Effects of biological, chemical and thermochemical pretreatments on biogas production from kitchen waste

The effects of biological (Pseudomonas sp.), chemical (NaOH) and thermochemical (0.5M NaOH was added followed by autoclaving at 121^oC for 30min) pretreatments of  kitchen waste (KW) for biogas generation and digester time (DT₉₀) reduction, were investigated in the present study. The results indicated that there were 11%, 26% and 346% increase of biogas yield for thermochemical, biological and chemical pretreated KW, respectively. The results imply the all the pretreatments gave better yield of biogas than the untreated KW. Obviously, compared with the untreated KW (control), the pretreated samples yielded higher daily biogas levels over shorter periods of time. All the pretreatments resulted to 42.9–71.4% reduction in digestion time (DT₉₀). Therefore, pretreatments could be an effective method for improving biodegradability and enhancing the highly efficient conversion of kitchen waste both to biogas.