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.

Made available in DSpace on 2014-10-09T12:36:40Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:59:09Z (GMT). No. of bitstreams: 1 04230.pdf: 1353263 bytes, checksum: ba0b1a87d30ef196c0398dd1d7b4ca6c (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Made available in DSpace on 2014-10-09T12:36:40Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:59:09Z (GMT). No. of bitstreams: 1 04230.pdf: 1353263 bytes, checksum: ba0b1a87d30ef196c0398dd1d7b4ca6c (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

<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)

Récemment, de nombreuses recherches ont été dévolues à la mise au point de réacteurs biphasiques, perçus comme une nouvelle technologie pour le traitement des polluants organiques dans les effluents gazeux. Ces réacteurs impliquent lutilisation dune seconde phase non aqueuse pour améliorer la solubilité et le transfert de masse des composés hydrophobes. Dans ce travail, nous avons développé un réacteur biphasique agité utilisant lhuile de silicone comme seconde phase. Initialement, Rhodococcus erythropolis T 902.1 a été sélectionné sur base de sa capacité à dégrader lisopropylbenzène (IPB), un composé choisi comme modèle représentatif de la famille du benzène. Deuxièmement, le transfert de masse de loxygène et de lIPB a été étudié en relation avec les conditions hydrodynamiques du réacteur et le type dhuile de silicone. Lutilisation dune proportion de 10 % dhuile de faible viscosité (10cSt) naffecte pas significativement le transfert de masse de loxygène. Cependant la grande solubilité de lIPB dans lhuile de silicone conduit à une forte augmentation du potentiel de transfert, spécialement pour les proportions en huile les plus élevées. Néanmoins, il ne semble pas utile de dépasser une proportion de 10 % car le KLaIPB et le KLaO2 diminuent drastiquement pour des proportions supérieures. Lexistence dune concentration optimale en élément biotique apparaît également. En effet, les concentrations optimales en biomasse (B) et extrait surfactant (ES) peuvent être évaluées à, respectivement 0,5 g/L et 0,7 g/L, elles assurent une valeur maximale du coefficient global de transfert de masse de loxygène (KLaO2). Plus spécifiquement, lES augmente laire interfaciale « a » en diminuant le diamètre des bulles tandis que la biomasse la diminue dès quune concentration de 1 g/L est atteinte. Au contraire, lES agit négativement sur le KL tandis que la biomasse laméliore globalement. En terme de performance, il est clairement montré que la taux de biodégradation de lIPB est davantage corrélé au débit gazeux de leffluent quà la concentration en polluant. Le réacteur biphasique a été suivi sur une période de 38 jours afin de caractériser son comportement à moyen terme pour différentes conditions opératoires. Lors dune phase dalimentation transitoire (10h/j), la capacité moyenne délimination est denviron 240 g/m3 pour une charge massique de 390 g/m3. Finalement, une approche originale a été développée en utilisant un bioréacteur de type scale-down pour reproduire les conditions hydrodynamiques rencontrées dans les réacteurs industriels. Il est clairement démontré que le polluant (IPB) affecte négativement lextrapolation en augmentant la vitesse de séparation de phase. Cependant cet impact négatif est largement compensé par la présence déléments biotiques qui stabilise fortement le système biphasique, rendant totalement envisageable lextrapolation à grande échelle. En conclusion, lutilisation dun réacteur biphasique eau-huile de silicone pour lélimination de concentrations élevées (~ 6g/m3) en polluants hydrophobes est adéquate. Le réacteur proposé présente de réelles opportunités pour le traitement biologique deffluents pollués par des composés hydrophobes. Son utilisation pourrait être envisagée lorsque loxydation thermique savère trop onéreuse ou lorsque les biofiltres classiques atteignent leurs limites ( >1 g/Nm3 et une charge volumique de 90m3/m3.h.)./Recently, a lot of research has been devoted to the study of two-phase partitioning bioreactors (TPPB) as new technology for xenobiotic degradation in gaseous effluents. These reactors involve the use of a second non-aqueous phase to improve the solubility and transfer of hydrophobic compounds. In this work, we have developed a stirred two-phase partitioning bioreactor using silicone oil as second phase. Initially, Rhodococcus erythropolis T 902.1 was selected on the basis of its capacity to metabolize isopropyl-benzene (IPB), used as representative of the benzene-containing compounds. Secondly, the mass transfer of both IPB and oxygen has been considered with relation to their influence on the hydrodynamics of the reactor and the type of silicone oil used. The addition of 10% low viscosity silicone oil (10 cSt) in the reactor does not significantly affect the oxygen transfer rate. The very high solubility of IPB in the silicone oil leads to an enhancement of the driving force term, especially when high proportion of silicone oil are used. However, it is not necessary to use a volume fraction higher than 10% since KLaIPB and KLaO2 decrease sharply at above such proportion. In addition, an optimal concentration appeared to exist for both biotic components, respectively 0,5 g/L and 0,7 g/L for biomass (B) and surfactant extract (SE) when the global mass transfer coefficient (KLa) of oxygen was measured in the TPPB. More specifically, SE improved the interfacial area a by decreasing the bubble diameter, while B reduced it at concentrations up to 1 g/L. In contrast, the SE concentration acted negatively on KL, while it was favoured by the B concentration. In term of performances, it was clearly shown that the biodegradation rate is more directly related to the inlet flow of IPB than to the concentration of IPB in the inlet gas. The TPPB was monitored for 38 days to characterise its behaviour under several operational conditions. During an intermittent loading phase (10 h/day), the average elimination capacity remained above 240 g/m3.h for an average IPB inlet load of 390 g/m3. h. Finaly, an original approach was developed using a scale-down bioreactor allowing to reproduce the hydrodynamics encountered under full scale TPPB. It was clearly shown that the IPB affects negatively the scaling-up of the process by increasing the speed of phase partitioning. However, this negative impact was strongly compensated by the presence of biotic compounds stabilizing the two phase system and rendering the scaling-up process feasible. In conclusion, the use of a water-silicone oil TPPB to remove a high inlet load of IPB was successful. The proposed reactor retains a high potential for the biological treatment of gas effluents polluted by hydrophobic aromatic compounds. The suggested process might be applied in the range of concentration and flow where thermal oxidation is too expensive (between 1 and 7 g/Nm3) or when the biofilters are usually limited, i.e. to treat a polluted effluent concentrated with > 1 g/Nm3 at a flow of 90m3/m3.h.