METHOD FOR THE PREPARATION OF BIOGAS BY ANAEROBIC CO-FERMENTATION OF ANIMAL MANURE AND STRAW THROUGH THE ADDITION OF BIOCHAR

The invention discloses a method for preparing biogas by promoting anaerobic co-fermentation of animal manure and straws by adding biochar, which comprises the following steps: (1) cleaning impurities in fresh animal manure, air-drying the straws, and crushing; (2) soaking the straws in a sodium hydroxide aqueous solution, then washing with water, and finally carrying out ultrasonic treatment; and (3) adding the animal manure, the straw, the charcoal and the water into a fermentation tank, heating while sealing, and introducing the biogas slurry for anaerobic fermentation after sealing is finished, so as to prepare the biogas. The method for preparing the biogas can effectively improve the total gas production rate and the total methane yield and shorten the residence time of produced gas.