الفهرس | Only 14 pages are availabe for public view |
Abstract The experimental works of this study were carried out in biogas laboratory, Agric. Eng. Dep., Fac. of Agric., Suez Canal Univ., Ismailia, Egypt. The present work aimed to study the effect of substrate type (100% cattle dung (CD), 100%chicken manure (CM) as monodigestion and amixture of themas co-digestion (CD+CM, 1:1 byweight) at TS 7.75%) and digester shape (horizontal and vertical) on quantity and qualityof biogas produced at various digestion temperatures of 20±3 (at winter), 29±3 (at summer) and 38±1 ºC (controlled temperature) and a digestion period of 60 days. The cumulative biogas or methane productions were found increase with increasing digestion time reaching their highest amounts at the end of experiments. Highly significant linearly correlations were observed. The horizontal digesters produced considerably high amounts of cumulative biogas or methane than the vertical ones. In all treatments of the three experiments, the cumulative and daily specific biogas and methane production followed the order: CD+CM > CD > CM, except for the vertical digesters at 38±1 ºC followed the order: CD+CM > CM > CD. This result demonstrated that, the co-digestion of CM with CD was more effective than the digestion with each of themalone. The highest average methane content of 68.1% (by volume) in biogas was observed in the vertical digesters fed with CD+CM at digestion temperature of 29±3 ºC. On the contrary, the lowest average methane content of 42.0%was found in the horizontal digesters loaded with CMalone at 38±1 ºC. The highest average specific biogas and methane production rates of 355 and 238 L kg-1VS added per day, respectively, were obtained from the horizontal digesters fed with CD+CMat 29±3 ºC, while the lowest rates of 79 and 32 L kg-1VS added per day were observed in the horizontal digesters loaded with CMalone at 38±1 ºC, respectively. This study demonstrated that the utilization of a mixture of CD+CM (1:1 by weight) with 7.75% TS as a substrate in the horizontal biogas digesters at ambient digestion temperature of 29±3 ºC and digestion time of 60 days gave the highest quantity and quality of biogas compared to all other treatments of the three. These results are recommended to apply on field-scale digesters. |