RESUMO
Sanitation equity and climate actions are world concerns stated by the United Nations in the Sustainable Development Goals. A significant source of greenhouse gas emissions is inputted by human wastes, either in developing countries through wastewater treatment plants, or in the underdeveloped world, through anaerobic digestion of fecal sludge in pit latrines. For the first time, an integrated process for CO2 reduction and capture is implemented in a thermally sustainable, latrine-like device that destroys fresh human feces using smoldering combustion, the FeD-Latrine. A gas looping oxidizes combustible gases and creates favorable conditions to capture CO2 in bed. CH4 and H2 molar fractions are decreased around 90 % and 30 %, respectively. CaO used as a sorbent captures up to 8 mmol of CO2 per gram, forming a stable CaCO3. Compared to kinetic-dominant processes for CO2 capture, we obtain an efficiency of around 52 %. Our findings show that using the FeD-Latrine to replace typical pit latrines reduces 60 % of the CO2-eq emissions.
Assuntos
Dióxido de Carbono , Banheiros , Humanos , Dióxido de Carbono/análise , Saneamento , Esgotos , GasesRESUMO
Electrical Resistance Tomography (ERT) has the potentialities of non-intrusive techniques and high temporal resolution which are essential characteristics for multiphase flow measurements. However, high background conductivities, such as saline water in oil extraction, impose a limitation in ERT image reconstruction. Focusing on the operational limits of an ERT tomography system operating in different conductivity backgrounds from 0.010 to 4.584 S/m, the impact on the image reconstruction was assessed via signal-to-noise variance. The signal-to-noise ratio (SNR) variance had a strong correlation (p-value = 5.40 × 10-15) with the image reconstruction quality at the threshold of 30 dB, reaching a correlation value of r = -0.92 in the range of 0.010-0.246 S/m. Regarding the position error of the phantom, p-value = 1.30 × 10-5 and r = -0.66 were attained. The global results revealed that the correlation of the mean of the SNR (p-value = 5 × 10-4 and r = 0.55) was kept unaltered through the whole conductivity range, showing that such a statistical index can induce bias in establishing the operational limits of the hardware.