Scherer P A, Vollmer G R, Fakhouri T, Martensen S
University of Applied Sciences Hamburg, D-21033 Hamburg-Bergedorf, Germany.
Water Sci Technol. 2000;41(3):83-91.
Different laboratory-scale, continuously driven reactor concepts (up to 3 reactors in series, max. 70 degrees C) for anaerobic digestion of the organic fraction of municipal grey waste were investigated. Over a period of 2 1/2 years several setups of reactors being daily fed and held in steady state balance were investigated. The perferred variant was a 2-stage setup with a HRT of 4.3 d for the 1st and 14.2 d for the 2nd reactor. Removal efficiencies of VS obtained by comparing the organic loading rate (OLR, g VS/l/d) of the effluent with the OLR of the feed could reach 80%. Removal efficiencies determined indirectly by the combined biogas yield of the 1st and 2nd reactor stage revealed even up to 91.5% of the theoretical possible yield of 807 l/kg VS. The produced gas had a methane content of 60-65%. A completely distinct hydrolysis stage with a gas production of only 1.6-5.5% of the theoretical yield could be reached by hyperthermophilic conditions (60-70 degrees C) or by a HRT of 1.25 d. It also demonstrated that a stable methanogenesis was not possible at temperatures of 60-70 degrees C. Kinetic analyses of the 2nd reactor stage revealed that the degradation of VS fell from 80 to 40% with raising organic loading rate (OLR) from 3 to 11 g VS/l/d. In contrast to this the VS-removal of the first hydrolysis reactor stage increased linearily from 5 to 20% at raising OLR's from 12 to 26 g VS/l/d. The same kinetics with linear increase exhibited the specific cellulose degradation with conversion rates of 0.1-3 x 109 g cellulose/single bacterium (10(-12) g)/d. This was an indication for the cellulose degradation as a rate limiting step. Both reactor stages combined allowed an optimal VS removal efficiency at OLR of 10 g VS/l/d. Analysis of bacterial populations of 28 reactors were referred either to eubacteria utilizing different sugars or cellulose or acetate or H2-CO2 or archaea (plus antibiotics) with acetate or H2-CO2 as substrate. H2-CO2 utilizers with numbers of 10(8)-10(10)/g TS dominated obviously the acetotrophic methanogens by the factor 10-10,000. This explained the observed short HRTs being possible.
研究了用于城市灰色垃圾有机组分厌氧消化的不同实验室规模、连续驱动的反应器概念（最多3个串联反应器，最高70摄氏度）。在2年半的时间里，研究了几种每日进料并保持稳态平衡的反应器设置。首选的变体是两阶段设置，第一反应器的水力停留时间（HRT）为4.3天，第二反应器为14.2天。通过比较流出物的有机负荷率（OLR，克挥发性固体/升/天）与进料的OLR获得的挥发性固体去除效率可达80%。通过第一和第二反应器阶段的联合沼气产量间接确定的去除效率甚至达到理论可能产量807升/千克挥发性固体的91.5%。产生的气体甲烷含量为60 - 65%。通过超嗜热条件（60 - 70摄氏度）或1.25天的HRT，可以达到一个完全不同的水解阶段，其气体产量仅为理论产量的1.6 - 5.5%。这也表明在60 - 70摄氏度的温度下不可能实现稳定的甲烷生成。第二反应器阶段的动力学分析表明，随着有机负荷率（OLR）从3克挥发性固体/升/天提高到11克挥发性固体/升/天，挥发性固体的降解率从80%降至40%。与此相反，随着OLR从12克挥发性固体/升/天提高到26克挥发性固体/升/天，第一个水解反应器阶段的挥发性固体去除率从5%线性增加到20%。相同的线性增加动力学也表现在特定纤维素降解上，转化率为0.1 - 3×10⁹克纤维素/单个细菌（10⁻¹²克）/天。这表明纤维素降解是一个限速步骤。两个反应器阶段结合在OLR为10克挥发性固体/升/天时可实现最佳的挥发性固体去除效率。对28个反应器的细菌种群分析涉及利用不同糖类、纤维素、乙酸盐、H₂ - CO₂的真细菌，或以乙酸盐或H₂ - CO₂为底物的古细菌（加抗生素）。以H₂ - CO₂为底物的利用者数量为10⁸ - 10¹⁰/克总固体，明显以10 - 10000的倍数主导乙酸营养型产甲烷菌。这解释了观察到的可能的短HRT。
