The purpose of this research was to examine the environmental impacts and risks associated with the production and use of a Performance Grade modifier from the re-refining process for recycled used lubricating oils. Life cycle assessment was used as a tool to assess the environmental impacts of four re-refining processes which produce an asphalt flux that is used as an asphalt cement extender and/or roofing asphalt extender. The four processes are: (1) Evergreen Oil, (2) Safety-Kleen, (3) deMenno/Kerdoon and (4) Chevron Trailblazer. On the basis of the assessment, the Chevron process is the closest to the 'future industrial practices' described by pollution prevention. Although the Chevron process is more energy intensive than the other three, it has the lowest emissions rate and does not generate wastewater or hazardous wastes. The life cycle comes full circle, i.e., the future industrial practices are achieved whereby most process waste production is eliminated, and as much remaining waste as possible is recycled, reused or reclaimed at the facility of origin or another facility. The Safety-Kleen process has the lowest energy consumption per gallon of used lubricating oil processed, as well as the lowest volume ratio of waste generated after Chevron's. The contribution to the body of knowledge is a life cycle assessment and health risk assessment for the manufacture and application of a modified Performance Grade asphalt using recycled used lubricating oil. The inventory assessment can be added to the U.S. EPA's Life Cycle Inventory database. The improvement assessment component of the Life Cycle Assessment was then used to assess the use of the asphalt flux from the Chevron Trailblazer process as a Performance Grade modifier in the production of Performance Grade asphalt. The use of the Performance Grade modifier produces a Performance Grade asphalt which is adaptable to a variety of environments and is effective over a wide range of temperatures, whereby the decrease in the upper and lower limits of the temperature range occurs in a ratio less than about 2 to 1, in about a 1 to 1 ratio. It further provides a method for producing such a Performance Grade asphalt. The ratio closest to 1 to 1 is the most desired and represents that for each degree achieved at lower temperature, the high temperature will also decrease by only one degree. It should be apparent that the Performance Grade modifier may be used to increase efficiency, lower production costs and simplify the production of Performance Grade asphalt. The contribution to knowledge was a U.S. Patent, 'Performance Grade Asphalt and Methods for Producing the Same'. (Abstract shortened by UMI.) / acase@tulane.edu

A pilot-scale test rig was constructed to simulate intrusion behavior associated with hydraulic transients. Initial tests were conducted using a high-speed datalogger to verify low/negative pressures. Results indicated negative pressures (maximum -12 psi) for 3 to 5 seconds following sudden valve closures. With steady state flow, three orifice diameters (1/8 ″, ¼″ and ½″ ) were overlaid with 3 or 4.5 feet of head to simulate cracks or leak points in a water distribution system. Based on volumetric measurements, average intrusion volumes associated with transients ranged from 47.3 to 550.2 mL. Based on chemical tracer (cesium) measurements, average intrusion volumes ranged from 11.4 to 71.2 mL for 1/8″ and ¼ ″ orifices, respectively. Differences were attributed primarily to dilution of cesium in the test rig. Results also were compared to theoretical and computer model predictions. Findings from this research demonstrate that external water and pathogens potentially can intrude into pipelines during transient events / acase@tulane.edu

Polymeric liners are widely used in rehabilitation of sewer and potable water lines and containment of solid waste and water (polymeric membranes). Studies conducted to date on the performance of polymeric liners considered the effect of mechanical stress, chemicals, moisture, and temperature. However, no study provided a measure of and tools for a practical method to determine the combined effects of in-situ stresses and exposure to chemicals on the long-term performance of liners. This research work aims at quantifying the simultaneous effects of chemical exposure and stress on material properties of polyethylene typically used in liners for pipeline rehabilitation and waste/water containment. An experimental method with a custom designed soaking apparatus was developed for exposing polymeric specimens to water treatment residuals and other abrasive chemicals under an applied stress. High and low density polyethylene specimens (63.5 x 12.7 x 3.2 mm) were mounted on the apparatuses and tested under different levels of deformation, temperature, and time while being exposed to chlorine and trichloroethylene solutions. Following the soaking under each of the foregoing conditions, the specimens were tested for their flexural strength in accordance with ASTM D 790. A computational analysis using the finite element method was performed to verify the results of the flexure tests and determine the stress and strain distribution over a bent specimen during exposure. The results did not indicate a significant effect of chlorine or TCE on degradation of HDPE and LDPE. The developed method with the chosen variables and their levels allows for an analytical interpretation for the effect of moisture and deformation on the long-term flexural modulus of elasticity, which is indicated by the degradation coefficient zeta. The effect of temperature on the degradation of the two tested materials was evident by the observed early failure in addition to the decreased flexural modulus of elasticity noted in the HDPE specimens. The equation proposed for zeta accounts for the effects of temperature and molecular weight distribution. However, analytical interpretation of the effects of these parameters is subject to a future study / acase@tulane.edu

This research is aimed at the design of novel adsorptive-reactive particles that are effective in the environmental treatment of dense non-aqueous phase liquids (DNAPLs) such as trichloroethylene (TCE). The attainable multifunctional particles have the ability to transport through soil, target contaminants directly, adsorb contaminants and break them down, holding a promising to be efficiently applied for in situ injection remediation technology The widespread occurrence of DNAPLs in groundwater and in soil is of serious environmental concern. Compared to traditional remediation technology, the in situ injection remediation technology using nanoscale zerovalent iron (NZVI) particles is the preferred method because it will not only potentially reduce the remediation cost and time substantially, but it may also directly access and target the contaminants. However, neat NZVI particles have a strong tendency to form aggregates, rendering them undeliverable to the specified contaminant zone. Additionally, the hydrophilicity of NZVI particles makes them hard to target contaminants directly, lowering the remediation efficiency To improve the performance of NZVI in in situ injection remediation technology, three different novel composites based on NZVI were developed successfully in this study, i.e. NZVI/silica, (carboxymethyl cellulose + NZVI)/carbon and NZVI/aerosol-carbon. In these composites, NZVI particles were incorporated in the silica matrix or supported on the carbon surface, respectively. Meanwhile, the following beneficial characteristics of these composites have been proved: (1) they are reactive to dechlorination of TCE due to the presence of reactive nanoscale zerovalent iron; (2) the supports (silica or carbon) exhibit hydrophobic property and thus serve as adsorbents for TCE, lowering bulk dissolved TCE concentrations without limiting the remediation rate and bringing TCE to the proximity of the zerovalent reduction sites. Adsorption coupled with reaction is an important concept in this research; (3) hydrophobic supports allow the nanocolloids to effectively partition into TCE phase upon encountering regions of bulk TCE after they transport through the saturated zone; (4) the nanocolloids are of the optimal size range for effective transport through groundwater; (5) the preparation processes are environmentally benign and economical and (6) the aerosol-assisted technology involved in the preparation of composites process is conducive to scale up, as it is a virtually continuous process In this thesis, the preparation and characterization of such systems are presented. The characteristics of adsorption, reaction, transport and partitioning relevant to the problem of TCE remediation are studied / acase@tulane.edu

The objective of this dissertation is to remediate groundwater contaminants such as trichloroethylene (TCE) by functional particles. The porous silica particles with zero valent iron were synthesized by an aerosol-assisted process and subsequent gas or liquid phase reduction. The surface properties of these particles were carefully controlled through silanol modification to realize the suitable particle affinity with target contaminants While aerosol silica particles incorporating nanoscale zero valent iron are reactive for groundwater TCE remediation, environmentally benign silica particles serve as effective carriers for nanoiron transport through soil. The presence of surface silanol groups on silica particles makes possible the surface property control via silanol modification using organic functional groups. This leads to preferred partition of particles on TCE/water interface. Additionally, aerosol silica particles with functional groups such as ethyl tails on the surface preferentially adsorb hydrophobic TCE during environmental remediation. This increases the local concentration of TCE in the vicinity of iron, thus promoting TCE degradation by iron The morphology of silica particles with iron can be controlled through introducing cetyltrimethyl ammonium bromide (CTAB) as the template. Solid silica particles with disordered mesostructure can be obtained at low CTAB concentration. A novel translation from solid particles to hollow spheres was observed at increased CTAB concentration. Low solubility of ferric chloride in ethanol has been found to be the key for such transition and a reasonable formation mechanism of hollow spheres will be proposed. Further thermal reduction of encapsulated ferric ions produces zero valent iron nanoparticles inside silica hollow spheres. The reactivity and partition characteristics of hollow particles with iron will also be discussed / acase@tulane.edu

The fate and distribution of heavy metal pollutants in estuary regions is of great concern in environmental studies due to their toxicity and cumulative properties. The interactions between the metal and sediments, especially the adsorption/desorption process, are the most important mechanisms which control the metal concentration in aqueous systems. The presence of natural organic materials such as humic and fulvic acid may alter the surface properties of sediments and suspended particles, as well as the speciation of metals in both the dissolved and adsorbed states In this study, a system consisting of Pb, Cu and Cd as typical heavy metal pollutants, montmorillonite as a model sediment and suspended particles together with purified humic acid as a representative of natural organic materials were selected as prototype materials to model the environmental system. The effect of environmental factors such as pH, salinity and concentrations on the interaction between metals, montmorillonite and humic acid were investigated in detail. A theoretical model featured by surface complexation reactions and triple layer theory combined with the Poisson-Boltzmann equation was developed and used to simulate the experimental data. The model was also used to predict surface properties such as potentials and the species of metals adsorbed both on the montmorillonite and humic acid The experimental results have shown that pH and ionic strength are the most important variables in controlling metal adsorption on either montmorillonite or humic acid. While a small increase in the adsorption of Cu and Cd on montmorillonite was observed in the presence of humic acid, the humic acid did not show as much of an effect as expected on metal adsorption in the concentration range tested in this study. The results also shown a high complexation capacity of humic acid for the metals, especially Cu and Pb. This might be the most significant role that humic acid plays in the environmental system Good agreement between theoretical modeling results and the experimental data proved the applicability of the theoretical model to this system. All the parameters in the model can be obtained experimentally. Given these parameters, theoretical calculations obtained using the model proposed in this study can give a detailed picture under actual environmental conditions. Also, the model calculations will help in the evaluation of the actual toxicity of heavy metal pollutants in the aquasystem / acase@tulane.edu

The purpose of this feasibility study was to examine the experimental behavior, environmental performance of oriented straw cable composites, and begin to develop a model of the composite. The material is made of wheat straws bound in cables of 50.8 mm (2 in.) diameter which were then used to reinforce a low strength cementititous matrix Several different components of the material were tested in a series of compression, tension, and bending tests. Tension test were performed on individual wheat straws and straw cables. Behavior of the straw cables, cable bundles, and oriented straw composite short columns were examined in compression. Larger scale experiments were conducted for oriented straw cable beams; they were tested in four point bending tests. Parameters such as length and straw type were examined in these tests. Comparing the compression tests performed on these low strength cementitious matrix samples with oriented straw cable reinforced cementitious matrices it was shown that the load carrying capacity was increased by more than 200%. A total of 65 different specimens were tested and the number of specimens was limited by the delivery of the production company A finite element modeling program ABAQUS was used to conduct finite element analysis (FEA) of the wheat straw and straw cables in tension and compression. The material properties for the model were obtained from both measured properties and literature sources available. The results obtained from experiments were in good agreement with the finite element models The environmental impacts of production and construction of the material was investigated by means of life cycle assessment (LCA) technique. A simple wall system was selected as the unit for the analysis and the life cycle impact assessment results were compared with a timber wall system. The comparisons showed production, construction, and disposal of an oriented straw cable composite wall system had larger environmental impact scores than a system constructed with timber in most of the impact categories mostly due to the cementitious matrix component of the composite The feasibility study showed that the material can be a good candidate for structural construction. The composite can offer an inexpensive, locally available, and environmentally friendly construction material that can be used in regions where these criteria are critical for housing needs / acase@tulane.edu

The fate of four trichlorophenols (TCP), six dichlorophenols (DCP), and three monochlorophenols (CP), were studied in anaerobic propionate enrichment systems. TCPs were more toxic than DCPs and CPs; 2,4,5-TCP was the most toxic compound to the propionate utilizers among the thirteen chlorophenols studied in this research. Most chlorophenols were reductively dechlorinated to less chlorinated compounds. Dechlorination at the ortho position was observed most frequently. 2,3,6-TCP was dechlorinated to form 2,3-DCP, which was then transformed into 2-CP and phenol. 2,3,5-TCP produced 3,5-DCP and subsequently 3-CP and phenol. 2,4,5-TCP was dechlorinated to produce 3,4-DCP followed by 3-CP and phenol. 2,4,6-TCP was dechlorinated sequentially at the ortho positions to produce 2,4-DCP and 4-CP, which then produced phenol. The chlorine in the meta positions of 3,5-DCP, 2,3-DCP, 2,5-DCP were removed to produce 3-CP, 2-CP, and 2-CP, respectively. 2,4-DCP and 2,6-DCP were dechlorinated at the ortho position to form 4-CP and 2-CP, respectively. 3,4-DCP was dechlorinated to produce 3-CP. Phenol was also detected during degradation of 2,3-DCP, 2,6-DCP, 3,5-DCP, 2-CP, 3-CP, and 4-CP. The overall removal of the selected chlorophenols by anaerobic propionate enrichment systems were in the following order: 2,3,5-TCP $>$ 2,3,6-TCP $>$ 3,5-DCP $>$ 2,4-DCP $>$ 2-CP $>$ 3,4-DCP, 2,3-DCP, 2,5-DCP $>$ 3-CP $>$ 2,4,5-TCP $>$ 2,6-DCP $>$ 2,4,6-TCP $>$ 4-CP The objective of Part II study was to determine the toxic effects and degradation of pentachlorophenol (PCP) in the presence of zinc in anaerobic propionate systems. Anaerobic toxicity assays (ATA), batch kinetic studies, and biodegradation studies were performed using serum bottles. PCP inhibition was modeled using both uncompetitive and noncompetitive inhibition kinetic models with an inhibition coefficient, K$\rm\sb{I},$ of 0.06 mg/l. Zinc toxicity showed that the competitive inhibition model was the best-fit model with a K$\rm\sb{I}$ of 1.1 mg/l. A combined competitive-uncompetitive inhibition model was the best-fit model in the presence of both PCP and zinc for propionate degradation. In the biodegradation studies, PCP removals were 72, 64, and 54% with spiked PCP concentrations of 2, 3, and 5 mg/l, respectively. In the presence of zinc, the removal of 2 mg/l and 3 mg/l of PCP decreased to 60% and 53%, respectively. The intermediates of PCP degradation were 2,4,6-trichlorophenol, 2,4-dichlorophenol, 4-chlorophenol, 2,3,5-trichlorophenol, 3,5-dichlorophenol, and 3-chlorophenol; lower concentrations of these intermediates were observed in the presence of zinc / acase@tulane.edu

Acrylic acid and formaldehyde are present in several industrial wastewaters including petrochemical wastes. The objectives of this study were to determine the anaerobic degradability of acrylic acid and formaldehyde in acidogenic and methanogenic systems and anaerobic treatability of petrochemical wastewaters containing acrylic acid and formaldehyde Acetate, propionate, and glucose enrichment cultures were used in serum bottle and chemostat studies. The results showed that the acrylic acid was degraded to propionate and acetate and without acclimation it completely inhibited propionate degradation and partially inhibited acetate degradation. In both the methanogenic and acidogenic chemostats, 98% of the acrylic acid was removed. However, the acidogenic chemostat had a significantly higher acrylic acid loading rate (416 mg/L-d) than the methanogenic chemostat (16.7-66.7 mg/L-d). Even at low acrylic acid loading rates, the propionate utilizers required a long time to acclimate to acrylic acid Formaldehyde showed severe toxicity to the acetate enrichment culture. As low as 10 mg/L of formaldehyde completely inhibited acetate utilization. Formaldehyde was, however, degraded while acetate utilization was inhibited. Degradation of formaldehyde (Initial concentration $\le$30 mg/L) followed Monod model with a rate constant, k, of 0.35-0.46 d$\sp{-1}$. At higher initial concentrations ($\ge$60 mg/L), formaldehyde degradation was inhibited and partial degradation was possible. The initial formaldehyde to biomass ratio, S$\sb0$/X$\sb0$, was useful to predict the degradation potential of high concentrations of formaldehyde in batch systems. The inhibition of formaldehyde degradation in batch systems could be avoided by repeated additions of low concentrations of formaldehyde (up to 30 mg/L). Methanogenic chemostats (14-day retention time) showed degradation of 1110 mg/L of influent formaldehyde with a removal capacity of 164 mg/g VSS-day. The results also showed that the acetate enrichment culture was not acclimated to formaldehyde even after 226 days The acetate enrichment culture, acclimated to acrylic acid and formaldehyde, successfully treated 25% of the 'Wastewater B' from a petrochemical plant containing high concentrations of acrylic acid (1650 mg/L) and formaldehyde (3330 mg/L) and other constituents. The removal efficiency for acetic acid, acrylic acid, formaldehyde, and COD were 99, 99, 99, and 91%, respectively. The unacclimated acetate enrichment culture can also be used to treat 'Wastewater A' containing low concentrations of acrylic acid (240 mg/L) and formaldehyde (30 mg/L). The system had 92, 99, 99, and 62% of removal efficiency for acetate, acrylate, formaldehyde, and COD, respectively / acase@tulane.edu

This thesis presents a Tree-Structured Regression (TSR) method to relate daily precipitation with a variety of free atmosphere variables. Historical data were used to identify distinct weather patterns associated with differing types of precipitation events. Models were developed using 67% of the data for training and the remaining data for model validation. Seasonal models were built for each of four U.S. sites; New Orleans Louisiana, San Antonio and Amarillo of Texas as well as San Francisco California. The average correlation by site between observed and simulated daily precipitation data series range from 0.69 to 0.79 for the training set, and 0.64 to 0.79 for the validation set. Relative humidity related variables were found to be the dominant variables in these TSR models. Output from an NCAR Climate System Model (CSM) transient simulation of climate change were then used to drive the TSR models for predicting precipitation characteristics under climate change. A preliminary screening of the GCM output variables for current climate, however, revealed significant problems for the New Orleans, San Antonio and Amarillo sites. Specifically, the CSM missed the annual trends in humidity for the grid cells containing these sites. CSM output for the San Francisco site was found to be much more reliable. Therefore, we present future precipitation estimates only for the San Francisco site. While both GCM and TSR predict very small change in overall annual precipitation, they differ significantly from season to season / acase@tulane.edu