Effect of Buffer (NaHCO3) and Waste Type in High Solid Thermophilic Anaerobic Digestion

The large organic matter of solid waste such as agricultural and municipal solid waste offer great potential for biogas production. Anaerobic digestion of green waste-food waste mixture at thermophilic temperature range was carried out with the primary aim of investigating the effect of buffer (NaHCO
3
) and waste type in the digestion process. For the purpose of initiation of the digestion process, 20 % granular sludge was added to each sample. The level of percentage total solids (TS) and volatile solids (VS) reduction and volume of biogas production was monitored for each sample. From Results obtained, Generally, it showed that cultures containing Food Waste and anaerobic sludge seed in the ratio 4:1 produced the highest volume of biogas of 6700 cc/gVS but with very poor pH stability while cultures containing Food Waste (FW), Green Waste (GW) and anaerobic sludge seed in the ratio 2:2:1 produced the highest biogas production of 5750 cc/gVS and volatile solids destruction with the best pH (6.2) stability when compared with the performances of the other non-chemically buffered cultures studied. The results also revealed the importance of waste type and proportions in natural pH control and regulation.