BIOGAS YIELD FROM INVASIVE WEED (Ageratum conyzoides L.) CO-DIGESTED WITH COW MANURE UNDER ANAEROBIC CONDITION

Abstract

Energy is one of the most important factors for human development and global economic growth. Renewable energy techniques give a great opportunity for the reduction of greenhouse gas emissions and decreasing global warming via replacing traditional energy sources. Biogas is a clean, environmental friendly and renewable form of energy generated when micro organisms degrade organic materials in the absence of oxygen. This study was aimed to evaluate the biogas production potential of Ageratum conyzoides and cow manure in combination or separately under anaerobic conditions. There was five treatments (T1=100%AC, T2=65%AC+35%CM, T3=50%AC+50%CM, T4=35% AC+65%CM and T5=100%CM) of substrates. The experiment was done by completely randomized design using batch mode operated digesters in the microbiology laboratory of Haramaya University for 30 days of fermentation. In all the treatments, Physico-chemical parameters such as pH, total solids, volatile solids, organic carbon, and carbon to nitrogen ratio were measured before and after AD. The experimental results showed that with the increment in biogas yield, there is a reduction in Total solids, Volatile solids, and organic carbon. Gas production was observed in all of the digesters from day two onwards of anaerobic digestion and measured by using the water displacement method. The highest amount of daily mean biogas was produced on the 12th day in T2 (54.83ml). The cumulative biogas yield measured from T1, T2, T3, T4, and T5 were 482.67ml, 805.33ml, 652.47ml, 544.83ml, and 410.30ml, respectively. The research result showed that it is possible to generate biogas from Ageratum conyzoides. Therefore, the researcher recommended that Ageratum conyzoides can be used in a mix ratio of 65% AC with 35% CD in large-scale production of biogas