Development of renewable energy sources such as ethanol has become a priority to meet growing energy demands. In the United States, the majority of ethanol is produced at dry mill facilities that convert corn to ethanol; these facilities can be a major emission source for volatile organic compounds (VOCs). Biofiltration is a promising VOC control technology but its effectiveness for the VOC mixtures emitted from ethanol production facilities has yet to be determined. The main goal of this research was to evaluate the feasibility of using biofiltration to treat ethanol plant air pollutants. To accomplish this, microbial degradation of four representative pollutants (formaldehyde, acetaldehyde, ethanol and acetic acid) was examined first in simplified batch reactors and then in a laboratory-scale biofilter system. The batch data indicate that, at a neutral pH, an enriched microbial consortium was capable of completely degrading formaldehyde, acetaldehyde and ethanol, and the Monod model was successfully utilized to describe single substrate degradation kinetics for these pollutants. However, the consortium only partially degraded acetic acid. In binary substrate experiments, acetaldehyde degradation was not significantly affected by either ethanol or formaldehyde. However, acetaldehyde inhibition of ethanol degradation was observed and inhibition kinetics were necessary to describe the observed ethanol removals. Formaldehyde degradation was inhibited in the presence of acetaldehyde and/or ethanol; however, further research will be required to identify the inhibtion. The biofilter study was performed to investigate the effects of pollutant loading, substrate mixtures and low pH on system performance. The results indicate that it is feasible to achieve greater than 97% overall removal efficiency at a short contact time of 5 seconds under neutral pH conditions. The level of substrate inhibition observed in the batch experiments was not evident in the biofilter experiments. However, low pH conditions gradually decreased the biofilter performance with a more significant impact on acetaldehyde, a result that was supported by batch data. Finally, a numerical model that integrated degradation kinetics was able to describe the biofilter performance under the test conditions. This research demonstrates that biofiltration has the potential to be a viable VOC treatment technology at corn-derived ethanol production facilities. / text

Over the past century chlorine has been a reliable disinfectant to reduce transmission of waterborne diseases in drinking water. Concerns about chlorination have increased since it was discovered in the 1970s that use of chlorine in drinking water produces trihalomethanes (THMs), when chlorine reacts with natural organic matter (NOM), which has been observed in increased levels in surface water during the past decades. THM and other disinfection by-products (DBPs) such as some of the haloacetic acids (HAAs) and some nitrosamines are considered probable human carcinogens by USEPA. Since DBPs are still formed even when using alternative disinfectants such as chloramines, treatment processes by which disinfection by-product precursors are removed continue to be studied. Many researchers have demonstrated that the use of pre-ozonation/biological processes in the production of drinking water has the potential to decrease levels of disinfection by-products in finished water more than conventional treatment alone. Two of the parameters which affect the efficiency of DBP precursor removal in biofilters are filter media and filter flow rate. In this research, the biofiltration process was examined using pilot-scale filters receiving ozonated water to determine the relative effectiveness of these parameters for influencing the removal of natural organic matter. The research presented in this thesis initially focuses on determining the effects of flow rate and filter media including GAC (granular activated carbon) and anthracite on decreasing the levels of THM, HAA and nitrosamine precursors in biologically active filters. In the second part, the performances of full-scale and pilot-scale filters at the Mannheim Water Treatment Plant were compared. THM and HAA precursor removal was found to decrease when loading rates were increased, likely due to associated shorter contact times in the filters. Also, higher THM and HAA precursor removal was always observed in the GAC filters than in the anthracite filters. However, removal of nitrosamines was not affected by flow rate or the type of filter media. In general, the pilot-scale filter performance was representative of full-scale filter performance, especially in regards to THM precursor and chlorine demand removal. Statistical evaluation and interpretation of the data for HAA and NDMA precursor removal was more difficult, likely due to the low concentrations of these DBPs which was near their method detection limits (MDLs) and also because of some operational problems with pilot filter #1. Despite these limitations, the results of this study add to the literature concerning the use of different types of media to support biofiltration and reduce DBP precursor concentrations during drinking water treatment.

Over the past century chlorine has been a reliable disinfectant to reduce transmission of waterborne diseases in drinking water. Concerns about chlorination have increased since it was discovered in the 1970s that use of chlorine in drinking water produces trihalomethanes (THMs), when chlorine reacts with natural organic matter (NOM), which has been observed in increased levels in surface water during the past decades. THM and other disinfection by-products (DBPs) such as some of the haloacetic acids (HAAs) and some nitrosamines are considered probable human carcinogens by USEPA. Since DBPs are still formed even when using alternative disinfectants such as chloramines, treatment processes by which disinfection by-product precursors are removed continue to be studied. Many researchers have demonstrated that the use of pre-ozonation/biological processes in the production of drinking water has the potential to decrease levels of disinfection by-products in finished water more than conventional treatment alone. Two of the parameters which affect the efficiency of DBP precursor removal in biofilters are filter media and filter flow rate. In this research, the biofiltration process was examined using pilot-scale filters receiving ozonated water to determine the relative effectiveness of these parameters for influencing the removal of natural organic matter. The research presented in this thesis initially focuses on determining the effects of flow rate and filter media including GAC (granular activated carbon) and anthracite on decreasing the levels of THM, HAA and nitrosamine precursors in biologically active filters. In the second part, the performances of full-scale and pilot-scale filters at the Mannheim Water Treatment Plant were compared. THM and HAA precursor removal was found to decrease when loading rates were increased, likely due to associated shorter contact times in the filters. Also, higher THM and HAA precursor removal was always observed in the GAC filters than in the anthracite filters. However, removal of nitrosamines was not affected by flow rate or the type of filter media. In general, the pilot-scale filter performance was representative of full-scale filter performance, especially in regards to THM precursor and chlorine demand removal. Statistical evaluation and interpretation of the data for HAA and NDMA precursor removal was more difficult, likely due to the low concentrations of these DBPs which was near their method detection limits (MDLs) and also because of some operational problems with pilot filter #1. Despite these limitations, the results of this study add to the literature concerning the use of different types of media to support biofiltration and reduce DBP precursor concentrations during drinking water treatment.

Biogas, composed principally of methane, has limited use in energy generation due to the presence of hydrogen sulphide (H2S). Biogas cannot be burned directly in an engine as H2S present causes corrosion in the reaction chamber. There currently exist various technologies for the removal of H2S from a gas stream, but most are chemically based, expensive, and are limited in use. The purpose of this study was to determine a biogas purification technique suitable for a small scale farm application; including using a technology inexpensive, efficient, robust and easy to operate. As such, biofiltration was investigated for H2S removal from biogas. Factors considered in the design of the biofiltration system included the source and conditioning of inoculum, type of packing material, and general operating conditions including inlet gas flow rate and H2S loading rate to the biofilter. Activated sludge conditioned in A. ferrooxidans media was an effective inoculum source. This was tested for growth support compatibility with gravel packing material, to be used in the biofilter. The inoculated packing material was loaded into the biofilter initially during start-up and acclimatization. In this study, synthetic biogas (49.9%volCH4, 49.9%volCO2, 2000ppmv H2S) mixed with air (totalling 4%vol O2) was added at 5-10L/hr to a biofilter of 0.4L gravel packing inoculated with conditioned activated sludge. Baseline H2S removal studies in a non-inoculated biofilter were performed with anticipated operating conditions, including an inlet gas stream at 7.5L/h (25oC, 1atm), resulting in 31-56% H2S removal. A factorial test performed found that air content in the inlet gas stream was the significant factor affecting the removal of H2S in the non-inoculated biofilter. Operation of the biofilter with biogas was done for 61 days, including 41 days for start-up and acclimatization and 20 days of H2S loading tests. Start-up and acclimatization with biogas resulted in complete H2S removal after 2 days, with an average overall H2S removal of 98.1%±2.9 std deviation over 34 days. Loading tests performed on the system ranged 5-12.4L/h (25oC, 1atm), with a loading rate of 27.8 to 69.5gH2S/m3h of filter bed. Throughout this test the average H2S removal rate was 98.9%±2.1 std deviation over 20 days. Although complete H2S breakthrough studies were not performed, these results indicate that biofiltration is a promising technology for H2S removal from biogas in a small scale application.

Biogas, composed principally of methane, has limited use in energy generation due to the presence of hydrogen sulphide (H2S). Biogas cannot be burned directly in an engine as H2S present causes corrosion in the reaction chamber. There currently exist various technologies for the removal of H2S from a gas stream, but most are chemically based, expensive, and are limited in use. The purpose of this study was to determine a biogas purification technique suitable for a small scale farm application; including using a technology inexpensive, efficient, robust and easy to operate. As such, biofiltration was investigated for H2S removal from biogas. Factors considered in the design of the biofiltration system included the source and conditioning of inoculum, type of packing material, and general operating conditions including inlet gas flow rate and H2S loading rate to the biofilter. Activated sludge conditioned in A. ferrooxidans media was an effective inoculum source. This was tested for growth support compatibility with gravel packing material, to be used in the biofilter. The inoculated packing material was loaded into the biofilter initially during start-up and acclimatization. In this study, synthetic biogas (49.9%volCH4, 49.9%volCO2, 2000ppmv H2S) mixed with air (totalling 4%vol O2) was added at 5-10L/hr to a biofilter of 0.4L gravel packing inoculated with conditioned activated sludge. Baseline H2S removal studies in a non-inoculated biofilter were performed with anticipated operating conditions, including an inlet gas stream at 7.5L/h (25oC, 1atm), resulting in 31-56% H2S removal. A factorial test performed found that air content in the inlet gas stream was the significant factor affecting the removal of H2S in the non-inoculated biofilter. Operation of the biofilter with biogas was done for 61 days, including 41 days for start-up and acclimatization and 20 days of H2S loading tests. Start-up and acclimatization with biogas resulted in complete H2S removal after 2 days, with an average overall H2S removal of 98.1%±2.9 std deviation over 34 days. Loading tests performed on the system ranged 5-12.4L/h (25oC, 1atm), with a loading rate of 27.8 to 69.5gH2S/m3h of filter bed. Throughout this test the average H2S removal rate was 98.9%±2.1 std deviation over 20 days. Although complete H2S breakthrough studies were not performed, these results indicate that biofiltration is a promising technology for H2S removal from biogas in a small scale application.

Nitrate, arsenic and vanadium are all potential groundwater contaminants. Traditional physical/chemical methodologies are often too technical or expensive for rural environments. Biofiltration has been shown to remove a wide range of contaminants depending on the operating parameters. This research examined the possibility of using the denitrifying bacteria, Paracoccus denitrificans, to remove nitrate, arsenic and vanadium simultaneously from groundwater with varying iron concentrations. During bench-scale testing nitrate concentrations were reduced by up to 73%, even with the metals present. Without iron, arsenic and vanadium removal was insignificant. Removal increased when iron was added as it was found that arsenic and vanadium could be removed adsorptively by iron hydroxides. With 1 mg/L of iron present, removal rates of 67% and 91% were achieved for arsenic and vanadium, respectively. When the iron was increased to 2 mg/L, the removal rates increased to 85% and 96%, respectively.

Microbial oxidation of methane has attracted interest as an alternative process for treating landfill gas emissions. Approaches have included enhanced landfill cover layers and biocovers, passive gas drainage and biofiltration, and active gas extraction and biofiltration. Previous research has shown that microbial methane oxidation is affected by a number of factors, many of which are dependent on the environment in which the process is occurring. The aim of this research was to evaluate the behaviour and performance of a passive landfill gas drainage and biofiltration system operating in a temperate climate, and to identify and quantify the factors that determine the behaviour and performance of the system under such conditions. To achieve this a series of field trials were undertaken in Sydney, Australia, over a period of 4 years. The trials were designed to evaluate the effect of a range of factors, including landfill gas loading rate, temperature and moisture content of the biofilter media, biofilter media characteristics, and climatic conditions. The results of the field trials showed that a passive gas drainage and biofiltration system operating in a temperate climate can achieve methane oxidation efficiencies > 90% and that the behaviour and performance of a passive gas drainage and biofiltration system is primarily dependent on 3 factors: the landfill gas loading rate, which varies; the temperature of the biofilter media, which is affected by the temperature of the landfill gas being treated, the level of microbial activity occurring in the biofilter, and local climatic conditions; and the moisture conditions within of the biofilter media, which is affected by local climatic conditions and the characteristics of the biofilter media. Relationships between these factors and the performance of a passive biofilter operating in a temperate climate were developed, where able. A number of design concepts for passive landfill gas drainage and biofiltration were developed. A process for assessing the feasibility of applying the concepts and designing a passive landfill gas drainage and biofiltration system was also developed. In addition, guidelines and recommendations for the design of a passive landfill gas drainage and biofiltration system operating in temperate climate were developed.

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Advanced water treatment (AWT)/reuse has become a necessity for many utilities across the globe as the quantity and quality of water resources has been diminished. In some locations including California, the full-advanced treatment (FAT) train is mandated including membrane filtration, reverse osmosis, and UV advanced oxidation. The application of carbon-based treatment has emerged as a cost-effective alternative to FAT in locations that cannot manage brine disposal. However, considering the relative novelty of this treatment technology for water reuse, the process still requires full-scale validation of treatment goals including pathogen reduction. While there are many constituents of concern in water reuse, exposure to pathogens remains the greatest acute health risk. The studies described herein examine pathogen and microbial surrogate reduction both full-scale and pilot-scale floc/sed-ozone-biofiltration advanced water treatment facility. Both culture and molecular-based methods were used to demonstrate removal in this case and pilot challenge testing was employed to address the shortcomings of full-scale monitoring and to address additional research objectives. The reduction of Cryptosporidum, Giardia, enteric viruses, pathogenic bacteria and their corresponding surrogate microorganisms (e.g. spore forming bacteria, coliphage) was quantified across the upstream wastewater treatment process and the AWT. In general, the removal of surrogate microorganisms was less than or equal that of the pathogens of interest thereby justifying their use in full-scale monitoring. Several limitations of full-scale monitoring were noted including low starting concentrations which resulted in large sample volume required to demonstrate log-reduction. Additionally, while molecular methods were sufficient to demonstrate reduction by physical treatment steps, they are unable to demonstrate inactivation. Therefore, ozone pilot testing was performed to evaluate the use of capsid integrity PCR for showing inactivation by ozonation. Additional testing was also performed to relate the LRV shown with culture methods to the LRV shown with PCR so as to create a relationship that can be used in future monitoring. While pathogen inactivation is a major concern in water reuse, these objectives must also be balanced with the formation of disinfection byproducts (DBPs) through ozonation. Given the elevated concentration of dissolved organic matter, relatively higher ozone doses are required in reuse applications when compared with water treatment applications in order to achieve the desired treatment goals (oxidation, disinfection). Pilot scale ozone testing was performed to evaluate ozone disinfection performance in unfiltered secondary effluent while balancing the formation of bromate and oxidation of trace organic contaminants (TrOCs). Two chemical bromate control methods were compared including preformed monochloramine (NH2Cl), and hydrogen peroxide (H2O2). Neither of these bromate control methods had any demonstrable impact on virus or coliform inactivation, however H2O2 eliminated measurable ozone exposure which is necessary for the inactivation of more resistant spore forming bacteria. Additionally, NH2Cl was shown to suppress *OH exposure and thus negatively impacted the oxidation of ozone resistant TrOCs, while H2O2 marginally improved TrOC oxidation. Finally, the use of H2O2 for bromate control necessitates the validation of an alternative framework for ozone process control. The existing ozone Ct framework has been shown to be prohibitively conservative especially for virus inactivation. In this study, the applied specific ozone dose (O3:TOC) and the change in UV254 absorbance were evaluated as ozone monitoring frameworks across a range of water quality characteristics. Elevated temperature and pH were shown to significantly impact ozone decay kinetics, and only marginally impact virus inactivation. Both frameworks that were evaluated were shown to be valid across all water quality conditions evaluated. Validating pathogen reduction across carbon-based reuse treatment trains is imperative in order to allow for more widespread application and regulatory confidence in the technology. Coagulation, floc/sed, ozone, and biofiltration were shown to be robust barriers for pathogen and surrogate reduction and recommended concentration and quantification methods are presented herein. The ozone challenge testing results also provide guidance to utilities using ozone for disinfection while controlling DBPs and enhancing organics oxidation in water reuse applications. / Doctor of Philosophy / Water reuse has become a necessity for many utilities across the globe as the quantity and quality of water resources has been diminished. In some locations including California, the full-advanced treatment (FAT) train is required including membrane filtration, reverse osmosis, and UV advanced oxidation. The application of carbon-based treatment has emerged as a cost-effective alternative to FAT in locations that cannot manage brine disposal. However, considering the relative novelty of this treatment technology for water reuse, the process still requires full-scale validation of treatment goals including pathogen reduction. While there are many constituents of concern in water reuse, exposure to pathogens remains the greatest acute health risk. The studies described herein examine pathogen and microbial surrogate reduction both full-scale and pilot-scale floc/sed-ozone-biofiltration advanced water treatment facility. Both culture and molecular-based methods were used to demonstrate removal in this case and pilot challenge testing was employed to address the shortcomings of full-scale monitoring and to address additional research objectives. The reduction of protozoa, viruses, bacteria and their corresponding surrogate microorganisms was quantified across the upstream wastewater treatment process and the water reuse treatment train. In general, the removal of surrogate microorganisms was less than or equal that of the pathogens of interest thereby justifying their use in full-scale monitoring. Several limitations of full-scale monitoring were noted including low starting concentrations which resulted in large sample volume required to demonstrate log-reduction. Additionally, while molecular methods were sufficient to demonstrate reduction by physical treatment steps, they are unable to demonstrate inactivation. Therefore, ozone pilot testing was performed to evaluate several methods to adapt these methods to reflect inactivation. While pathogen inactivation is a major concern in water reuse, these objectives must also be balanced with the formation of disinfection byproducts through ozonation. Given the elevated concentration of dissolved organic matter, relatively higher ozone doses are required in reuse applications when compared with water treatment applications in order to achieve the desired treatment goals (oxidation, disinfection). Pilot scale ozone testing was performed to evaluate ozone disinfection performance in wastewater effluent while balancing the formation of byproducts and oxidation of trace organic contaminants. Two chemical byproduct control methods were compared including preformed monochloramine, and hydrogen peroxide. Neither of these bromate control methods had any demonstrable impact on virus or coliform inactivation, however H2O2 eliminated measurable ozone exposure which is necessary for the inactivation of more resistant spore forming bacteria. Additionally, monochloramine was shown to suppress hydroxyl radical exposure and thus negatively impacted the oxidation of ozone resistant organic contaminants, while hydrogen peroxide marginally improved oxidation. Finally, the use of hydrogen peroxide for bromate control necessitates the validation of an alternative framework for ozone process control. The existing framework that relies on ozone exposure has been shown to be conservative especially for virus inactivation. In this study, the applied specific ozone dose and the change in UV254 absorbance were evaluated as ozone monitoring frameworks across a range of water quality characteristics. Elevated temperature and pH were shown to impact ozone decay kinetics and virus inactivation to varying degrees. Both frameworks that were evaluated were shown to be valid across all water quality conditions evaluated. Validating pathogen reduction across carbon-based reuse treatment trains is imperative in order to allow for more widespread application and regulatory confidence in the technology. Coagulation, flocculation/sedimentation, ozone, and biofiltration were shown to be robust barriers for pathogen and surrogate reduction and recommended concentration and quantification methods are presented herein. The ozone challenge testing results also provide guidance to utilities using ozone for disinfection while controlling disinfection byproducts and enhancing organics oxidation in water reuse applications.