Journal of Pure and Applied MicrobiologyVol. 8 No. 2

The Hydrolysis Kinetics of Kitchen Waste and Each of Its Components in Sequencing Batch Anaerobic Digestion

Feng Lei*, Xu Jie, Zhang Xu Dong and Li Run Dong

Liaoning Province Clean Energy Key Laboratory, Shenyang Aerospace University, Shenyang - 110 136 , China.

Received on 09 January 2014 and accepted on 18 March 2014

 

ABSTRACT

With zero- and first-order kinetics, the hydrolysis and gas production process during the batch anaerobic digestion of single components and mixed kitchen waste were analyzed. It was found that in the single-component system, the zero-order kinetic and first-order kinetic fitting results were close, with a coefficient of correlation R2 of 0.95. The descending of the tested components by their hydrolysis and gas-production speed was proteins > starches > celluloses > lipids, and the hydrolysis constants k for the components were correspondingly 0.0366, 0.0331, 0.0215, and 0.0154. The zero- and first-order kinetic fitting results were close. The gas production process had some proportional relationship with the hydrolysis process, but had no obvious relationship with the acid-production acidogenesis process. For mixed kitchen wastes, the four-component first-order kinetics model, which considers the multiple components being hydrolyzed separately with different hydrolysis constants k, had the best fitting effect; the coefficient of correlation R2 was over 0.95. The kinetic fitting effects of the other models, the zero-order kinetics and the single-component first-order kinetics which treats the mixture as a whole with a common hydrolysis characteristics and the k = 0.02, as well as the two-component first-order kinetics which divided the mixture into rapid hydrolysis and slow hydrolysis groups, were all not ideal.

Keywords : Multiple components; Gas production; The first-order kinetics?kinetic fitting.