Biogas production by pine needles co-digested with food waste through anaerobic digestion

Abstract

We all know that the population of the world is increasing day by day with increase in the population the energy demand is also increasing. Our current energy resources like coal, fossil fuel, natural gas etc are depleting at very fast rate. Therefore we need to shift our focus to some other energy resources . Anaerobic digestion process could be one of our option . Anaerobic digestion is a process in which micro-organism break down organic material in the absence of oxygen resulting in the formation of gas which can be used as the source of clean energy. The objective of this research is to identify the credibility of food waste and pine needles co digested with each other at organic loading rate of 0.05, 0.1, 0.15, 0.2 and 0.25 and at ratios of 25%(PN):75%(FW) by mass , 75%(PN):25%(FW) by mass and 50%(PN):50%(FW) by mass and to identify the best biogas yield at different organic loading rate and at different ratio and to study the effect of temperature variations on biogas production. For this study six continuous flow digesters were set up three at controlled temperature of 25OC and three are exposed to atmospheric conditions. The digesters placed at fix temperature are named as D2 , D4 and D6 of ratios25(PN):75(FW),75(PN):25(FW)and 50(PN):50(FW) and the digesters placed at atmospheric conditions are named as D1,D3 and D5 of ratios25(PN):75(FW) , 75(PN):25(FW) ,50(PN):50(FW) . HRT (Hydraulic Retention Time ) for the digesters was of 6 days . On every 7th day feed was changed and the different parameters like pH , Temperature and biogas yield was measured . The biogas production at different OLR(Organic Loading Rate) and at different ratios for all the digesters was measured and compared. After comparing the results it was found out that the biogas production of digesters which are kept at controlled temperature is high then that of those who are placed at ambient temperature. The digesters of ratio D2 25(PN):75(FW) by mass placed at incubated temperature has given maximum biogas yield.