Factors Affecting Productive Rate of VFA during High-Concentration Anaerobic Hydrolysis and Acidogenesis in Dairy Manure

Abstract

High-concentration anaerobic fermentation of dairy manure was investigated using an anaerobic batch reactor under laboratory conditions at 20°C. Daily average productive rate of CODVFA was used as response functions, and three factors (temperature, liquid concentration, and retention time) were selected as input variables in the process of hydrolysis and acidogenesis of dairy manure. The study used a central composite rotatable orthogonal experimental design. The influential regularities of every parameter on every index were analyzed with a single-parameter method. The ranges of temperature, liquid concentration and retention time were 25°C to 35°C, 6% to 10%,and 2 to 12 days respectively. Experimental results showed that daily average productive rate of CODVFA was greatly influenced by temperature, with retention time a secondary influence, and liquid concentration having the least influence.