Anaerobic digestion of energy crops in batch

Batch digestion of energy crops at mesophilic temperature indicates that the rate of anaerobic digestion of energy crops into methane may first reach its maximum rate after several days for energy crops such as maize, oat, ryegrass, and wheat that are less degradable than sugars and fats. Experiments show that the cumulative methane production pattern from energy crops rather follows a sigmoidal, and not exponential, curve shape. Implications are that optimal usage of energy crops should involve an evaluation of their degradation kinetics, specifically the rate of which they are converted into methane, and the optimal digester hydraulic retention time and or reactor configuration for the specific energy crop.

► Energy crop pretreatment effects should be evaluated through multiple parameters.
► Certain digester configurations may favour specific types of energy crops.
► Cumulative CH4 production from energy crops sometimes follow a sigmoidal pattern.