Anaerobic digestion and biogas production from food wastes

In this study, anaerobic digestion and biogas production of food wastes was investigated in the batch system. Food wastes was obtained from restaurant of Gazi University Faculty of Engineering and Architecture. Anaerobic bacterial culture was obtained from the laboratory of Waste Water Treatment Plant of ASKİ. In experimental studies twenty glass reactors was used had volume of 250 ml and connected to a graduaded burets for collection of produced gases during anaerobic digestion of wastes. In this study, in order to reach maximum production rate of biogas and maximum anaerobic digestion, the effect of temperature, pH and solid material ratio were Investigated. Experimental studies, were designed according to The method of Box- Wilson experimental design. The result were analyzed by Essential Regression program as statistically. The results were found that model equations and R2 values for the production rate of biogas (Yi), the percent decrease of COD (chemical oxygen demand)(Y2) and the production rate of acetic acid (Y3) respectively as follows; Yi= (-85,84 + 2,476Xi + 11,61X2 + 1,187X3 - 0,02694Xj2 - 0,04375XiX2 - 0,02719 X1X3 - 0,771 X22 - 0,01277X32) R2 : 0,964 Y2= (-2743,0 + 74,llXi + 388,65X2 + 40,49Xs - 0,768Xi2 - l,562XiX2- 0,938XiX3- 25,53X22 - 0,413 X32) R2: 0,972 Y3 = (-255,27 + 7,548X, + 35,85X2 + 1,072X3 - 0,102Xi2 - 2,768X22 -0,06582X32) R2: 0,807 With the use of the developed models a maximum biogas production rate of 1,21 ml/(gsolid.h), maximum percent decrease COD of 40,26 % and maximum acetic acid production rate of 5,24 mg/(g solid, h) respectively were obtained when temperature, pH and solid material ratio respectively were 37,27 °C, 6,47 and % 6,79; 38,26 °C, 6,44 and % 5,64 and 37,11 °C, 6,48 and % 8,14. Science code : 603.03.03 Key Words : Anaerobic digestion, biogas production, food waste, statistical analysis Page number : 140 Adviser : Yrd. Doç. Dr. S. Ferda MUTLU