No description available.

The efficacy of low frequency dosing, and application of the insect growth regulator pyriproxyfen, for the control of sewage filter flies, was assessed. The low dosing frequency trials targeted primarily Sylvicola fenestralis, but also the chironomids Limnophyes minimus and Metriocnemus hygropetricus. The trials of pyriproxyfen targeted Psychoda altemata. Three trials, assessing the effect of a range of dosing frequencies (20 down to 6 doses h-1), on filters with 50mm and 75mm slag media were undertaken. Retention time studies demonstrated that an increased surge or pulse of the applied sewage passed rapidly through the filter when the dosing frequency was reduced below 10, and at or below 12 doses h-1, for filters with 50mm and 75mm media, respectively. A significant (P < 0.05) increase in the wash-out of S. fenestralis egg masses, and a highly significant (P < 0.01) reduction in S.fenestralis larval numbers and adult emergence was recorded, in filters with a dosing frequency below 10, and at or below 12 doses h-1, for filters with 50mm and 75mm media. S. fenestralis populations were positively correlated (P < 0.05) with dosing frequency and retention. Surface film accumulation was not appreciably reduced, but accumulation deeper into the filters was altered. Chironomid populations were significantly (P < 0.05) increased in filters with a reduced dosing frequency. Low frequency dosing did not effect the nondipteran fauna, or the long-term BOD purification efficiency of the filters. Two trials, assessing the efficacy of pyriproxyfen were undertaken. In the first, pyriproxyfen was applied as an aqueous suspension, at a concentration of 0.5mg 1-1. Significant (P < 0.05) reductions in the emergence of P. altemata adults were achieved for 22 days. Reductions ranged from 19% to 77%. In the second trial pyriproxyfen was applied as the granular formulation, Sumilarv®, at a dose rate of 77.4 g m-2 of filter area. Significant (P < 0.05) reductions in adult emergence were achieved for 28 days. Control ranged from 35% to 92%. No adverse effects on the non-dipteran filter fauna, the purification efficiency I or the invertebrates in the river receiving the works effluent, were detected.

No description available.

No description available.

The work explains how the dynamics of the release of water vapors from flux during the Control Atmosphere Brazing influences the process conditions important for the quality of the brazed product. The process involves sequential events such as continuous ramp-up heating, flux and filler melting, reactive flow, isothermal dwell and rapid quench solidification performed under the controlled atmosphere. During this complex process effluents are released. Some effluents are detrimental for the product quality (water vapor) and some are harmful for the environment (HF). We selected to study water vapor emissions with an objective to quantify these emissions and to consider their influence on the manufacturing process. Experiments were conducted using different fluxes. Findings are presented to compare the vapors released in each case. The objective is not necessarily to develop a metric for sustainability, but to understand the kinetics of an effluent release. A simple predictive model has been devised to approximate experimental data behavior. The data from the TGA analysis obtained from other sources, and the dew point temperature history from the controlled atmosphere brazing experiments performed in course of this work, have been used for the purpose of comparison and analysis.

Le respect des normes de rejets aqueux industriels imposées par la directive cadre sur l’eau (échéances en 2021) concernant les micropolluants, et notamment les phtalates, nécessite la mise au point de procédés de traitement innovants. L’étude du procédé basé sur le couplage ozone/charbon actif a ainsi été effectuée. Après la détermination des propriétés chimiques et texturales des charbons actifs testés, l’efficacité de ce couplage pour l’élimination des phtalates a été éprouvée selon plusieurs critères : cinétique d’élimination des polluants cibles, évolution de la minéralisation et de la toxicité au cours du traitement. La comparaison des résultats obtenus avec ceux de méthodes classiques (ozonation et adsorption seules) a mis en évidence le fort potentiel du couplage ozone/charbon actif, qui permet d’obtenir une élimination rapide des polluants ainsi qu’une minéralisation et une détoxification avancées dans toutes les conditions expérimentales testées. Ce couplage c’est aussi révélé efficace lors du traitement de matrices plus complexes, telle qu’une eau de sortie de station d’épuration. En outre, cette étude a permis de déterminer les propriétés chimiques et texturales du charbon actif favorisant ce procédé. Il a aussi été montré que ce matériau joue un rôle d’initiateur et de promoteur de radicaux libres (les réactions sont très majoritairement de nature radicalaire) ainsi que de support réactionnel. Enfin, cette étude a montré qu’une régénération in situ du matériau, économiquement très intéressante, pourrait être obtenue au cours du traitement. / In order to comply with the standards governing the discharge of industrial effluents (Water Framework Directive, target date 2021) concerning micropollutants, in particular phthalates, innovative wastewater treatment processes have to be used. The present research addresses this issue through a study of ozone/activated carbon coupling. After determining the textural and chemical properties of several activated carbons, the efficiency of this coupling for the removal of phthalates was tested according to the following criteria: degradation kinetics of the target pollutants and evolution of both toxicity and mineralization during the process. Compared to the classical methods (ozonation or adsorption used separately), coupling proved to be highly efficient. It enables the fast removal of pollutants with a significant decrease in mineralization and toxicity. Coupling also proved to be efficient for the treatment of more complex matrices such as municipal wastewater treatment outflow. Moreover, the activated carbon properties which favour the process have also been determined. It is shown that, in this coupling, the material acts as a radical initiator and promoter (the reactions are mainly radical in nature) and as a reaction support. Lastly, the study also shows that in situ regeneration of the activated carbon, which would be economically attractive, could be achieved during the process.

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<p> Filtered final effluent was chlorinated at various doses using calcium and sodium hypochlorite in order to study the effect of chlorination on the soluble organics present in final effluents. The biochemical oxygen demand (BOD) was measured over a period of five days and carbon analyses (TOC) were performed during the course of the reaction. Chemical oxygen demand tests (COD) on filtered chlorinated-dechlorinated and unchlorinated sewage at various doses were also performed. It was found that chlorination did not bring about a BOD5 reduction nor rendered the soluble organics bioresistant or toxic to micro-organisms, owing to the presence of ammonia, as there was no significant difference in the extent of carbon degradation. The COD as well as TOC before and after chlorination remained unchanged indicating that there was no loss of organic content due to chlorination.</p> <p> The pure compounds, glutamic acid, alanine, histidine, glycine, ammonia, phenol, n-butylamine, acetic acid and maleic acid were chlorinated at various chlorine doses in the presence and absence of ammonia and with chloramines. Glutamic acid and phenol were chlorinated at various pH levels. The oxidation of glycine by sodium hypochlorite was also studied. It was found that pH influences the rate of reaction considerably and that the presence of ammonia, whether free or combined as chloramines, slowed down the rate and prevented the oxidation of glycine from occurring.</p> <p> The effect of chlorine residuals on the seed micro-organisms was also investigated. Three levels of residuals, 0.2, 0.5 and 0.8 mg/1 available chlorine, were employed. The chlorine demand of the sewage was satisfied prior to the addition of these residuals. The BOD was also monitored over a period of five days. The results indicated that longer lag phases resulted from the application of higher residuals and the lowest BOD was observed to occur at the highest residual. However, some microorganisms survived chlorination as evidenced by the exertion of a BOD at the 0.8 mg/1 available chlorine level.</p> <p> The seeding technique employed by previous workers for measuring the BOD5 of unfiltered chlorinated-dechlorinated sewage was also investigated. It was found that even when the unchlorinated sample was not seeded, it contained a higher microbial concentration as evidenced by plate counts performed on both chlorinated-dechlorinated seeded and unchlorinated unseeded samples at two dilutions commonly employed in BOD5 determinations. Associated with these results was a BOD4 reduction of about 2.2 mg/1/mg/1 Cl absorbed. Seeding of the samples, at best, provides a uniformly mixed microbial population but not necessarily a uniform microbial concentration. These results could possibly explain the BOD5 reductions observed on unfiltered chlorinated effluents.</p> / Thesis / Master of Engineering (MEngr)

The host microbiome (mainly bacteria) is essential for host immune function, metabolism, and digestion. Alterations in these microbes, known as dysbiosis, generally results in adverse effects to the host, including diseases. Dysbiosis can be induced from exposures to various anthropogenic contaminants including constituents of municipal wastewater treatment effluents (MWWEs), namely, pharmaceuticals, antibiotics, and excess nutrients. Despite MWWEs being one of the largest dischargers to aquatic ecosystems, impacts of these contaminants on exposed organism microbiomes, especially in aquatic insects, is unclear. In addition, some aquatic contaminants may transfer to riparian habitats through predation on emergent insects that were exposed to contaminants as larvae, and subsequently alter microbiomes of terrestrial predators. Our study evaluated whether MWWEs altered microbiomes of freshwater larval and adult insects and their riparian spider predators using effluent-associated bacteria and stable nitrogen isotopes (δ15N) to confirm effluent exposure. We analyzed microbiome compositions through sequencing of the V3-V4 hypervariable region of the 16S rRNA gene and analyzed food web dynamics with stable carbon (δ13C) and nitrogen (δ15N) isotopes. We found that insects and spiders were enriched in δ15N at one site downstream of wastewater outfalls, indicating exposure to effluents and transfer of nutrients to terrestrial ecosystems. Microbiomes of most larval and adult insects were altered downstream of wastewater outfalls and had lower relative abundances of endosymbiont bacteria, shifts in bacterial diversities, increases in abundances of effluent-associated bacteria, and downregulation of some biosynthesis pathways than those collected at upstream sites. However, spider microbiomes had little evidence of dysbiosis, and were distinct from those of adult insects, despite a close association in their isotopic signatures. Overall, this study provides evidence of biological impacts from MWWEs to exposed insects and suggests that changes in microbial communities of invertebrates may be used as an effective indicator of effluent exposure as part of monitoring frameworks. / Thesis / Master of Science (MSc) / Municipal wastewater treatment facilities release contaminants into aquatic ecosystems that may affect the health of exposed organisms, including their microbiome, which contains bacteria essential for host digestion and immune function. Alterations in microbiomes of contaminant-exposed aquatic insects are poorly characterized and such effects may be transferred to terrestrial ecosystems through emergent insects. This study evaluated microbiomes and food web dynamics of freshwater insects and riparian spiders upstream and downstream of wastewater treatment facilities in the Bow River, AB. Results indicate that microbiomes of some downstream aquatic insects had lower relative abundances of endosymbiont bacteria, shifts in bacterial diversities, and increases in abundances of effluent-associated bacteria than those collected at upstream sites, but no such changes were observed in the spider predators. This study improves our understanding of how freshwater insect microbiomes are altered by municipal wastewater effluents and suggests that directly effluent-exposed organisms are more at risk of dysbiosis.