Since their discovery in 1973, rotaviruses have been reported to be responsible for waterborne outbreaks of gastroenteritis. The simian rotavirus (SA11) was used as a model for the human strains during the development of the method for concentration of rotaviruses from drinking and naturally occurring waters. The microporous filter method developed was capable of recovering an average of 49% of the input virus from 20 liters of tap water and an average of 31% from 378 liters. Of the various eluents evaluated, a mixture of 10% tryptose phosphate broth and 3% beef extract (pH 10.0) was found to give the greatest efficiency of elution. The 1MDS filters were found to be superior to the 50S for the concentration of SA11. The method developed was successfully used to concentrate viruses from environmental waters. Indigenous viruses were isolated from waters in Bolivia and Colombia. Several treatment plants as well as raw surface and groundwaters were sampled for the presence of entero— and rotaviruses. Rotaviruses were isolated from one sample which had undergone complete treatment and met all current standards for potability. This study indicated that enteric viruses can be found in drinking waters considered safe due to the absence of indicator bacteria. Prior to this study there were no reports of the occurrence of enteric viruses in water in Colombia or Bolivia. The results of this study also indicate the need for some type of virus monitoring of waters which are contaminated with sewage in order to evaluate the impact of these viruses on the population.

Revised; Originally Published: 2006 / 2 pp.

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Reverse Osmosis membranes have been successfully proven to remove almost 99% of chemicals dissolved in seawater. However, removal of certain trace elements, such as boron is challenging and relatively low for seawater reverse osmosis desalination plants compared to thermal desalination plants. Boron is naturally occurring and is present in seawater at an average concentration of 4.5-5 mg/L. While boron is a vital element, its toxicity has been proven on crops, animals and possibly humans. Additionally, boron should be removed to comply with the current guideline value of 0.5 mg/L, for drinking water, issued by the World Health Organization (WHO), which is barely attained by a single-pass process seawater reverse osmosis plant. Currently, multipass reverse osmosis membrane operations with pH modifications are the only valid method for boron removal. However, this is not economically efficient as it requires higher energy and chemicals consumptions. The objective of this study was to investigate boron removal by commercial TFC RO membranes in addition to custom-made KAUST-synthesized TFC membrane. Five membrane samples were examined: Toray, Sepro, Koch, and KAUST in-house synthesized membrane. Three different feed pH conditions were used: pH6, pH8, and pH10. Filtration experiments were conducted in two parts. In experiment 1, all five membranes were examined for boron rejection in a dead-end permeation system, whereas in experiment 2 the two membranes with the highest boron rejection from experiment 1 were tested in a cross-flow system. Permeate and feed samples were taken continuously and analyzed for boron concentration, rejection calculation. Membrane surfaces were characterized according to hydrophilicity, roughness and surface charge. The results showed for all the tested membranes that boron rejection increased as the feed pH increased. KAUST, defect-free TFC, showed the highest performance for boron rejection for all pH conditions, although, it shows the roughest surface. Toray membranes 80LB and 80B exhibited the second highest boron rejection and had the most negatively charged membrane surfaces. It was observed in this study that the rejection of boron by a membrane is due to size exclusion and charge repulsion mechanisms. It was concluded that, the KAUST, defect free TFC has the potential to be applicable for boron rejection in industrial application as it has better boron rejection than commercially available RO membranes.

Compared to conventional nitrification and denitrification, anaerobic ammonium oxidation (anammox) is a more energy saving and cost effective process for biological nitrogen removal (BNR). To date, the anammox process has been applied widely and designed mainly to treat sidestream wastewaters. However, only 15%-20% of the influent domestic sewage nitrogen loading is present in the sidestream, while the bulk of it still needs to be removed from the mainstream. Research efforts thus have shifted from sidestream to mainstream applications of anammox, including the application of anammox bioreactors at low temperature, low influent ammonium strength, and under the presence of organic carbon (characteristic of municipal mainstream wastewaters). In this dissertation research, the applicability of anammox process in lab-scale and full-scale mainstream systems have been studied. The overall goals of this dissertation research were (1) to develop an effective strategy to enrich an anammox moving bed biofilm reactor (MBBR) under low influent nitrogenous substrate concentration and ambient temperature (23 Cº), and link microbial ecology to the process performance of the enriched anammox MBBR; (2) to explore the catabolism and anabolism of anammox bacteria in a mainstream MBBR before and after dosing of organic carbon; (3) to extend the strategy of mainstream anammox enrichment under ambient temperature (23 Cº) to low temperature (15 Cº) , and link microbial ecology to the process performance; (4) to evaluate the microbial community structure, kinetics and performance during startup and long-term operation of a full-scale mainstream anammox process; (5) to investigate the reliability of the new enriched mainstream anammox MBBR under the imposition of additional wet weather flow; (6) to develop a reliable and sensitive mothed of hydrazine determination in anammox reactor. First, an anammox MBBR was successfully enriched under low nitrogenous substrate and ambient temperature. It needs to be addressed that, even with the limited fraction of Candidatus “Kuenenia stuttgartiensis” in the coming inoculum from the sidestream MBBR, Candidatus “Kuenenia stuttgartiensis” was effectively enriched in the biofilm biomass of the mainstream MBBR. Moreover, the enhanced activity of Candidatus “Kuenenia stuttgartiensis” was demonstrated through this whole time series experiments, and achieved the most competitive level among all functional groups. Therefore, the importance and necessity of bioaugmentation are addressed during the enrichment of mainstream anammox process. Second, successful enrichment of a mainstream anammox moving bed biofilm reactor was accomplished at low nitrogenous substrate and low temperature. 16S amplicon sequencing was employed to investigate the microbial ecology of the biomass in the biofilm and suspension. Results showed the dominance of Candidatus "Kuenenia" related anammox bacteria in the biofilm of mainstream reactor, though Nitrospira spp. related nitrite oxidizing bacteria were still detected in a limited fraction. These results are crucial to show the effective enrichment of anammox reactor by bioaugmentation even under low temperature, especially in a practical way. Third, the performance, kinetics and microbial ecology were studied before, during and after the imposition of additional organic carbon. The dosing of organic carbon resulted in a reversible negative impact on both the activity of AMX and the reactor performance. Stable isotope probe and 16S amplicon sequencing were applied to investigate the metabolism of functional groups. The results showed anammox bacteria are not capable of assimilating acetate, while the community assimilating 13C-labeled acetate was mainly assigned to denitrifiers. Presence of denitrifiers were observed in the mainstream MBBR and stayed inactive without sufficient organic carbon. In sum, these results demonstrate that the mainstream anammox process as tested was resilient to a short period imposition of organic carbon. Fourth, the performance and microbial ecology of the ambient-temperature mainstream anammox were investigated under wet weather condition. Based on the full recovery of reactor performance as well as the stable microbial ecology, the applicability of the mainstream MBBR under wet weather conditions was demonstrated. Fifth, real-time polymerase chain reaction was applied to evaluate the startup and operation of two parallel sidestream DEMONTM systems as well as the initiation of the mainstream anammox process through bioaugmentation. Results provided the evidence that anammox bacteria was the most abundant functional group in two parallel DEMONTM systems, showing the successful startup in the sidestream. Furthermore, anammox bacteria were selectively retained in the mainstream with high bioaugmentation rates from the sidestream. These results are critical to demonstrate the significance of bioaugmentation in the startup of mainstream anammox system even in full-scale wastewater water treatment plant. Finally, a sensitive and reliable spectrophotometric method was proposed to measure hydrazine concentration in anammox reactor. The concentration of hydrazine could be precisely determined in the presence of nitrite, when a certain amount of sulfamic acid is introduced. In sum, the application and characterization of anaerobic ammonium oxidation (anammox) process to treat sidestream and mainstream wastewaters in both lab-scale and full-scale was investigated in detail. From a practical perspective, the knowledge gained can lead to a better design and operation of engineered nitrogen removal process.

The phosphorus removal characteristics of several gravel-based constructed wetland systems (CWSs) in the treatment of secondary sewage effluent was studied.Investigations were conducted on water quality parameters (redox potential, pH, dissolved oxygen and temperature) which affect phosphorus adsorption to substrata.Laboratory phosphorus adsorption experiments on Richmond CWS gravel substrata, a gravel used in Griffith CWS trials and a locally available soil, Hawkesbury sandstone, involved ion-exchange experiments and calculation of Langmuir and Freundlich adsorption isotherms and column adsorption/desorption trials.Six steelworks by-products were investigated in laboratory studies, to determine their potential for use as phosphorus adsorbers in a CWS: granulated blast furnace slag(GBF), blast furnace slag(BF), steel slag(SS), fly ash(FA), bottom ash(BA) and coal wash(CW).The ability to adsorb phosphorus was then correlated to the chemical attributes of each substratum.Of the six steelworks by-products screened in laboratory-based studies as substrata for P removal in a CWS, BF and SS slags showed the most potential due to their high phosphorus adsorption capacity and useable matrix size.Further research is recommended to evaluate the sustainability of using slags for P removal (as well as other contaminants present in wastewater), using full scale CWSs, which should include an evaluation of any likely environmental impacts using leachability and toxicity studies. / Doctor of Philosophy (PhD)(Environmental Science)

The membrane bioreactor (MBR) is becoming increasingly popular for wastewater treatment, mainly due to its capability of producing high quality effluent with a relatively small footprint. However, high plant maintenance and operating costs due to membrane fouling limit the wide spread application of MBRs. Membrane fouling generally depends on the interactions between the membrane and, the activated sludge mixed liquor, which in turn, are affected by the chosen operating conditions. The present research study aimed to explore the process performance and membrane fouling in the membrane enhanced biological phosphorus removal (MEBPR) process under different operating conditions by, (1) comparing two MEBPRs operated in parallel, one with constant inflow and another with a variable inflow, and by, (2) operating the MEBPRs with different solids retention times (SRT). On-line filtration experiments were conducted simultaneously in both MEBPR systems by using test membrane modules. From the transmembrane pressure (TMP) data of the test membrane modules, it was revealed that fouling propensities of the MEBPR mixed liquors were similar in both parallel reactors under the operating conditions applied, although the fouling propensity of the aerobic mixed liquors of both reactors increased when the SRT of the reactors was reduced. Routinely monitored reactor performance data suggest that an MEBPR process with a varying inflow (dynamic operating condition) performs similarly to an MEBPR process with steady operating conditions at SRTs of 10 days and 20 days. Mixed liquor characterization tests were conducted, including critical flux, capillary suction time (CST), time to filter (TTF) and, bound and soluble extracellular polymeric substances (EPS) were quantified, to evaluate their role on membrane fouling. The tests results suggest that the inflow variation in an MEBPR process did not make a significant difference in any of the measured parameters. With decreased SRT, an increase in the concentrations of EPS was observed, especially the bound protein, and the bound and soluble humic-like substances. This suggests that these components of activated sludge mixed liquors may be related to membrane fouling. No clear relationship was observed between membrane fouling and other measured parameters, including critical flux, normalized CST and normalized TTF.

Due to the age and operating experience of Bruce Power units, equipment ageing and obsolescence has become one of the main challenges that need to be resolved for all systems, structures and components in order to ensure a safe and reliable production of energy. The research objectives of this thesis will focus on methodology for modernization of Start- Up Instrumentation (SUI), both in-core and Control Room equipment, using a new generation of detectors and cables in order to manage obsolescence. The main objective of this thesis is to develop a new systematic approach to SUI installation/replacement procedure development and optimization. Although some additional features, such as real-time data monitoring and storage/archiving solutions for SUI systems are also examined to take full advantage of today’s digital technology, the objective of this thesis does not include detailed parametrical studies of detector or system performance. Instead, a number of technological, operational and maintenance issues associated with Start-Up Instrumentation systems at Bruce Power will be identified in this project and a structured approach to developing a replacement/installation procedure that can be standardized and used across all of the domestic CANDU stations is proposed. Finally, benefits of Hierarchical Control Chart (HCC) methodology for all stages of plant life management, such as system design, development, operation and maintenance are demonstrated. Keywords: Task Breakdown and Analysis methodology, installation/removal procedure development and optimization, risk-based analysis and optimization, Hierarchical Control Chart (HCC) methodology for system maintenance and troubleshooting, Start-Up Instrumentation (SUI), Ion Chambers, Fission Chambers, proportional counters, Shutdown System 1 (SDS1), Shutdown System 2 (SDS2). / UOIT