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Ubonratchathani, Thailand

Rodriguez Serrezuela R.,Antonio Narino University | Carvajal Pinilla L.A.,Environmental Engineering Program
International Journal of Ecology | Year: 2015

Lutzomyia longiflocosa is considered the most likely vector of cutaneous leishmaniasis in the sub-Andean region of the upper valley of the Magdalena River between 1,000 and 2,000 meters in the Department of Huila, Colombia. L. longiflocosa is anthropophilic, has endophagic behavior, and is especially important since its dominance in epidemics recorded in the last decade in the departments of Huila, Tolima, and the outbreak in Norte de Santander. The aim of our work is to identify ecological determinants in forest microhabitat level defining the abundance of L. longiflocosa. We use sampling; this was performed in 56 microhabitats of 28 forests with CDC traps for two consecutive nights from 18:00 to 06:00 hours. Each microhabitat (favorable and unfavorable) was located 10 m from the ecotone, with an approximate area of 10 m2. Thirty-five variables were examined as potential explanatory variables which were recorded in each microhabitat. Regression models were used to identify ecological determinants. Our results confirm that there are favorable microhabitats in the forest with specific ecological determinants that define the aggregated distribution of the species and provide the conditions necessary for survival and abundance of L. longiflocosa. © 2015 Ruthber Rodríguez Serrezuela and Luis Alexander Carvajal Pinilla. Source

Chen H.,Taiyuan University of Technology | Chen Y.-C.,Environmental Engineering Program
Journal of Residuals Science and Technology | Year: 2013

The aim is to optimize a rapid DNA extraction protocol for biosolids that provides high recovery and purity, and to evaluate potential biases on both quantitative and qualitative microbial analyses. A protocol with 3-step sequential DNA extractions using a modified lysis buffer and purification by a commercial DNA kit was developed and compared to a previously known high recovery solvent-based extraction method, a commercial soil DNA kit with single extraction, and the same commercial kit protocol except extracted with the modified lysis buffer. The developed protocol showed more than 7 times DNA recovery compared to the commercial kit, and comparable E. coli concentrations to the solvent-based method. Direct adoption of the commercial soil kit showed significantly lower recovery and underestimation of E. coli compared to the high recovery protocols. A simple switch of the lysis buffer also improved the DNA recovery by 5 times. Species diversity indexes from pyrosequencing analysis on the other hand showed scatter results from all protocols and only as much as 76% similarity was observed among any paired protocols. Phylogenetic analysis showed a shift of dominance as DNA recovery increases. Overall, this work shows that the developed protocol allows extraction of high quality and quantity DNA within 3 hr. However, qualitative comparisons of species structure may still vary. © 2013 DEStech Publications, Inc. Source

Chen Y.-C.,Environmental Engineering Program | Higgins M.J.,Bucknell University | Beightol S.M.,Bucknell University | Murthy S.N.,DC Water and Sewer Authority | Toffey W.E.,Effluential Synergies LLC
Water Research | Year: 2011

The objective of this research was to investigate whether a preferential stimulation of microorganisms in anaerobically digested biosolids can occur after dewatering and if it can lead to pathogen indicator regrowth and odor generation upon storage. Laboratory incubation simulating biosolids storage indicates that both odorant generation, based on total volatile organic sulfur compound concentrations (TVOSCs) and pathogen indicator regrowth, based on fecal coliform densities follow similar formation and reduction patterns. The formation and reduction patterns of both odor compounds and fecal coliforms imply that groups of microorganism are induced if shearing disturbance is imposed during dewatering, but a secondary stabilization can be achieved soon after 1-2 weeks of storage. The occurrence of the induction is likely the microbial response to substrate release and environmental changes, such as oxygen, resulting from centrifuge shearing. The new conditions favor the growth of fecal coliforms and odor producing bacteria, and therefore, results in the observed fecal coliforms regrowth and odor accumulation during subsequent storage. However, when both substrate and oxygen deplete, a secondary stabilization can be achieved, and both odor and fecal coliforms density will drop. © 2011 Elsevier Ltd. Source

Treese D.P.,Environmental Engineering Program | Clark S.E.,Environmental Engineering Program | Baker K.H.,Life Science Program
Advances in Civil Engineering | Year: 2012

Subsurface infiltration and surface bioretention systems composed of engineered and/or native soils are preferred tools for stormwater management. However, the disturbance of native soils, especially during the process of adding amendments to improve infiltration rates and pollutant removal, may result in releases of nutrients in the early life of these systems. This project investigated the nutrient release from two soils, one disturbed and one undisturbed. The disturbed soil was collected intact, but had to be air-dried, and the columns repacked when soil shrinkage caused bypassing of water along the walls of the column. The undisturbed soil was collected and used intact, with no repacking. The disturbed soil showed elevated releases of nitrogen and phosphorus compared to the undisturbed soil for approximately 0.4 and 0.8m of runoff loading, respectively. For the undisturbed soil, the nitrogen release was delayed, indicating that the soil disturbance accelerated the release of nitrogen into a very short time period. Leaving the soil undisturbed resulted in lower but still elevated effluent nitrogen concentrations over a longer period of time. For phosphorus, these results confirm prior research which demonstrated that the soil, if shown to be phosphorus-deficient during fertility testing, can remove phosphorus from runoff even when disturbed. Copyright © 2011 Daniel P. Treese et al. Source

Clark S.E.,Environmental Engineering Program | Pitt R.,University of Alabama
World Environmental and Water Resources Congress 2012: Crossing Boundaries, Proceedings of the 2012 Congress | Year: 2012

Stormwater treatment is entering a new phase with stormwater management systems being required to meet specific numeric objectives, as opposed to the historic approach of meeting guidance-document-provided percent removal rates. Meeting numeric discharge requirements will require designers to better understand and apply the physical, chemical, and biological processes underpinning these treatment technologies. This paper focuses on the potential unit treatment operations available for stormwater treatment and how this theoretical information can be applied to stormwater control practice design. © 2012 ASCE. Source

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