Biomedical subjects

U Zaiss

Publications and source records attributed to U Zaiss.

3 recordsLinked to original sources

PubMed1988

[Quantitative studies of the elimination of coliphages and other fecal indicators during wastewater treatment].

Concentrations of coliphages, coliforms, enterococci and fluorescent Pseudomonas were monitored in several wastewater purification steps of the treatment plant Wolfenbüttel during one year. Their number varied widely during the investigation period, but was independent of seasons. In the course of sewage treatment, including primary settling, activated sludge purification, simultaneous precipitation, trickling filters and oxidation pond, the concentration of indicators decreased gradually. The coliphages were most resistant, exhibiting only a decimal elimination value of 1.7 log10 units as compared to the bacterial indicators with elimination values ranging between 2.4 and 2.8 log10 units in the whole process. The most efficient purification step revealed to be the activated sludge procedure including simultaneous phosphate precipitation with iron hydroxides and sedimentation. On an average 1.7% of the coliphages present in raw sewage or 9.8.10.11 phages were discharged into the river Oker everyday, 0.64% remained in the sludge. Numbers of indicators in the water of the oxidation pond and those seeded into river water were continuously reduced during 3 days. Also in these laboratory experiments, the coliphages were more resistant than the bacteria, but no evidence was found to support the view that coliphages play a role in the reduction of the number of coliform bacteria. Even after addition of peptone which stimulated growth of E. coli the coliphages were inactivated more rapidly. The behaviour of coliphages during the purification process is compared with literature data about enteroviruses.

Bacteria↗

PubMed1982

Microbial methane oxidation in the River Saar.

In the River Saar, the distribution of methane-oxidizing bacteria and their metabolic activity were determined in vertical and longitudinal profiles. At the sediment surface about two orders of magnitude more methane oxidizers were detected than in the overlying water. In the river as well as in laboratory experiments, the rate of methane oxidation was closely related to the concentration of methane. Most of the methane produced by methanogenic bacteria in the the sediment escaped into the atmosphere. On the average only 1.2% of the produced methane was oxidized in the water phase.

Fresh Water↗

PubMed1981

Dispersal and fate of coliphages in the River Saar.

The dispersal of coliphages was analysed quantitatively in longitudinal profiles of the partially canalized River Saar. The numbers of coliphages ranged between 0 and 2380 PFU (plaque-forming units)/ml in the water and between 0 and 2550 PFU/g in the sediments, depending on the degree of fecal pollution. In canalized parts the phages were found mainly in the sediments, whereas in non-canalized parts they prevailed in the water phase (Fig. 3). Determinations performed at municipal sewage water outfalls revealed that in the canalized part most of the phages precipitated to the sediment on a water course of only about 250 m (Fig. 5). In the non-canalized part of the River Saar, sediments were not contaminated to this extent, since phages rather remained in the water, due to high current velocities (Fig. 5). According to these results coliphages are, just like some fecal bacteria, closely associated with particles. They are rapidly inactivated in the sediment and water (inactivation rates: 0.12 to 0.66 d-1).

Clostridium perfringens↗