THE UTILIZATION OF BIOGAS SLUDGE BIOCHAR TO LEAD ZERO WASTE SYSTEM IN BIOGAS IMPLEMENTATION: THE EFFECT OF VOLUME ON CARBON DIOXIDE AND METHANE CONTENT

Biogas is a solution to slow the effects of global warming by converting and trapping methane of manure into energy. To make biogas cleaner and more environmentally friendly, residue from biogas also should be treated. The strategy is to recycle biogas sludge to be an adsorbent for biogas purification because it will reduce waste generation. It means the utilization of sludge leads to a zero-waste biogas system. The study was to investigate the use of biochar from biogas sludge and find the optimal condition for biogas purification. Five treatment of biochar-based biogas sludge were be conducted, every column of adsorption filled with 100% of the volume zeolite, 50% of the volume zeolite and biochar, 25% of the volume zeolite and 75% of the volume of biochar, and the last 100% of the volume biochar. The results showed that 5 treatments of biochar reduced carbon dioxide (impurity gas in biogas) and the largest reduction of carbon dioxide presented by 100% of the volume biochar. The decrease in carbon dioxide by 100% volume of zeolite is almost the same as the decrease in carbon dioxide by 100% volume of biochar. But the system also decreased the methane content in proportion to the decrease in carbon dioxide. The reduction in carbon dioxide also affected the temperature of biogas combustion and calorific value. We agree that using 100% of the volume biochar from sludge can replace zeolite in biogas purification but further modification is also needed to increase the value of methane.