Abstract
Desulfurization of anaerobic digestion gas was investigated using photoreactors equipped with sterilizing lamp radiating ultraviolet with a wavelength of 254 nm or ozone lamp with wavelengths of 254 nm and 184 nm. When the digestion gas was injected with oxygen gas, the utilization of ozone lamp removed H2S more effectively than a combination of sterilizing lamp and TiO2 thin film. The H2S removal rate was increased proportionally with an increase in the initial H2S concentration. Humidifying the digestion gas enhanced the H2S removal rate. SO2 as by-product from H2S degradation was removed from the gas into a separate liquid with high alkalinity from dewatering machine for anaerobically digested sludge. Installing of the photoreactor and gas washer in front of an existing desulfurizer could reduce the amount of desulfurizing reagent by almost half. However, cheaper lamp and photocatalysis responsive to vacuum ultraviolet will be needed for the practical use of photoreactor.
