DEVELOPMENT OF A DIGESTER FOR THE PRODUCTION OF BIOGAS FROM QUAIL WASTE AND JATROPHA CAKE

Abstract

The need for alternative source of renewable energy apart from crude oil cannot be over emphasized. A biogas digester was designed, fabricated and tested. Investigations were made into the production of biogas from Quail droppings and Jatropha seed cake. The design setup consists of the digester (which comprises of the stirrer and 1.5 hp electric motor) connecting hoses, filters, the storage tank and the burner). All the components were designed using standard equations. Biogas was produced by charging the slurry into the digester through the inlet channel and a hose was used to connect the digester and the water displacement tank which was already filled with water to the bream, a second hose was also used to connect the water displacement tank to the temporary storage tank where the displaced water is channeled to and the volume of the water displaced was measured and recorded daily for the two slurry The digester temperature, ambient temperature, pH and biogas production were monitored during the experiment. Results showed the C:N ratio of 8:1 for Jatropha and 7:1 for quail droppings were noticed at the initial stage which decreases with the passage of substrate decomposition. In the experimental sets, initial pH value of Jatropha substrate and Quail dropping substrates were found to be 6.35+0.07 and 6.85+0.21 respectively. The proximate analysis showed that volatile solid, total solid and moisture content for Jatropha seed cake before the experiment were 89.40+1.18 %, 95.65+1.00 % and 4.35+1.00 % while that of quail droppings were 31.40+1.18%, 38.34+1.04% and 61.67+1.04% respectively. As the decomposition proceeded, the pH value gradually increased up to 7.55+0.21 and 8.95+0.07 indicating the stability of organic matter. Moisture content on wet basis is 4.35+1.00% and 61.67+1.04% for Jatropha and Quail droppings. These values latter increased to 82.77+1.01% and 81.42+0.49% respectively. On the average, 50kg of Jatropha seed cake and 50kg of Quail waste produced a total 135, 605 cm3 and 63,775 cm3 of biogas respectively. The gas produced from both substrates were tested with a burner and burned smoothly producing blue flame, indicating that the ratio of methane gas generated was higher than other gases produced. In conclusion, high yield of biogas was achieved for both quail droppings and Jatropha seed cake and hence both substrate are good biomass for the production of biogas.