Landfill sanitary leachate is an effluent with complex characteristics that still presents some challenges for treatment. From the stabilization of the organic matter which occurs over the years in a landfill, the leachate biodegradability decreases, decreasing the biological treatment efficiency. The objective of this research was to identify the characteristics of leachate from an old landfill, located in Curitiba-BR, using conventional and spectroscopic methods. Two collects of raw leachate were carried out at the Curitiba Municipal Landfill in different periods, which were denominated P11 and P12. The analyzes performed were pH, COD, BOD, DOC, color and solids, as well as UV-Vis and fluorescence spectroscopies. The results indicated that the leachate was influenced by precipitation taxes and it is possible to infer that this landfill is in the aging process, since the leachate presented recalcitrant characteristics. The organic matter presented a strong humification degree due to the presence of aromatic substances, such as humic and fulvic acids, indicating that physical-chemical treatment should be applied to this leachate. In addition, the spectroscopic analysis brought additional information, with a quicker and lower reagent consumption than conventional methods. Thus, these spectroscopic techniques can be considered promising tools to monitor the leachate, assist in the identification of the landfill decomposition stage, and subsidize the planning for proper leachate treatment.
The increasing accumulation of waste in the environment has several environmental and public health impacts. In contrast, the circular economy emerges as a model that seeks the return of waste to the production chain. An alternative for the reinsertion of these materials to the production cycle is their conversion into biochar by the pyrolysis process. Thus, this study aims to produce, perform the initial characterization and compare biochars obtained from two different matrices: sludge from sewage treatment plants and orange peels. The sludge samples were pyrolyzed at 450 °C (BL450) and 650 °C (BL650). While the orange peel biochars were produced at 400 °C (BC400) and 600 °C (BC600). Yields were determined and analyzes of scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) were also performed. The yields obtained were 32% (BC400), 28% (BC600), 46% (BL450) and 38% (BL650). The presence of pores was identified in the BC400 and BC600 SEM micrographs. However, for the BL450 and the BL650 samples, heterogeneous and asymmetric surfaces were observed. From the EDX analysis the absence of trace metals and the presence of compounds potentially beneficial to the soil and plants were found, which can act as binders in the adsorption process. In addition, due to their mostly carbonaceous composition, biochars are resistant to decomposition and can contribute to the carbon sequestration process. The yields obtained indicate a reduction of the mass of waste, which can be advantageous for handling and transportation. As a result, the production of biochar from non-conventional materials, such as sewage sludge and orange peels, can be seen as an attractive alternative for waste management, since it assists the reintroduction of these materials in the production chain, according to the concept of circular economy.
ResumoInvestigou-se nesse estudo o processo de coagulação/precipitação seguido da radiação ultravioleta visando o tratamento terciário de esgoto sanitário proveniente de lagoas de polimento. Para isto foram feitos ensaios de laboratório em jart-test para simular a coagulação e em reator UV para simular a desinfecção, variando-se as condições operacionais. O processo demonstrou bom desempenho, verificando-se moderada remoção de turbidez (27%-66%), DQO (22%-53%), cor aparente (22%-64%), cor verdadeira (34%-60%), fósforo (31%-52%), sólidos totais (2%-21%) e sólidos suspensos (10%-30%). A fim de melhorar o processo de coagulação foram realizados testes com polímeros aniônicos e catiônicos, sendo que o catiônico apresentou melhores resultados. A dosagem de coagulante considerada ótima foi 60 mg.L -1 de cloreto férrico combinado com 20 mg.L -1 de polímero catiônico. Na melhor configuração operacional obtida alcançou-se inativação de 4,65 log para CT e 4,60 log para E. coli, obtendo-se remoções de 62,7% de turbidez, 65,3% e 69,7% de cor aparente e cor verdadeira respectivamente, 50,3% de DQO e 47,3% de sólidos suspensos. Conclui-se que este processo pode ser considerado adequado para a remoção de poluentes de uma lagoa de polimento, mas deve ser observada a qualidade do efluente quanto à presença excessiva de algas que pode prejudicar o tratamento, dificultando o processo. Palavras-chave: Esgoto sanitário. Coagulação. Desinfecção ultravioleta. AbstractIn this research the process of coagulation/precipitation followed by ultraviolet disinfection was investigated for tertiary treatment of sewage from polish pond. Were done laboratory tests using jarttest to simulate coagulation and in reactor UV to simulate disinfection, varying operational conditions. The process demonstrated a good performance, had been verified moderate removal of turbidity (27%-66%), COD (22%-53%), apparent color (22%-64%), real color (22%-64%), phosphorus (31%-52%), total solids (31%-52%) and suspended solids (10%-30%). To improve the process of coagulation were realized tests with anionic and cationic polymers, and the cationic showed the best results. The dose of coagulant considered optimal was 60 mg.L -1 of ferric chloride combined with 20 mg.L -1 of polymer cationic. In the best operational configuration was obtained inactivation of 4,65 log to CT, and 4,60
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