Host: Japan Society of Material Cycles and Waste Management
Name : The 31st Annual Conference of Japan Society of Material Cycles and Waste Management
Number : 31
Location : [in Japanese]
Date : September 16, 2020 - September 18, 2020
Anaerobic digestion (AD) can convert organic waste into energy by utilizing microbiological processes. Nevertheless, this system with two-stage configuration still experiences an issue, particularly pH drops. To create a low-carbon energy system, we evaluate the performance of crushed oyster shells as alkaline substitutes in two-stage anaerobic digesters. The result shows that control treatment using alkali has the highest VS (1.18%) and COD (27.7 g/L). Oyster shell treatment has lower VS (1.14%) and COD (25.01 g/L). As a result of comparing greenhouse gas (GHG) emissions in using NaOH and oyster shells by the LCA method, the equivalent weight of CO2 emission from the oyster shell is 0.15 times of alkali. In the methanogenesis stage, alkali treatment produced 24% higher methane gas yield in the highest OLR (422.01 mlCH4/gVS in 2.6 gVS/L/day) compared to oyster shell treatment (321.32 ml CH4/gVS in 2.8 gVS/L/day). Highest methane gas percentage produced from alkali treatment (77.53%), while in oyster shell treatment highest methane gas percentage is 71.11%. Alkali treatment performs better in methane gas production using two-stage anaerobic digesters, but oyster shells offer advantages in terms of practicality, stability, and environmental impact.
