Biodiesel purification processes generate wastewater streams that require a large amount of energy when distillation is used as a treatment technology. Process simulation software was used to show that an alternative water treatment process involving ion exchange would require only 31% of the energy used by distillation. Experiments showed that multiple washing stages were required to meet the standard specification for sodium, an impurity present in crude biodiesel, when washing biodiesel made from used frying oil. A comparison was made between washing biodiesel in a cross-current washing configuration and a counter-current configuration. Both configurations met the specification for sodium within three washing stages; however, the counter-current configuration required less water, making it the more efficient process. Lastly, the removal of sodium from wastewater samples using an ion exchange resin was experimentally investigated. The results validated the use of ion exchange to reduce energy consumption in biodiesel purification.

Lower production rate of solids in attached growth moving bed bioreactor (MBBR) systems as compared to conventional activated sludge (AS) systems makes them an attractive choice for municipal wastewater treatment (Ødergaard et al. 1994). However, the production of biologically-produced solids in MBBR systems is currently not well defined and requires additional investigation. Three identical MBBR reactors were operated under the same dissolved oxygen (DO) concentration, influent pH and volume of Anoxkalnes media in two different experimental phases. In the first phase, the hydraulic retention time (HRT) kept constant in three reactors and SALR increased and in the second phase, the SALR was the constant parameter while HRT increased. These two phases were implemented to investigate the effect of variations in HRT and SALR on biologically-produced solids in MBBR reactors. This study demonstrated that HRT and SALR play an important role in settling characteristics of the biologically-produced solids in MBBR systems.

Biodiesel purification processes generate wastewater streams that require a large amount of energy when distillation is used as a treatment technology. Process simulation software was used to show that an alternative water treatment process involving ion exchange would require only 31% of the energy used by distillation. Experiments showed that multiple washing stages were required to meet the standard specification for sodium, an impurity present in crude biodiesel, when washing biodiesel made from used frying oil. A comparison was made between washing biodiesel in a cross-current washing configuration and a counter-current configuration. Both configurations met the specification for sodium within three washing stages; however, the counter-current configuration required less water, making it the more efficient process. Lastly, the removal of sodium from wastewater samples using an ion exchange resin was experimentally investigated. The results validated the use of ion exchange to reduce energy consumption in biodiesel purification.

Subsurface drip distribution is an important on-site wastewater treatment technique which is widely used with various soil types and restricted site conditions. It can distribute pretreated wastewater uniformly into soil. Some recent field applications showed low application uniformities, which was reflected in overloading of the field near the supply manifold while low emitter discharge rates occurred at the end of lateral. Designers are seeking appropriate operation pressures and drip zone configurations to improve system application uniformity. This research was conducted to test some popular wastewater drip products in both lab and field-scale experiments. The first goal of this study was to evaluate the performance of five subsurface drip products under eight operational pressures ranging from 0 to 310 kPa (45 psi). After evaluation of each group of 60 emitters, results showed that Netafim Bioline pressure compensating (PC) emitters exhibited a uniformity coefficient (UC) of 95% with a coefficient of variance (Cv) of 4.9%. The average UC of Geoflow Wasteflow products is 94.4% and Cv value is 6.8%. Flow rate and pressure relationships (Q-H curves) were developed for each drip emitter tested. By analyzing low and normal operational pressure ranges, Q-H curves were fitted to the data and resulted in R2 values ranging from 1.000 to 0.414. Geoflow pressure compensating products possess the features of non-pressure compensating emitters under low pressure head. Netafim PC products are characterized as pressure compensating over the full range of operational pressures and emit water with nominal uniformity during low pressure range. To evaluate drip zone configurations with respect to distribution uniformity, a field-scale experiment was set up and three drip tubing products were tested in different dosing and operation schemes. Three factors of wastewater drip system design were tested. System operation pressure (138 kPa/20 psi and 276 kPa/40 psi); different pressure control components (pressure regulator/recirculation valve) and schemes (continuous flushing/intermittent flushing); and supply line length (7.6 m/25 ft, 15.2 m/50 ft, and 30.4 m/100 ft) were evaluated to compare their influence on water application uniformity. It was concluded that, for Geoflow PC and NPC products, among all three factors, system operational pressure has the greatest effect on drip system application uniformity; supply line length has the least influence. For Netafim PC tubing, pressure control scheme has the greatest effect on drip system application uniformity; supply line length has the least influence. The optimal combination of the three factors could save more than 10 minutes of dosing time to meet the required dosing application uniformity. An engineering computation example on system fill time was presented and compared to experimental results to demonstrate the possible gap between typical design processes and real field application.

The ubiquitous use of antibiotics has led to an increasing number of antibioticresistant bacterial strains, including strains that are multidrug resistant, pathogenic, or both. Numerous studies have been conducted showing the presence of antibioticresistance genes (ARGs) and antibiotic-resistant and multidrug resistant bacteria in wastewater and drinking water treatment plants. There is also evidence to suggest that ARGs spread to the environment, and to humans and animals, through wastewater effluents. The overall objective of this study was to investigate the effect of UV light disinfection on ARGs and antibiotic resistant bacteria. Wastewater effluent samples from a wastewater treatment plant (WWTP) in Texas were evaluated for differences in abundance and diversity of tetracycline resistant bacteria before and after UV treatment. The effects of photoreactivation or dark repair on the reactivation of bacteria present in WWTP effluent after UV disinfection were also examined. Culture based methods were used to characterize viable heterotrophic, tetracycline resistant heterotrophic, E. coli, and tetracycline resistant E. coli bacteria present before and after UV treatment. Molecular methods were used to characterize the diversity of organisms present and to test for the presence of tet(Q), a tetracycline resistance gene associated with human origins. UV disinfection was found to be as effective at reducing concentrations of resistant heterotrophs and E. coli as it was at reducing total bacterial concentrations. The lowest survival ratio following UV disinfection was observed in tetracycline-resistant E. coli, showing it to be particularly susceptible to UV treatment. Photoreactivation and dark repair rates were found to be comparable to each other for all bacterial populations. UV disinfection was found to significantly alter the community composition of tetracycline-resistant bacteria, though it did not have the same effect on the total bacterial community.

Thesis (Ph. D.)--University of Queensland, 2002. / Includes bibliographical references.

Thesis (M.S.) in Civil Engineering--University of Maine, 2001. / Includes vita. Advisory Committee: Chet A. Rock, Prof. of Civil and Environmental Engineering, Advisor; Willem Brutsaert, Prof. of Civil and Environmental Engineering; Rose Mary Seymour, Asst. Prof. of Bio-Resource Engineering. Includes bibliographical references (leaves 100-104).

The semiconductor industry has been growing at a fast pace in the last several decades and this growth is expected to continue in the future. One process that is repeated several times in a microchip fabrication is the Chemical Mechanical Planarization (CMP). CMP is a critical process that must be employed after the metal deposition step to eliminate any topography over which the next layer must be processed. Today, copper interconnect is widely used. In addition to possess a high resistance to electro migration effects and low electrical resistivity, copper techniques require fewer (approximately 25%) processing steps. CMP and post-CMP cleaning processes are projected to account for 50 percent of the water consumed by fabrication's ultra pure water. While there are a variety of treatment schemes currently available for the removal of heavy metals from CMP wastewater streams, many introduce additional chemicals to the process, have large space requirement, or are not effective. Polyethyleneimine (PEI) is well known to use in the ion metal affinity chromatography (IMAC) due to the great metal ion binding abilities. While work has been conducted on the use of PEI on membrane filtration for binding metals from industrial wastewaters, the experiments performed in this research are novel with respect to the waste (Cu CMP) treated as well as the method of packed bed column treatment. This research focused primarily on the study of an alternative technique to remove both metal ions and metal-chelated complexes from Cu CMP wastewater streams. Not only copper, wastewater often contains chelating agents, surfactant, organic compounds, and inhibitors. Thus, most of the time copper ions form complexes with chelating agents, which made typical ion exchange resins ineffective. The work, then, explored the effect of components typically found in Cu CMP waste streams on the binding of copper ions to PEI. The competitive binding of copper between PEI and other complexing agents were also investigated. A secondary focus of this study was to fully develop and characterize the column performance and behavior. This includes the understanding of the chemistry of CMP waste characterization. This treatment technique using a PEI packed bed column showed great copper binding capacity. The column is capable of removing Cu CMP waste streams, which contain both copper ions and copper complexes, due to the unique ability of PEI that can play both cation and anion exchanger roles. This waste treatment technique is feasible for the semiconductor industry as large volumes of copper contaminated solutions from actual waste can be concentrated twelve-fold for metal recovery using hydrochloric acid. The adsorbent can be regenerated more than hundred of times with changing in the performance and the reproducibility.

The aim of the work described in this thesis was to study the removal of ammonium ions from water by ion exchange. The classical technique is to use biological nitrification and denitrification to convert ammonia into nitrogen gas. Removal by ion exchange offers a number of advantages, such as the ability to handle shock loadings and to polish water to a very high specification. The ion exchanger used in this project was clinoptilolite, a naturally occurring zeolite. Previous research has included characterisation of clinoptilolite, the effect of other common cations on uptake, biological regeneration, and a few other studies. A comparison with other exchangers was also conducted. Much of the available literature is concerned with clinoptilolite and occasionally with mordenite, however modern ion exchangers are polymer based. Two polymeric ion exchangers (Dowex 50w-x8, and Purolite MN500) were evaluated in this project. The main scope of this thesis was to look at the effect that organic pollutants has on ammonium ion removal during ion exchange. The results of batch equilibrations of NH4+ and the three exchanger resins can be seen in chapter 4.0. They show that the presence of an organic compound enhanced the uptake of NH4+ in most cases onto clinoptilolite and Purolite MN500. There was no apparent uptake onto Dowex 50w-x8. Further experiments with a sample of real industrial wastewater (woolscour wastewater) showed varied results, showing that each site should carry out its own pilot scale testing during plant design. Other experimental work showed that the exchanger resins adsorb little or none of the organic compounds in solution. These results can be seen in chapter 5.0. ii Removal of ammonia from wastewater by ion exchange in the presence of organics. Studies in a packed column showed that the presence of organic compounds had little or no effect on NH4+ removal. There was however an increase in capacity after each regeneration of the bed and continued removal after breakthrough. The same results were achieved in the control experiment with no organic compounds present, hence these results are not related to the presence of an organic compound. The presence of NH4+ and various compounds did however provide micro-organisms with substrates from which to grow causing hydraulic difficulties in the column. See chapter 6.0 for these results. The final section of experimental work studied whether the presence of organic compounds changed the rate of uptake of NH4+. The results in chapter 7.0 show that there was no effect on the rate of NH4+ uptake.

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