Efficient Anaerobic Co-Digestion of Municipal Food Waste and Kitchen Wastewater for Bio-Hydrogen Production

Abstract

The effect of addition of kitchen wastewater (KWW) on H₂ fermentation of municipal food waste (MFW) was investigated in a mesophillic anaerobic baffled reactor (ABR). A better H₂ production of 5.54 ± 0.9 lH₂d⁻¹., and H₂ yield of 164 ± 22 mlH₂gCOD removed⁻¹d⁻¹., was achieved for co-digestion of MFW+KWW as compared to MFW diluted with raw water at a mixing ratio of 1:2, respectively. However, co-digestion process was strongly dependent on the applied pH, COD/TKj-N ratio, and hydraulic retention time (HRT). At pH value of 5, H₂ potential (P) and maximum H₂ production rate (R_m) were 6912 ml and 141 mlh⁻¹., which were dropped with increasing pH values between 6.2 and 9.0. H₂ yield increased from 93.2 ± 12 to 150.9 ± 7 mlH₂gVS removed⁻¹d⁻¹., when the COD/TKj-N ratio was increased from 12 to 24.1. Nevertheless, a further increase in COD/TKj-N ratio to greater than 24.1 resulted in a significant drop in H₂ yield. Increasing the HRT from 1.82 to 4.6 d., significantly (p < 0.01) increased the H₂ yield from 156 ± 73 to 329 ± 131 mlH₂gVSremoved⁻¹d⁻¹. Similar trends were observed for conversion of protein, lipids, and carbohydrate.

• Co-digestion
• Municipal food waste
• Kitchen wastewater
• Hydrogen
• Anaerobic baffled reactor

Additional information

Funding

The authors would like to thank the Science & Technology Development FUND (STDF), Egypt, for financially supporting this research through funding the young research grant, project no. 267.