No description available.

Thesis (Ph.D)--Civil and Environmental Engineering, Georgia Institute of Technology, 2009. / Committee Co-Chair: Huang, Ching-Hua; Committee Co-Chair: Kim, Jae-Hong; Committee Member: Li, Qilin; Committee Member: Mulholland, James; Committee Member: Wine, Paul; Committee Member: Yiacoumi, Sotira. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Results from this study, which has investigated the impact of the treatment technologies of chlorination, ozonation and UV irradiation on pool water quality are reported. The aim of the study was to evaluate the effect of these technologies in an unbiased way using a unique protocol, and to calculate a mass balance across the pool system. Data refer to a protocol based on operation of a 2.2m (cubed) capacity pilot swimming pool, which allows the comparison of technologies applied with reference to the propensity to generate the chlorinated disinfection by-products (DBPs) of chloramines and trihalomethanes (THMs). The protocol makes use of a specially developed body fluid analogue (BFA), containing simulant endogenous organic matter, with a soiling analogue consisting of commercial humic acid (HA). Using this analogue, levels of organic carbon (OC) and chloramines similar to those recorded in real pools have been obtained, along with somewhat lower levels of THMs. Results revealed conventional chlorination leads to steady-state TOC and DBP levels following an equilibrium period of 200-600 hours, with concentration values which are dependent on BFA loading rate. Following equilibration nitrate is the only DBP accumulating in the pool water, accounting for between 4% and 28% of the ammoniacal nitrogen loaded into the pool depending upon the operating conditions (primarily the Cl:N ratio). Both UV irradiation and ozonation, the latter combined with downstream adsorption, provide a similar efficacy in reducing chloramine levels, with their effect on THM and nitrate formation being highly dependent on the pH level and chlorine dose rate. This study builds on previous experimentation by including a more rigorous analysis of ozone-GAC with respect to DBP formation, a unique analysis of UV irradiation and a more comprehensive mass balance calculation of C, Cl and N across the pool. The study has established that no accumulation of carbon takes place in the pool, contrary to postulations made in previous published studies, and that the balance between the chloramines and THM DBPs is significantly affected by the HA loading.

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Liquid phase catalytic hydrodechlorinations can provide a convenient and environmentally friendly method for treating organic chlorinated compounds in waste streams generated during the manufacturing of agrochemicals. During such treatment hydrochloric acid is generated as a by-product, which can be easily neutralized employing a base to yield an inorganic salt. This work describes the results obtained during the liquid phase hydrodechlorination of 2,6-dichlorophenol (2,6-DCP) and 2,4,6-trichlorophenol (2,4,6-TCP). The hydrodechlorination of these chlorinated phenolic compounds in a mixture of methanol and water was investigated using supported and unsupported palladium catalysts to yield lower chlorinated phenols or phenol. Various parameters were investigated such as catalyst concentration, ammonium formate concentration, effect of base addition and effect of temperature. During this study two methods of hydrodechlorination were also investigated such as hydride-transfer hydrogenolysis, using ammonium formate, and hydrogenolysis, using dihydrogen. These methods offer a mild treatment in terms of the reaction temperature with temperatures used below 800C. A comparison of the palladium catalyst systems using these methods also showed that Pd/C produced the best results in terms of the hydrodechlorination rate and the selectivity towards phenol. When the ammonium formate method was used, complete hydrodechlorination of both substrates was achieved in 1h of reaction time at a selectivity of 100 percent towards phenol. A comparison of the method using dihydrogen and Pd/C showed that the reaction rate and the selectivity towards phenol during the hydrodechlorination of 2,6-DCP were 87.92 percent and 93.30 percent. Similarly, the reaction rate and selectivity during 2,4,6- TCP hydrodechlorination were 63.77 percent and 70.57 percent. These results were achieved in a reaction time of 3 hours. A high catalyst loading increases the reaction rate at the expense of selectivity, due to the formation of cyclohexanone, formed during further hydrogenation of phenol. The formation of cyclohexanone was limited at high temperatures (ca. 800C) with none detected during the hydrodechlorination of 2,6-DCP and 0.19 percent during the hydrodechlorination of 2,4,6-TCP. Evaluation of the hydrodechlorination parameters showed that the catalytic efficiency of the Pd/C catalysts was inhibited as the reaction proceeded due to the formation of HCl as by-product. A significant increase in the reaction rate was achieved when the reaction was performed in the presence of an inorganic base, which neutralized HCl.

The regioselectivity in Pd(0)-catalyzed direct arylation of pyrrole, thiophene, and indole can be improved by blocking some of the reactive sites with a chloride group, leading to increased yields of the desired regioisomers. Competition experiments and computational studies show that the blocking group also activates the substrates toward arylation. Due to the activated nature of chlorinated heteroaromatics, rare and sought after regioisomers, such as 3-arylthiophenes, can be obtained under mild conditions in good yields. Chlorine-bearing thiophenes arylated at C3 and C4 have the potential to undergo controlled regioregular polymerization under conditions developed in the field of polythiophene chemistry. Mechanistic studies support the hypothesis that the arylation of the substrates under investigation likely proceeds via the CMD transition state.

Orientador: Bruno Coraucci Filho / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-26T17:38:42Z (GMT). No. of bitstreams: 1 Albano_PauloVitor_M.pdf: 3074541 bytes, checksum: 6b0f67ea4023640d18132645c437f8d0 (MD5) Previous issue date: 2014 / Resumo: A cloração é a tecnologia mais aplicada dentre os diversos processos utilizados para desinfecção das águas residuárias, devido ao custo reduzido e praticidade de aplicação, quando comparada com as demais técnicas. O inconveniente do uso deste tipo de técnica é a possibilidade de formação de subprodutos de desinfecção, dentro dos quais se destaca os trialometanos (TAMs). O presente trabalho avaliou a formação de TAMs em esgoto tratado de uma lagoa facultativa, submetido a um sistema de desinfecção por meio da utilização de ATCI. Avaliou também a eficiência deste sistema na desinfecção do efluente da lagoa facultativa. A avaliação consistiu de ensaio experimental, realizado em laboratório, para definição da dosagem e do tempo de contato; além do teste em escala real com a implantação do sistema de desinfecção na lagoa facultativa, situada no município de Itirapuã - SP. Os resultados obtidos demonstram que o sistema foi efetivo na desinfecção do efluente com uma aplicação de 10mg/L de cloro residual total e sem formação significativa de TAM, em média abaixo dos 3,0 µg/L, aparentemente devido à presença de concentrações elevadas de nitrogênio amoniacal (N-NH3) no efluente, da ordem de 43,0 mg/L. Conclui-se que a utilização do ATCI torna-se interessante devido à segurança, simplicidade das instalações e facilidade operacional / Abstract: Chlorination is the most technology applied among the different processes used for disinfection of wastewater, due to reduced cost and practicality of application compared with other techniques. The disadvantage of using this type of technique is the possibility of formation of disinfection byproducts within which stands trihalomethanes (TAMs). This study evaluated the formation of TAMs in treated sewage from a facultative pond, subjected to a disinfection system through the use of ATCI. Also evaluated the efficiency of this system for the disinfection of effluent from facultative pond. The evaluation consisted of an experimental test performed in the laboratory, to define the dosage and time of contact; beyond the full-scale test with the implementation of the disinfection system in the facultative pond, located in the municipality of Itirapuã - SP. The results demonstrated that the system was effective in disinfection of the effluent with an application of 10 mg / L of total chlorine residual and without significant formation of TAM on average below 3.0 g / L, apparently due to the presence of high concentrations of ammonia nitrogen (NH3-N) in the effluent of the order of 43.0 mg / L. We conclude that the use of ATCI becomes interesting due to security, simplicity of installation and operational ease / Mestrado / Saneamento e Ambiente / Mestre em Engenharia Civil

No description available.

<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)