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Articles 1 - 11 of 11
Full-Text Articles in Physical Sciences and Mathematics
Proteomic Analysis Of Ethene-Enriched Groundwater Microcosms From A Vinyl Chloride-Contaminated Site, Adina S. Chuang, Yang Oh Jin, Laura S. Schmidt, Yalan Li, Samuel Fogel, Donna Smoler, Timothy E. Mattes
Proteomic Analysis Of Ethene-Enriched Groundwater Microcosms From A Vinyl Chloride-Contaminated Site, Adina S. Chuang, Yang Oh Jin, Laura S. Schmidt, Yalan Li, Samuel Fogel, Donna Smoler, Timothy E. Mattes
Adina Howe
Contamination of groundwater with vinyl chloride (VC), a known human carcinogen, is a common environmental problem at plastics manufacturing, dry cleaning, and military sites. At many sites, there is the potential to cleanup VC groundwater plumes with aerobic VC-oxidizing microorganisms (e.g., methanotrophs, etheneotrophs, and VC-assimilating bacteria). Environmental biotechnologies that reveal the presence and activity of VC-oxidizing bacteria in contaminated groundwater samples would provide valuable lines of evidence that bioremediation of VC is occurring at a site. We applied targeted shotgun mass spectrometry-based proteomic methods to ethene-enriched groundwater microcosms from a VC-contaminated site. Polypeptides from the enzymes alkene monooxygenase (EtnC) and …
Attachment Of Bacterial Indicators To Particulates In Runoff From Various Soils, Michelle L. Soupir, Saied Mostaghimi
Attachment Of Bacterial Indicators To Particulates In Runoff From Various Soils, Michelle L. Soupir, Saied Mostaghimi
Michelle L. Soupir
A field study was conducted to examine the fate of E. coli and enterococci transport from three bare soil types receiving cowpat treatments and develop relationships between bacterial partitioning and phosphorous and carbon transport. Particles sizes to which cells preferentially associated were also identified.
Partitioning Of E. Coli And Enterococci Between Planktonic And Sorbed Phases In Runoff From Pasturelands, Michelle L. Soupir, H. E. Saied Mostaghimi, Elizabeth F. Alphin
Partitioning Of E. Coli And Enterococci Between Planktonic And Sorbed Phases In Runoff From Pasturelands, Michelle L. Soupir, H. E. Saied Mostaghimi, Elizabeth F. Alphin
Michelle L. Soupir
Pathogens are the leading cause of surface water impairments in Virginia. Currently, Nonpoint Source (NPS) pollution models are most frequently used to determine the maximum allowable loading rates of bacteria from identified sources and they typically simulate bacterial transport to surface waters as a planktonic or free pollutant. Very few models attempt to partition between the planktonic and attached phases primarily because data on bacteria partitioning during overland flow events are currently not available. A field study was conducted to evaluate the partitioning of E. coli and enterococci between the planktonic and attached phases in runoff from pasturelands and to …
Modeling Bacteria Fate And Transport In Watersheds To Support Tmdls, Brian L. Benham, Claire Baffaut, Rebecca W. Zeckoski, Kyle R. Mankin, Yakov A. Pachepsky, Ali M. Sadeghi, Kevin M. Brannan, Michelle L. Soupir, Matthew J. Habersack
Modeling Bacteria Fate And Transport In Watersheds To Support Tmdls, Brian L. Benham, Claire Baffaut, Rebecca W. Zeckoski, Kyle R. Mankin, Yakov A. Pachepsky, Ali M. Sadeghi, Kevin M. Brannan, Michelle L. Soupir, Matthew J. Habersack
Michelle L. Soupir
Fecal contamination of surface waters is a critical water-quality issue, leading to human illnesses and deaths. Total Maximum Daily Loads (TMDLs), which set pollutant limits, are being developed to address fecal bacteria impairments. Watershed models are widely used to support TMDLs, although their use for simulating in-stream fecal bacteria concentrations is somewhat rudimentary. This article provides an overview of fecal microorganism fate and transport within watersheds, describes current watershed models used to simulate microbial transport, and presents case studies demonstrating model use. Bacterial modeling capabilities and limitations for setting TMDL limits are described for two widely used watershed models (HSPF …
Release And Transport Of Nutrients From Livestock Manure Applied To Pastureland, Michelle L. Soupir, Saied Mostaghimi, Eugene R. Yagow, David H. Vaughan
Release And Transport Of Nutrients From Livestock Manure Applied To Pastureland, Michelle L. Soupir, Saied Mostaghimi, Eugene R. Yagow, David H. Vaughan
Michelle L. Soupir
Land applications of manure from confined animal systems and direct deposit by grazing animals are both major sources of nutrients in streams. An understanding of the overland transport mechanisms from land applied waste is needed to improve design of best management practices and modeling of NPS pollution. Release and transport plots were established to study in-field nutrient release and transport from pasturelands receiving phosphorus based livestock waste applications. The release plots determined the concentrations available to be transported to the edge of the field in runoff. Four manure treatments (turkey litter, liquid dairy manure, standard cowpies, and none) and three …
Modeling Vegetative Filter Performance With Vfsmod, Matthew J. Helmers, Dean E. Eisenhauer, Michael G. Dosskey, Thomas G. Franti
Modeling Vegetative Filter Performance With Vfsmod, Matthew J. Helmers, Dean E. Eisenhauer, Michael G. Dosskey, Thomas G. Franti
Matthew J. Helmers
The model VFSMOD was used to investigate the effect of varying watershed characteristics and buffer dimensions on the sediment trapping efficiency of vegetative filters. This investigation allows for a better understanding of how watershed characteristics, buffer dimensions, and storm characteristics impact the performance of vegetative filters. Using VFSMOD, relationships that estimate sediment trapping efficiency from the ratio of filter area and field area were developed for different sites. These relationships have been applied for field assessment of concentrated flow.
Optimering Van Koagulasie En Flokkulasie In Die Herwinning Van Koelwater Uit Oliesintese-Afvalwater, Johannes Van Leeuwen, P. Wille
Optimering Van Koagulasie En Flokkulasie In Die Herwinning Van Koelwater Uit Oliesintese-Afvalwater, Johannes Van Leeuwen, P. Wille
Johannes van Leeuwen
The activated sludge process, which is used in the purification of an oil synthesis effiuent, produces an effiuent which is high in turbidity. The water also contains a lot of dispersed bacterial growth which is not removed during sedimentation. Flocculation is essential to remove these materials. The average diameter of the colloids was found to be 0,92/'m. The zeta potential of the colloids was determined in an attempt to correlate it to the amount of flocculant required. The value was relatively constant at -13,88 mV, which indicates that a cationic·coagulant was required. The required dosage to achieve clarification by means …
Ozonation For Non-Filamentous Bulking Control In An Activated Sludge Plant Fuel Synthesis Waste Transfer, Johannes Van Leeuwen
Ozonation For Non-Filamentous Bulking Control In An Activated Sludge Plant Fuel Synthesis Waste Transfer, Johannes Van Leeuwen
Johannes van Leeuwen
A zero discharge mode of operation at the South African fuel synthesis plants necessitates the infinite recycle of treated industrial waste water. The treatment process incorporates activated sludge units in which non-filamentous bulking and carry-over of solids often occurs. The use of ozone for the control of this non-filamentous binding was investigated on a 33 l/d small pilot-scale plant. An ozone dosage of 1 g per kg mixed liquor suspended solids per day could reduce the diluted sludge volume index from an average of 125 to about 70 ml/g mainly by preventing zoogleal growths, the main contributor to the non-filamentous …
Bulking Control With Ozonation In A Nutrient Removal Activated Sludge System, Johannes Van Leeuwen
Bulking Control With Ozonation In A Nutrient Removal Activated Sludge System, Johannes Van Leeuwen
Johannes van Leeuwen
The control of sludge bulking by ozonation was studied on four parallel pilot-scale (100 l/d) biological nutrient removal systems. Bulking was caused by filamentous organisms which typically occur in nutrient removal systems, i.e. Type 0092, Tpye 0041 and Microthrix parvicella. Continuous dosing of ozone, at 1; 2 and 4g O3/kg mixed liquor suspended solids (MLSS).d resulted in a diluted sludge volume index of about 50 ml/g less than the unozonated control. Ozonation was more effective in the sludge cycle than directly into the aeration basin. Nitrification-denitrification was not affected, not even at dosages of 30 g O3/kg MLSS.d. Biological phosphate …
Ozonation At The Stander Water Reclamation Plant, Johannes Van Leeuwen, J. Prinsloo
Ozonation At The Stander Water Reclamation Plant, Johannes Van Leeuwen, J. Prinsloo
Johannes van Leeuwen
The results achieved by ozonation at the Stander Water Reclamation Plant, Pretoria, are discussed. A packed column together with an injector mixing device gave ozone· utilization levels higher than 95 % at dosages of about 10 mg/ dm3. Redistribution plates in the packing proved necessary to prevent poor adsorption due to backmixing in the gas phase. Disinfection is satisfactory if total oxidant residuals can be maintained at more than 0,2 mg/dm3 for 15 min. The results indicated that ozonation also lowered the chemical oxygen demand and total organic carbon concentration in the water. In spite of the fact that it …
Studies On Disinfection And Chemical Oxidation With Ozone And Chlorine In Water Reclamation, W. R. Ross, Johannes Van Leeuwen, W. O. K. Grabow
Studies On Disinfection And Chemical Oxidation With Ozone And Chlorine In Water Reclamation, W. R. Ross, Johannes Van Leeuwen, W. O. K. Grabow
Johannes van Leeuwen
Laboratory studies showed that Pseudomonas aeruginosa, Aeromonas hydrophila and Acinetobacter anitratum are more resistant to chlorine and ozone than Escherichia coli. Pseudomonas aeruginosa was the most resistant of all strains tested and was selected as test organism for pilot plant studies on the efficiencies of chlorine and ozone disinfection. The disinfectants proved equally efficient for the disinfection of chlorine demand-free water but ozone was much more efficient in the case of water with a chlorine demand. This difference was confirmed to be due to the property of chlorine to react with nitrogenous substances to form chloramines which are less efficient …