Usack Joseph G, Wiratni Wiratni, Angenent Largus T
Biological and Environmental Engineering, Cornell University, Riley-Robb Hall, Ithaca, NY 14853, USA.
Chemical Engineering, Gadjah Mada University, Jalan Grafika 2 Kampus UGM, Yogyakarta 55281, Indonesia.
ScientificWorldJournal. 2014 Mar 13;2014:318054. doi: 10.1155/2014/318054. eCollection 2014.
A government-sponsored initiative in Indonesia to design and implement low-cost anaerobic digestion systems resulted in 21 full-scale systems with the aim to satisfy the cooking fuel demands of rural households owning at least one cow. The full-scale design consisted of a 0.3 m diameter PVC pipe, which was operated as a conventional plug-flow system. The system generated enough methane to power a cooking stove for ∼ 1 h. However, eventual clogging from solids accumulation inside the bioreactor proved to be a major drawback. Here, we improved the digester configuration to remedy clogging while maintaining system performance. Controlled experiments were performed using four 9-L laboratory-scale digesters operated at a temperature of 27 ± 1 °C, a volatile solids loading rate of 2.0 g VS · L(-1) · day(-1), and a 21-day hydraulic retention time. Two of the digesters were replicates of the original design (control digesters), while the other two digesters included internal mixing or effluent recycle (experimental digesters). The performance of each digester was compared based on methane yields, VS removal efficiencies, and steady-state solids concentrations during an operating period of 311 days. Statistical analyses revealed that internal mixing and effluent recycling resulted in reduced solids accumulation compared to the controls without diminishing methane yields or solids removal efficiencies.
印度尼西亚一项由政府发起的倡议旨在设计并实施低成本厌氧消化系统，最终建成了21个全尺寸系统，目标是满足至少拥有一头奶牛的农村家庭的烹饪燃料需求。全尺寸设计包括一根直径0.3米的PVC管，其作为传统的推流式系统运行。该系统产生的甲烷足以供烹饪炉灶使用约1小时。然而，生物反应器内部固体物质积累导致的最终堵塞被证明是一个主要缺陷。在此，我们改进了消化器配置以解决堵塞问题，同时保持系统性能。使用四个9升的实验室规模消化器进行了对照实验，实验在27±1°C的温度、2.0克挥发性固体·升⁻¹·天⁻¹的挥发性固体负荷率以及21天的水力停留时间条件下运行。其中两个消化器是原始设计的复制品（对照消化器），而另外两个消化器包括内部混合或出水循环（实验消化器）。在311天的运行期内，基于甲烷产量、挥发性固体去除效率和稳态固体浓度对每个消化器的性能进行了比较。统计分析表明，与对照相比，内部混合和出水循环减少了固体物质积累，同时并未降低甲烷产量或固体去除效率。
