Comparing the effect of total solids concentration on bio-hydrogen production potential of food waste and its derivatives under mesophilic thermophilic conditions

The effect of three total solid (ts) concentrations of 7.5,10 and 12.5% on bio-hydrogen production potential of food waste (fw) in comparison with noodle waste (nw) and rice waste (rw) derived from fw were studied after co-digesting the wastes with heat shocked sludge under mesophilic (37°c) and thermophilic (55°c) conditions. the increase in ts concentration from 7.5% to 10% found an effective way to improve cumulative bio-hydrogen production from all tested wastes. as a whole,7.5% ts concentration represented higher conversion efficiency of volatile solids into bio-hydrogen and the highest experimental yield of 95.8ml/vsfed was observed in 7.5%nw digester under thermophilic conditions. the increase in temperature within experimental range found an effective way to increase bio-hydrogen production potential of fw and nw only,whereas the same increase in temperature caused negative impact on bio-hydrogen production potential of rw. the optimum time period for active bio-hydrogen production found to be 24-7 2h of incubation. after 72h of incubation,the bio-hydrogen production reduced considerably in all reactors due to an abrupt increase in volatile fatty acid,and due to inhibition of bio-hydrogen production the drop in ph was also decreased. © 2016,university of agriculture. all rights reserved.