McKeown Rory M, Scully Colm, Mahony Thérèse, Collins Gavin, O'Flaherty Vincent
Microbial Ecology Laboratory, Department of Microbiology, Environmental Change Institute, National University of Ireland, Galway (NUI, Galway), University Road, Galway, Ireland.
Water Res. 2009 Apr;43(6):1611-20. doi: 10.1016/j.watres.2009.01.015. Epub 2009 Jan 30.
The feasibility of long-term (>3 years), low-temperature (4-15 degrees C) and anaerobic bioreactor operation, for the treatment of acidified wastewater, was investigated. A hybrid, expanded granular sludge bed-anaerobic filter bioreactor was seeded with a mesophilic inoculum and employed for the mineralization of moderate-strength (3.75-10 kg chemical oxygen demand (COD)m(-3)) volatile fatty acid-based wastewaters at 4-15 degrees C. Bioprocess performance was assessed in terms of COD removal efficiency (CODRE), methane biogas concentration, and yield, and biomass retention. Batch specific methanogenic activity assays were performed to physiologically characterise reactor biomass. Despite transient disimprovements, CODRE and methane biogas concentrations exceeded 80% and 65%, respectively, at an applied organic loading rate (OLR) of 10 kgCODm(-3)d(-1) between 9.5 and 15 degrees C (sludge loading rate (SLR), 0.6 kgCOD kgVSSd(-1)). Over 50% of the granular sludge bed was lost to disintegration during operation at 9.5 degrees C, warranting a reduction in the applied OLR to 3.75-5 kgCODm(-3)d(-1) (SLR, c. 0.4-0.5kgCOD kgVSSd(-1)). From that point forward, remarkably stable and efficient performance was observed during operation at 4-10 degrees C, with respect to CODRE (>or=82%), methane biogas concentration (>70%) and methane yields (>4l(Methane)d(-1)), suggesting the adaptation of our mesophilic inoculum to psychrophilic operating conditions. Physiological activity assays indicated the development of psychroactive syntrophic and methanogenic populations, including the emergence of putatively psychrophilic propionate-oxidising and hydrogenotrophic methanogenic activity. The data suggest that mesophilic inocula can physiologically adapt to sub-optimal operational temperatures: treatment efficiencies and sludge loading rates at 4 degrees C (day, 1243) were comparable to those achieved at 15 degrees C (day 0). Furthermore, long-term, low-temperature bioreactor operation may act as a selective enrichment for psychrophilic methanogenic activity from mesophilic inocula. The observed efficient and stable bioprocess performance highlights the potential for long-term, low-temperature bioreactor operation.
研究了长期（>3年）、低温（4 - 15摄氏度）和厌氧生物反应器运行处理酸化废水的可行性。一个混合的膨胀颗粒污泥床 - 厌氧滤池生物反应器接种了嗜温接种物，并用于在4 - 15摄氏度下对中等强度（3.75 - 10 kg化学需氧量（COD）m(-3)）基于挥发性脂肪酸的废水进行矿化。根据化学需氧量去除效率（CODRE）、甲烷沼气浓度和产量以及生物质保留情况评估生物过程性能。进行批次特定产甲烷活性测定以从生理上表征反应器生物质。尽管有短暂的性能下降，但在9.5至15摄氏度之间施加有机负荷率（OLR）为10 kgCODm(-3)d(-1)（污泥负荷率（SLR），0.6 kgCOD kgVSSd(-1)）时，CODRE和甲烷沼气浓度分别超过80%和65%。在9.5摄氏度运行期间，超过50%的颗粒污泥床因解体而损失，因此需要将施加的OLR降低至3.75 - 5 kgCODm(-3)d(-1)（SLR，约0.4 - 0.5kgCOD kgVSSd(-1)）。从那时起，在4 - 10摄氏度运行期间观察到了非常稳定和高效的性能，在CODRE（≥82%）、甲烷沼气浓度（>70%）和甲烷产量（>4l（甲烷）d(-1)）方面，这表明我们的嗜温接种物适应了嗜冷操作条件。生理活性测定表明出现了嗜冷性共生和产甲烷菌群，包括假定的嗜冷性丙酸氧化和氢营养型产甲烷活性的出现。数据表明嗜温接种物可以在生理上适应次优操作温度：4摄氏度（第1243天）的处理效率和污泥负荷率与15摄氏度（第0天）时相当。此外，长期低温生物反应器运行可能会从嗜温接种物中选择性富集嗜冷产甲烷活性。观察到的高效稳定生物过程性能突出了长期低温生物反应器运行的潜力。
