In response to water supply depletion challenges, countries such as Australia, the United States, and Namibia have implemented technologies that treat wastewater up to the standards permissible to use for irrigation, toilet flushing, and even drinking water. However, many of these countries have been unable to successfully implement some of their ambitious reclaimed water reuse projects due to negative public perceptions of recycling wastewater. The focus of this study was to understand which factors in risk perception theory are the most influential in shaping community perceptions of reclaimed water reuse as a future source of drinking water within Hillsborough County. The research design was comprised of a mixed methodology approach (quantitative and qualitative analyses). The methods for assessing how each of the five main factors played a role in shaping risk perception in each of the communities was comprised of three main analyses, including spatial, statistical (through multiple regression modelling in R), and personal interview data (an HOA leader, one key informant, and a focus group). Residents (n=417) from various neighborhoods were interviewed through surveys which will evaluate factors found in literature that have been shown to have the most effect in shaping risk perception theory.

The objective of this thesis is to provide a detailed investigation of phosphorus transformations in constructed wetlands. Five replicate Wetland Units were constructed adjacent the wastewater treatment plant in Richmond, Australia. Each wetland was supplied with secondary or tertiary sewage effluent and planted identically with species of schoenoplectus, Phragmites, and Triglochin. Detention times for each Unit were established at 5 or 15 days. Phosphorus concentrations were monitored routinely at the inlet and outlet of each Unit, with a number of specific studies conducted to investigate internal transformations. These studies, undertaken in 1994 and 1995, determined that plants were the dominant phosphorus store in the short term, during wetland establishment and that sediments were the dominant long-term phosphorus storage compartment. Laboratory investigations indicated that there was no significant role for bacteria or algae in the water column relating to phosphorus sequestering, although microorganisms appeared to have some role in the translocation of phosphorus to soil binding sites. After phosphorus contacted the soil surface, transpiration related entrainment of surface water and direct phosphorus uptake by plants were the dominant mechanisms for causing phosphorus to move deeper through the soil substrate. Removal of phosphorus from the interstitial water was by incorporation to biomass or direct sorption to soil binding sites / Doctor of Philosophy (PhD)

The most cost effective treatment scheme for effluent from Midfield Meats, an abattoir in Warrnambool, Australia, was evaluated via a series of laboratory and commercial scale experiments. Effectiveness was measured in terms of suspended solids (SS) and biological oxygen demand (BOD) reduction. Economic assessment was based on predicted reduction in trade waste charges versus infrastructure and running costs. From the range of potential treatment technologies, those deemed most appropriate for trialling included pre-screening, sedimentation, coagulation and flocculation treatment and dissolved air floatation (DAF). Prior to evaluation of treatment types, flow, loads and contaminant characterisation of the waste streams was conducted to aid in selection of treatment type and capacity. Prescreening was found to be the most cost effective, followed by sedimentation, coagulation and flocculation treatment and finally DAF. The most economical treatment scheme that satisfied the requirements of Midfield Meats included a combination of prescreening and sedimentation. DAF and coagulation and flocculation treatment satisfactorily treated the wastewater, however were not cost effective under the current trade waste agreement.

The primary objective of this study was to evaluate the rates of nitrate removal for a nitrate containing, low organic carbon wastewater interacting with four different carbon-containing solid substrates (alder woodchips, corn silage, manure and woodchip biochar). Batch systems were tested for nitrate removal, and systems with a combination of three carbon substrates (75% woodchips, 12.5% silage, and 12.5% manure or woodchip biochar by mass) produced average nitrate removal rates of 571 and 275 mg-N L⁻¹ D⁻¹, and systems containing the carbon substrates individually produced rates between 11.4 - 3.3 mg-N L⁻¹ D⁻¹. Silage proved to be the dominant carbon substrate providing high quantities of organic carbon to fuel denitrification. With the introduction of semi-continuous flow, all systems had nitrate removal rates that converged to 13.3 – 6.4 mg-N L⁻¹ D⁻¹, which is approximately two orders of magnitude smaller than the rates of the mixture systems in the batch experiment. Silage appeared to be removed from of the systems with liquid exchange potentially causing the rate decreases. Columns filled with various volume fractions of woodchips (100%, 25%, 12.5%, and 0%) produced nitrate removal rates between 30.8 – 2.4 mg-N L⁻¹ D⁻¹ at a 24 hour and 12 hour hydraulic residence time (HRT). Greater nitrate removal was achieved with higher HRTs and larger fractions of woodchips (the 100% woodchip system at a 24 hour HRT produced the fastest nitrate removal rate of 30.8 mg-N L⁻¹ D⁻¹). When rates were normalized to the amount of woodchips in each column, higher efficiency was found in lower woodchip fraction systems (the 12.5% woodchip column produced the highest normalized nitrate removal rate of 56 mg-N L⁻¹ D⁻¹ L[subscript woodchips]⁻¹). Woodchips proved to be best suited as a long term carbon substrate for nitrate removal in a system containing a nitrate concentrated, low organic carbon wastewater. However, large amounts of woodchips were necessary to achieve nitrate removal greater than 50%. A 41 acre hypothetical wetland with a 3.3 day HRT and a nitrate influent concentration of 45 mg-N L⁻¹ would require 30,000 yd³ of woodchips to achieve 68% nitrate removal based on the values obtained in the bench scale column experiment. / Graduation date: 2012

Phosphorus (P) is a pollutant in freshwater systems because it promotes eutrophication. The dairies in the North Bosque and its water body segments import more P than they export. Dairies accumulate P-rich effluent in lagoons and use the wastewater for irrigation. As more P is applied as irrigation than is removed by crops, P accumulates in the soil. During intense rainfall events, P enters the river with stormwater runoff and can become bio-available. Reducing the P applied to the land would limit P build up in the soil and reduce the potential for P pollution. Since wastewater P is associated with suspended solids (SS), the flocculants, poly-DADMAC and PAM, were used to reduce SS. To precipitate soluble P from the effluent, NH4OH was added to raise the pH. Raw effluent was collected from a dairy in Comanche County, TX, and stored in 190-L barrels in a laboratory at Texas A&M University. Flocculant additions reduced effluent P content by as much as 66%. Addition of NH4OH to the flocculated effluent raised the pH from near 8 to near 9, inducing P precipitation, further reducing the P content. The total P reduction for the best combination of treatments was 97%, a decrease from 76 to 2 mg L-1. If this level of reduction were achieved in dairy operations, P pollution from effluent application would gradually disappear.

The purposes of this study are¡G(1) comparing the treatment efficiency with advanced and traditional drinking water treatment plants in southern Taiwan¡F(2) assessing the treatment efficiency and formation of disinfection by-products in advanced water treatment processes¡F(3) assessing the feasibility of wastewater recycling and treatment efficiency of wastewater treatment units¡F(4) evaluating corrosion of drinking water transportation pipelines and reproducing of chlorination by-products. This study found that the removal efficiency of turbidity, iron, manganese, coliform group and total bacterial count were approximately 99% by advanced and traditional purification processes. The concentrations of ammonia-N (NH3-N), nitrite nitrogen and nitrate nitrogen were lower drinking water quality standard. Pellet softening process was designed following coagulation/sedimentation unit to increase 8~14% and 6~20% removal efficiency of alkalinity and total hardness (TH) concentrations. The removal efficiency of total dissolved solids (TDS) was approximately 3~15% by advanced water treatment processes better than traditional water treatment processes. In the formation of disinfection by-products (DBPs), the trihalomethanes (THMS) and haloacetic acid (HAA5) were efficiently decreased by advanced purification processes. Bromate concentrations which lower detection limit were treated by ozonation process during the study periods. Advanced treatment processes should control the dosage of ozone and post-chlorine to avoid production of DBPs. In wastewater reuse, the treatment efficiency of suspended solids (SS) was 48¡ã99%, respectively, showing the significant removal efficiency of the wastewater process. However, the removal efficiencies of NH3-N, total organic carbon (TOC) and chemical oxygen demand (COD) are limited by wastewater treatment processes. Because NH3-N, TOC and COD of the mixing supernatant and raw water are regulated raw water quality standards, supernatant reuse is feasible and workable during wastewater processes at this plant. Overall, analytical results indicated that supernatant reuse is feasible. The Chengcing Lake water treatment plant significantly reduced alkalinity, Ca2+ concentration and TH concentration via pellet softening treatment: however, reducing the Langelier saturation index (LSI) value of water could cause some adverse effects on distribution systems. Operational conditions by Pingding water treatment plant was added base to water can be tried to adjust pH to maintain a slightly positive LSI value, whereas for water with low hardness and alkalinity.

<p>Current global water scarcity and the spectre of a future critical shortage are driving the need for novel and energy saving water technology approaches. Desalination of seawater and the reuse of treated wastewater effluent, which have historically been viewed as undesirable water sources, are increasingly being explored as sources for reducing water consumption. Although the dominant technologies for taking these water sources to potable quality, energy consumption still makes them unsustainable for widespread application. Membrane distillation (MD) is an innovative water purification method that has shown promise as a technology that can address several of these issues. MD is a membrane process that produces very high quality product water. However, similarly to other thermal desalting processes, MD utilizes heat as the dominant source of energy rather than pressure, and can potentially be used to produce water at higher recoveries (and therefore less waste) than is feasible with existing approaches. Another important advantage of MD is that the water separation occurs at modest temperatures (<90oC), opening the door for the utilization of currently usable waste heat sources. Despite these advantages, MD is primarily a lab scale technology, and key questions concerning process performance, including flux magnitude, energy efficiency, fouling propensity, membrane performance, and long-term system performance must be addressed to fully vet this technology. </p><p>This work is represents an attempt to provide insight into several of these issues. The overarching approach taken throughout this project is the parallel evaluation of ceramic membranes alongside commonly used polymeric (PTFE) membranes. The combined factors of MD being a relatively nascent technology and the fundamental separation mechanism point toward initial real-world applications of MD for the treatment of high concentration water that may necessitate membranes exposure to harsher thermal and chemical environments. The robust and inert nature of ceramics make them ideal candidates for such application, although their hydrophilic surface do allow for direct implementation in MD. The first phase of this work details the evaluation of several candidate surface treatments for modifying ceramic membranes and shows that aluminum oxide ceramic membranes can be successfully modified with perfluorodecyltriethoxysilane to possess the necessary hydrophobicity for MD application. The effectiveness of the surface treatment in modifying the membrane surface chemistry was assessed using a multitude of analytical approaches, which showed that the modified ceramic surface attained high hydrophobicity and thus are suitable for application of the membranes in direct contact membrane distillation (DCMD).</p><p>The next phase of research details the development and verification of a model for DCMD performance. The relative membrane performance was compared, with the polymeric membrane consistently outperforming the modified ceramics, which was attributed to a combination of superior thermal and physical membrane characteristics. Beyond attempting to evaluate the performance differences, this model allows the consideration of various operational scenarios, focusing on membrane flux and energy performance as various membrane and operational parameters change to determine conditions that maximize MD performance as well as provide insight critical to develop MD-specific membranes. </p><p>Finally, membrane performance was evaluated during the treatment water containing various organic foulants as well for the treatment of municipal wastewater. The results showed that the level of fouling was highly dependent on foulant type, with alginate identified as a component that produces severe fouling under all conditions evaluated, and wastewater fouling being relatively minimal. Membrane cleaning solutions were implemented to show that near-complete flux recovery was attainable, and plain deionized water was shown to be as effective as sodium hypochlorite.</p> / Dissertation

The ubiquitous nature of antibiotic resistance and antibiotic resistance genes (ARGs) among environmental pathogens from a variety of wastewater effluents, suggests that the aquatic environment, and specifically alternative wastewater treatment systems, may act as reservoirs for drug resistant bacteria and ARGs, thereby contributing to the widespread dissemination of antibiotic resistance. More research is necessary to contribute to our understanding of the occurrence, fate, and mobility of antibiotic resistance and ARGs among bacterial indicators of faecal contamination as well as pathogenic bacteria within Canadian wastewater treatment systems. The primary objective of this research was to determine the prevalence, fate, and potential transfer of bacterial resistance and ARGs among selected environmental pathogens exposed to alternative wastewater treatment systems, while considering the impact of treatment strategies on the expression of antibiotic resistance. A detailed analysis was initially conducted with respect to the characterization and quantification of microbial populations (including antibiotic resistant bacteria) in a variety of treatment systems and waste effluent sources. Traditional culture-based screening techniques in combination with molecular characterization (through colony or multiplex PCR), and molecular quantification using real-time quantitative PCR were utilized in order to help establish a preliminary environmental assessment of selected pathogens (Escherichia coli, Enterococcus spp., Salmonella spp.) and ARGs (tetA, blaSHV, & ampC) within a variety of wastewater treatment systems (lab-scale mesocosms, constructed wetland, constructed lagoon system, and pilot-scale biological nutrient removal (BNR) system). Overall, the level of multiple antibiotic resistance (MAR) among culturable indicator (E. coli & Enterococcus spp.) and environmental bacteria was high (reaching 100% in several instances) within different types of wastewater treatment systems and effluent sources (poultry waste effluent, municipal wastewater, aquaculture wastewater). Common antibiotic resistance profiles among E. coli isolates included simultaneous resistance to between three and five antimicrobials, whereas common MAR profiles among Enterococcus spp. isolates showed resistance to ten or more antibiotics. Real time quantitative PCR was used to determine the concentration of three bacterial pathogens; E. coli, Enterococcus faecalis, and Salmonella spp., and three ARGs; tetA, ampC, and blaSHV, within a variety of wastewater samples. Based on the results, it was concluded that high concentrations of ARGs were present in the treated effluent (10⁴- 10⁶ target gene copies/100 mL), regardless of system type (i.e. constructed lagoon, pilot-scale BNR, or constructed wetland), which may ultimately serve as a potential route for entry of ARGs and antibiotic resistant bacteria into the natural environment. Water is considered an important medium for transfer of resistance genes and resistant bacteria to the broader environment. Few studies have examined the transferability via conjugation of ARGs in E. coli and Salmonella spp. isolated from wastewater. Identification of three resistance determinants (tetA, strA, strB) conferring resistance to tetracycline and streptomycin was performed on selected multi-drug resistant Salmonella spp. and E. coli isolates. The potential for transfer of tetracycline and streptomycin resistance genes was demonstrated through broth conjugation experiments using multi-drug resistant Salmonella spp. and E. coli isolates as donors, and E. coli K12 as the recipient. Conjugation was successfully observed in 75% (9/12) of donor isolates, occurring in both Salmonella spp. and E. coli isolates. Six strains (50%) were capable of transferring their tetA, strA, and strB genes to the recipient strain, resulting in 58.5% (38/65) of total transconjugant strains acquiring all three resistance determinants. The results confirm the role of environmental bacteria (isolated from wastewater treatment utilities) as a reservoir of antibiotic resistance and ARGs, containing mobile genetic elements, which are capable of disseminating and transferring ARGs. As concerns about water quality and environmental contamination by human and agricultural effluents have increased, it has become increasingly more important to consider the prevalence and transferability of ARGs to opportunistic and human pathogens. As observed in this research, the ubiquitous nature of multi-drug resistant bacteria in water and wastewater effluents, the presence of diverse ARGs of human and veterinary health significance, as well as the transfer of resistance determinants through conjugative plasmids to recipient bacteria, suggests that environmental exposure through contact or consumption with contaminated water is probable. However, a lack of critical information still exists regarding the movement of resistance genes within and between microbial populations in the environment. In addition, the extent of human exposure to ARGs and antibiotic resistant bacteria is still not well understood, and future studies on human exposure to these resistant contaminants are necessary.

Increased development in Canadas northern environments has increased the need for accurate methods to detect adverse impacts on tundra ecosystems. Ammonium nitrate is a common water pollutant associated with many industrial and municipal activities, including diamond mining, and is of special concern due to the toxicity of ammonia in aquatic systems. One solution to reduce exposure of sensitive aquatic systems to nitrogenous compounds is to atomize (atmospherically disperse in fine particles) contaminated water over the arctic tundra which will reduce N loading to surface water. However, the toxicity of ammonium nitrate to arctic soils is poorly understood. In this study I investigate the potential toxicity of ammonium nitrate solutions to arctic soil functions such as carbon mineralization, nitrification and plant growth, to determine concentrations that can be applied without causing significant inhibition to these processes. <p>Arctic ecosystems are based on a soil type termed a cryosol that has an underlying permafrost layer. Often these soils are subject to cryoturbation, a process which heaves and mixes the soil, bringing the mineral horizons to the surface. I hypothesized that phytotoxicity test results in arctic soils would be highly variable compared to other terrestrial ecosystems due to the cryoturbation process and subsequent range of soil characteristics. The variability associated with phytotoxicity tests was evaluated using Environment Canadas standardized plant toxicity test in three cryoturbated soils from Canadas arctic exposed to a reference toxicant, boric acid. The phytotoxicity of boric acid to northern wheatgrass (<i>Elymus lanceolatus </i>) in cryosols was much greater than commonly reported in other soils, with less than 150 ug boric acid g-1 soil needed to inhibit root and shoot growth by 20%. There was also large variability in the phytotoxicity test results, with coefficients of variation for 10 samples ranging from 160 to 79%. Due to this variability in cryoturbated arctic soils, more than 30 samples should be collected from each control and potentially impacted area to accurately assess contaminant effects, and ensure that false negatives of toxicant impacts in arctic soils are minimized. <p>To characterize the toxicity of ammonium nitrate I exposed a variety of arctic soils and a temperate soil to different concentrations of ammonium nitrate solution over a 90 day time period. Dose responses of carbon mineralization, nitrification and phytotoxicity test parameters were estimated for ammonium nitrate applications. In addition to direct toxicity, the effect of ammonium nitrate on ecosystem resistance was investigated by dosing nitrogen impacted soils with boric acid. Ammonium nitrate solutions had no effect on carbon mineralization activity, and affected nitrification rates in only one soil, a polar desert soil from Cornwallis Island. In contrast, ammonium nitrate applications (43 mmol N L-1 soil water) significantly impaired seedling emergence, root length and shoot length of northern wheatgrass. Concentrations of ammonium nitrate in soil water that inhibited plant parameters by 20% varied between 43 to 280 mmol N L-1 soil water, which corresponds with 2,100 to 15,801 mg L-1 in the application water. Arctic soils were more resistant to ammonium nitrate toxicity than the temperate soil under these study conditions. However, it is not clear if this represents a general trend for all polar soils, and because nitrogen is an essential macro-nutrient, nitrogenous toxicity should likely be considered a special case for soil toxicity. As soil concentrations could be maintained under inhibitory levels with continual application of low concentrations of ammonium nitrate over the growing season, atomization of wastewater contaminated with ammonium nitrate is a promising technology for mitigation of nitrogen pollution in polar environments. <p>Increased development in Canadas northern environments has increased the need for accurate methods to detect adverse impacts on tundra ecosystems. Ammonium nitrate is a common water pollutant associated with many industrial and municipal activities, including diamond mining, and is of special concern due to the toxicity of ammonia in aquatic systems. One solution to reduce exposure of sensitive aquatic systems to nitrogenous compounds is to atomize (atmospherically disperse in fine particles) contaminated water over the arctic tundra which will reduce N loading to surface water. However, the toxicity of ammonium nitrate to arctic soils is poorly understood. In this study I investigate the potential toxicity of ammonium nitrate solutions to arctic soil functions such as carbon mineralization, nitrification and plant growth, to determine concentrations that can be applied without causing significant inhibition to these processes. <p>Arctic ecosystems are based on a soil type termed a cryosol that has an underlying permafrost layer. Often these soils are subject to cryoturbation, a process which heaves and mixes the soil, bringing the mineral horizons to the surface. I hypothesized that phytotoxicity test results in arctic soils would be highly variable compared to other terrestrial ecosystems due to the cryoturbation process and subsequent range of soil characteristics. The variability associated with phytotoxicity tests was evaluated using Environment Canadas standardized plant toxicity test in three cryoturbated soils from Canadas arctic exposed to a reference toxicant, boric acid. The phytotoxicity of boric acid to northern wheatgrass (<i>Elymus lanceolatus </i>) in cryosols was much greater than commonly reported in other soils, with less than 150 ug boric acid g-1 soil needed to inhibit root and shoot growth by 20%. There was also large variability in the phytotoxicity test results, with coefficients of variation for 10 samples ranging from 160 to 79%. Due to this variability in cryoturbated arctic soils, more than 30 samples should be collected from each control and potentially impacted area to accurately assess contaminant effects, and ensure that false negatives of toxicant impacts in arctic soils are minimized. <p>To characterize the toxicity of ammonium nitrate I exposed a variety of arctic soils and a temperate soil to different concentrations of ammonium nitrate solution over a 90 day time period. Dose responses of carbon mineralization, nitrification and phytotoxicity test parameters were estimated for ammonium nitrate applications. In addition to direct toxicity, the effect of ammonium nitrate on ecosystem resistance was investigated by dosing nitrogen impacted soils with boric acid. Ammonium nitrate solutions had no effect on carbon mineralization activity, and affected nitrification rates in only one soil, a polar desert soil from Cornwallis Island. In contrast, ammonium nitrate applications (43 mmol N L-1 soil water) significantly impaired seedling emergence, root length and shoot length of northern wheatgrass. Concentrations of ammonium nitrate in soil water that inhibited plant parameters by 20% varied between 43 to 280 mmol N L-1 soil water, which corresponds with 2,100 to 15,801 mg L-1 in the application water. Arctic soils were more resistant to ammonium nitrate toxicity than the temperate soil under these study conditions. However, it is not clear if this represents a general trend for all polar soils, and because nitrogen is an essential macro-nutrient, nitrogenous toxicity should likely be considered a special case for soil toxicity. As soil concentrations could be maintained under inhibitory levels with continual application of low concentrations of ammonium nitrate over the growing season, atomization of wastewater contaminated with ammonium nitrate is a promising technology for mitigation of nitrogen pollution in polar environments.

Treatment of industrial wastewaters contaminated with toxic and hazardous organics can be a costly process. In the case of acrylonitrile production, due to highly volatile and toxic nature of the contaminant organics, production wastewaters are currently disposed by deepwell injection without treatment. Under the terms granting deepwell injection of the waste, alternative treatments must be investigated, and an effective treatment identified. Cells of two Gram-positive bacteria, Rhodococcus sp. DAP 96253 and R. rhodochrous DAP 96622 were evaluated for their potential as biocatalysts for detoxification of acrylonitrile production wastewaters. Rhodococcus sp. DAP 96253 and R. rhodochrous DAP 96622 when multiply induced, are capable of utilizing the hazardous nitrile and amide components present in the wastewater as sole carbon and/or nitrogen sources, employing a 2-step enzymatic system involving nitrile hydratase (NHase) and amidase enzymes. There is a significant potential for overproduction of NHase upon multiple induction. However, high-level multiple induction required the presence of highly toxic nitriles and/or amides in the growth medium. Asparagine and glutamine were identified as potent inducers with overexpression at 40% of total soluble cellular protein as NHase. In native form (either cell free enzymes or whole cells) the desired NHase is very labile. In order to develop a practical catalyst to detoxify acrylonitrile production wastewaters, it is necessary to significantly improve and enhance the stability of NHase. Stabilization of desired NHase activity was achieved over a broad range of thermal and pH conditions using simultaneous immobilization and chemical stabilization. Previously where 100% of NHase activity was lost in 24 hours in the non-stabilized cells, retention of 20% of initial activity was retained over 260 days when maintained at 50-55 C, and for over 570 days for selected catalyst formulations maintained at proposed temperature of the biodetoxification process. In addition, NHase and amidase enzymes from Rhodococcus sp. DAP 96253 were purified. Cell free NHase was characterized for its substrate range and effect of common enzyme inhibitors and was compared to available information for NHase from other organisms. As a result of this research a practical alternative to the deepwell injection of acrylonitrile production wastewaters is closer to reality.