Department of Environmental Biotechnology, University of Warmia and Mazury in Olsztyn, Sloneczna 45G, 10-709 Olsztyn, Poland.
Department of Environmental Biotechnology, University of Warmia and Mazury in Olsztyn, Sloneczna 45G, 10-709 Olsztyn, Poland.
Waste Manag. 2018 Jul;77:140-146. doi: 10.1016/j.wasman.2018.05.016. Epub 2018 May 14.
The use of digestate in agriculture has been an efficient way to mitigate greenhouse gas emissions through the recycling of organic materials. However, harmful effects can arise if the organic matter is unstable. The goal of this study was to determine the biological stability (4-day oxygen demand for degradation of readily biodegradable organic matter (AT4), 21-day anaerobic biogas potential (GP21), and organic matter (VS) content) of six digestates after mesophilic digestion, and that of the corresponding post-digestates after psychrophilic post-digestion. Moreover, the kinetics of the changes in biological stability during post-digestion were determined. Mesophilic digestion of six multi-component agri-food feedstocks consisting of maize silage, bovine manure, mallow silage, pig slurry, glycerin, and spent wash from distillation was carried out at an organic loading rate of 2-3 kg VS/(m·d), and at a hydraulic retention time of 45-60 days. Digestates were left in stirred reactors, imitating storage digesters, and kept for the next 120 d under anaerobic psychrophilic conditions (20 ± 1 °C) for further stabilization. The additional biogas yields during post-digestion (50.9-114.9 dm/kg TS) accounted for 8.5-27.4% of the biogas productivity of the feedstocks and 40-80% of that of the digestates. The efficiency of the loss of organic matter content was 22.5-40.2%. The decrease in the values of AT4, GP21 and VS content made the post-digestates more biologically stable than the digestates (digestates: AT4 = 13.7-67.0 mg O/g TS, GP21 = 71.5-130.1 dm/kg TS; post-digestates: AT4 = 6.6-37.4 mg O/g TS, GP21 = 15.7-79.2 dm/kg TS). For digestates and post-digestates, AT4 values strongly correlated with GP21 values.
在农业中使用消化物是通过回收有机物质来减少温室气体排放的有效方法。然而，如果有机物质不稳定，就会产生有害影响。本研究的目的是确定六种消化物在中温消化后的生物稳定性（易生物降解有机物质的 4 天需氧量（AT4）、21 天厌氧沼气潜力（GP21）和有机物（VS）含量），以及相应的低温消化后的后消化物的生物稳定性。此外，还确定了低温消化过程中生物稳定性变化的动力学。六种多组分农业食品饲料（包括青贮玉米、牛粪、锦葵青贮、猪粪、甘油和蒸馏废醪）在有机负荷率为 2-3kgVS/（m·d）和水力停留时间为 45-60d 的条件下进行中温消化。消化物留在搅拌反应器中，模仿储存消化器，并在接下来的 120d 内保持在厌氧低温条件（20±1°C）下进一步稳定。低温消化期间的额外沼气产量（50.9-114.9dm/kgTS）占进料生物产气率的 8.5-27.4%和消化物的 40-80%。有机物含量损失效率为 22.5-40.2%。AT4、GP21 和 VS 含量值的降低使后消化物比消化物具有更高的生物稳定性（消化物：AT4=13.7-67.0mgO/gTS，GP21=71.5-130.1dm/kgTS；后消化物：AT4=6.6-37.4mgO/gTS，GP21=15.7-79.2dm/kgTS）。对于消化物和后消化物，AT4 值与 GP21 值具有很强的相关性。
