Publicação
Valorization of leached waters through conversion in liquid fertilizers
| Resumo: | An unprecedented demographic explosion occurred in the last decades at a global level. The negative impacts of this event stand out, affecting the social, economic and mainly environmental spheres. In the environmental aspect, an important consequence is the growing production of solid wastes, due partially to the population increase. However, the development of effective technologies for the treatment of these wastes did not accompany such growth, and currently the most used method for this is landfill disposal. Even with the possibility of alternatives, the use of landfills for the disposal of solid wastes will be necessary over a long period, with the inevitable consequence of the generation of leachate streams. The objective of this work is the development, design and implementation of processes for physicochemical conversion of leachate liquid effluents from a composting process in liquid fertilizers with a standardized and reproducible composition. The leachate sample was collected in February 2019 from the slurry storage tank of the company “Resíduos do Nordeste”, EIM (Urjais, Mirandela, Portugal). The stream is produced and recovered from a composting line from a mechanical and biological waste treatment plant. From this original sample, three additional materials were obtained: a filtered sample for the removal of the solid fraction (Filtro 03/04), two concentrated samples by simple distillation, with two concentration levels in volume basis: 1,19x and 1,85x in relation to the original leachate sample. The four samples (the original leachate and the three processed samples) were submitted to a sequence of analyzes, in order to compare its composition and properties with the current Portuguese and European legislation specifications for liquid fertilizers. The selected characterization parameters were: Total Organic Carbon (TOC), pH, Conductivity, Percentage of Dry Matter, Density, and Heavy Metals, Phosphorus, Potassium and Nitrogen contents. Adsorption tests were performed with the Filter 03/04 sample, with two adsorbents of different origin, the first produced from an organic compound, resulting from a centralized composting process, obtained from the same landfill that provided the Original sample. The second adsorbent tested is activated clays, originating from four different deposits in Kazakhstan. After treatment with the adsorbents, the same analyzes were performed previously, aiming to evaluate the efficiency of the adsorbents. The characterization results were then used to verify the framework for later use of the original leachate and/or the processed samples as liquid organomineral fertilizers, and to assess the specific needs of composition tuning for the non-processed leachate sample. A concentration process for the original sample of 1,19x (v/v) has been determined to allow the reaching of at least 3% TOC, a content legally required. Additionally, treatment is required for the removal of nickel and chromium from the samples. The metals zinc, copper, cadmium and lead have been quantified and are within the limits specified in the Regulation of the European Parliament and of the Council (2019). A flowchart for the proper treatment of this leachate was proposed, with the intention of using it as liquid organomineral fertilizer. |
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| Autores principais: | Vertonha, Maria Thais |
| Assunto: | Leachate Organic fertilizer Organomineral fertilizer Wastewater treatment |
| Ano: | 2020 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Instituto Politécnico de Bragança |
| Idioma: | inglês |
| Origem: | Biblioteca Digital do IPB |
| Resumo: | An unprecedented demographic explosion occurred in the last decades at a global level. The negative impacts of this event stand out, affecting the social, economic and mainly environmental spheres. In the environmental aspect, an important consequence is the growing production of solid wastes, due partially to the population increase. However, the development of effective technologies for the treatment of these wastes did not accompany such growth, and currently the most used method for this is landfill disposal. Even with the possibility of alternatives, the use of landfills for the disposal of solid wastes will be necessary over a long period, with the inevitable consequence of the generation of leachate streams. The objective of this work is the development, design and implementation of processes for physicochemical conversion of leachate liquid effluents from a composting process in liquid fertilizers with a standardized and reproducible composition. The leachate sample was collected in February 2019 from the slurry storage tank of the company “Resíduos do Nordeste”, EIM (Urjais, Mirandela, Portugal). The stream is produced and recovered from a composting line from a mechanical and biological waste treatment plant. From this original sample, three additional materials were obtained: a filtered sample for the removal of the solid fraction (Filtro 03/04), two concentrated samples by simple distillation, with two concentration levels in volume basis: 1,19x and 1,85x in relation to the original leachate sample. The four samples (the original leachate and the three processed samples) were submitted to a sequence of analyzes, in order to compare its composition and properties with the current Portuguese and European legislation specifications for liquid fertilizers. The selected characterization parameters were: Total Organic Carbon (TOC), pH, Conductivity, Percentage of Dry Matter, Density, and Heavy Metals, Phosphorus, Potassium and Nitrogen contents. Adsorption tests were performed with the Filter 03/04 sample, with two adsorbents of different origin, the first produced from an organic compound, resulting from a centralized composting process, obtained from the same landfill that provided the Original sample. The second adsorbent tested is activated clays, originating from four different deposits in Kazakhstan. After treatment with the adsorbents, the same analyzes were performed previously, aiming to evaluate the efficiency of the adsorbents. The characterization results were then used to verify the framework for later use of the original leachate and/or the processed samples as liquid organomineral fertilizers, and to assess the specific needs of composition tuning for the non-processed leachate sample. A concentration process for the original sample of 1,19x (v/v) has been determined to allow the reaching of at least 3% TOC, a content legally required. Additionally, treatment is required for the removal of nickel and chromium from the samples. The metals zinc, copper, cadmium and lead have been quantified and are within the limits specified in the Regulation of the European Parliament and of the Council (2019). A flowchart for the proper treatment of this leachate was proposed, with the intention of using it as liquid organomineral fertilizer. |
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