| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 5.64 MB | Adobe PDF |
Authors
Advisor(s)
Abstract(s)
O presente relatório aborda a crescente preocupação ambiental das estações de
tratamento de águas residuais, identificadas como potenciais fontes de emissão de gases
de efeito de estufa (GEE). O foco principal deste estudo é a medição das emissões de
metano em várias etapas do tratamento da estação de tratamento de águas residuais de
Paço de Sousa, da empresa SIMDOURO.
Este estudo iniciou-se com uma pesquisa sobre métodos de amostragem e
quantificação de GEE, metano e óxido nitroso. Seguiu-se a recolha de amostras pontuais
das fases líquida e gasosa (usando sacos Tedlar) em pontos selecionados do processo de
tratamento, e a medição de metano por cromatografia gasosa com detetor de ionização de
chama. A curva de calibração considerada mais apropriada para este estudo apresenta um
limite de deteção de 6,67×10-4 mg, um limite de quantificação de 2,22×10-3 mg, um
desvio padrão de 2,29×105 µV, um coeficiente de correlação de 0,978 e a seguinte
equação de reta Área do pico =1,03×109×massa de metano –7,19×105
.
Nas amostras gasosas obtiveram-se os seguintes níveis de metano para a obra de
entrada, gradagem, SEDIPAC 3D, reator biológico em arejamento, espessador gravítico
e biofiltro: 0,003, 0,009, 0,0021, 0,0018, 0,090 e 0,074 mg/L respetivamente. Nas
amostras líquidas se mediram níveis de metano para a obra de entrada, gradagem,
SEDIPAC 3D, reator biológico em arejamento e espessador gravítico, respetivamente de
0,118, 0,021, 0,376, 0,001 e 0,648 mg/L. Verificando-se que a etapa em que se registou
maior concentração de metano foi o espessador gravítico, nas amostras gasosas e líquidas.
Atualmente, a empresa utiliza um método de cálculo baseado em fatores de
emissão para estimar as emissões de metano e óxido nitroso, que estima que as emissões
para o ano de 2022 tenham sido de 9647 kg CO2 equivalente/ano. A partir dos resultados
da amostragem em fase gasosa, foram estimados fatores de emissão individuais para cada
etapa do tratamento, tendo-se obtido para a obra de entrada, gradagem, SEDIPAC 3D,
reator biológico em arejamento e espessador gravítico: 1,53×10-4
, 1,67×10-4
, 1,10×10-3
,
1,34×10-4
kg de metano/ t SST e 1,98×10-4
kg de metano/ t ST, respetivamente.
This report addresses the increasing environmental concern regarding wastewater treatment plants, which have been identified as potential sources of greenhouse gas (GHG) emissions. The primary focus of this study is to measure methane emissions at different stages of treatment at the Paço de Sousa WWTP. The study began with research into methods for sampling and quantifying GHGs, methane and nitrous oxide. This was followed by the collection of spot samples of methane the liquid and gas phases (using Tedlar bags) at selected points in the treatment process, followed by their measurement by gas chromatography with a flame ionization detector. The calibration curve considered most appropriate for the needs and objectives of this study has a detection limit of 6.67E-04 mg, a quantification limit of 2.22×10-3 mg, a standard deviation of 2.29×105 mg, a correlation coefficient of 0,978 and is described by the following line equation Peak area =1.03×109 x methane mass – 7.19×105 . The methane levels obtained in the gas samples at various stages, including the inlet works, grading, SEDICAP 3D, aerated biological reactor, gravitational thickener and biofilter, were as follows: 0.003, 0.009, 0.0021, 0.0018, 0.090 and 0.074 mg/L, respectively. In the liquid samples, methane levels were observed for the inlet works, grading, SEDICP 3D, aerated biological reactor and gravitational thickener, respectively: 0.118, 0.021, 0.376, 0.001 and 0.648 mg/L. In both phases, the stage with the highest concentration was the gravitational thickener. The company currently employs a theoretical calculation method that relies on emission factors to estimate methane and nitrous oxide emissions, which estimates that emissions for the year 2022 would be 9647 kg CO2 equivalent/year. The results of the gas phase sampling were used to estimate the individual emission factors for each stage of treatment, and the following values were obtained for the inlet works, grading, SEDIPAC 3D, biological aeration reactor and gravitational thickener: 1.53×10-4 , 1.67×10-4 , 1.10×10- 3 , 1.34×10-4 and 1.98×10-4 kg of methane per t of total solids, respectively.
This report addresses the increasing environmental concern regarding wastewater treatment plants, which have been identified as potential sources of greenhouse gas (GHG) emissions. The primary focus of this study is to measure methane emissions at different stages of treatment at the Paço de Sousa WWTP. The study began with research into methods for sampling and quantifying GHGs, methane and nitrous oxide. This was followed by the collection of spot samples of methane the liquid and gas phases (using Tedlar bags) at selected points in the treatment process, followed by their measurement by gas chromatography with a flame ionization detector. The calibration curve considered most appropriate for the needs and objectives of this study has a detection limit of 6.67E-04 mg, a quantification limit of 2.22×10-3 mg, a standard deviation of 2.29×105 mg, a correlation coefficient of 0,978 and is described by the following line equation Peak area =1.03×109 x methane mass – 7.19×105 . The methane levels obtained in the gas samples at various stages, including the inlet works, grading, SEDICAP 3D, aerated biological reactor, gravitational thickener and biofilter, were as follows: 0.003, 0.009, 0.0021, 0.0018, 0.090 and 0.074 mg/L, respectively. In the liquid samples, methane levels were observed for the inlet works, grading, SEDICP 3D, aerated biological reactor and gravitational thickener, respectively: 0.118, 0.021, 0.376, 0.001 and 0.648 mg/L. In both phases, the stage with the highest concentration was the gravitational thickener. The company currently employs a theoretical calculation method that relies on emission factors to estimate methane and nitrous oxide emissions, which estimates that emissions for the year 2022 would be 9647 kg CO2 equivalent/year. The results of the gas phase sampling were used to estimate the individual emission factors for each stage of treatment, and the following values were obtained for the inlet works, grading, SEDIPAC 3D, biological aeration reactor and gravitational thickener: 1.53×10-4 , 1.67×10-4 , 1.10×10- 3 , 1.34×10-4 and 1.98×10-4 kg of methane per t of total solids, respectively.
Description
Keywords
Greenhouse Gases (GHG) Methane wastewater treatment plant (WWTP) Emission Factors