The effect of organic loading rate on bio-hydrogen production from pre-treated rice straw waste via mesophilic up-flow anaerobic reactor.

Effect of organic loading rate (OLR) on the continuous biological H(2) production from pretreated rice straw waste using a mesophilic up-flow anaerobic reactor (UAR) was investigated for 140 d. OLR was varied from 7.1 to 26 g COD/ld. H(2) yield was significantly increased from 95.5 to 117 mmol/d, when OLR was largely increased from 7.1 to 21.4 gCOD/ld, respectively. However, further increase in OLR up to 26 g COD/ld, showed a decreasing trend to 107.1 mmol/d. Likewise, H(2) production increased with OLR at the range of 7.1-21.4 g COD/ld, and reached the maximum H(2) production of 2.6l/d. However, the H(2) production started to decrease with the further increase of OLR, and dropped to 2.2l/d at OLR of 26 g COD/ld. The COD and carbohydrate removal efficiency were over 70% and 80% at OLRs of 7.1-21.4 g COD/ld, and decreased thereafter.