Landfilling is the most common approach to dispose of municipal solid wastes but inevitably leads to leachate formation. Persistent UV quenching substances (UVQS) in landfill leachate can affect the effectiveness of UV disinfection in municipal wastewater treatment systems when leachate co-treatment is applied. Membrane electrochemical reactor (MER) treatment was investigated to reduce the UV quenching capability and simultaneously recover resources in the leachate as an effective onsite pre-treatment. Ion-selective membranes were used in this MER to create two different conditions: a low-pH anolyte for organic oxidation and a high-pH catholyte for ammonia recovery. The MER achieved significantly higher removals of both dissolved organic carbon and UV254nm absorbance than membrane-less electrochemical treatment. The MER was able to remove a large percentage of total nitrogen from the leachate while recovering about half of the influent ammonia in the catholyte with less specific energy consumption. The second study coupled MER with Fenton oxidation through providing synergistic benefits with the low solution pH, reduced organics, and ammonia removal. This two-stage coupled system reduced the more leachate COD than the standalone Fenton process treating raw leachate. Also, the usage of chemicals as Fenton reagents has been greatly reduced: FeSO4 and H2O2 by 39%, H2SO4 by 100%, and NaOH by 55%. Consequently, the sludge production was reduced by 51% in weight and 12% in volume. Despite electricity consumption by the MER, the coupled system cost $4.76 per m3 leachate less than the standalone Fenton treatment. More notably, direct Fenton oxidation removed only 21% of ammonia; in comparison, the MER-Fenton system removed ammonia by 98% with the possibility for recovery at a rate of 30.6 -55.2 kg N m-3 reactor d-1. Those results demonstrated that coupling MER with the Fenton process could mitigate some inherent drawbacks of Fenton oxidation such as ineffective ammonia removal, high acid and chemical reagents dose requirements, and a large amount of sludge generation. The third study investigated the formation of total halogenated organics (DBP) and the associated toxicity as the side effect of leachate treatment in the MER. Compared to the 4538±100 µg L-1 from the control membrane-less electrochemical oxidation reactor, the amount of DBP generated in the MER only accounted for 19.1±4.5 % after the same treatment period. The total toxicity value (26.6 ×10-3 ) was low for MER effluent, only 15.1% of that in the control group. Both high pH and high ammonia concentration introduced more DBP mass and toxicity production after MER treatment. DBP concentrations were shown to increase with applied current density and possible temperature raise. With 67.5% of DBP mass concentration and 74.4% of the additive toxicity removal, the granular activated carbon (GAC) electrode system was shown more effective than GAC adsorption alone in remediating DBP harmful effects. This dissertation introduced MER as a promising technology for the treatment of leachate through performance demonstration, process integration and by-product remediation. / Doctor of Philosophy / Municipal solid waste is often disposed of in landfills because of the most economics and convenience. However, one of the most challenging problems is the leachate formation and treatment. In the US, leachate is currently often diluted in domestic wastewater treatment systems; meanwhile, the persistent contaminants in landfill leachate can lower the effectiveness of UV disinfection and result in high cost and permit violation. In this study, the membrane electrochemical reactor (MER) using electricity as the driving force was applied to solve the issue and simultaneously recover valuable resources in the leachate. Membranes as a barrier for selective ions were used in this MER to create two different conditions with different purposes: a low-pH anolyte for organic oxidation and a high-pH catholyte for ammonia recovery. The MER achieved significantly higher contaminants removals than membrane-less electrochemical treatment. The second study coupled MER with one of the established advanced oxidation processes, also known as Fenton oxidation through providing mutual benefits with the low solution pH, reduced organics, and ammonia removal/recovery. This two-stage coupled system reduced the leachate contaminants effectively towards the direct discharge standard. In addition, the usage of chemical reagents, as well as the amount of process residual, has significantly been reduced. The third study investigated the formation of by-products as the side effect of leachate treatment in the MER. Compared to the membrane-less reactor, the undesirable by-products generated in the MER only accounted for one fifth after the same treatment period. A granular activated carbon electrode system was shown effective in remediating the harmful effects. This dissertation introduced MER as a promising technology for the treatment of leachate as one of the toughest wastewaters.

Prediction of subsurface migration of contaminant through soils involves analyses of unsaturated and saturated flow of water and advective dispersive transport of contaminant species. A finite element model is developed here for such an analysis. It is based on the transient nonlinear Richard's equation for the unsaturated flow and the mass transport equation using advective dispersive transport phenomenon. The model makes it possible to make advance predictions of the spread of the contaminant with respect to time and space, into the ground water system. The hydraulic properties of the unsaturated soils and the dispersion characteristics need to be obtained for such an analysis. The unsaturated flow parameters are obtained from a functional relationship between capillary pressure head and moisture saturation, and can be determined from laboratory tests on simple column samples of soils. A general expression is assumed to account for the effect of velocity dependence of the hydrodynamic dispersion coefficient in the mass transport problem. A computer program POLUT2D is developed based on the above assumptions. Pre and post processors for the computer program POLUT2D are also developed for interactive input of data and graphics displays of results. The computer program is first evaluated by comparing the results of a problem given in the literature with the results obtained by POLUT2D. The factors affecting the contaminant movement and distribution such as dispersivities, hydraulic conductivities and the effect of cutoff walls in controlling the spread of contaminant plume are studied. Also in this regard, the movement and spread of a contaminant at a landfill site in New Castle County, Delaware, is studied by comparing the simulated pattern of plume with the observed pattern. / Master of Science

<p>Landfill leachate contains a variety of contaminants and is created when rainwater percolates the landfill. For landfill management the leachate is the main issue that can cause problems to the environment. At the landfill of Fläskebo, Renova AB treats the leachate in a local treatment plant. The treatment consists of a chemical treatment step with chemical precipitation, flocculation, sedimentation and filtration, and a final step with a carbon and peat filter. Renova has to ensure that the condition of the leachate reaches the regulation set for the landfill before it is released to the recipient. This regulation has not yet been established and a final suggestion will be given to the county administrative board in spring 2006.</p><p>In this master thesis the chemical treatment of Fläskebo is optimized. A comparison between the control program and the regulation was made to estimate the contamination of the leachate. Also the effectiveness of the two steps is evaluated. For optimization, the leachate was first tested in a laboratory with different coagulants and flocculants.</p><p>The purpose was to increase the precipitation of particles and metals; arsenic, cadmium, chromium, mercury, lead, copper, nickel and zinc through sweep floc coagulation and hydroxide precipitation. After the laboratory tests the precipitation was tested in the treatment plant with higher pH and coagulant. Also the process control for sodium hydroxide was examined.</p><p>The leachate had a small content of organic matter and nutrients, but had a large content of halogenated substances (AOX) and the heavy metals nickel and copper. High concentrations of contaminants were reduced better than low concentrations in the two treatment steps. The carbon and peat filter material also caused an increase of the arsenic content in the leachate after filtration. From the laboratory work the results showed a better reduction of metals with iron-chloride, PlusJÄRN and the anjonic polyacrylamid, Fennopol A. Because of the high content of chloride the iron- sulphate, PurFect was chosen for further tests. The optimal pH for the heavy metals arsenic, zinc, copper and nickel was between pH 9 and 9, 5. The precipitation in the treatment plant showed better results with sodium hydroxide and a higher pH, pH 9 in the flocculation basin. An increase of the coagulant PurFect from 202 mg/l to 225 mg/l meant only a higher chemical cost. The process control of sodium hydroxide showed an oscillating and unstable control performance, which may lead to a higher consumption of chemicals.</p> / <p>Lakvatten har varierande föroreningsgrad och karaktär och bildas då regnvatten perkolerar igenom en deponi. För en deponiverksamhet är lakvattnet den huvudsakliga påverkan på den omgivande miljön. Vid en av Renova ABs deponier, Fläskebo, utanför Göteborg sker reningen av vattnet i den lokala reningsanläggningen. Reningen består av kemisk fällning, flockning, sedimentering och filtrering samt ett kol- och torvfilter. För att få släppa ut lakvattnet har Renova just nu ett prövotidsvillkor på lakvattnets kvalité och till våren 2006 skall förslag på slutgiltiga utsläppsvillkor lämnas till Länsstyrelsen.</p><p>I detta examensarbete har den kemiska reningen av lakvattnet från Fläskebo optimerats utifrån lakvattnets karaktär. Lakvattnets föroreningsgrad bedömdes efter en jämförelse av analysresultatet inom kontrollprogrammet och riktvärdena i prövotidsvillkoret. Dessutom utvärderades effektiviteten i varje enskilt reningssteg, den kemiska reningen och kol- och torvfiltret. För optimering av den kemiska reningen testades lakvattnet först på lab med olika fällnings- och flockningsmedel. Uppgiften var att öka partikelfällningen och reducera metallerna arsenik, kadmium, krom, kvicksilver, bly, koppar, nickel och zink i lakvattnet genom svepkoagulering och hydroxidfällning.</p><p>Utifrån resultaten på lab testades sedan fällningen i full skala, pH höjdes i flockningsbassängen och så även dosen fällningsmedel till vattnet. En inledande undersökning av regleringen av lutdosering gjordes med några stegsvarsexperiment.</p><p>Lakvatten innehöll låga halter av organiskt material och närsalterna kväve och fosfor, medan de halogena ämnena (AOX) och tungmetallerna nickel och koppar var höga. De båda reningsstegen, kemisk rening och kol- och torvfiltret var generellt bra på att rena föroreningar i höga koncentrationer men var sämre vid låga. Kol- och torvfiltret ökade koncentrationen i vattnet av arsenik genom materialets interna läckage. I fällningsförsöken gav järnkloriden, PlusJÄRN och den anjoniska polyakrylamiden, Fennopol A bäst resultat i att avskilja metaller. Järnsulfaten PurFect gav näst bäst resultat och valdes istället för järnkloriden för vidare försök då kloridhalten i lakvattnet redan var högt. Optimalt pH för arsenik, zink, koppar och nickel var inom pHintervallet 9 och 9,5. Fällningen i full skala ute i verket visade ett bättre resultat vid tillsatt lut och ett högre pH (pH 9) i flockningsbassängen. Däremot betydde en höjning av fällningskemikalien från 202 mg/l PurFect till 225 mg/l enbart en ökad kemikaliekostnad och en överdosering. Det visade sig dessutom att lutregleringen var svängig och på gränsen till instabil. Regulatorn bör därför ses över så att risken för ökad kemikaliekonsumption och kostnader minskar.</p>

A series of laboratory accelerated immersion tests are used to examine the effects of different chemicals found in municipal solid waste leachate, geomembrane thickness, and incubation temperatures on the degradation of different high density polyethylene geomembranes. It was found that surfactant was the key leachate constituent affecting antioxidant depletion while salts accelerated degradation of the mechanical properties, especially stress crack resistance. Immersed in synthetic leachate, the time to nominal failure at 35oC was predicted to be 62% longer for the 2.5 mm, and 12% longer for the 2.0 mm, than for the 1.5 mm geomembrane tested. The antioxidant depletion in synthetic leachate and air at temperatures > 85oC was consistent with what would be expected from Arrhenius modeling based on data from lower temperatures (≤ 85oC). However, the early depletion rates in water incubation decreased with the increase of the temperature above 100oC. It was also found that at temperatures above 100oC, there was significant change in the polymer morphology that affected the stress crack resistance at early incubation times prior to polymer degradation. Large-scale geosynthetic liner longevity simulators (GLLSs) which simulated field conditions were used to investigate the susceptibility of pre-aged high density polyethylene geomembranes to stress cracking and to evaluate the performance of geomembranes under a 150 mm sand protection layer. A pre-aged geomembrane with a 560 g/m2 geotextile protection layer experienced brittle rupture at local gravel indentations. The time to failure was correlated to the incubation temperatures. The use of a sand protection layer not only delayed antioxidant depletion compared to that with a traditional geotextile protection but also substantially reduced the long-term tensile strains in the geomembrane below the allowable strain limits. / Thesis (Ph.D, Civil Engineering) -- Queen's University, 2013-11-26 12:36:01.538

O tratamento e a disposição final de resíduos sólidos urbanos é um dos grandes problemas ambientais da atualidade. No caso dos aterros sanitários, as áreas para implantação desses empreendimentos são cada vez mais escassas, especialmente nos grandes centros urbanos, exatamente onde há grande geração de resíduos. É notória a necessidade de se buscar alternativas adequadas para a disposição final de resíduos sólidos urbanos. A correta disposição de resíduos em aterros sanitários exige que esses empreendimentos sejam tratados de forma integral, desde a escolha do local, o desenvolvimento do projeto e a execução da obra até o gerenciamento da operação e ações correlatas de monitoramento ambiental. O objetivo dessas ações é minimizar os potenciais impactos ao meio ambiente, dos quais o de maior gravidade é a contaminação do solo e das águas pelos lixiviados gerados nos aterros. Os lixiviados de aterros sanitários são produzidos durante toda sua vida útil e após seu encerramento, devendo ser coletados, tratados e monitorados por várias décadas. Atualmente, não se sabe de maneira precisa qual é o volume e por quanto tempo ocorre a geração de lixiviados na maioria dos aterros sanitários no Brasil. Para esse trabalho realizou-se o levantamento dos aterros sanitários em operação e encerrados no período de 1998 a 2012 na Região Metropolitana de São Paulo, bem como da geração de lixiviados durante o mesmo período. A partir dessas informações traçou-se a série histórica referente a esse período, a partir da qual se pode inferir a grandeza da problemática para os próximos anos. Também são abordadas as necessidades futuras do sistema de tratamento de lixiviados. / The treatment and final disposal of urban solid wastes is one of the great environmental problems of present. In the case of sanitary landfills, the areas for settlement of such projects are increasingly scarce, especially in great urban areas, exactly where there is great waste production. It is notable the necessity of searching adequate alternatives for the final disposal of solid wastes. The correct disposal of solid wastes in sanitary landfills requires that these projects be treated in an integral approach, since the choice of the site, the project development, and the execution of the construction, to the operation management and correlated environmental monitoring actions. The intent of such actions is to minimize potential risks to the environment, being one of the most serious the soil and water contamination by the leachate generated in landfills. Landfill leachate is produced during the operation and after closure of landfills. They must be collected, treated and monitored for several decades. Currently, in most of landfills in Brazil, there is no accurate information about the volume of generated leachate and for how long it is produced. For this dissertation it has been held a survey of operating and closed landfills from 1998 to 2012 in the metropolitan area of São Paulo, as well as the leachate generated. Using these data, a historical series of this period has been traced, from which one can infer the magnitude of the problem for the next years. This study also addresses future need of the leachate treatment system.

Ainda são poucas as cidades brasileiras que dão destino adequado aos seus resíduos sólidos urbanos. A disposição de resíduos em aterros sanitários é hoje uma das formas mais econômicas e adequadas de disposição. A grande quantidade de matéria orgânica presente nos resíduos domiciliares, a umidade própria dos resíduos, a infiltração de águas de chuvas e as atividades microbiológicas, faz com que se gere no interior dos aterros os líquidos percolados. Esses líquidos apresentam elevada demanda química de oxigênio (DQO) e são potencialmente poluidores. Este trabalho avaliou a eficiência e a viabilidade da utilização de um reator anaeróbio horizontal de leito fixo (RAHLF), no tratamento de líquidos percolados coletados nos aterros sanitários de Bauru-SP e Rio Claro-SP. O reator, em escala piloto, constituiu-se de um tubo de PVC com 3,0 m de comprimento e 14,5 cm de diâmetro interno, perfazendo uma relação comprimento por diâmetro (L/D) de aproximadamente 20 e volume de aproximadamente 50 L. O reator possuía coletor de gases e amostradores intermediários ao longo do comprimento, em posições correspondentes a L/D de 4, 8, 12 e 16. Como suporte de imobilização foi utilizada espuma de poliuretano com densidade de 20 kg.m-3 na forma de cubos de aproximadamente 10 mm de lado. Os percolados foram coletados e armazenados em uma câmara fria a 5ºC e o reator foi mantido com temperatura controlada em uma câmara a 30ºC. Ao se operar o sistema por oito semanas, com o percolado coletado em Bauru-SP, não houve adaptação da biomassa devido, provavelmente, às altas concentrações de NH3. Utilizando o percolado de Rio Claro-SP, o sistema apresentou inicialmente baixas eficiências, mesmo com tempo de detenção hidráulica de 25 dias. Mas após mudanças na estratégia de operação, utilizando-se um substrato sintético na adaptação e a substituindo-se o percolado por outro coletado no mesmo aterro, o sistema reagiu muito bem, obtendo-se eficiências de aproximadamente 80% em termos de remoção de DQO, com tempo de detenção hidráulica de 2,5 dias e com DQO afluente da ordem de 5.000 mg/L. / Even today, only few Brazilian cities give adequate destiny to urban solid wastes. The waste disposal at sanitary landfills is currently one of the most economical and adequated way of waste disposal. The high quantity of organic matter in domiciliary wastes, the waste own moisture, the rainwater infiltration and the microbiological activities lead to the leachate generation into the landfill. This liquid has a high chemical oxygen demand (COD) concentration, and is a potential pollutant. This work evaluated the viability and the efficiency of the use of a horizontal anaerobic immobilized sludge reactor (HAIS reactor) for leachate treatment collected from Bauru-SP and Rio Claro-SP landfills. The reactor, in pilot scale, was constructed using a 3,0 m of length and 14,5 cm internal diameter PVC pipe, with a length-diameter ratio (L/D) of approximately 20, and an approximately 50 L volume. The reactor had gas collectors and intermediate samplers in the direction of its length, in positions corresponding to L/D equal to 4, 8, 12 and 16. For immobilization support it was utilized polyurethane foam with 20 kg.m-3 of density in cube form, with side of approximately 10 mm. The leachate was collected and stored in a cold chamber at 5ºC and the reactor was maintained at controlled temperature in a chamber at 30ºC. Operating the system with the leachate from Bauru-SP during eight weeks, there was no biomass acclimatization due, probably, to high NH3 concentrations. When utilizing the leachate from Rio Claro-SP the system had, initially, low efficiencies, even with a hydraulic retention time of 25 days. But after changes in the operation strategy, changing the leachate by one other collected in the same place, the system reacted very well, obtaining efficiencies of approximately 80% in terms of COD removal, with a hydraulic retention time of 2,5 days and an inlet COD at the range of 5.000 mg/L.

O presente trabalho discute o recebimento de lixiviado de aterros sanitários em estações de tratamento do sistema público de esgotos para tratamento conjunto. Descreve os processos de geração do lixiviado nos aterros e faz uma avaliação desse recebimento em quatro estações de tratamento em operação no Estado de São Paulo que empregam processos biológicos de tratamento por lodos ativados convencional e por batelada, lagoas de estabilização (anaeróbia seguida de facultativa) e lagoas aeradas. Também apresenta a variação da produção de lixiviado em aterros sanitários em função dos períodos de chuva e seca, estabelecidos pela precipitação observada no período avaliado. Conclui que o tratamento conjunto de lixiviado de aterro é uma alternativa a ser considerada no planejamento dos sistemas de resíduos sólidos e de esgotos sanitários. A adoção do tratamento conjunto traz benefícios a esses sistemas e à sociedade, pois pode representar economia de escala, atendimento às exigências legais e conformidade ambiental, promovendo melhores condições de saúde pública / This work discuss the receipt of sanitary landfill leachate by public wastewater treatment plants for joint treatment. It describes the processes theough which leachate is generated in landfills and assesses its receipt in four wastewater treatment plants in the state of São Paulo that employ biological processes such as conventional and batch activated sludge and stabilization ponds (anaerobic pond followed by facultative pond). Additionally, the work shows the variation in the production of leachate during the dry and rainy seasons, which were established based on the volume of rainfall during the period of study. The conclusion is that the joint treatment of landfill leachate by wastewater treatment plants with the appropriate technical and operational criteria is na alternative to be considered in the planning of solid waste and sanitary sewer systems and the society because it would result in economy of scale, compliance with legal and environmental legislation, and improvement of public health

Apesar de surgir como um país emergente, infelizmente a situação do saneamento básico no Brasil é bastante precária. Dos 5.507 municípios brasileiros apenas 52,2% possuem algum tipo de serviço de esgotamento sanitário (IBGE, 2000). Diante deste cenário alarmante, soluções individuais passam a ganhar mais importância. A adoção de tanques sépticos como uma alternativa para a solução do esgoto sanitário, em regiões carentes de rede de esgoto, passa a ser viável devido ao seu baixo custo e eficiência satisfatória. No entanto, a operação inadequada dessas pequenas unidades podem se tornar um passivo ambiental, em virtude do lodo produzido, subproduto da degradação anaeróbia. A solução mais fácil e prática seria a sua disposição em Estações de Tratamento de Efluente, no entanto é uma minoria dos municípios brasileiros, 20,2% (IBGE, 2000), que contam com estas unidades. A proposta do presente trabalho foi simular a comportamento da disposição do Lodo de Tanques Sépticos (LTS) em aterros sanitários, juntamente com resíduos sólidos domiciliares (RSD). Por meio de quatro reatores anaeróbios, com 50 litros cada, avaliaram-se os efeitos da degradação anaeróbia da Fração Orgânica do RSD (FORSD) na presença de LTS. Todos os reatores possuíam a mesma quantidade de FORSD, 28 kg. Cada unidade experimental recebeu quantidades diferentes de LTS: reator 1 = 0 L; reator 2 = 4,9 L; reator 3 = 9,8 L e reator 4 = 14,7 L. O monitoramento acompanhou as características químicas e a quantidade do lixiviado, a composição do biogás e as mudanças físico-químicas na mistura de FORSD e LTS no início e no final do experimento. Entre os resultados obtidos, destaca-se a eficiência de remoção de DQO da FORSD, 21%, 51%, 68% e 73% para os reatores 1, 2, 3 e 4 respectivamente. E a aceleração na degradação anaeróbia nos reatores que receberam LTS, devido a produção precoce de metano, aparecimento no 40º dia nos reatores tratados com LTS e pela disponibilidade imediata de nutrientes, observada pelas análises de nitrogênio amoniacal. / Despite being an emerging country, unfortunately the sanitary situation of Brazil is quite precarious. Only 52.2% of the 5,507 brazilian municipalities have some type of sanitary service (IBGE, 2000). In this alarming scenario, individual solutions are gaining more importance. The adoption of septic tanks as an alternative to the solution of the sewage becomes viable due to its low cost and satisfactory performance. However, the inappropriate operation of these small units can become an environmental problem because of the produced sludge, sub product of anaerobic degradation. This material must be managed adequately and securely to prevent possible contamination of soil and water. The easiest and practice solution would be its disposal in sewage treatment stations, however there are only 20.2% (IBGE, 2000) of all the brazilian cities which rely on these units. The purpose of this study was to evaluate the performance of the disposal of sludge from septic tanks (LTS) in landfills, along with domestic solid waste (RSD). Using four anaerobic reactors, with 50 liters each, the effects of anaerobic degradation of organic fraction of the RSD (FORSD) in the presence of LTS were evaluated. All reactors had the same amount of FORSD, 28 kg. Each experimental unit received different amounts of LTS: Reactor 1 = 0 L; Reactor 2 = 4.9 L, Reactor 3 = 9.8 L and Reactor 4 = 14.7 L. The monitoring followed the characteristics and quantity of leachate, the composition of biogas and changes in physical-chemical mixture of FORSD and LTS at the beginning and the end of the experiment. The results highlight the efficiency of removal of the DQO of FORSD, 21%, 51%, 68% and 73% for reactors 1, 2, 3 and 4, respectively, and the acceleration in the degradation in anaerobic reactors that received LTS, due to early production of methane, appearing in 40º day in reactors treated with LTS and the ready availability of nutrients, observed by the analysis of ammonia nitrogen.

O lixiviado de aterro sanitário é um efluente gerado a partir da mistura de líquidos produzidos na degradação de resíduos sólidos e a água pluvial que infiltra o depósito de material. Estudos na literatura, abordando tratamento de lixiviados de aterro sanitário, indicam que os processos biológicos podem não ser suficientes para que os padrões de lançamento vigentes na legislação sejam cumpridos. Neste contexto os processos oxidativos avançados estão sendo apontados como uma alternativa atrativa para efluentes que apresentam baixa biodegradabilidade. A presente pesquisa objetivou avaliar, em escala de bancada, a tratabilidade do lixiviado de aterro sanitário com aplicação do tratamento de oxidação eletroquímica seguida pelo tratamento biológico de um sistema de lodos ativados operado em batelada. A eletro-oxidação promove a remoção ou degradação de espécies poluentes, direta ou indiretamente, por meio de processos que não necessitam de adição de grandes quantidades de produtos químicos. Nos ensaios realizados com lixiviado bruto e com lixiviado alcalinizado submetido ao tratamento físico-químico de air stripping não houve necessidade de adicionar eletrólitos suporte para a oxidação química ocorrer e ao longo de tais ensaios a matéria foi mensurada quanto à DQO, COT e COD. Quando aplicada a eletro-oxidação no lixiviado bruto (sem tratamento prévio), houve 87% de remoção de DQO utilizando o anodo DDB com aplicação de 48 A h L-1 (densidade de corrente de 100 mA cm-2) e 65% de remoção da DQO quando utilizado o anodo DSA, nas mesmas condições. Analogamente, foram obtidos valores percentuais de remoção de COT de 70 e 60%, respectivamente e ainda 61 e 67% em relação ao COD. A fim de se complementar os estudos quanto à atuação da eletroquímica no tratamento do lixiviado de aterros sanitários, o efluente eletro-oxidado foi adicionado a um sistema de lodos ativados em duas proporções volumétricas distintas (2,5 e 5%) combinadas com esgoto sanitário (97,5 e 95%, respectivamente). Para controle e possível análise na eficiência, foram realizados ensaios com lixiviado bruto (5% de lixiviado bruto e 95% de esgoto sanitário) e somente esgoto sanitário (100%). Foram obtidos valores de remoção de DQO de: 75% em condição 100% esgoto sanitário, 64% com adição 2,5% de lixiviado eletro-oxidado, 57% com adição de 5% de lixiviado eletro-oxidado e 38% com adição de 5% de lixiviado bruto, além de valores percentuais de remoção de COT em cerca de 56, 52, 47 e 37%, respectivamente. E ainda foram obtida remoções nos valores de DBO na ordem de 91, 87, 64 e 24%, respectivamente. De forma geral, o sistema combinado proposto atingiu eficiências consideráveis e se mostrou compatível com o intuito de se estudar o aumento da tratabilidade por meio da aplicação de processos eletroquímicos em lixiviado bruto. / The landfill leachate is a wastewater generated from the mixture of liquids produced in the degradation of solid waste and rainwater that infiltrates the landfill. Studies in the literature approaching the treatment of landfill leachate indicate that biological processes may not be sufficient for the discharge standards prevailing in the present legislation. In this context the advanced oxidation processes (AOP) are being singled out as an attractive alternative for wastewater with a low biodegradability. This study aimed to evaluate, in a bench scale treatability of landfill leachate treatment with application of electrochemical oxidation followed by biological treatment of an activated sludge batch system. The electro-oxidation promotes the removal or degradation of pollutants species directly or indirectly, through processes which do not require addition of large amounts of chemicals. For tests with raw leachate and leachate with alkaline subjected to physico- chemical treatment of air stripping, there was no need to add support for electrolytes and chemical oxidation occurs over such trials the subject was measured as the COD, TOC and DOC. When applied the electro-oxidation in the raw leachate (without treatment) was reached 87% for COD removal using the DDB anode with the application of 48 L h-1 (current density 100 mA cm-2) and 65% COD removal when using the DSA anode under the same conditions. Similarly, the percentage values of TOC removal are 70 and 60 % respectively and also 61 and 67% compared to the DOC was obtained. In order to complement the studies regarding the performance of the electrochemical treatment of landfill leachate, the electro-oxidized effluent was added to an activated sludge system in two different volume ratios (2,5 and 5%) combined with sewage (97.5 and 95%, respectively). For control and possible efficiency analysis, testing with raw leachate (5% and 95 % crude leachate sanitary sewer) and only sanitary wastewater (100 %) were performed. Values of COD removal was obtained: 75% in 100% sewage condition, 64% with addition of 2,5% leachate electro- oxidized , with 57% addition of 5% leachate electro- oxidized and 38% with the addition of 5% raw leachate , and percentage values of TOC removal by about 56, 52, 47 and 37% , respectively. And BOD removal values were obtained in the order of 91, 87, 64 and 24%, respectively. In general, the proposed combined system has achieved considerable efficiency and proved to be compatible with the aim of studying the increased tractability through the use of electrochemical processes raw leachate.

Durante anos, o lixo da cidade de Guaratinguetá foi aterrado e o seu produto recalcitrante não passou por nenhum tratamento físico ou mesmo químico, percolando diretamente sob o aterro. Mesmo tendo sido desativado e transformado em Parque Ecológico, o material depositado no local ao longo dos anos, continuará a ser decomposto por microrganismos e continuará a ser produzido o lixiviado como fonte de poluição ambiental. Inicialmente, fez-se a caracterização do chorume \"in natura\", demonstrando-se como fonte de matéria orgânica recalcitrante, com massa molar característica de macromoléculas (5,58 kDa e polidispersidade de 1,16), DBO não determinável pela recalcitrância molecular e/ou pela ação tóxica e DQO característica de lixiviado estabilizado (1.013 mg L-1). A fração inorgânica total, dada pela quantidade de sólidos fixos, foi de 3.670 mg L-1, valor esse 3,6 vezes maior que a fração orgânica. O estudo de tratamento do chorume, por ozonização catalítica homogênea foi desenvolvido, principalmente, pelo uso seqüencial de dois arranjos ortogonais de Taguchi, sendo o primeiro, matriz L16, para estudo exploratório dos fatores mais importantes na redução percentual da DQO. Os fatores estudados foram vazão de ozônio, concentração dos íons Fe2+, Fe3+, Zn2+, Mn2+, Ni2+ e Cr3+, pH do meio reacional e presença/ausência de fonte de radiação UV (254 nm). Dentre os metais de transição, os íons Fe2+ e Fe3+ demonstraram-se como mais viáveis como catalisadores na geração de radicais livres hidroxilas devido à sua significância estatística (p = 0,005), e por terem maior tolerância ao descarte no meio ambiente (menor toxicidade) frente aos demais íons. Com a utilização do arranjo ortogonal L8 de Taguchi, foi possível atingir degradação máxima de DQO da ordem de 50 %. A melhor configuração dos fatores, visando aumentar o percentual de redução da DQO foi: vazão de ozônio igual a 5 L h-1 (589,9 mg h-1 O3), concentração de íon de íon ferroso igual a 10 mg L-1, concentração de íon férrico igual a 5 mg L-1 e pH 5. / During many years, the garbage of Guaratinguetá city was landfilled and its recalcitrant product was not submitted to any physical or chemical treatment, leaching directly through the area. After deactivating and transforming the landfill into an Ecological Park, the material deposited in the place by the past years, will continue being decomposed by microorganisms and will continue producing the leached one as a mean of environment pollution. Initially, the leachate \"in natura\" was characterized, demonstrating itself as a source of recalcitrant organic substance with a higher molecular size characteristic of 5,58 kDa and polidispersity of 1,16 and stabilized effluent (not determinable DBO due to molecular recalcitrance and/or toxicity and DQO of 1,013 mg L-1). The total inorganic fraction, given by the amount of total fixed solids was 3,670 mg L-1, which means 3,6 times bigger than the organic fraction. The study of leachate treatment by homogeneous catalytic ozonation was given, mainly, for the sequential use of two Taguchi\'s orthogonal arrangements, being the first, L16 design, for exploratory studies of the most important factors in the percentual reduction of DQO. The factors studied were the ozone outflow, the Fe2+, Fe3+, Zn2+, Mn2+, Ni2+ and Cr3+ ions concentration, the reaction medium pH and the presence/absence of UV radiation source UV (254 nm). Amongst the transition metals, Fe2+ and Fe3+ ions have demonstrated to be as more viable as free hydroxyl radicals catalyst due to its statistics significance (p = 0,005) and also because they have a greater tolerance to the environment discarding (less toxicity) compared to the other ions. The use of L8 Taguchi\'s orthogonal arrays gives the possibility to reach 50 % maximum COD depletion. The best factors configuration, using COD percentage reduction as experimental design response was: 5 L h-1 (589,9 mg h-1 O3) ozone outflow, 10 mg L-1 ferrous concentration, 5 mg L-1 ferric ion concentration and pH 5.