The research presented in this paper evaluates the potential impact of municipal solid waste (MSW) landfill leachate quality on the loss of metals from discarded treated wood during disposal. The loss of arsenic (As), chromium (Cr), copper (Cu), and boron (B) from several types of pressure-treated wood (CCA: chromated copper arsenate, ACQ: alkaline copper quaternary, CBA: copper boron azole, and DOT: disodium octaborate tetrahydrate) using leachate collected from 26 MSW landfills in Florida was examined. The toxicity characteristic leaching procedure (TCLP), the synthetic precipitation leaching procedure (SPLP), and California's waste extraction test (WET) were also performed. The results suggested that loss of preservative components was influenced by leachate chemistry. Copper loss from CCA-, ACQ- and CBA-treated wood was similar in magnitude when in contact with landfill leachates compared to synthetic TCLP and SPLP solutions. Ammonia was found as one of the major parameters influencing the leaching of Cu from treated wood when leached with MSW landfill leachates. The results suggest that disposal of ACQ- and CBA-treated wood in substantial quantity in MSW landfills may elevate the Cu concentration in the leachate; this could be of potential concern, especially for a bioreactor MSW landfill in which relatively higher ammonia concentrations in leachate have been reported in recent literature. For the As, Cr and B the concentrations observed with the landfill leachate as the leaching solutions were over a range from some sample showing the concentrations below and some showing above the observed value from corresponding SPLP and TCLP tests. In general the WET test showed the highest concentrations.

Given the increase in nanomaterial (NM) use in consumer products and the large fraction of waste placed in landfills worldwide, the probability of these products reaching municipal solid waste (MSW) landfills at the end of their useful life is high. Since nanotechnology use is still in its early stages, there are currently no regulations pertaining to the disposal of NMs and their fate in MSW landfills is still unknown. Understanding the fate of NMs in MSW landfills is vital to ensure the proper handling of these novel materials from cradle to grave; such research will provide information on how these NMs can be safely introduced into the environment. This research seeks to understand the fate of NMs within waste environments by examining the interactions between NMs and landfill leachate components. The primary focus of this thesis is the effect of Zinc Oxide (ZnO) on biological landfill processes, solids aggregation, and chemical speciation of Zn in landfill leachate following the addition of crystalline, nanosized ZnO coated with triethoxycaprylylsilane. This research (1) observed the effects of coated ZnO on five-day biochemical oxygen demand (BOD5) and biochemical methane potential (BMP), (2) examined effects of solids aggregation on the fate of ZnO, (3) quantified the concentration of Zinc (Zn) by size fractions, and (4) modeled the chemical speciation of Zn in landfill leachate using Visual MINTEQ. No change in dissolved Zn was observed after coated ZnO was exposed to “middle-aged” leachate. Upon exposure to “mature” leachate there was an increase in dissolved Zn assumed to be a result of the dissociation of ZnO. Solids data supported the aggregation of particles in both middle aged and mature leachate. There was an increase in the Zn concentration in leachate fractions greater than 1500 nm presumably due to the dispersion of normally insoluble ZnO ii nanoparticles (NPs) following the interaction with humic acids (HA). ZnO did not inhibit anaerobic or aerobic processes in either middle aged or mature leachate, presumably due to the relatively low concentration of dissolved ionic Zn. Despite the observation of increased dissociation upon exposure to mature leachate, the presence of dissolved organic matter (DOM) may have hindered the ability for dissolved ionic Zn to become bioavailable. Fractionation, BOD5 and BMP tests, and chemical speciation modeling provided insight on the mobility of ZnO in landfills and the absence of inhibitory effects on landfill processes. Aggregation of ZnO NPs may prevent movement through traditional containment systems (i.e. geomembrane liners) due to the increased particle size. However, the increased dispersion suggests that ZnO NPs will be transported out of the landfill in the leachate, however biological treatment of leachate should be unaffected by the presence of ZnO. The bioavailability of Zn was not substantially affected by the presence of ZnO due to affinity of dissolved Zn for DOM. However, due to the heterogeneity of landfill leachate and the utilization of different NM coatings, it is challenging to predict the overall mobility of other NMs in a landfill.

No / In the search for an efficient and economical method to treat a leachate generated from a controlled municipal solid waste landfill site (Jebel Chakir) in the region of greater Tunis in Tunisia, ozone alone and ozone combined with hydrogen peroxide were studied. The leachate was characterised by high COD, low biodegradability and intense dark colour. A purpose-built reactor, to avoid foaming, was used for the study. It was found that ozone efficacy was almost doubled when combined with hydrogen peroxide at 2 g/L but higher H2O2 concentrations gave lower performances. Enhancement in the leachate biodegradability from about 0.1 to about 0.7 was achieved by the O3/H2O2 system. Insignificant changes in pH that may due to buffering effect of bicarbonate was found. A small decrease in sulphate concentrations were also observed. In contrast, chloride concentration declined at the beginning of the experiment then increased to reach its initial value. Estimates of the operating costs were made for comparison purposes and it was found that the O3/H2O2 system at 2 g/L H2O2 gave the lowest cost of about 3.1 TND (2.3 USD)/kg COD removed.

A presente pesquisa abordou o estudo em escala real do tratamento de lixiviado de aterro sanitário em um sistema composto por dois filtros anaeróbios seguidos de dois banhados construídos. O trabalho foi desenvolvido na estação de tratamento de lixiviado do aterro sanitário pertencente à Central de Resíduos do Recreio, localizada em Minas do Leão/RS. Pretendeu-se verificar a eficiência do sistema na remoção de matéria orgânica e de nitrogênio amoniacal. A fase 1 da pesquisa, que avaliou o desempenho dos filtros anaeróbios quando operados em série, indicou que a quase totalidade da remoção de matéria orgânica facilmente biodegradável ocorreu no primeiro filtro, evidenciando que, para o tratamento do lixiviado em questão, não é interessante a utilização de dois filtros anaeróbios de fluxo ascendente semelhantes em série. A fase 2 avaliou o desempenho dos filtros anaeróbios operados em paralelo e dos banhados construídos. Foi possível concluir-se que: filtros anaeróbios de fluxo ascendente são excelente alternativa para o tratamento de lixiviado de aterro sanitário, pois podem viabilizar remoções de matéria orgânica superiores a 50%; banhados construídos representam uma ecotecnologia interessante para o complemento do tratamento de lixiviado, pois podem viabilizar elevadas remoções de N-amoniacal. / This study discussed the sanitary landfill leachate treatment in a full scale system composed by two upflow anaerobic filters followed by two constructed wetlands. The research was developed at the landfill leachate treatment station owned by Recreio Central Waste, located in Minas do Leão/RS. The objective of the study was to verify the efficiency of the system in the removal of organic matter and ammonia nitrogen. The phase 1 of the study, which evaluated the performance of anaerobic filters when operated in series, indicated that almost all of the removal of organic matter readily biodegradable occurred in the first filter, showing that, for the treatment of leachate concerned, it is not interesting the use of two similar upflow anaerobic filters in series. The phase 2 assessed the performance of the anaerobic filters, operated in parallel, and the constructed wetlands. It could be concluded that: upflow anaerobic filters are excellent alternative for the sanitary landfill leachate treatment, as they may facilitate removal of organic matter greater than 50%; constructed wetlands represent an interesting eco-technology to complement the leachate treatment, which can enable high removals of N-ammonia.

A presente pesquisa objetivou estudar a remoção de matéria orgânica e nitrogênio de lixiviados de aterro sanitário, através do processo biológico de nitritação/desnitritação, operando um reator de lodos ativados em bateladas sequenciais e pós-tratamento físico químico. O trabalho foi dividido em cinco etapas. Durante a primeira, buscou-se ajustar a duração das etapas anóxica e aerada e as condições operacionais, assim como avaliar a utilização da matéria orgânica presente no lixiviado como fonte de carbono. Ao longo de 16 ciclos de tratamento, os resultados da etapa anóxica indicaram que a duração desta não deveria ser maior que uma hora. A desnitritação ficou limitada ao baixo conteúdo de matéria orgânica de fácil biodegradação no lixiviado, o que levou a baixas taxas, entre 0,010 e 0,142 kg.N-NO2-/ m³.dia. Na segunda etapa, foi ajustada a duração da reação anóxica em uma hora, registrando taxa de desnitritação volumétrica média de 1,704 kg.N-NO2-/ m³.dia, assim como remoção de 80% da DBO e 47% de COT, o que indica que a maior parte da matéria orgânica biodegradável foi empregada pelos micro-organismos heterotróficos na desnitritação. Ao final da fase aeróbia, ao longo da primeira e segunda etapa, mantendo uma concentração de oxigênio dissolvido na massa de líquido do reator de 2,0 mg.O2/L, foi possível alcançar eficiências de remoção de N-NH3 de 98% com predominância do N-NO2-, evidenciado pela relação N-NO2-/(N-NO2-+ N-NO3-) próximo de 1. As taxas volumétrias de nitritação variaram na faixa de 0,095 e 0,199 kg.N-NH3/m³.dia. Como o sobrenadante do reator principal apresentava concentrações elevadas de N-NO2- ao final da fase aeróbia, o efluente foi aplicado em um reator de polimento adicionou-se etanol como fonte de carbono. O tratamento complementar ocorreu sem desequilíbrios, apesar do prolongado tempo de reação anóxica requerido para reduzir toda a massa de nitrito introduzida no sistema, fato que levou a registrar baixas taxas de desnitritação, entre 0,221 e 0,052 kg N-NO2-/kg SSV.dia. Durante a quarta etapa, foi avaliado em um segundo reator de lodo ativado em bateladas sequenciais o processo de nitritação/desnitritação, adicionando dentro do reator, ao início da fase anóxica, o etanol para a redução biológica de todo o nitrogênio oxidado a nitrogênio gasoso. Com concentrações de OD no conteúdo do reator de 2,0 mg.O2/L e valores de pH de 8,27±0,27, a relação N-NO2-/(N-NO2- + N-NO3-) não foi superior a 70% nos 9 ciclos estudados, indicando a presença de nitrato. A hipótese que melhor explica a situação refere-se à possibilidade de que a biomassa esteja se adaptando as novas condições operacionais e a probabilidade de que a adição do etanol durante a reação anóxica possa estar criando condições que favorecem a atividade das bactérias oxidantes de nitrito, assim como os menores diâmetros de floco. A quinta etapa compreendeu a aplicação de um pós-tratamento com redução do pH, adição de sais de ferro e carvão ativado em pó (CAP). Nestes testes, foram registradas remoções de COT e cor de de 93% e 98% respectivamente, mantendo pH em 3,0 e dosagens de 300 mg.Fe+³/L e 15 g.CAP/L. / This research aimed to study the removal of organic matter and nitrogen from landfill leachate through biological process of nitritation/denitritation, operating an activated sludge reactor in sequential batches, and physical- chemical post treatment. The work was divided into five stages. During the first stage, was tried to adjust the duration of the anoxic and aerated stages and operational conditions, and evaluate the use of organic matter present in the leachate as a carbon source. Over 16 cycles of treatment, the results of the anoxic stage indicated that this duration should not be greater than one hour. The denitritation was limited by the low organic matter rapidly biodegradable content into the leachate, which led to low rates between 0.010 and 0.142 kg.N-NO2-/ m³.day. During the second stage, was adjusted the duration of the anoxic reaction to one hour, and showed medium volumetric denitritation rate of 1.704 kg.N-NO2-/m³.day, as well as removal of 80% of BOD and 47% of TOC. These results indicate, most of the biodegradable organic matter was used for heterotrophic microorganisms for denitritation. At the end of aerobic phase, during the first and second stage, and maintaining a concentration of oxygen dissolved into the liquid mass of the reactor in 2.0 mg.O2/L, it was possible to achieve removal efficiencies of NH3-N to 98% with predominance of N-NO2- , that was evidenced by the ratio N-NO2-/(N-NO2-+ N-NO3-) close to 1. The volumetric nitritation rates varied from 0,095 to 0,199 kg.N-NH3/m³.day. The effluent from the principal reactor contained high concentrations of N-NO2- at the end of the aerobic phase, for that reason it was applied a polishing stage where was added ethanol as a carbon source. Complementary treatment transcurred without problems, just was required a prolonged anoxic reaction to reduce the entire mass of nitrite introduced into the system, fact that lead to register low rates of denitritation, between 0.221 and 0.052 kg N-NO2-/kg SSV.day. During the fourth stage, was evaluated in a second activated sludge sequential batch reactor; the nitritation/desnitritation process added ethanol inside the reactor, at the beginning of the anoxic phase, for the biological reduction from nitrogen oxidized to nitrogen gaseous. Maintained OD concentrations into the reactor of 2,0 mg.O2/L and pH values of 8.27± 0.27, the N-NO2-/(N-NO2- + N-NO3-) ratio was not higher than 70% during the 9 cycles studied, indicating the presence of nitrate. The best hypothesis which explains this situation, related to the possibility of the biomass was adapted to the new operating conditions, and the possibility to addition ethanol at the begging of anoxic reaction, may be created adequate conditions for oxidizer nitrite bacteria, as well as the small floc diameters. The fifth stage consisted to apply a physical-chemical post-treatment with pH and addition of iron salts and powdered activated carbon (PAC). During these tests, was removal 93% and 98% of TOC and color respectively, with pH to 3,0 and doses of 300 mg.Fe+³/L and 15 g.PAC/L.

As melhoras nas condições de disposição de resíduos sólidos em aterros sanitários teve, como conseqüência, a geração de um efluente com um grande potencial poluidor, o lixiviado de aterro sanitário, que anteriormente percolava pelo solo. Com o confinamento da massa de lixo e a impermeabilização do aterro, o lixiviado começou a ser coletado exigindo que o mesmo fosse tratado. A necessidade do tratamento deste efluente está relacionada com sua toxidade,pois contém altas concentrações de amônia, metais e alta carga orgânica que se originam da decomposição de compostos contidos no interior do aterro sanitário. Nesta pesquisa olixiviado é submetido a um pré-tratamento biológico com remoção de nitrogênio, no qual a maior parte da matéria orgânica, principalmente a facilmente biodegradável, é consumida,sobrando apenas compostos de cadeias longas de difícil biodegradabilidade e compostos inorgânicos, que são denominados compostos recalcitrantes, sendo em grande parte formados por substâncias húmicas. A intenção do trabalho foi maximizar a remoção destes compostos por meio de um tratamento físico-químico, realizado pelo processo de coagulação-floculação e é considerado uma forma complementar ao tratamento biológico. A pesquisa foi dividida em diversas etapas, em escala de bancada utilizando o jar teste, variando condições de pH de 2,0 a 5,0 e 10 a 12,0, com dosagens de coagulantes de 400mg Fe+³/l e polímeros aniônicos de alto peso molecular com dosagens de 0,5mg/l a 10,0 mg/l, a fim de encontrar a melhor condição de remoção dos compostos recalcitrantes, com o intuito de melhorar ao máximo as condições do efluente a fim de causar o menor impacto possível do mesmo ao ser lançado em cursos de água. De acordo com as variações na condição de tratamento do lixiviado, definiu-se que, com a diminuição do pH a 4,0 seguido de dosagens de 400mg Fe+³/l e ainda com a adição de 2,0 mg/l de polímero, foi possível atingir condições de remoção da ordem de 98% de cor e 80% de COT, indicando que a utilização de polímero é eficiente no processo de tratamento físico químico pelo processo de coagulação floculação de lixiviado de aterro sanitário / The improvements in the conditions of solid waste disposal in landfills has, as a consequence, the generation of an effluent polluted with great potential, landfill leachate, which previously percolated through the soil. With the containment of the waste stream and sealing of the landfill, the leachate began to be collected by requiring that it be treated. The need for treatment of wastewater is related to its toxicity, because it contains high concentrations of ammonia, metals and high organic load originating from the decomposition of compounds contained within the landfill. In this research the leachate is subjected to a pre- biological treatment with nitrogen removal, in which most of the organic matter, especially the readily biodegradable, is consumed, leaving only long-chain compounds difficult biodegradability and inorganic compounds, which are called recalcitrant compounds, being largely composed of humic substances. The intention of this study was to maximize the removal of these compounds by means of a physical-chemical treatment, performed by coagulation-flocculation process and is considered a complement to a biological treatment. The research was divided into several stages, using bench scale jar test conditions of pH ranging from 2.0 to 5.0 and 10 to 12.0, with dosages of coagulants Fe+³ 400 mg/l anionic polymers high molecular weight with dosages of 0.5 mg/l to 10.0 mg/l, in order to find the best condition for removal of recalcitrant compounds, with the most to improve the conditions of the effluent in order to cause minimum possible impact thereof to be released into waterways. According to the variations in the treatment condition of the leachate, it was decided that, with decreasing pH to 4.0 followed by doses of 400 mg Fe+³/l, even with the addition of 2.0 mg/l polymer conditions it was possible to achieve removal of about 98% color and 80% TOC, indicating that the use of polymer is effective in the physical-chemical treatment process by coagulation flocculation process for landfill leachate.

Os processos biológicos apresentam o menor custo de todas as técnicas atualmente aplicadas para o tratamento de lixiviados de aterros sanitários. Porém, eles não vêm demonstrando capacidade em degradar a matéria orgânica recalcitrante presente nesse tipo de água residuária. O presente estudo teve por objetivo avaliar a possibilidade da utilização de enzimas, que são largamente empregadas na indústria, como auxílio em tal remoção. Após a caracterização do lixiviado do aterro sanitário da cidade de Paulínia, verificou-se que o mesmo se encontrava em adiantada fase de biodegradação, com pH de 8,40 ± 0,14; baixa concentração de matéria orgânica facilmente biodegradável (DBO de 857 ± 475 mgO2/L) e altas concentrações de N-NH3(2343 ± 399 mg/L) e de Carbono Orgânico Total (2066 ± 746 mg/L). A investigação experimental foi realizada em duas etapas, empregandose um reator de lodo ativado em bateladas sequencial, com biomassa adaptada ao lixiviado. Na primeira etapa, utilizando o planejamento fatorial completo 2³, verificouse que aumentando o pH e diminuindo a concentração inicial de N-NH3 era possível evitar o acúmulo de nitrogênio amoniacal no sistema a partir da remoção total desse composto. Porém, a inibição às bactérias oxidantes da amônia não foi cessada, pois a eficiência de oxidação via biológica chegava no máximo a 49,1%, sendo os 50,9% restantes atribuídos à volatilização de nitrogênio amoniacal, que era intensificada com o aumento do pH. A segunda etapa teve por objetivo a remoção de matéria orgânica recalcitrante, medida como COT, presente no lixiviado de aterro sanitário, com a utilização da enzima lacase. Esta demonstrou uma expressiva capacidade de remoção de nitrito, de 127 mgNO2 -/L para menos que 0,1 mgNO2 -/L em 4 dias, e de COT, passando de 2333 mgC/L para 1400 mgC/L, ao ser utilizada sozinha, e de 1317 mgC/L para 174 mgC/L quando utilizada juntamente com bactérias heterotróficas. Ao final, observou-se remoções superiores a 99,9% de N-NH3 mantendo-se a concentração de OD=2,4 mg/L, pH=8,5 e concentração de N-NH3 inicial em torno de 270 mg/L. Remoções de 92,3% de nitrito e 40% de COT foram obtidas ao se adicionar a enzima ao efluente nitritado, porém foi observado um aumento na concentração de COT e de NKT após a inserção da solução enzimática, devido a uma alta concentração desses compostos na mesma. / The biological process is the one with the lowest cost of all the techniques currently used for the treatment of landfill leachate. However, it has not demonstrated ability to degrade recalcitrant organic matter present in this type of wastewater. This study aimed to evaluate the possibility of using enzymes, which are already used in industry, as an aid in such removal. After characterizing the Paulinia´s landfill leachate, wich was used in this study, it was found that it was in an advanced stage of degradation, with a pH of 8.40 ± 0.14; low concentration of readily biodegradable organic matter (BOD of 857 ± 475 mgO2/L) and high ammonia nitrogen (2343 ± 399 mgN/L) and Total Organic Carbon - TOC (2066 ± 746 mgC/L). The experimental research was conducted in two stages, using a sequential batch reactor with biomass adapted to the leachate. In the first step, using a full factorial design 2³, it was found that by increasing pH and decreasing the initial concentration of NH3-N is possible to avoid the accumulation of ammonia in the system by the total removal of that compound. However, the inhibition of ammonia oxidizing bacteria is not ceased. The biological pathway for oxidation efficiency reaches the maximum at 49.1%, with the remaining 50.9% being attributed to the volatilization of ammonia, which is enhanced with increasing pH. The second stage was aimed at removing recalcitrant organic matter, measured by the COT present in landfill leachate, with the use of laccase enzyme. The enzyme demonstrated a significant nitrite removal capacity, decreasing its concentration of 127 mgNO2 -/L to less than 0.1 mgNO2 -/L, and the TOC, from 2333 mgC/L to 1400 mgC/L in the same period time.

A presente pesquisa objetivou estudar a remoção de matéria orgânica e nitrogênio de lixiviados de aterro sanitário, através do processo biológico de nitritação/desnitritação, operando um reator de lodos ativados em bateladas sequenciais e pós-tratamento físico químico. O trabalho foi dividido em cinco etapas. Durante a primeira, buscou-se ajustar a duração das etapas anóxica e aerada e as condições operacionais, assim como avaliar a utilização da matéria orgânica presente no lixiviado como fonte de carbono. Ao longo de 16 ciclos de tratamento, os resultados da etapa anóxica indicaram que a duração desta não deveria ser maior que uma hora. A desnitritação ficou limitada ao baixo conteúdo de matéria orgânica de fácil biodegradação no lixiviado, o que levou a baixas taxas, entre 0,010 e 0,142 kg.N-NO2-/ m³.dia. Na segunda etapa, foi ajustada a duração da reação anóxica em uma hora, registrando taxa de desnitritação volumétrica média de 1,704 kg.N-NO2-/ m³.dia, assim como remoção de 80% da DBO e 47% de COT, o que indica que a maior parte da matéria orgânica biodegradável foi empregada pelos micro-organismos heterotróficos na desnitritação. Ao final da fase aeróbia, ao longo da primeira e segunda etapa, mantendo uma concentração de oxigênio dissolvido na massa de líquido do reator de 2,0 mg.O2/L, foi possível alcançar eficiências de remoção de N-NH3 de 98% com predominância do N-NO2-, evidenciado pela relação N-NO2-/(N-NO2-+ N-NO3-) próximo de 1. As taxas volumétrias de nitritação variaram na faixa de 0,095 e 0,199 kg.N-NH3/m³.dia. Como o sobrenadante do reator principal apresentava concentrações elevadas de N-NO2- ao final da fase aeróbia, o efluente foi aplicado em um reator de polimento adicionou-se etanol como fonte de carbono. O tratamento complementar ocorreu sem desequilíbrios, apesar do prolongado tempo de reação anóxica requerido para reduzir toda a massa de nitrito introduzida no sistema, fato que levou a registrar baixas taxas de desnitritação, entre 0,221 e 0,052 kg N-NO2-/kg SSV.dia. Durante a quarta etapa, foi avaliado em um segundo reator de lodo ativado em bateladas sequenciais o processo de nitritação/desnitritação, adicionando dentro do reator, ao início da fase anóxica, o etanol para a redução biológica de todo o nitrogênio oxidado a nitrogênio gasoso. Com concentrações de OD no conteúdo do reator de 2,0 mg.O2/L e valores de pH de 8,27±0,27, a relação N-NO2-/(N-NO2- + N-NO3-) não foi superior a 70% nos 9 ciclos estudados, indicando a presença de nitrato. A hipótese que melhor explica a situação refere-se à possibilidade de que a biomassa esteja se adaptando as novas condições operacionais e a probabilidade de que a adição do etanol durante a reação anóxica possa estar criando condições que favorecem a atividade das bactérias oxidantes de nitrito, assim como os menores diâmetros de floco. A quinta etapa compreendeu a aplicação de um pós-tratamento com redução do pH, adição de sais de ferro e carvão ativado em pó (CAP). Nestes testes, foram registradas remoções de COT e cor de de 93% e 98% respectivamente, mantendo pH em 3,0 e dosagens de 300 mg.Fe+³/L e 15 g.CAP/L. / This research aimed to study the removal of organic matter and nitrogen from landfill leachate through biological process of nitritation/denitritation, operating an activated sludge reactor in sequential batches, and physical- chemical post treatment. The work was divided into five stages. During the first stage, was tried to adjust the duration of the anoxic and aerated stages and operational conditions, and evaluate the use of organic matter present in the leachate as a carbon source. Over 16 cycles of treatment, the results of the anoxic stage indicated that this duration should not be greater than one hour. The denitritation was limited by the low organic matter rapidly biodegradable content into the leachate, which led to low rates between 0.010 and 0.142 kg.N-NO2-/ m³.day. During the second stage, was adjusted the duration of the anoxic reaction to one hour, and showed medium volumetric denitritation rate of 1.704 kg.N-NO2-/m³.day, as well as removal of 80% of BOD and 47% of TOC. These results indicate, most of the biodegradable organic matter was used for heterotrophic microorganisms for denitritation. At the end of aerobic phase, during the first and second stage, and maintaining a concentration of oxygen dissolved into the liquid mass of the reactor in 2.0 mg.O2/L, it was possible to achieve removal efficiencies of NH3-N to 98% with predominance of N-NO2- , that was evidenced by the ratio N-NO2-/(N-NO2-+ N-NO3-) close to 1. The volumetric nitritation rates varied from 0,095 to 0,199 kg.N-NH3/m³.day. The effluent from the principal reactor contained high concentrations of N-NO2- at the end of the aerobic phase, for that reason it was applied a polishing stage where was added ethanol as a carbon source. Complementary treatment transcurred without problems, just was required a prolonged anoxic reaction to reduce the entire mass of nitrite introduced into the system, fact that lead to register low rates of denitritation, between 0.221 and 0.052 kg N-NO2-/kg SSV.day. During the fourth stage, was evaluated in a second activated sludge sequential batch reactor; the nitritation/desnitritation process added ethanol inside the reactor, at the beginning of the anoxic phase, for the biological reduction from nitrogen oxidized to nitrogen gaseous. Maintained OD concentrations into the reactor of 2,0 mg.O2/L and pH values of 8.27± 0.27, the N-NO2-/(N-NO2- + N-NO3-) ratio was not higher than 70% during the 9 cycles studied, indicating the presence of nitrate. The best hypothesis which explains this situation, related to the possibility of the biomass was adapted to the new operating conditions, and the possibility to addition ethanol at the begging of anoxic reaction, may be created adequate conditions for oxidizer nitrite bacteria, as well as the small floc diameters. The fifth stage consisted to apply a physical-chemical post-treatment with pH and addition of iron salts and powdered activated carbon (PAC). During these tests, was removal 93% and 98% of TOC and color respectively, with pH to 3,0 and doses of 300 mg.Fe+³/L and 15 g.PAC/L.

Estudos recentes constataram a existência de processos que permitem a atenuação natural dos contaminantes presentes nos lixiviados. O adequado entendimento destes processos pode originar benefícios possíveis de serem aplicados em aterros antigos, novos ou naqueles que ainda serão concebidos. O presente estudo avaliou o comportamento e a atenuação de contaminantes dos líxiviados no solo, por meio de experimento desenvolvido em colunas de percolação e, para a avaliação da atenuação este teste é indicado por refletir as condições naturais e as características adsortivas do solo, propiciando uma melhor simulação da atenuação. O lixiviado e o solo utilizados neste experimento são provenientes do aterro sanitário de São Carlos - SP. O solo utilizado foi caracterizado quanto à composição física, química, biológica e mineralógica para verificar o transporte do percolado nas colunas e a interação solo-contaminante. Na área do aterro foram feitas perfurações, ensaios de condutividade hidráulica e avaliação da geologia local, para conhecimento das características físicas, químicas, biológicas, mineralógicas e geológicas do solo in situ. Este foi classificado como arenoso, apresentando características físicas e químicas que não se enquadram nos parâmetros adequados para sua utilização em áreas de disposição de resíduos sólidos urbanos, pois, a capacidade de troca de cátions, superfície específica, potencial hidrogeniônico e classe textural arenosa, evidenciam que este solo possui deficiente capacidade de retenção e imobilização de contaminantes. Além disso, pela observação in situ, constata-se que a área de disposição de resíduos sólidos de São Carlos esta situado sobre rochas da Formação Botucatu, sendo que a mineralogia do solo presente no local é composta de quartzo, caulinita, goethita, hematita, gibsita e ilita. O ensaio de condutividade hidráulica indicou que o solo presente na base do Aterro sanitário não atende a valor de permeabilidade exigida por norma, o que poderá permitir a infiltração de água da chuva, aumentando a produção do lixiviado e sua movimentação no perfil, podendo atingir as águas subterrâneas. Assim, foram traçadas curvas características do transporte de contaminantes nas amostras efluentes monitoradas durante o processo de percolação, coletadas a cada 0,25 volume de poros até atingir 10,0 volume de poros percolados. As curvas características do transporte de contaminantes traçadas apresentaram baixas concentrações de Chumbo, Cádmio, Ferro, Zinco, Manganês, Cálcio, Magnésio, Cobre, Cromo nas amostras fluentes. Já o Sódio, Potássio, Cloro, Níquel e Alumínio foram preferencialmente percolados com o lixiviado, evidenciando a variação da faixa de concentração de cada elemento no percolado. Os perfis de concentração dos metais pesados mostraram que existe uma frente de contaminação. As curvas de retenção de metais no solo mostraram que a preferência de sorção apresentada pelos solos nas colunas foi : Cobre > Cádmio > Cálcio > Zinco > Magnésio > Potássio > Manganês > Fósforo > Ferro > Níquel > Alumínio. Cujos valores retidos no solo das colunas podem estar evidenciando a capacidade deste solo em reter contaminantes.O solo em questão apresentou baixo potencial para retenção dos contaminantes presentes no lixiviado, classificado como arenoso e, com características químicas que não se enquadram nos parâmetros adequados para sua utilização em áreas de disposição de resíduos sólidos urbanos. / Recent studies had found the existence of processes that allow a natural attenuation of the leachates\'s cotaminants. An adequate understanding of these processes may originate benefits, that may be applied in ancient, new or to be created landfills. This work evaluated the contaminant\'s behavior and attenuation, contaminants existing in soil\'s leaching, throughout an experiment developed in percolation columns. This is the indicated examination for evaluate the attenuation, because it reflects soil\'s natural conditions and adsorptive characteristics, providing a better simulation of it\'s attenuation. The leachate and the soil used in this experiment came from Sao Carlos-SP landfill. The used soil has been characterized as its mineralogical\'s and physical chemical-biological\'s composition, looking for the percolated\'s transportation inside the columns, and for the interaction soil-contaminant. The landfill\'s area has been several times drilled, tested as it\'s hydraulic conductivity and assessment of local geology, in order to know the physical, chemical, biological, mineralogical and geological in situ soil\'s characteristics. This, has been classified as sandy, and, by presenting chemical characteristics that does not reach the adequated value for utilization on solid urban wastes, due to the values of CTC, SE, pH, and the textural sandy class, what shows a deficient buffering capacity in retaining and immobilisating contaminants. By observation in situ, has been found that Sao Carlos\'s solids disposal waste is located over rocks from the Botucatu formation, and the mineralogy of it is composed of quartz, caulinith, goethith, hematith, gibsith an ilith. The hydraulic conductivity test has indicated that the soil in the base of the sanitary landfill does not reaches the permeability values required by the standards, what may allow rain water\'s infiltration, and raises the amount of leachate and it\'s movement onto the ground, and even the leachete to reach the underground waters. So, has been drawn the characteristics curves of the contaminant\'s transportation in the effluents samples found during the percolation process, collected by every 0,25 VP until it reaches 10,0 VP percolated. The characteristical curves of the contaminant\'s transportation drawn showed low concentrations in the effluent samples of Lead, Cadmium, Iron, Zinc, Manganese, Calcium, Magnesium, Cooper, Chromium. Also, Sodium, Potassium, Chlorine, Nickel and Aluminium had been preferencially percolated within the leachate, what evidentiates the variation in the range of concentrations of every percolated element. The concentration profiles from heavy metal\'s had shown that there is a front of contamination. The retention curves from the soil\'s retaining metal showed that the preferency for the sorption was: Cooper > Cadmium > Calcium > Zinc > Magnesium > Potassium > Manganese > Phosphorus > Iron > Nickel > Aluminium, whose values may point the soil\'s ability in retaining contaminants. The studied soil has presented low potential in retain contaminants from the leachete, and is characterized as sandy, and it\'s chemical features shall not be framed according the standards parameters to be utilized in solid urban waste\'s disposal.

Landfill leachates are a concern in the Pacific Region where they may contribute contaminants to the coastal marine environment. Poor waste management and pollution of coastal waters are amongst the major environmental problems in Kiribati, particularly in South Tarawa. An investigation of areas adjacent to coastal landfill sites; Betio, Kiribati and Auckland, New Zealand was undertaken. The Kiribati case study investigated metal contamination in marine sediments at an operational landfill while the New Zealand study was adjacent to a coastal landfill decommissioned in the 1970s. Surficial sediments (top 15 cm) were collected along transects. At both the New Zealand and Kiribati sites, 3 transects adjacent to the landfill and 1 control transect were sampled. The sediments were analyzed for particle size distribution, organic matter content, and Cd, As, Cr, Cu, Pb, Hg, Ni and Zn concentrations. The pH was also measured. The Kiribati study site had a groundwater pH of 7.14 - 8.85, and sediment materials were dominated by sand with a low organic matter content (1.60 - 2.21 %). At the Kiribati sites Cd, As, and Ni were below the detection limits. The Cr, Cu, Pb and Zn concentrations were lower at the Kiribati control transect than the landfill transects. Cr level decreased away from the landfill indicating the landfill as a possible source. However, Cu and Zn did not show any distribution pattern suggesting other potential sources (port and shipwrecks) may have contributed to the elevated levels. At the Kiribati landfill and control transects the Cr, As, Cd, Cu, Pb, Ni, and Zn concentration were below the Effects Range-Low (ERL) and the threshold Effects levels (TEL) of the Sediment Quality Guidelines (SQCs) of the National Oceanographic and Atmospheric Administration (NOAA) and the Florida Department of Environmental Protection, indicating no potential adverse ecological effects on the biota. At the Kiribati control site the Cr, As, Cd, Cu, Pb, Ni and Zn concentrations were within the background ranges published for clean reef sediment but the concentration at the landfill transects exceeded the background ranges. The concentration of mercury at both the control and landfill transects in Kiribati exceeded the Effects Range-Median (ERM) and the Probable Effects Level (PEL) of the SQGs indicating potential adverse ecological effects on the local benthic communities. The New Zealand study site sediments had a pH of 6.22 - 7.24, and comprised up to 90 % clay/silt, with an organic matter content of 5 - 22 %. At the New Zealand landfill transects Arsenic concentrations decreased away from the landfill indicating the landfill as a possible source. Other metals such as Cr did not show a pattern of distribution along the transects, or with depth, suggesting that the landfill was not the only source of these metals. There was a weak correlation between organic matter content, particle size distribution, and metal enrichment. At the New Zealand site, there were no marked differences in metal concentrations between the landfill and control transects suggesting the landfill was not the only source of metals and that the wider urban or industrial run-off may have contributed. All the metal concentrations, except Hg and Zn, exceeded the ERL and the TEL values indicating the potential for adverse ecological effects of metals on the benthic communities. At the New Zealand site the Hg and Zn concentrations exceeded both the ERM and PEL of the SQGs and are considered highly contaminated.