Thesis (MScEng) -- Stellenbosch University, 2014. / ENGLISH ABSTRACT: Urine contains up to 80% of nitrogen, 50 % of phosphates and 90 % of potassium of the total load in domestic wastewater but makes up less than 1% of the total volume (Larsen et al., 1996). The source separation and separate treatment of this concentrated waste stream can have various downstream advantages on wastewater infrastructure and treated effluent quality. The handling of undiluted source separated urine however poses various challenges from the origin onward. The urine has to be transported to a point of discharge and ultimately has to be treated in order to remove the high loads of organics and nutrients. Wilsenach (2006) proposed onsite treatment of source separated urine in a sequencing batch reactor before discharging it into the sewer system. This study focused on the treatment of urine in a sequencing batch reactor (SBR) primarily for removal of nitrogen through biological nitrification-denitrification. The aim of the study was to determine nitrification and denitrification kinetics of undiluted urine as well as quantification of the stoichiometric reactions. A further objective was to develop a mathematical model for nitrification and denitrification of urine using experimental data from the SBR. The SBR was operated in 24 hour cycles consisting of an anoxic denitrification phase and an aerobic nitrification phase. The sludge age and hydraulic retention time was maintained at 20 days. pH was controlled through influent urine during volume exchanges. Undiluted urine for the study was obtained from a source separation system at an office at the CSIR campus in Stellenbosch. Conditions in the reactor were monitored by online temperature, pH and ORP probes. The OUR of the system was also measured online. One of the main challenges in the biological treatment of undiluted urine was the inhibiting effect thereof on nitrification rate. The anoxic mass fraction was therefore limited to 17 % in order to allow longer aerobic phases and compensate for the slow nitrification rates. Volume exchanges were also limited to 5% of the reactor volume in order to maintain pH within optimal range. Samples from the reactor were analysed for TKN, FSA-N, nitrite-N, nitrate-N and COD. From the analytical results it was concluded that ammonia oxidising organisms and nitrite oxidising organism were inhibited as significant concentrations of ammonia-N and nitrite-N were present in the effluent. It was also concluded that nitrite oxidising organisms were more severely inhibited than ammonia oxidising organisms as nitrate-N was present in very low concentrations in the effluent and in some instances not present at all. Ultimately the experimental system was capable of converting 66% of FSA-N to nitrite- N/nitrate-N of which 44% was converted to nitrogen gas. On average 48% of COD was removed. A mathematical model was developed in spreadsheet form using a time step integration method. The model was calibrated with measured online data from the SBR and evaluated by comparing the output with analytical results. Biomass in the model was devised into three groups, namely heterotrophic organisms, autotrophic ammonia oxidisers (AAO) and autotrophic nitrite oxidisers (ANO). It was found that biomass fractionation into these three groups of 40% heterotrophs, 30% AAO and 30% ANO produced best results. The model was capable of reproducing the general trends of changes in substrate for the various organism groups as well as OUR. The accuracy of the results however varies and nearexact results were not always achievable. The model has some imperfections and limitations but provides a basis for future work.

Dynamic modelling and optimization of three different processes namely (a) bulk polymerization of styrene, (b) solution polymerization of methyl methacrylate (MMA) and (c) emulsion copolymerization of Styrene and MMA in batch and semi-batch reactors are the focus of this work. In this work, models are presented as sets of differential-algebraic equations describing the process. Different optimization problems such as (a) maximum conversion (Xn), (b) maximum number average molecular weight (Mn) and (c) minimum time to achieve the desired polymer molecular properties (defined as pre-specified values of monomer conversion and number average molecular weight) are formulated. Reactor temperature, jacket temperature, initial initiator concentration, monomer feed rate, initiator feed rate and surfactant feed rate are used as optimization variables in the optimization formulations. The dynamic optimization problems were converted into nonlinear programming problem using the CVP techniques which were solved using efficient SQP (Successive Quadratic Programming) method available within the gPROMS (general PROcess Modelling System) software. The process model used for bulk polystyrene polymerization in batch reactors, using 2, 2 azobisisobutyronitrile catalyst (AIBN) as initiator was improved by including the gel and glass effects. The results obtained from this work when compared with the previous study by other researcher which disregarded the gel and glass effect in their study which show that the batch time operation are significantly reduced while the amount of the initial initiator concentration required increases. Also, the termination rate constant decreases as the concentration of the mixture increases, resulting rapid monomer conversion. The process model used for solution polymerization of methyl methacrylate (MMA) in batch reactors, using AIBN as the initiator and Toluene as the solvent was improved by including the free volume theory to calculate the initiator efficiency, f. The effects of different f was examined and compared with previous work which used a constant value of f 0.53. The results of these studies show that initiator efficiency, f is not constant but decreases with the increase of monomer conversion along the process. The determination of optimal control trajectories for emulsion copolymerization of Styrene and MMA with the objective of maximizing the number average molecular weight (Mn) and overall conversion (Xn) were carried out in batch and semi-batch reactors. The initiator used in this work is Persulfate K2S2O8 and the surfactant is Sodium Dodecyl Sulfate (SDS). Reduction of the pre-batch time increases the Mn but decreases the conversion (Xn). The sooner the addition of monomer into the reactor, the earlier the growth of the polymer chain leading to higher Mn. Besides that, Mn also can be increased by decreasing the initial initiator concentration (Ci0). Less oligomeric radicals will be produced with low Ci0, leading to reduced polymerization loci thus lowering the overall conversion. On the other hand, increases of reaction temperature (Tr) will decrease the Mn since transfer coefficient is increased at higher Tr leading to increase of the monomeric radicals resulting in an increase in termination reaction.

Dynamic modelling and optimization of three different processes namely (a) bulk polymerization of styrene, (b) solution polymerization of methyl methacrylate (MMA) and (c) emulsion copolymerization of Styrene and MMA in batch and semi-batch reactors are the focus of this work. In this work, models are presented as sets of differential-algebraic equations describing the process. Different optimization problems such as (a) maximum conversion (Xn), (b) maximum number average molecular weight (Mn) and (c) minimum time to achieve the desired polymer molecular properties (defined as pre-specified values of monomer conversion and number average molecular weight) are formulated. Reactor temperature, jacket temperature, initial initiator concentration, monomer feed rate, initiator feed rate and surfactant feed rate are used as optimization variables in the optimization formulations. The dynamic optimization problems were converted into nonlinear programming problem using the CVP techniques which were solved using efficient SQP (Successive Quadratic Programming) method available within the gPROMS (general PROcess Modelling System) software. The process model used for bulk polystyrene polymerization in batch reactors, using 2, 2 azobisisobutyronitrile catalyst (AIBN) as initiator was improved by including the gel and glass effects. The results obtained from this work when compared with the previous study by other researcher which disregarded the gel and glass effect in their study which show that the batch time operation are significantly reduced while the amount of the initial initiator concentration required increases. Also, the termination rate constant decreases as the concentration of the mixture increases, resulting rapid monomer conversion. The process model used for solution polymerization of methyl methacrylate (MMA) in batch reactors, using AIBN as the initiator and Toluene as the solvent was improved by including the free volume theory to calculate the initiator efficiency, f. The effects of different f was examined and compared with previous work which used a constant value of f 0.53. The results of these studies show that initiator efficiency, f is not constant but decreases with the increase of monomer conversion along the process. The determination of optimal control trajectories for emulsion copolymerization of Styrene and MMA with the objective of maximizing the number average molecular weight (Mn) and overall conversion (Xn) were carried out in batch and semi-batch reactors. The initiator used in this work is Persulfate K2S2O8 and the surfactant is Sodium Dodecyl Sulfate (SDS). Reduction of the pre-batch time increases the Mn but decreases the conversion (Xn). The sooner the addition of monomer into the reactor, the earlier the growth of the polymer chain leading to higher Mn. Besides that, Mn also can be increased by decreasing the initial initiator concentration (Ci0). Less oligomeric radicals will be produced with low Ci0, leading to reduced polymerization loci thus lowering the overall conversion. On the other hand, increases of reaction temperature (Tr) will decrease the Mn since transfer coefficient is increased at higher Tr leading to increase of the monomeric radicals resulting in an increase in termination reaction.

Neste trabalho estudou-se o processo de coplimerização em emulsão de estireno e acrilato de butila em processo semicontínuo onde o produto final é um látice com alto teor de sólidos. Foi realizada uma série de experimentos de copolimerização em emulsão em um reator de vidro, empregando receitas com teores de sólidos na faixa de 50 a 64% em massa. Foram estudados os seguintes fatores: teor de sólidos, teor de ácido acrílico, teor de emulsificantes e tempo de adição dos monômeros. Os efeitos estudados são avaliados principalmente em termos de conversão, diâmetro médio das partículas, concentração de partículas, número médio de radicais por partícula, taxa de polimerização, viscosidade e fração de coágulos. Também se avaliou a distribuição de tamanhos de partículas para o processo. Utilizando informações experimentais e da literatura, foi aplicado um modelo matemático para o processo, com razoável adequação aos dados experimentais. / The aim of this work was the study of the high solid contents emulsion copolymerization of styrene and butyl acrylate in semi-batch process. Copolymerization reactions were undertaken in a glass reactor, and recipes with solid contents up to 64 wt.% were used. Were evaluated the effects of: solid contents on recipe, amounts of acrylic acid and surfactants on recipe and monomer feeding time. The effects were evaluated in terms of conversion, particle mean diameter, and particle concentration, average number of radicals per particle, polymerization rate, viscosity and coagulum content. It was performed a characterization of the particle size distribution for this process. Using experimental observations and literature information, it was applied a mathematical model for this process, with satisfactory agreement with experimental data.

A presente pesquisa propôs avaliar a remoção biológica do nitrogênio pela via simplificada (nitritação) utilizando fenol como fonte de carbono na etapa anóxica (desnitritação) em um sistema de lodos ativados com biomassa em suspensão. Para tanto operou-se um reator piloto (volume útil de 20 litros) em bateladas seqüenciais alimentado com 5 (cinco) litros de água residuária sintética. A investigação foi caracterizada pela utilização do fenol (1.000 mg C6H5OH/L) e pelo aumento gradual da concentração de nitrogênio amoniacal no despejo líquido sintético (200; 300 e 500 mg N/L) buscando as condições que permitissem a predominância do N-NO2 - ao final da fase aeróbia dos ciclos de tratamento e utilização do fenol pelos microrganismos heterotróficos para redução do nitrogênio oxidado durante a fase anóxica. Para a presente pesquisa as condições para predominância do N-NO2 - na massa líquida do reator ao final da etapa aeróbia foram: pH @ 8,3 associado à extensão do período aeróbio do ciclo de tratamento que garantisse uma concentração mínima de amônia livre (> 0,3 mg NH3/L) no conteúdo do reator piloto. Com estas condições, a relação N NO2 - / (N-NO2 - + N-NO3 -) variou entre 89 e 99%. Mantendo uma concentração de 1,0 mg O2/L no conteúdo do reator durante afase aeróbia e tempo de residência hidráulico de três dias, as eficiências de remoção de N-NH3 variaram entre: 89 e 98% com concentrações no afluente próximas a 200 mg N/L (nove ciclos de tratamento); 95 e 98% para concentrações no afluente da ordem de 300 mg N/L (cinco ciclos de remoção) e 95 e 97% com concentrações no afluente próximas a 500 mg N/L (três ciclos de tratamento). Para temperaturas entre 23,5 e 33°C e concentrações de sólidos em suspensão voláteis entre 3.420 e 2.175 mg SSV/L no conteúdo do reator, a taxa de nitrificação específica variou entre 0,01 e 0,05 kg N-NH3/ kg SSV. dia. Concentrações máximas de amônia livre da ordem de 16 mg NH3/L e de ácido nitroso livre entre 0,001 e 0,009 mg HNO2/L no conteúdo do reator piloto não inibiram a oxidação biológica do nitrogênio. Fenol, em concentrações no afluente próximas a 1.000 mg C6H5OH/L, mostrou-se adequado como única fonte de carbono para remoção de nitrogênio, via nitrito, para concentrações afluentes da ordem de 200 e 300 mg N/L. As eficiências de remoção do nitrogênio oxidado variaram entre 97 e 100%, utilizando taxas de aplicação volumétricas próximas a 0,03 kg fenol /m3.hora.. As taxas de "desnitritação" específicas variaram entre 0,01 e 0,05 kg N-NO2 - / kg SSV .dia; a relação alimento/microrganismo (A/M) esteve compreendida entre 0,06 e 0,13 kg fenol / kg SSV. dia; a relação fenol removido/N-NOx removido variou entre 2,1 e 3,2 g fenol removido / g NNOx removido e as eficiências de remoção do fenol, durante a etapa anóxica estiveram compreendidas entre 37 e 67%. Taxas de aplicação volumétricas da ordem de 0,07 kg fenol /m3.hora inibiram a "desnitritação" biológica. Os três ciclos de tratamento da etapa conduzida com concentração de 500 mg N/L no afluente, foram marcados pela inibição da "desnitritação" e acúmulo de fenol, causados pelas elevadas concentrações de N-NO2 - (@80 a 98 mg N-NO2 -/L) na massa líquida do reator. Ainda durante essa etapa, a coleta de amostra na fase anóxica dos ciclos de remoção para realização de ensaios exploratórios, associando cromatografia gasosa e espectrometria de massa, detectaram a formação de 2 e 4 - nitrofenol no conteúdo do reator piloto. / This research proposes to evaluate an activated sludge system with suspended biomass in a pilot scale aiming to remove nitrogen by a simplified way (nitritation) using phenol as the carbon source of the anoxic phase (denitritation). A pilot reactor of 20-liters volume was operated in sequence batch stages fed with 5-liters of a synthetic wastewater. The investigation was characterized by the use of phenol (1,000 mg C6H5OH/L) and the gradual increase of ammonium nitrogen concentration in the synthetic wastewater (200, 300 and 500 mg N/L) searching the conditions that allowed the prevalence of N-NO2 - in the end of the aerobic phase of the treatment cycles and the use of phenol for the heterotrophic microorganisms to reduce the oxidized nitrogen during the anoxic phase. To the present research, the conditions to N-NO2 - prevalence in the reactor liquid mass in the end of the aerobic phase were: pH @ 8.3 associated to the extension of the aerobic period of the treatment cycle which guarantees a minimum concentration of free ammonia (> 0.3 mg NH3/L) in the pilot reactor content. Considering these conditions, the relation N-NO2 - / (N-NO2 - + NNO3 -) varied between 91 and 99%. Maintaining a concentration of 1.0 mgO2/L in the reactor content and hydraulic residence time of three days, the removal efficiencies of N-NH3 vary between: 89 and 98% to influent concentrations near 200 mg N/L (nine treatment cycles); 95 and 98% to influent concentrations of the order of 300 mg N/L (five removal cycles) and 95 and 97% to influent concentrations near 500 mg N/L (three treatment cycles). To temperature between 23,5 and 33°C and volatile suspended solid concentrations between 3,420 and 2,175 mg SSV/L in the reactor, the specific nitrification rate varied between 0.01 and 0.05 kg N-NH3/ kg SSV.d-1. Maximum concentrations of free ammonia in the pilot reactor of the order of 16 mg NH3/L and nitrous acid between 0.001 and 0.009 mg HNO2/L didn?t inhibit the nitrogen biological oxidation. Influent phenol concentrations near 1,000 mg C6H5OH/L showed to be adequate as single carbonsource to nitrogen removal as nitrite to influent concentrations of the order of 200 and 300 mg N/L. The oxidized nitrogen removal efficiencies vary between 97 and 100%, using volumetric loading rates near 0.03 kg phenol/m3.hour. The specific denitritation rates vary between 0.01 and 0.05 kg N-NO2 - / kg SSV.d-1; the food / microorganism ratio (F/M) was between 0.06 and 0.13 kg phenol / kgSSV.d-1; phenolremoved/N-NOxremoved ratio varied between 2.1 and 3.2 g phenolremoved/ g N-NOxremoved and phenol removal efficiencies during the anoxic phase were between 37 and 67%. Volumetric loading rates of the order of 0.06 kg phenol / m3.hour inhibited the biological denitritation. The three treatment cycles of the phase conducted with influent concentration of 500 mg N/L showed denitritation inhibition and phenol accumulation caused by high concentrations of N-NO2 - (@80 to 98 mg N-NO2 -/L) in the reactor liquid mass. During this phase, the sampling of the anoxic phase of the removal cycles to the initial tests associating gas chromatography and mass spectrophotometer detected the formation of 2 and 4-nitrophenol in the pilot reactor content.

Neste trabalho estudou-se o processo de coplimerização em emulsão de estireno e acrilato de butila em processo semicontínuo onde o produto final é um látice com alto teor de sólidos. Foi realizada uma série de experimentos de copolimerização em emulsão em um reator de vidro, empregando receitas com teores de sólidos na faixa de 50 a 64% em massa. Foram estudados os seguintes fatores: teor de sólidos, teor de ácido acrílico, teor de emulsificantes e tempo de adição dos monômeros. Os efeitos estudados são avaliados principalmente em termos de conversão, diâmetro médio das partículas, concentração de partículas, número médio de radicais por partícula, taxa de polimerização, viscosidade e fração de coágulos. Também se avaliou a distribuição de tamanhos de partículas para o processo. Utilizando informações experimentais e da literatura, foi aplicado um modelo matemático para o processo, com razoável adequação aos dados experimentais. / The aim of this work was the study of the high solid contents emulsion copolymerization of styrene and butyl acrylate in semi-batch process. Copolymerization reactions were undertaken in a glass reactor, and recipes with solid contents up to 64 wt.% were used. Were evaluated the effects of: solid contents on recipe, amounts of acrylic acid and surfactants on recipe and monomer feeding time. The effects were evaluated in terms of conversion, particle mean diameter, and particle concentration, average number of radicals per particle, polymerization rate, viscosity and coagulum content. It was performed a characterization of the particle size distribution for this process. Using experimental observations and literature information, it was applied a mathematical model for this process, with satisfactory agreement with experimental data.

A presente pesquisa propôs avaliar a remoção biológica do nitrogênio pela via simplificada (nitritação) utilizando fenol como fonte de carbono na etapa anóxica (desnitritação) em um sistema de lodos ativados com biomassa em suspensão. Para tanto operou-se um reator piloto (volume útil de 20 litros) em bateladas seqüenciais alimentado com 5 (cinco) litros de água residuária sintética. A investigação foi caracterizada pela utilização do fenol (1.000 mg C6H5OH/L) e pelo aumento gradual da concentração de nitrogênio amoniacal no despejo líquido sintético (200; 300 e 500 mg N/L) buscando as condições que permitissem a predominância do N-NO2 - ao final da fase aeróbia dos ciclos de tratamento e utilização do fenol pelos microrganismos heterotróficos para redução do nitrogênio oxidado durante a fase anóxica. Para a presente pesquisa as condições para predominância do N-NO2 - na massa líquida do reator ao final da etapa aeróbia foram: pH @ 8,3 associado à extensão do período aeróbio do ciclo de tratamento que garantisse uma concentração mínima de amônia livre (> 0,3 mg NH3/L) no conteúdo do reator piloto. Com estas condições, a relação N NO2 - / (N-NO2 - + N-NO3 -) variou entre 89 e 99%. Mantendo uma concentração de 1,0 mg O2/L no conteúdo do reator durante afase aeróbia e tempo de residência hidráulico de três dias, as eficiências de remoção de N-NH3 variaram entre: 89 e 98% com concentrações no afluente próximas a 200 mg N/L (nove ciclos de tratamento); 95 e 98% para concentrações no afluente da ordem de 300 mg N/L (cinco ciclos de remoção) e 95 e 97% com concentrações no afluente próximas a 500 mg N/L (três ciclos de tratamento). Para temperaturas entre 23,5 e 33°C e concentrações de sólidos em suspensão voláteis entre 3.420 e 2.175 mg SSV/L no conteúdo do reator, a taxa de nitrificação específica variou entre 0,01 e 0,05 kg N-NH3/ kg SSV. dia. Concentrações máximas de amônia livre da ordem de 16 mg NH3/L e de ácido nitroso livre entre 0,001 e 0,009 mg HNO2/L no conteúdo do reator piloto não inibiram a oxidação biológica do nitrogênio. Fenol, em concentrações no afluente próximas a 1.000 mg C6H5OH/L, mostrou-se adequado como única fonte de carbono para remoção de nitrogênio, via nitrito, para concentrações afluentes da ordem de 200 e 300 mg N/L. As eficiências de remoção do nitrogênio oxidado variaram entre 97 e 100%, utilizando taxas de aplicação volumétricas próximas a 0,03 kg fenol /m3.hora.. As taxas de "desnitritação" específicas variaram entre 0,01 e 0,05 kg N-NO2 - / kg SSV .dia; a relação alimento/microrganismo (A/M) esteve compreendida entre 0,06 e 0,13 kg fenol / kg SSV. dia; a relação fenol removido/N-NOx removido variou entre 2,1 e 3,2 g fenol removido / g NNOx removido e as eficiências de remoção do fenol, durante a etapa anóxica estiveram compreendidas entre 37 e 67%. Taxas de aplicação volumétricas da ordem de 0,07 kg fenol /m3.hora inibiram a "desnitritação" biológica. Os três ciclos de tratamento da etapa conduzida com concentração de 500 mg N/L no afluente, foram marcados pela inibição da "desnitritação" e acúmulo de fenol, causados pelas elevadas concentrações de N-NO2 - (@80 a 98 mg N-NO2 -/L) na massa líquida do reator. Ainda durante essa etapa, a coleta de amostra na fase anóxica dos ciclos de remoção para realização de ensaios exploratórios, associando cromatografia gasosa e espectrometria de massa, detectaram a formação de 2 e 4 - nitrofenol no conteúdo do reator piloto. / This research proposes to evaluate an activated sludge system with suspended biomass in a pilot scale aiming to remove nitrogen by a simplified way (nitritation) using phenol as the carbon source of the anoxic phase (denitritation). A pilot reactor of 20-liters volume was operated in sequence batch stages fed with 5-liters of a synthetic wastewater. The investigation was characterized by the use of phenol (1,000 mg C6H5OH/L) and the gradual increase of ammonium nitrogen concentration in the synthetic wastewater (200, 300 and 500 mg N/L) searching the conditions that allowed the prevalence of N-NO2 - in the end of the aerobic phase of the treatment cycles and the use of phenol for the heterotrophic microorganisms to reduce the oxidized nitrogen during the anoxic phase. To the present research, the conditions to N-NO2 - prevalence in the reactor liquid mass in the end of the aerobic phase were: pH @ 8.3 associated to the extension of the aerobic period of the treatment cycle which guarantees a minimum concentration of free ammonia (> 0.3 mg NH3/L) in the pilot reactor content. Considering these conditions, the relation N-NO2 - / (N-NO2 - + NNO3 -) varied between 91 and 99%. Maintaining a concentration of 1.0 mgO2/L in the reactor content and hydraulic residence time of three days, the removal efficiencies of N-NH3 vary between: 89 and 98% to influent concentrations near 200 mg N/L (nine treatment cycles); 95 and 98% to influent concentrations of the order of 300 mg N/L (five removal cycles) and 95 and 97% to influent concentrations near 500 mg N/L (three treatment cycles). To temperature between 23,5 and 33°C and volatile suspended solid concentrations between 3,420 and 2,175 mg SSV/L in the reactor, the specific nitrification rate varied between 0.01 and 0.05 kg N-NH3/ kg SSV.d-1. Maximum concentrations of free ammonia in the pilot reactor of the order of 16 mg NH3/L and nitrous acid between 0.001 and 0.009 mg HNO2/L didn?t inhibit the nitrogen biological oxidation. Influent phenol concentrations near 1,000 mg C6H5OH/L showed to be adequate as single carbonsource to nitrogen removal as nitrite to influent concentrations of the order of 200 and 300 mg N/L. The oxidized nitrogen removal efficiencies vary between 97 and 100%, using volumetric loading rates near 0.03 kg phenol/m3.hour. The specific denitritation rates vary between 0.01 and 0.05 kg N-NO2 - / kg SSV.d-1; the food / microorganism ratio (F/M) was between 0.06 and 0.13 kg phenol / kgSSV.d-1; phenolremoved/N-NOxremoved ratio varied between 2.1 and 3.2 g phenolremoved/ g N-NOxremoved and phenol removal efficiencies during the anoxic phase were between 37 and 67%. Volumetric loading rates of the order of 0.06 kg phenol / m3.hour inhibited the biological denitritation. The three treatment cycles of the phase conducted with influent concentration of 500 mg N/L showed denitritation inhibition and phenol accumulation caused by high concentrations of N-NO2 - (@80 to 98 mg N-NO2 -/L) in the reactor liquid mass. During this phase, the sampling of the anoxic phase of the removal cycles to the initial tests associating gas chromatography and mass spectrophotometer detected the formation of 2 and 4-nitrophenol in the pilot reactor content.

With the increasing demand for biodiesel, the accumulation of byproduct, crude glycerol has become a problem which needs to be solved. Lactic acid is one of the value-added chemical which can be produced from glycerol that has wide uses in food and chemical industry. Although glycerol can be converted to lactic acid with an alkali as the catalyst at high glycerol conversion (100 mol%) and lactic acid yield (around 90 mol%), the high alkalinity would cause severe corrosiveness to a stainless steel reactor. In this study two tasks were performed to convert glycerol to lactic acid with satisfactory conversion and selectivity, and to reduce the corrosiveness of reaction medium. First, CaO was used as solid base catalyst. The highest lactic acid yield achieved was 40.8 mol% with a 97.8 mol% glycerol conversion, when operating at 290°C after 150 min reaction with molar ratio of CaO: glycerol=0.3. Also CaO has advantages such as high lactic acid productivity (3.35 g/(min·L)) and reusability. Meanwhile, CaO can be used as the catalyst for both biodiesel production and the following crude glycerol conversion to lactic acid. Second, for glycerol conversion with NaOH as catalyst, a fed-batch reactor was applied to continuously supply NaOH during reaction process, compensating the OH- neutralized by newly formed lactic acid. The optimal lactic acid yield of 80.5 mol%, with 92.8% glycerol conversion was obtained at 300 °C for 220min, with 1.1 M glycerol initial concentration. A first-order kinetic model for glycerol concentration versus time was developed and verified experimentally under conditions with different initial glycerol concentration and reaction temperature. Although crude glycerol samples contained large amount of impurities, both methods, conversion with solid base catalyst and with fed-batch reactor, were applied successfully to three crude glycerol samples provided by biodiesel manufacturers, and the lactic acid yield reached 52.3 mol% and 72.7 mol% respectively. Finally, the corrosion issue of different methods was compared based on the Fe3+ concentration (analyzed with atomic-absorption spectroscopy) in the products. Both methods of glycerol conversions, with solid base catalyst and fed-batch reactor, can reduce the corrosiveness of glycerol conversion with an alkali as the catalyst.

Water infrastructure on Aboriginal communities in Canada, and specifically Northern Manitoba is in sub-standard condition. A recent Government of Canada study indicated that an estimated $1.5 billion would need to be spent to improve this infrastructure. September 2003 through July 2004, an examination of the effectiveness of a membrane bioreactor (MBR) in a Northern Manitoban Aboriginal community took place. This study was intended to identify and test an appropriate and effective solution for the lack of adequate wastewater treatment in these communities. The MBR system, employing a Zenon ZW-10 ultrafiltration membrane, was designed and constructed at the University of Manitoba. It was installed and tested in two phases at the Opaskwayak Cree Nation Reserve in Northern Manitoba. Phase I was a direct comparison between the pilot-scale MBR and the community’s existing Sequencing Batch Reactor (SBR) with sand filter. This phase occurred from September 2003 until December 2003. The MBR, with an SRT of 20-days and an HRT of 10 hours, outperformed the SBR in every category despite 2 mechanical/electrical failures that resulted in the loss of biomass from the MBR. The SBR/Sand filter combination had BOD, TSS, and TKN concentrations of 30.3 mg/L, 27.5 mg/L, and 8.4 mg/L, respectively. By comparison, the BOD, TSS, and TKN concentrations in the MBR effluent were <6 mg/L, <5 mg/L, and 1.3 mg/L respectively. Phase II, from March 2004 through July 2004, tested the overall MBR efficacy and intended to assess a novel remote control and monitoring system. The MBR SRT was adjusted to 40-days and, as expected, the MBR MLVSS concentration increased to a relatively stable 5000 mg/L. The MBR continued to provide high quality effluent with some exceptions. Despite the 0.034 μm pore size, the total coliforms and TSS measured in the effluent were higher than in Phase I. This indicates a compromised membrane, faulty sampling procedures, or biological regrowth downstream of the membrane. This failure could point to the need for some form of tertiary disinfection. Also in Phase II, a remote control and monitoring program was implemented. The controlling PC was controlled via the internet using pcAnywhere software. The software allowed for real-time monitoring and complete control of the pilot system. In conclusion, the pilot-scale MBR yielded consistent, high quality wastewater effluent and this would benefit the pristine environments existing in Manitoba’s north. The potential hands-free operation could be utilized to provide support to communities lacking sufficient wastewater treatment know-how. / February 2006

No description available.