Beating treatment to enhance digestibility of fresh grass

Anaerobic digestion (AD) is one of the most popular biomass conversion technologies. AD can be further divided into four stages: pre-treatment, digestion, gas upgrading and digestate. The main goal of pre-treatment is to improve degradability of the material in order to enhance gas production and anaerobic digester performance. Beating treatment as a new mechanical treatment technique has been applied in this work. Laboratory scale mesophilic AD was operated to determine the methane yield from fresh grass and the potential efficiency increase in methane production. Fresh grass as main substrate has been treated in three deferent levels of beating treatment (5-min, 15-min treatment, and 40-min treatment). Many experiments have been carried out according to these levels of treatment and the amount of biogas was measured for each treatment. The average amount of biogas produced before and after beating treatment was compared. Composition analyses of different chemical compounds in biogas have been measured. Significant improvements were achieved in the degradability during the AD and in the biogas production from the pre-treated fresh grass.