The production of dairy cow manure in Korea amounted to approximately 22 thousand tonnes/day in 2012. Dairy cow manure includes saw dust or rice hull that are usually used to protect cow claw in bedded pack dairy barn. Composting has been one of the best alternatives for the dairy cow manure treatment. However recently anaerobic technology has brought more interest in production of biogas as a renewable energy. Compared to other potential treatment options, anaerobic digestion followed by composting appears to be a promising and economically feasible technology. It is therefore important to know the substrate characteristics on the anaerobic ultimate biodegradability and degradation rates of dairy cow manure to design the mesophilic anaerobic digestion system.

The first order batch reaction rate coefficient, represented k, is the one of most useful parameter to describe the degree of anaerobic degradation of animal manure. An ideal batch reaction yields straight line, indicating a single decay rate coefficient. However the reaction curves usually consisted of the linear form with a steep slope (k1) during the initial period of operation, followed by a gradual non-linear transition, and then a second linear line with a slower slope (k2). In this study the multiple reaction rate coefficients at their corresponding biodegradable substrate fractions (S1 and S2) were calculated to evaluate the degradation kinetics of dairy cow manure during the batch reaction.