Die Dissemination von Antibiotika-Resistenzen gilt als eine der größten Bedrohungen der menschlichen Gesundheit des 21. Jahrhunderts. Über die Resistenzsituation in der aquatischen Umwelt ist derzeit noch wenig bekannt. Thema der vorliegenden Arbeit ist es, die Resistenzsituation in fäkal belasteten Oberflächengewässern zu erfassen und verschiedene Abwasserreinigungstechnologien bezüglich ihrer Eliminationsleistung von fakultativ pathogenen und Antibiotika-resistenten Keimen zu bewerten.
Antibiotic resistance is one of the most serious health threats of the 21th century. Whereas resistance levels are permanently surveyed in hospital, little is known about the fate and the behavior of antibiotic resistant bacteria living in aquatic environments. The present work addresses the resistance levels in fecal contaminated surface waters and evaluates advanced sewage treatment technologies concerning their elimination of facultative pathogenic and antibiotic resistant bacteria.
Umfang: IX, 186 S.
Preis: €40.00 | £37.00 | $70.00Buchdetails
Propionic acid is an important intermediate produced during anaerobic degradation of biowaste and a precursor of a large amount of methane. Its accumulation during biomethanation is however a common problem resulting in stagnation phases in biogas production. During this study, the deeper insight into the process of propionic acid degradation was intended by using modern analytical chemistry, standard microbiological approach and molecular biology for describing and explaining the problem.
Umfang: XVI, 152 S.
Preis: €40.00 | £37.00 | $70.00Buchdetails
Experiments with capillary fringes (CF) in quartz sand were conducted. The respiratory activity, cell growth or the biofilm formation by different soil bacteria in the CF were examined. Highest bacterial activity and cell adsorption on the sand particles were detected between the almost water saturated and unsaturated CF-region. Primarily in this transition zone the bacteria strongly influenced the vertical oxygen diffusion and reduced the hydraulic conductivity due to biological clogging.
Umfang: XXVII, 166 S.
Preis: €42.00 | £39.00 | $74.00Buchdetails
Two fixed bed reactors for nitrification with either polyethylene/clay sinter lamellas (FBR A) or porous ceramic rings (FBR B) were continously run for treating synthetic saline wastewater. Seawater from Hafen Büsum was used as an inoculums. The performance of the system was evaluated under different operating conditions.
A better overall nitrification without nitrite accumulation was observed in FBR B during continuous incubation. However, in term of ammonia (AOR) and nitrite oxidation rates (NOR) that were determined in batch incubations, FBR A revealed a higher AOR and NOR of 6 and 7 mg N L-1 h-1, compared to the AOR and NOR of 5 and 5.9 mg N L-1 h-1 in FBR B, respectively.
For studies of the effect of fluctuating salinity on the nitrification, polyethylene/clay sinter lamellas or porous ceramic rings from FBR A and B, respectively, were used as a source of immobilized nitrifiers. Salt concentrations were decreased from 3.5% to 0.03% via 2, 1 and 0.5% and increased from 3.5% to 5, 7 and 9%.
A similar result for AOR and NOR during batch incubation was obtained for both substrata in FBR A and FBR B. The salinity changes influenced more the nitrite oxidizing bacteria (NOB) than the ammonia oxidizing bacteria (AOB).
Measurement of oxidation rates during changing conditions show that the NORs were always higher than the AORs in all reactors, especially in initial phase. However, NORs were more sensitive to the salinity fluctuation than AORs, especially at lower salinity. The AORs remained constant for 0.5-3.5% NaCl and dropped to 70% and 68.5% after the salt concentration was brought to 0.034 or 5%, respectively. The NORs decreased significantly to 62% and 87.5% of initial rates after the salt concentration was changed to 2 and 5%, respectively.
Non-halotolerant nitrifiers reactors with fresh polyethylene/clay as supporting material were inoculated with water samples taken from a "Brackwasser"-location at the North Sea and were continuously run. The salt content in medium was 0% at the start and was then increased up to 10.5%.
Increases of the salt concentration in a non-salt-adapted FBR suppressed more to NOR than AOR. When salinity was increased from 0.03% to 0.5, 1 and 2%, AORs remained constant. The AORs were approx. 90% of initial rates after the salt concentrations were increased stepwise to 3.5%, whereas the NORs decreased to 85, 52 and 36% of initial rate after salinity was increased to 1, 2 and 3.5%, respectively.
Umfang: XXIV, 173 S.
Preis: €39.50 | £36.00 | $70.00Buchdetails
Anaerobic digestion of the organic fraction of municipal solid waste as such or together with food waste, press water or patatoes sludge was investigated to equilibrate methane production within a day or over the weekend, when no OFMSW was available. A stable co-digestion process could be achieved with COD degradation between 60 and 80 %. The max. organic loading rates were 28 kg COD/L,d. For stable methane production the OLR during Co-digestion should not excede 22,5 kg/L,d.
Umfang: XIV, 131 S.
Preis: €27.50 | £25.00 | $49.00Buchdetails
Phenol and chlorophenols are among the most important class of raw materials in chemical industry. These compounds also list among priority pollutants. The main problem in treating phenol or chlorophenol containing wastewater is the toxicity it exerts to the microbial flora in biological treatment plants. This may lead to partial or complete treatment plant failure, when the microbial flora is not adapted to phenol concentrations in the influent. The purpose of this thesis was to adapt the microbial flora of domestic sewage sludge to phenol and 2-chlorophenol at high concentration under continuous feeding conditions for long time periods and to study the response of suspension and fixed biofilm systems to transient loading and operation.
Umfang: XXXIII, 134 S.
Preis: €33.50 | £31.00 | $59.00Buchdetails
Um das Gefährdungspotential von Abwasser aus undichten Kanälen beurteilen zu können, müssen Untersuchungen von verschiedenen Disziplinen bezüglich Mengen, Konzentration, Kolmation, aeroben und anaeroben Bedingungen, gesättigten und ungesättigten Böden, Partikelfraktion und gelöster Fraktion des kommunalen Abwassers, Abbaubarkeit von CSB bzw. Stickstoff und Ausfällungen und Remobilisierung von Schwermetallen durchgeführt werden. Diese Arbeit sollte einen Beitrag zur Klärung der Elimination und von Abbauvorgängen im ungesättigten und gesättigten Untergrund, sowie die Bilanzierung der Stoffumsetzungen und Kontamination von Sandböden und Grundwasser während der Abwasserversickerung aus undichten Kanälen leisten.
Umfang: XV, 187 S.
Preis: €26.50 | £25.00 | $47.00Buchdetails
Abwasserkanäle erleiden im Verlauf ihrer Nutzung Schäden durch Abnutzung, Alterung oder sonstige Einwirkung, die zu Undichtigkeiten führen können. Durch die Undichtigkeiten kann entweder unbelastetes Fremdwasser aus dem umgebenden Erdreich bei hohem Grundwasserstand in die Rohrleitung eindringen oder große Mengen Abwasser bei niedrigem Grundwasserstand durch die schadhaften Stellen über die Kanalbettung aus ihr austreten. Undichte Abwasserkanäle können ein hohes Gefährdungspotential darstellen.
Diese Arbeit befasst sich mit den Änderungen der Abwasserinhaltsstoffe aus undichten Kanälen und der Kontamination von Sandböden während der Abwasserversickerung.
Umfang: XIX, 156 S.
Preis: €30.90 | £29.00 | $55.00Buchdetails
An Anaerobic Fixed Bed (AnFB) reactor was run as an upflow anaerobic reactor with an arrangement of supporting material for growth of a biofilm. The supporting material was made from Liapor-clay-polyethylene sinter lamellas (Herding Co., Amberg).
The AnFB reactor was used for treating high concentrations of whey-containing wastewater. Optimal operating conditions for whey treatment at a concentration of COD in the influent of around 50 g whey·l-1 were found for a hydraulic retention time (HRT) in the range of 4-8 days or an organic loading rate (OLR) less than 10 kg COD·m-3·d-1. This is a higher load than normally applied in praxis reactors.
Accumulation of volatile fatty acids (VFAs) happened when the AnFB was supplied with surplus whey solution at a high OLR or when it was oxygenated. VFAs were accumulated faster when the HRT was changed from 12 days to 6 days compared to a change of HRT from 6 days to 4 days. However, at a HRT of 6 days, the accumulated VFAs were completely degraded after an adaptation period of about 5 days, whereas the accumulated VFAs at a HRT of 4 days remained constant upon time and could not be degraded during further incubation.
The conversion process (acetogenesis and methanogenesis) of VFAs was influenced by the pH in the reactor. Acetate and n-Butyrate were converted faster at neutral or slightly alkaline pH, while propionate was degraded faster at slightly acidic pH-value.
The population in the AnFB contained hydrogen-utilizing methanogenic bacteria, formate-utilizing methanogenic bacteria, methanol-utilizing methanogenic bacteria, acetoclastic methanogenic bacteria and sulfate-reducing bacteria as the final-stage organism of whey degradation. Acetogenic and methanogenic bacteria grew slower and were present at much lower numbers than acidogenic bacteria. This made the acid degradation rate less than the acid production rate. The minimal HRT in the whey reactor was thus dependent on acid degradation rates.
Acetate-utilizing methanogens seemed to be unable to grow as single cells. They preferred to grow in a particulate or attached manner on a support material. The biofilm on the support materials provided a lower redox potential and an anaerobic environment that was obligately needed by these bacteria. The addition of a reducing agent was necessary to keep the few culturing acetoclastic methanogens in suspended cultures active.
H2/CO2 was the best methanogenic substrate for the bacteria in the effluent suspension of whey reactor, followed by formate and methanol. The least degradable substrate in suspension cultures was acetate. The optimal H2 gas concentration for methanogens was provided at 2.25 bar.
Ferric ions addition or the addition of a mix of minerals improved acetate degradation and methane production rates more than two-folds. The redox potential + reducing agent was low enough for methanogenesis. An AnFB-reactor would be a suitable means for stabilizing wastewater from dairy processing. Liapor-clay-polyethylene sinter lamellas in a regularly arrangement could be the substratum for biofilm formation. A minimum HRT of 4-6 days should be planned or a maximum OLR rate 10 kg COD·m-3·d-1 not exceeded.
Umfang: XIII, 135 S.
Preis: €22.50 | £21.00 | $40.00Buchdetails