responsible to the shift of the species composition towa

ISSN:0323-4320    

DOI:10.1002/aheh.19910190411

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY