James N Jensen

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A study was conducted to examine the influence of hydraulic retention time (HRT) and solid retention time (SRT) on the removal of tetracycline in the activated sludge processes. Two lab-scale sequencing batch reactors (SBRs) were operated to simulate the activated sludge process. One SBR was spiked with 250 microg/L tetracycline, while the other SBR was(More)
Tetracycline, one of the most widely used antibiotics, is excreted into wastewater after consumption by humans and animals. The focus of this research was to evaluate the fate of tetracycline resistant bacteria in the activated sludge process as a function of tetracycline loading. The studies were conducted with aerobic biological sequencing batch reactors(More)
The objective of this research was to elucidate the fate of tetracycline resistant bacteria as a function of activated sludge organic loading rate and growth rate. Techniques employed to evaluate the effect of these factors on the fate of tetracycline resistant bacteria were: (1) resistant bacteria concentrations in the SBR biomass; (2) production of(More)
Suspended solids interfere with the efficiency of disinfection using UV radiation by decreasing the rate of disinfection and inducing tailing. However, conventional measures of solids (total suspended solids, turbidity, and UV transmittance) do not adequately predict the presence or degree of these effects. Bacteria and viruses can become associated with(More)
The effect of sequencing batch reactor operation on presence and concentration of tetracycline-resistant organisms was studied as a function of organic loading rate (OLR) and solids retention time (SRT), with and without supplemented influent tetracycline. These effects were evaluated using bacterial counts, bacterial production, system growth rate, and(More)
Chlorine added during wastewater disinfection may be consumed through reactions with chlorine-demanding chemical species. In this study, a mechanistically based kinetic model for chlorine demand in the presence of ammonia was developed and validated with laboratory studies on ammonia-nitrite systems, and then applied to breakpoint curves obtained with(More)
The present study explored the application of a 20-kHz ultrasound unit for the disinfection of domestic wastewater. Experiments were conducted in batch with an ultrasound probe. The disinfection efficiency of fecal coliform increased with ultrasound power input from 0.003 log kill/min at 70 W/L to 1.8 log kill/min at 1250 W/L. Disinfection data are(More)
Current disinfection models generally are either empirical modifications of Chick's law (linear survivor curves) or hit or site models modified from the radiation literature. In this paper, a general disinfection model is developed that assumes a large number of inactivation sites. From a probabilistic model of damaged site distribution, the normalized(More)
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