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Laura Lackey

Mercer University, College of Liberal Arts - Chemistry, Faculty Member

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Tufts University

Antonio Pantaleo

Università degli Studi di Bari

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Mansoura University

Moscow State University

Tania C Cordova- Sintjago

Santa Fe College

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Papers by Laura Lackey

Learning Styles And Freshman Retention: What Are The Links?

One of the most urgent issues in engineering education relates to levels of attrition and retenti... more One of the most urgent issues in engineering education relates to levels of attrition and retention of undergraduate engineering students. Most institutions track this data at the university level, meaning that university administrators are easily able to identify students who switch majors from engineering to other areas or identify students who leave the university completely, but there is minimal follow-up data provided at the college and department level. Our research examines the issue of first-semester attrition from the following perspectives: (1) the individual differences perspective: can data from a 10-minute psychological learning-style survey distributed on the first day of class be used as a means of early-identification of firstsemester engineering students who may not continue in engineering? (2) the correlational feedback perspective: what correlations exist between learning-style survey scores and end-ofsemester qualitative survey data? Findings in this study will be further examined from a multi-university perspective: one smaller, private university with relatively low levels of attrition, and another large, urban university with a higher average rate of attrition between the first and second semesters of engineering education. Our conclusions will explore the similarities between our students and faculty, the disparities between the two institutions, and look for multiple methods to strengthen both programs by increased levels of understanding and knowledge regarding attrition and retention patterns.

Control of gas contaminants in air streams through biofiltration

According to the National Institute for Occupational Safety and Health (NIOSH), the maximum styre... more According to the National Institute for Occupational Safety and Health (NIOSH), the maximum styrene concentration allowed in the work place is 50 ppm for up to a 10-hour work day during a 40-hour work week. The US EPA has classified styrene as one of the 189 hazardous air pollutants listed under Title 3 of the Clean Air Act Amendments to be reduced by a factor of 90% by the year 2000. Significant quantities of styrene are emitted to the atmosphere each year by boat manufacturers. A typical fiberglass boat manufacturing facility can emit over 273 metric tons/year of styrene. The concentration of styrene in the industrial exhaust gas ranges from 20 to 100 ppmv. Such dilute, high volume organically tainted air streams can make conventional abatement technologies such as thermal incineration, adsorption, or absorption technically incompetent or prohibitively expensive. An efficient, innovative, and economical means of remediating styrene vapors would be of value to industries and to the environment. Biofilter technology depends on microorganisms that are immobilized on the packing material in a solid phase reactor to remove or degrade environmentally undesirable compounds contaminating gas streams. The technology is especially successful for treating large volumes of air containing low concentrationsmore » of contaminants. The objective of this study was to investigate the feasibility of using biofiltration to treat waste gas streams containing styrene and to determine the critical design and operating parameters for such a system.« less

Efficacy of Using a Single, Non-Technical Variable to Predict the Academic Success of Freshmen Engineering Students

Journal of Engineering Education, 2003

This paper evaluates the efficacy of using freshman student scores from one non-technical assignm... more This paper evaluates the efficacy of using freshman student scores from one non-technical assignment to predict academic success as measured by cumulative grade point average after completion of the first two semesters enrolled at the Mercer University School of Engineering. The predictor assignment is keeping a dialectic course notebook and corresponds to the student's attitude, persistence, and organizational skills rather than math and science preparedness. Statistical analysis, at the 99 percent confidence level, indicated that there was a strong relationship between the student notebook scores and grade point average. Although there was scatter in the data, this one variable does provide insight into student success in the Mercer University Engineering program. Success in engineering programs has been linked to a variety of intellectual and non-cognitive skills. Researchers have historically used scores from the mathematics portion of the SAT to distinguish persisters from those who either drop out of the engineering curriculum and enter into an alternate field of study and those who no longer pursue any type of secondary education .

Biological Sand Filter Performance Test Using Multiple Methods for Pathogen Detection: a Longitudinal Field Study in Kenya

Water Air and Soil Pollution, Jul 1, 2019

Fifty biological sand filters (BSFs) housed in 70-L plastic containers were built and installed i... more Fifty biological sand filters (BSFs) housed in 70-L plastic containers were built and installed in the West Pokot County of Kenya. Half of the BSFs were installed in June 2010; the remainder were installed in June 2012. BSF performance was analyzed during June 2012 and 2015. Performance indicators included the removal of turbidity and fecal and total coliforms. In 2012, 17 of the original 25 BSFs installed were operational, and their performance was evaluated. In 2015, 15 of the BSFs were operational. BSF performance during 2015 showed an average fecal coliform removal of 98.9%. The most common reasons provided to explain why the BSF installed was no longer in use included the family moved and the BSF was too heavy to carry, and the effluent pipe broke. Relative affluence was observed using the Progress out of Poverty Index (PPI)™. With an increase in elevation, we noted a decrease in PPI. The average PPI for homesteads with operation BSFs was 10 points higher than homes where the BSFs were in disrepair. An assay to estimate Escherichia coli presence and concentration was modified, and the results were compared with more traditional field enumeration methods. The field assay used a five-compartment bag to quantify the most probable number (MPN) of E. coli to provide a low-tech option to field workers in developing country to test the viability of drinking water sources. We used a Hach medium, varying from that prescribed by Aquagenx. Results from using the modified method compared well with the more traditional field assay.

Antibacterial effectiveness of metallic nanoparticles deposited on water filter paper by magnetron sputtering

Surface & Coatings Technology, Jun 1, 2019

There is a high interest in nanomaterials that effectively deactivate different types of bacteria... more There is a high interest in nanomaterials that effectively deactivate different types of bacteria and provide alternatives to chemical substances and antibiotics. This research is reporting the antibacterial performance in contaminated water of flexible structures consisting of thin metallic films deposited on water filter paper. Coatings were performed at low temperatures using high vacuum direct current (DC) magnetron sputtering deposition. The effectiveness of different metallic nanoparticles in functionalizing the fibrous surfaces and deactivating bacteria from water was tested during the experiment. The surface morphology of coated filter paper was characterized using digital optical microscopy and scanning electron microscopy (SEM). The fibrous substrates provided large area of exposure for metals to bacteria. X-Ray diffraction and Energy Dispersive X-ray Spectrometer (EDS) were used to identify the chemical composition of the structures. The antibacterial performance was evaluated against Escherichia coli (E-coli) and total coliforms using the standardized membrane filtering technique for water and wastewater examination. Silver and copper effectively deactivate coliforms from water with copper providing higher performance. The antibacterial effect of copper and silver coatings with different thicknesses as well as the nanolayered combination of the two metals was also investigated. It was observed that coatings remained adherent to substrates and the antibacterial performance was maintained over consecutive exposures.

The Impacts of Highway Construction in the Ocmulgee Old Fields Reserve

Proceedings of the Water Environment Federation, 2002

... Hornbeam, Ash, Maple Maple Trumpet creeper, Poison ivy Grass, "Pepper" ... It is im... more ... Hornbeam, Ash, Maple Maple Trumpet creeper, Poison ivy Grass, "Pepper" ... It is important to note that the only evidence of human habitation in this region “immediately” following the end of the last ice-age relates to the discovery of a clovis point arrowhead found during the ...

Pseudomonas putida B2: a tod-lux bioluminescent reporter for toluene and trichloroethylene co-metabolism

Journal of Industrial Microbiology & Biotechnology, 1997

A tod-lux transcriptional fusion bioluminescent reporter strain, Pseudomonas putida B2, was devel... more A tod-lux transcriptional fusion bioluminescent reporter strain, Pseudomonas putida B2, was developed to permit on-line analysis of trichloroethylene (TCE) transformation by toluene dioxygenase (todC1C2BA) in Pseudomonas putida F1. Strain B2 was exposed to toluene in growing and resting cell bioluminescence assays. The growing cells showed a direct correlation between bioluminescence and toluene concentration, while resting cells showed reproducible bioluminescence with repeated toluene exposures. In addition, P. putida B2 was encapsulated in alginate beads and used in a packed bed flow-through differential volume reactor. The TCE feed into the differential volume reactor was constant at 20 mg L-1 and toluene was pulsed in square-wave perturbations at 10 mg L-1. The system showed a direct correlation between the expression of the tod operon (as monitored by light output) and the co-metabolism of TCE. Approximately 20% of the TCE and 50% of the toluene was removed at a flow rate of 0.4 ml min-1. This approach allowed the on-line monitoring of tod gene expression and its relation to TCE biotransformation.

Introduction to environmental engineering

Prentice Hall eBooks, 2009

Bench-Scale Ozonation of Waste Activated Sludge

World Environmental and Water Resources Congress 2008, May 1, 2008

Ozonation of acid yellow 17 dye in a semi-batch bubble column

Journal of Hazardous Materials, Nov 16, 2006

A semi-batch bubble column was used to evaluate the effect of ozonation on the removal of acid ye... more A semi-batch bubble column was used to evaluate the effect of ozonation on the removal of acid yellow 17 dye from water. Results indicate that ozonation is very effective at removing acid yellow 17 dye from synthetic textile wastewater. The ozone consumed to apparent dye removal ratio ranged from 2 to 15,000 mg ozone per mg of dye decolorized and was dependent on both ozonation time and apparent dye concentration. The biodegradability of the dye wastewater was evaluated by monitoring changes in 5-day biochemical oxygen demand (BOD 5 ) with respect to chemical oxygen demand (COD). Results indicate that the wastewater biodegradability increased with an increase in ozonation time. Film theory was used to kinetically model the gas-liquid reactions occurring in the reactor. Modeling results indicated that during the first 10-15 min of ozonation, the system could be characterized by a fast, pseudo-first-order regime. With continued ozonation, system kinetics transitioned through a moderate then to a slow regime. Successful modeling of this period required use of a kinetic equation corresponding to a more inclusive condition. Model results are presented.

Bench-Scale Ozonation of Raw Industrial and Municipal Wastewater

This project involved the design, operation, and testing of a bench-scale ozonation wastewater tr... more This project involved the design, operation, and testing of a bench-scale ozonation wastewater treatment system. Untreated municipal and industrial wastewater was collected from the influent chamber to the Rocky Creek Wastewater Treatment Plant (WWTP) in Macon, Georgia. The industrial wastewater consisted of paper mill effluent from the Graphic Packaging Plant adjacent to the Rocky Creek WWTP. The Rocky Creek WWTP treats wastewater in an extended aeration activated sludge process. To accomplish this research, a 10-liter clear PVC, semi-batch, bubble column was used to disperse ozone bubbles through a porous diffuser near the bottom of the column. Three 24-hour runs were conducted on each type of wastewater. The ozone was administered at loading rates of 0.60, 4.70, and 9.92 mg O 3 /min, respectively, to 6 liters of either raw municipal or industrial wastewater. The following parameters were measured frequently during each 24-hour run: pH, chemical oxygen demand (COD), ammonia, nitrite, nitrate, phosphorus, conductivity, turbidity, total suspended solids (TSS), volatile suspended solids (VSS), total dissolved solids (TDS), and total volatile solids (TVS). Overall COD removal for the municipal and industrial wastewater averaged 82% and 84%, respectively, whereas, overall TSS removal averaged 83% and 81%, respectively. The ozonation degradation rate constant (K D ) based on TSS destruction ranged from 0.054 hr –1 to 0.072 hr –1 for the municipal wastewater and from 0.017 hr –1 to 0.066 hr –1 for the industrial wastewater.

Ozone Treatment of Acid Yellow 17 Dye

Critical Transitions in Water and Environmental Resources Management, Jun 25, 2004

Modeling the Effect of Ozonation on Acid Yellow 17 Dye in a Semi-Batch Bubble Column

A pilot-scale ozonation process employing a semi-batch column was used to study the removal of ac... more A pilot-scale ozonation process employing a semi-batch column was used to study the removal of acid yellow dye 17 from synthetic wastewater in a semi-batch bubble column. The effect of initial dye concentration on system performance was evaluated. This study utilized an 11.12-L, clear, PVC column that was filled with 8-L of tap water tainted with the acid yellow 17 dye for each experimental run conducted. Ozone was supplied to the system by sparging the gas through three porous stainless steel filters fixed in the reactor 0.15-m from the bottom of the column. The ozone supply rate was held constant at 3.78 L/min. Acid yellow 17 dye concentration (measured as A400), chemical oxygen demand (COD), five-day biochemical oxygen demand (BOD5) and the quantity of ozone utilized was measured as a function of ozonation time during each experimental run. Results indicate that ozonation is very effective at removing acid yellow 17 dye from synthetic textile wastewater. The biodegradability of the dye in the synthetic wastewater was evaluated by monitoring changes in BOD5 with respect to COD. The initial BOD5:COD ratio was 0.0083 and over time increased by an order of magnitude to a maximum ratio of 0.126 at 30 minutes. These results indicate that the biodegradability of the wastewater increased with an increase in ozonation time. Two-film theory was used to kinetically model the gas-liquid reactions occurring in the reactor. Modeling results indicated that during the first 10 to 15 min of ozonation, the system could be characterized by a fast, pseudo-first order regime. By combining a differential mole balance on the gas phase ozone concentration within the reactor with film theory, this initial period of the ozonation reaction was successfully modeled. With continued ozonation, system kinetics transitioned through a moderate then to a slow regime. Successful modeling of this period required use of a kinetic equation corresponding to a more inclusive condition. Model results are presented. Copyright ASCE 2005 EWRI 2005 Introduction Textile industry wastewater often contains high concentrations of color and therefore poses a wide variety of issues to receiving streams including the introduction of recalcitrant or toxic compounds and a decrease in relative clarity or turbidity. A common treatment for color containing wastewater is ozonation as this type of process has been shown to remove color (Adams and Gorg, 2002) and chemical oxygen demand (COD) (El-Din and Smith, 2002) and to increase the biodegradability (BOD5:COD) of the wastewater (Zhou and Smith, 1997). Acid yellow 17 dye is a common additive found in ordinary household products such as shampoo, bubble bath, shower gel, liquid soap, multi-purpose cleanser, dishwashing liquid and alcoholbased perfumes. As regulations associated with dyestuff are tightened, associated industries are faced with finding economically viable water treatment solutions. Two-film theory (Lewis and Whitman, 1924) is traditionally used to model mass transfer and associated reactions. For simplicity, many reactions are described as either “slow” or “fast” because relatively simple solutions exist for these regimes. For example, for an instantaneous, reversible reaction typified by a Hatta number (Ha) greater than 3, the reaction is assumed “fast” and an analytical solution is available. For a “slow” reaction, (Ha<0.3), it is assumed that the reaction occurs within the bulk fluid and the reaction rate can be determined from standard kinetic theory. Danckwerts (1970) and van Krevelen and Hoftijzer (1948) have developed approximate methods for the transition region characterized by 0.3<Ha<3. The focus of this study can be characterized as follows: 1. to evaluate the effect of ozone on the removal of acid yellow 17 dye from a synthetic wastewater, and 2. to develop a model based on film theory to describe the removal of COD associated with acid yellow 17 dye by ozonation in a semi-batch reactor. Materials and Methods All experiments were conducted in a semi-batch bubble column. The column was fabricated from clear 7.62 cm schedule 40 PVC pipe and was 2.44 m in height. The gas feed was sparged through three stainless steel filters with 10 um porosity. The sparging system entered the side of the reactor 15.24 cm from the bottom of the column. Ozone was produced with the Ozotech, Inc. OZ2BTUSL ozone generator. The air feeding the ozone generator was conditioned using the Power Prep Model Titan (Ozotech, Inc.). The carrier gas flow rate was maintained at a constant of 3.78 L/min resulting in a uniform ozone introduction to the system of 79.2 mg O3/min. Figure 1 shows a schematic of the equipment utilized. Copyright ASCE 2005 EWRI 2005

Preparing engineering students for working in teams through senior design projects

This paper explores teaming and its cultivation in senior capstone design projects to better prep... more This paper explores teaming and its cultivation in senior capstone design projects to better prepare students for occupational interaction with other professionals, clients, and management to solve complex or open-ended problems. Teaming is deemed an important skill for engineers, by organizations employing engineers and other professionals. In the global marketplace organizations that value and capitalize on these skills can be more agile and competitive. The impact of current and future trends on teaming, including outsourcing and globalization, are discussed in terms of non-technical skills required for practicing engineers and the preparation of new engineers. Parallels between senior design projects and actual industry projects are drawn to highlight the key personal interaction skills and tools required for success. Examples of successful student teams and professional teams are presented for discussion. Measurements of project and teaming success by industry and professional organizations are presented. Topics include: traditional, global and virtual team structures emphasizing the nontechnical aspects necessary for modern teams including, team communication, diversity and cultural aspects, problem resolution, and other elements necessary for project success.

Power to the People: Energy Audits

Comparing two empirical models used to predict process parameter dynamics during ozonation of synthetic dye wastewater

Journal Of Environmental Science And Health, Part A, Jan 5, 2009

Bench-scale ozonation study of waste activated sludge

Journal Of Environmental Science And Health, Part A, 2009

A bench-scale ozonation study was conducted on waste activated sludge (WAS) in a 10-L, clear PVC,... more A bench-scale ozonation study was conducted on waste activated sludge (WAS) in a 10-L, clear PVC, semi-batch, bubble column reactor. Two separate runs were performed on 5-L samples of WAS obtained from the Rocky Creek Wastewater Treatment Plant (WWTP) in Macon, Georgia. The Rocky Creek facility uses the extended aeration activated sludge process to treat domestic wastewater. Ozone was sparged through a porous diffuser at an application rate of 0.0525 mg O(3) min(- 1) at contact times of 9 days and 12 days, respectively, during Runs #1 and #2. Parameters that were monitored during the study included: alkalinity, ammonia, conductivity, nitrite, nitrate, pH, phosphate, solids degradation rate coefficient (K(D)), soluble chemical oxygen demand (SCOD), total chemical oxygen demand (TCOD), total dissolved solids (TDS), total solids (TS), total volatile solids (TVS), turbidity, and unstirred sludge volume index (SVI(u)). Ozone was very effective at removing TCOD and TS. TCOD removals were 43% and 99% respectively for Runs #1 and #2. Total solids removal during Runs #1 and #2 was 50% and 95%, respectively. The degradation rate coefficient (K(D)) based on VSS was 0.17 days(- 1) and 0.54 days(- 1) for Runs #1 and #2. Both the nitrate and phosphate concentrations increased as ozone contact time increased during each run. The unstirred SVI decreased with an increase in ozone contact time, however, extended ozonation caused the SVI to increase. Actual ozone dosages for Runs #1 and #2 were 0.0036 and 0.011 mg O(3) per mg TS removed.

Encouraging High School Students To Learn About Bioremediation

This paper presents a laboratory activity for high school students used to stimulate their intere... more This paper presents a laboratory activity for high school students used to stimulate their interest in environmental engineering and the role of bioremediation in cleaning up the environment. The proposed laboratory activity utilized six, 2-L plastic bottles that contain 100-grams of indigenous soil in each to serve as bioreactors. Varying amounts of glucose are added to the reactors, which are monitored with time for a period of five to ten days. Questions for assessing the exercise along with sample laboratory results are provided.

Design, Operation, and Analysis of a Biological Sand Filter Using Copper as a Disinfectant

World Environmental and Water Resources Congress 2013, May 28, 2013

Aqua Clara International (ACI) is a nonprofit organization that uses biological sand filters (BSF... more Aqua Clara International (ACI) is a nonprofit organization that uses biological sand filters (BSFs) to provide economical, clean water to families in developing countries. ACI often recommends loading 20 L/d in BSFs in which a brass alloy is included as a disinfectant. A bench-scale study was conducted to investigate the effectiveness of using copper as the disinfectant. Five filters were constructed to compare different arrangements and amounts of copper shavings to a control, Column 1. The control was modeled after ACI design specifications but no metallic disinfectant was included. Columns 2 – 5 were also scaled according to ACI recommendations. Columns 2 and 3 each contained 4.7 g of copper, and Columns 4 and 5 each contained 2.35 g. In columns 2 and 4, copper was placed in a single layer; while in Columns 3 and 5, the copper was dispersed throughout the fine sand. After 31 days of testing, the average removal efficiency for total coliforms in Columns 1 – 5 was 96.5%, 93.9%, 97.4%, 95.4%, and 97.5% respectively. A single, 20 L/d, BSF was constructed with 94 g of copper dispersed throughout the fine sand layer. The average removal efficiency for fecal coliforms and turbidity was 97.3% and 65.7%, respectively.

Engineering Student Self-assessment in a Capstone Design Course

Learning Styles And Freshman Retention: What Are The Links?

One of the most urgent issues in engineering education relates to levels of attrition and retenti... more One of the most urgent issues in engineering education relates to levels of attrition and retention of undergraduate engineering students. Most institutions track this data at the university level, meaning that university administrators are easily able to identify students who switch majors from engineering to other areas or identify students who leave the university completely, but there is minimal follow-up data provided at the college and department level. Our research examines the issue of first-semester attrition from the following perspectives: (1) the individual differences perspective: can data from a 10-minute psychological learning-style survey distributed on the first day of class be used as a means of early-identification of firstsemester engineering students who may not continue in engineering? (2) the correlational feedback perspective: what correlations exist between learning-style survey scores and end-ofsemester qualitative survey data? Findings in this study will be further examined from a multi-university perspective: one smaller, private university with relatively low levels of attrition, and another large, urban university with a higher average rate of attrition between the first and second semesters of engineering education. Our conclusions will explore the similarities between our students and faculty, the disparities between the two institutions, and look for multiple methods to strengthen both programs by increased levels of understanding and knowledge regarding attrition and retention patterns.

Control of gas contaminants in air streams through biofiltration

According to the National Institute for Occupational Safety and Health (NIOSH), the maximum styre... more According to the National Institute for Occupational Safety and Health (NIOSH), the maximum styrene concentration allowed in the work place is 50 ppm for up to a 10-hour work day during a 40-hour work week. The US EPA has classified styrene as one of the 189 hazardous air pollutants listed under Title 3 of the Clean Air Act Amendments to be reduced by a factor of 90% by the year 2000. Significant quantities of styrene are emitted to the atmosphere each year by boat manufacturers. A typical fiberglass boat manufacturing facility can emit over 273 metric tons/year of styrene. The concentration of styrene in the industrial exhaust gas ranges from 20 to 100 ppmv. Such dilute, high volume organically tainted air streams can make conventional abatement technologies such as thermal incineration, adsorption, or absorption technically incompetent or prohibitively expensive. An efficient, innovative, and economical means of remediating styrene vapors would be of value to industries and to the environment. Biofilter technology depends on microorganisms that are immobilized on the packing material in a solid phase reactor to remove or degrade environmentally undesirable compounds contaminating gas streams. The technology is especially successful for treating large volumes of air containing low concentrationsmore » of contaminants. The objective of this study was to investigate the feasibility of using biofiltration to treat waste gas streams containing styrene and to determine the critical design and operating parameters for such a system.« less

Efficacy of Using a Single, Non-Technical Variable to Predict the Academic Success of Freshmen Engineering Students

Journal of Engineering Education, 2003

This paper evaluates the efficacy of using freshman student scores from one non-technical assignm... more This paper evaluates the efficacy of using freshman student scores from one non-technical assignment to predict academic success as measured by cumulative grade point average after completion of the first two semesters enrolled at the Mercer University School of Engineering. The predictor assignment is keeping a dialectic course notebook and corresponds to the student's attitude, persistence, and organizational skills rather than math and science preparedness. Statistical analysis, at the 99 percent confidence level, indicated that there was a strong relationship between the student notebook scores and grade point average. Although there was scatter in the data, this one variable does provide insight into student success in the Mercer University Engineering program. Success in engineering programs has been linked to a variety of intellectual and non-cognitive skills. Researchers have historically used scores from the mathematics portion of the SAT to distinguish persisters from those who either drop out of the engineering curriculum and enter into an alternate field of study and those who no longer pursue any type of secondary education .

Biological Sand Filter Performance Test Using Multiple Methods for Pathogen Detection: a Longitudinal Field Study in Kenya

Water Air and Soil Pollution, Jul 1, 2019

Fifty biological sand filters (BSFs) housed in 70-L plastic containers were built and installed i... more Fifty biological sand filters (BSFs) housed in 70-L plastic containers were built and installed in the West Pokot County of Kenya. Half of the BSFs were installed in June 2010; the remainder were installed in June 2012. BSF performance was analyzed during June 2012 and 2015. Performance indicators included the removal of turbidity and fecal and total coliforms. In 2012, 17 of the original 25 BSFs installed were operational, and their performance was evaluated. In 2015, 15 of the BSFs were operational. BSF performance during 2015 showed an average fecal coliform removal of 98.9%. The most common reasons provided to explain why the BSF installed was no longer in use included the family moved and the BSF was too heavy to carry, and the effluent pipe broke. Relative affluence was observed using the Progress out of Poverty Index (PPI)™. With an increase in elevation, we noted a decrease in PPI. The average PPI for homesteads with operation BSFs was 10 points higher than homes where the BSFs were in disrepair. An assay to estimate Escherichia coli presence and concentration was modified, and the results were compared with more traditional field enumeration methods. The field assay used a five-compartment bag to quantify the most probable number (MPN) of E. coli to provide a low-tech option to field workers in developing country to test the viability of drinking water sources. We used a Hach medium, varying from that prescribed by Aquagenx. Results from using the modified method compared well with the more traditional field assay.

Antibacterial effectiveness of metallic nanoparticles deposited on water filter paper by magnetron sputtering

Surface & Coatings Technology, Jun 1, 2019

There is a high interest in nanomaterials that effectively deactivate different types of bacteria... more There is a high interest in nanomaterials that effectively deactivate different types of bacteria and provide alternatives to chemical substances and antibiotics. This research is reporting the antibacterial performance in contaminated water of flexible structures consisting of thin metallic films deposited on water filter paper. Coatings were performed at low temperatures using high vacuum direct current (DC) magnetron sputtering deposition. The effectiveness of different metallic nanoparticles in functionalizing the fibrous surfaces and deactivating bacteria from water was tested during the experiment. The surface morphology of coated filter paper was characterized using digital optical microscopy and scanning electron microscopy (SEM). The fibrous substrates provided large area of exposure for metals to bacteria. X-Ray diffraction and Energy Dispersive X-ray Spectrometer (EDS) were used to identify the chemical composition of the structures. The antibacterial performance was evaluated against Escherichia coli (E-coli) and total coliforms using the standardized membrane filtering technique for water and wastewater examination. Silver and copper effectively deactivate coliforms from water with copper providing higher performance. The antibacterial effect of copper and silver coatings with different thicknesses as well as the nanolayered combination of the two metals was also investigated. It was observed that coatings remained adherent to substrates and the antibacterial performance was maintained over consecutive exposures.

The Impacts of Highway Construction in the Ocmulgee Old Fields Reserve

Proceedings of the Water Environment Federation, 2002

... Hornbeam, Ash, Maple Maple Trumpet creeper, Poison ivy Grass, "Pepper" ... It is im... more ... Hornbeam, Ash, Maple Maple Trumpet creeper, Poison ivy Grass, "Pepper" ... It is important to note that the only evidence of human habitation in this region “immediately” following the end of the last ice-age relates to the discovery of a clovis point arrowhead found during the ...

Pseudomonas putida B2: a tod-lux bioluminescent reporter for toluene and trichloroethylene co-metabolism

Journal of Industrial Microbiology & Biotechnology, 1997

A tod-lux transcriptional fusion bioluminescent reporter strain, Pseudomonas putida B2, was devel... more A tod-lux transcriptional fusion bioluminescent reporter strain, Pseudomonas putida B2, was developed to permit on-line analysis of trichloroethylene (TCE) transformation by toluene dioxygenase (todC1C2BA) in Pseudomonas putida F1. Strain B2 was exposed to toluene in growing and resting cell bioluminescence assays. The growing cells showed a direct correlation between bioluminescence and toluene concentration, while resting cells showed reproducible bioluminescence with repeated toluene exposures. In addition, P. putida B2 was encapsulated in alginate beads and used in a packed bed flow-through differential volume reactor. The TCE feed into the differential volume reactor was constant at 20 mg L-1 and toluene was pulsed in square-wave perturbations at 10 mg L-1. The system showed a direct correlation between the expression of the tod operon (as monitored by light output) and the co-metabolism of TCE. Approximately 20% of the TCE and 50% of the toluene was removed at a flow rate of 0.4 ml min-1. This approach allowed the on-line monitoring of tod gene expression and its relation to TCE biotransformation.

Introduction to environmental engineering

Prentice Hall eBooks, 2009

Bench-Scale Ozonation of Waste Activated Sludge

World Environmental and Water Resources Congress 2008, May 1, 2008

Ozonation of acid yellow 17 dye in a semi-batch bubble column

Journal of Hazardous Materials, Nov 16, 2006

A semi-batch bubble column was used to evaluate the effect of ozonation on the removal of acid ye... more A semi-batch bubble column was used to evaluate the effect of ozonation on the removal of acid yellow 17 dye from water. Results indicate that ozonation is very effective at removing acid yellow 17 dye from synthetic textile wastewater. The ozone consumed to apparent dye removal ratio ranged from 2 to 15,000 mg ozone per mg of dye decolorized and was dependent on both ozonation time and apparent dye concentration. The biodegradability of the dye wastewater was evaluated by monitoring changes in 5-day biochemical oxygen demand (BOD 5 ) with respect to chemical oxygen demand (COD). Results indicate that the wastewater biodegradability increased with an increase in ozonation time. Film theory was used to kinetically model the gas-liquid reactions occurring in the reactor. Modeling results indicated that during the first 10-15 min of ozonation, the system could be characterized by a fast, pseudo-first-order regime. With continued ozonation, system kinetics transitioned through a moderate then to a slow regime. Successful modeling of this period required use of a kinetic equation corresponding to a more inclusive condition. Model results are presented.

Bench-Scale Ozonation of Raw Industrial and Municipal Wastewater

This project involved the design, operation, and testing of a bench-scale ozonation wastewater tr... more This project involved the design, operation, and testing of a bench-scale ozonation wastewater treatment system. Untreated municipal and industrial wastewater was collected from the influent chamber to the Rocky Creek Wastewater Treatment Plant (WWTP) in Macon, Georgia. The industrial wastewater consisted of paper mill effluent from the Graphic Packaging Plant adjacent to the Rocky Creek WWTP. The Rocky Creek WWTP treats wastewater in an extended aeration activated sludge process. To accomplish this research, a 10-liter clear PVC, semi-batch, bubble column was used to disperse ozone bubbles through a porous diffuser near the bottom of the column. Three 24-hour runs were conducted on each type of wastewater. The ozone was administered at loading rates of 0.60, 4.70, and 9.92 mg O 3 /min, respectively, to 6 liters of either raw municipal or industrial wastewater. The following parameters were measured frequently during each 24-hour run: pH, chemical oxygen demand (COD), ammonia, nitrite, nitrate, phosphorus, conductivity, turbidity, total suspended solids (TSS), volatile suspended solids (VSS), total dissolved solids (TDS), and total volatile solids (TVS). Overall COD removal for the municipal and industrial wastewater averaged 82% and 84%, respectively, whereas, overall TSS removal averaged 83% and 81%, respectively. The ozonation degradation rate constant (K D ) based on TSS destruction ranged from 0.054 hr –1 to 0.072 hr –1 for the municipal wastewater and from 0.017 hr –1 to 0.066 hr –1 for the industrial wastewater.

Ozone Treatment of Acid Yellow 17 Dye

Critical Transitions in Water and Environmental Resources Management, Jun 25, 2004

Modeling the Effect of Ozonation on Acid Yellow 17 Dye in a Semi-Batch Bubble Column

A pilot-scale ozonation process employing a semi-batch column was used to study the removal of ac... more A pilot-scale ozonation process employing a semi-batch column was used to study the removal of acid yellow dye 17 from synthetic wastewater in a semi-batch bubble column. The effect of initial dye concentration on system performance was evaluated. This study utilized an 11.12-L, clear, PVC column that was filled with 8-L of tap water tainted with the acid yellow 17 dye for each experimental run conducted. Ozone was supplied to the system by sparging the gas through three porous stainless steel filters fixed in the reactor 0.15-m from the bottom of the column. The ozone supply rate was held constant at 3.78 L/min. Acid yellow 17 dye concentration (measured as A400), chemical oxygen demand (COD), five-day biochemical oxygen demand (BOD5) and the quantity of ozone utilized was measured as a function of ozonation time during each experimental run. Results indicate that ozonation is very effective at removing acid yellow 17 dye from synthetic textile wastewater. The biodegradability of the dye in the synthetic wastewater was evaluated by monitoring changes in BOD5 with respect to COD. The initial BOD5:COD ratio was 0.0083 and over time increased by an order of magnitude to a maximum ratio of 0.126 at 30 minutes. These results indicate that the biodegradability of the wastewater increased with an increase in ozonation time. Two-film theory was used to kinetically model the gas-liquid reactions occurring in the reactor. Modeling results indicated that during the first 10 to 15 min of ozonation, the system could be characterized by a fast, pseudo-first order regime. By combining a differential mole balance on the gas phase ozone concentration within the reactor with film theory, this initial period of the ozonation reaction was successfully modeled. With continued ozonation, system kinetics transitioned through a moderate then to a slow regime. Successful modeling of this period required use of a kinetic equation corresponding to a more inclusive condition. Model results are presented. Copyright ASCE 2005 EWRI 2005 Introduction Textile industry wastewater often contains high concentrations of color and therefore poses a wide variety of issues to receiving streams including the introduction of recalcitrant or toxic compounds and a decrease in relative clarity or turbidity. A common treatment for color containing wastewater is ozonation as this type of process has been shown to remove color (Adams and Gorg, 2002) and chemical oxygen demand (COD) (El-Din and Smith, 2002) and to increase the biodegradability (BOD5:COD) of the wastewater (Zhou and Smith, 1997). Acid yellow 17 dye is a common additive found in ordinary household products such as shampoo, bubble bath, shower gel, liquid soap, multi-purpose cleanser, dishwashing liquid and alcoholbased perfumes. As regulations associated with dyestuff are tightened, associated industries are faced with finding economically viable water treatment solutions. Two-film theory (Lewis and Whitman, 1924) is traditionally used to model mass transfer and associated reactions. For simplicity, many reactions are described as either “slow” or “fast” because relatively simple solutions exist for these regimes. For example, for an instantaneous, reversible reaction typified by a Hatta number (Ha) greater than 3, the reaction is assumed “fast” and an analytical solution is available. For a “slow” reaction, (Ha<0.3), it is assumed that the reaction occurs within the bulk fluid and the reaction rate can be determined from standard kinetic theory. Danckwerts (1970) and van Krevelen and Hoftijzer (1948) have developed approximate methods for the transition region characterized by 0.3<Ha<3. The focus of this study can be characterized as follows: 1. to evaluate the effect of ozone on the removal of acid yellow 17 dye from a synthetic wastewater, and 2. to develop a model based on film theory to describe the removal of COD associated with acid yellow 17 dye by ozonation in a semi-batch reactor. Materials and Methods All experiments were conducted in a semi-batch bubble column. The column was fabricated from clear 7.62 cm schedule 40 PVC pipe and was 2.44 m in height. The gas feed was sparged through three stainless steel filters with 10 um porosity. The sparging system entered the side of the reactor 15.24 cm from the bottom of the column. Ozone was produced with the Ozotech, Inc. OZ2BTUSL ozone generator. The air feeding the ozone generator was conditioned using the Power Prep Model Titan (Ozotech, Inc.). The carrier gas flow rate was maintained at a constant of 3.78 L/min resulting in a uniform ozone introduction to the system of 79.2 mg O3/min. Figure 1 shows a schematic of the equipment utilized. Copyright ASCE 2005 EWRI 2005

Preparing engineering students for working in teams through senior design projects

This paper explores teaming and its cultivation in senior capstone design projects to better prep... more This paper explores teaming and its cultivation in senior capstone design projects to better prepare students for occupational interaction with other professionals, clients, and management to solve complex or open-ended problems. Teaming is deemed an important skill for engineers, by organizations employing engineers and other professionals. In the global marketplace organizations that value and capitalize on these skills can be more agile and competitive. The impact of current and future trends on teaming, including outsourcing and globalization, are discussed in terms of non-technical skills required for practicing engineers and the preparation of new engineers. Parallels between senior design projects and actual industry projects are drawn to highlight the key personal interaction skills and tools required for success. Examples of successful student teams and professional teams are presented for discussion. Measurements of project and teaming success by industry and professional organizations are presented. Topics include: traditional, global and virtual team structures emphasizing the nontechnical aspects necessary for modern teams including, team communication, diversity and cultural aspects, problem resolution, and other elements necessary for project success.

Power to the People: Energy Audits

Comparing two empirical models used to predict process parameter dynamics during ozonation of synthetic dye wastewater

Journal Of Environmental Science And Health, Part A, Jan 5, 2009

Bench-scale ozonation study of waste activated sludge

Journal Of Environmental Science And Health, Part A, 2009

A bench-scale ozonation study was conducted on waste activated sludge (WAS) in a 10-L, clear PVC,... more A bench-scale ozonation study was conducted on waste activated sludge (WAS) in a 10-L, clear PVC, semi-batch, bubble column reactor. Two separate runs were performed on 5-L samples of WAS obtained from the Rocky Creek Wastewater Treatment Plant (WWTP) in Macon, Georgia. The Rocky Creek facility uses the extended aeration activated sludge process to treat domestic wastewater. Ozone was sparged through a porous diffuser at an application rate of 0.0525 mg O(3) min(- 1) at contact times of 9 days and 12 days, respectively, during Runs #1 and #2. Parameters that were monitored during the study included: alkalinity, ammonia, conductivity, nitrite, nitrate, pH, phosphate, solids degradation rate coefficient (K(D)), soluble chemical oxygen demand (SCOD), total chemical oxygen demand (TCOD), total dissolved solids (TDS), total solids (TS), total volatile solids (TVS), turbidity, and unstirred sludge volume index (SVI(u)). Ozone was very effective at removing TCOD and TS. TCOD removals were 43% and 99% respectively for Runs #1 and #2. Total solids removal during Runs #1 and #2 was 50% and 95%, respectively. The degradation rate coefficient (K(D)) based on VSS was 0.17 days(- 1) and 0.54 days(- 1) for Runs #1 and #2. Both the nitrate and phosphate concentrations increased as ozone contact time increased during each run. The unstirred SVI decreased with an increase in ozone contact time, however, extended ozonation caused the SVI to increase. Actual ozone dosages for Runs #1 and #2 were 0.0036 and 0.011 mg O(3) per mg TS removed.

Encouraging High School Students To Learn About Bioremediation

This paper presents a laboratory activity for high school students used to stimulate their intere... more This paper presents a laboratory activity for high school students used to stimulate their interest in environmental engineering and the role of bioremediation in cleaning up the environment. The proposed laboratory activity utilized six, 2-L plastic bottles that contain 100-grams of indigenous soil in each to serve as bioreactors. Varying amounts of glucose are added to the reactors, which are monitored with time for a period of five to ten days. Questions for assessing the exercise along with sample laboratory results are provided.

Design, Operation, and Analysis of a Biological Sand Filter Using Copper as a Disinfectant

World Environmental and Water Resources Congress 2013, May 28, 2013

Aqua Clara International (ACI) is a nonprofit organization that uses biological sand filters (BSF... more Aqua Clara International (ACI) is a nonprofit organization that uses biological sand filters (BSFs) to provide economical, clean water to families in developing countries. ACI often recommends loading 20 L/d in BSFs in which a brass alloy is included as a disinfectant. A bench-scale study was conducted to investigate the effectiveness of using copper as the disinfectant. Five filters were constructed to compare different arrangements and amounts of copper shavings to a control, Column 1. The control was modeled after ACI design specifications but no metallic disinfectant was included. Columns 2 – 5 were also scaled according to ACI recommendations. Columns 2 and 3 each contained 4.7 g of copper, and Columns 4 and 5 each contained 2.35 g. In columns 2 and 4, copper was placed in a single layer; while in Columns 3 and 5, the copper was dispersed throughout the fine sand. After 31 days of testing, the average removal efficiency for total coliforms in Columns 1 – 5 was 96.5%, 93.9%, 97.4%, 95.4%, and 97.5% respectively. A single, 20 L/d, BSF was constructed with 94 g of copper dispersed throughout the fine sand layer. The average removal efficiency for fecal coliforms and turbidity was 97.3% and 65.7%, respectively.

Engineering Student Self-assessment in a Capstone Design Course