(622e) Biohydrogen Production from Gamma Irradiation Disintegrated Sewage Sludge: Effect of Ferrous Ions

Biohydrogen production from sewage sludge can achieve dual benefits of clean energy generation and waste management. Pretreatment process plays a vital role in biohydrogen production from sewage sludge. This study 25 kGy adopted gamma irradiation as pretreatment, explored the effect of ferrous ions (Fe²⁺) on sludge disintegration and subsequent hydrogen production at neutral conditions. Results showed that sludge dissolution increased with the increase of Fe²⁺ dose from 0 to 1000 mg/L. Detailed analysis showed that releasement of protein prefers higher Fe²⁺ addition, while highest soluble polysaccharides was obtained at 800 mg/L Fe²⁺ addition. Indicating a proper amount of Fe²⁺ can promote the sludge disintegration by gamma irradiation. Dark fermentation was also promoted. Highest hydrogen yield of 12.23 mL/g VS_added was obtained from 25 kGy-200 mg/L Fe²⁺ pretreated sludge, which was 2.2 times of control test. The accumulation of volatile fatty acids was enhanced from 837.2 mg/L to 1708.0 mg/L with 1000 mg/L Fe²⁺ addition. Microbial analysis showed that the addition of Fe²⁺ significantly promoted the enrichment of Paraclostridium sp. and elimination of Enterobacter sp. Characteristics of sludge throughout the pretreatment and fermentation process were also analyzed by Excitation Emission Matrix Spectra (EEM). Interactions of sludge dissolution, hydrogen production, microbial distribution as well as Fe²⁺ concentration were also explored through Principal Component Analysis (PCA).