Improving hydrogen recovery from anaerobic co-digestion of algae and food waste by high-pressure homogenisation pre-treatment

Lake algae can be digested anaerobically to produce hydrogen (H-2), but the efficiency of actual processes is limited. Improving the hydrogen yield could be done by hydrolysis and tuning nutrients. Here, we pre-treated Taihu lake algae by high-pressure homogenisation; then, this product was co-digested with food waste for hydrogen recovery. Results showed that the average particle size of algae decreased to 65.48 mu m after 60 MPa pre-treatment, which is 43.09% smaller than that the control. The disintegration degree rose from 1.54% to 23.13%, and the soluble chemical oxygen demand rose from 3.21 g/L to 11.20 g/L in wet algae after 100 MPa pre-treatment. The maximum hydrogen yield was 39.87 mL per g of volatile solids. The pre-treatment effect on hydrogen generation performance was not significant when the pressure exceeded 60 MPa. Overall, we observed that high-pressure homogenisation is a fast and efficient method for algae pre-treatment, thus promoting anaerobic co-digestion of wet algae and food waste for hydrogen bio-recovery.

Automated summary

Lake algae can be anaerobically digested to produce hydrogen, with potential efficiency improvements through pre-treatment techniques such as high-pressure homogenisation. Co-digestion of pre-treated algae with food waste showed increased hydrogen yield, suggesting high-pressure homogenisation as a fast and efficient method for algae pre-treatment to promote hydrogen bio-recovery.