Babaei Azadeh, Shayegan Jalal
Department of Chemical and Petroleum Engineering, Sharif University of Technology, Tehran, Iran.
J Environ Health Sci Eng. 2020 Jan 2;17(2):1077-1084. doi: 10.1007/s40201-019-00422-6. eCollection 2019 Dec.
Anaerobic digestion is a promising technology for simultaneous treatment of biodegradable organic matter of municipal solid waste (MSW) and production of renewable energy. Mixing modes and temperature have influences on biogas production in anaerobic digesters treating MSW. Therefore, in this study, digester was operated at different modes of mixing and temperatures to obtain design criteria.
The experiments were carried out in a semi-continuous digester. In the first part of the investigation, temperature was set at 25, 28, 31 and 34 °C. During this step, digester content was mixed in an intermittent mode by mechanical mixers. In the second part of the study, mixing condition of the digester was set at various modes: continuous, intermittent (15 min on and 30 min off) and minimal (twice in a batch).
Digestion with a temperature in this range resulted in biogas yield of 0.23-0.33 m biogas/kg VS, with a methane content of 60.2-71.8% in biogas. The methane content and yield decreased with reduction of digestion temperature. However, this reduction was almost negligible from 34 to 31 °C. In addition, in comparison to intermittent mixing, continuous and minimal mixing modes reduced the biogas production by 40% and 50%, respectively. Therefore, in this digester greatest biogas yield of 0.33 ± 0.02 m biogas/kg VS were obtained at 34 °C and intermittent mixing mode.
Based on the data obtained from this study, temperature in the range of 31-34 °C and intermittent mixing is suggested as a base for design purposes.
厌氧消化是一种很有前景的技术，可同时处理城市固体废物（MSW）中的可生物降解有机物并生产可再生能源。混合模式和温度会影响处理MSW的厌氧消化器中的沼气产量。因此，在本研究中，消化器以不同的混合模式和温度运行以获得设计标准。
实验在半连续消化器中进行。在研究的第一部分，温度设定为25、28、31和34°C。在此步骤中，消化器内容物通过机械搅拌器以间歇模式混合。在研究的第二部分，消化器的混合条件设定为各种模式：连续、间歇（开15分钟，关30分钟）和最小（一批中两次）。
在此温度范围内进行消化，沼气产量为0.23 - 0.33立方米沼气/千克挥发性固体（VS），沼气中甲烷含量为60.2 - 71.8%。甲烷含量和产量随消化温度降低而下降。然而，从34°C降至31°C时，这种下降几乎可以忽略不计。此外，与间歇混合相比，连续和最小混合模式分别使沼气产量降低了40%和50%。因此，在此消化器中，在34°C和间歇混合模式下获得了最高沼气产量0.33±0.02立方米沼气/千克VS。
基于本研究获得的数据，建议将31 - 34°C的温度范围和间歇混合作为设计依据。
