Bertin Lorenzo, Colao Maria Chiara, Ruzzi Maurizio, Marchetti Leonardo, Fava Fabio
DICASM, Faculty of Engineering, University of Bologna, viale Risorgimento 2, I-40136 Bologna, Italy.
Microb Cell Fact. 2006 Apr 5;5:16. doi: 10.1186/1475-2859-5-16.
Olive mill wastewater (OMW) is the aqueous effluent of olive oil producing processes. Given its high COD and content of phenols, it has to be decontaminated before being discharged. Anaerobic digestion is one of the most promising treatment process for such an effluent, as it combines high decontamination efficiency with methane production. The large scale anaerobic digestion of OMWs is normally conducted in dispersed-growth reactors, where however are generally achieved unsatisfactory COD removal and methane production yields. The possibility of intensifying the performance of the process using a packed bed biofilm reactor, as anaerobic treatment alternative, was demonstrated. Even in this case, however, a post-treatment step is required to further reduce the COD. In this work, a biological post-treatment, consisting of an aerobic biological "Manville" silica bead-packed bed aerobic reactor, was developed, tested for its ability to complete COD removal from the anaerobic digestion effluents, and characterized biologically through molecular tools.
The aerobic post-treatment was assessed through a 2 month-continuous feeding with the digested effluent at 50.42 and 2.04 gl(-1)day(-1) of COD and phenol loading rates, respectively. It was found to be a stable process, able to remove 24 and 39% of such organic loads, respectively, and to account for 1/4 of the overall decontamination efficiency displayed by the anaerobic-aerobic integrated system when fed with an amended OMW at 31.74 and 1.70 gl(-1)day(-1) of COD and phenol loading rates, respectively. Analysis of 16S rRNA gene sequences of biomass samples from the aerobic reactor biofilm revealed that it was colonized by Rhodobacterales, Bacteroidales, Pseudomonadales, Enterobacteriales, Rhodocyclales and genera incertae sedis TM7. Some taxons occurring in the influent were not detected in the biofilm, whereas others, such as Paracoccus, Pseudomonas, Acinetobacter and Enterobacter, enriched significantly in the biofilter throughout the treatment.
The silica-bead packed bed biofilm reactor developed and characterized in this study was able to significantly decontaminate anaerobically digested OMWs. Therefore, the application of an integrated anaerobic-aerobic process resulted in an improved system for valorization and decontamination of OMWs.
橄榄油加工废水（OMW）是橄榄油生产过程中的水性流出物。鉴于其高化学需氧量（COD）和酚类含量，在排放前必须进行净化处理。厌氧消化是处理此类废水最具前景的工艺之一，因为它能在去除污染物的同时产生甲烷。大规模处理OMW通常在分散生长反应器中进行，但COD去除率和甲烷产率通常不尽人意。已证明使用填充床生物膜反应器强化该工艺性能作为厌氧处理替代方案的可能性。然而，即便如此，仍需要一个后处理步骤来进一步降低COD。在本研究中，开发了一种生物后处理工艺，该工艺由一个好氧生物“曼维尔”硅胶珠填充床好氧反应器组成，测试了其从厌氧消化废水中完全去除COD的能力，并通过分子工具对其进行了生物学表征。
通过连续两个月以50.42和2.04 g l⁻¹天⁻¹的COD和酚负荷率向反应器中进料厌氧消化废水来评估好氧后处理工艺。结果发现该工艺稳定可靠，能够分别去除24%和39%的此类有机负荷，当以31.74和1.70 g l⁻¹天⁻¹的COD和酚负荷率向厌氧 - 好氧集成系统进料经修正的OMW时，该工艺对总去污效率的贡献率为1/4。对好氧反应器生物膜中生物质样品的16S rRNA基因序列分析表明，该生物膜中定殖有红杆菌目、拟杆菌目、假单胞菌目、肠杆菌目、红环菌目以及分类地位不确定的TM7属。进水样品中出现的一些分类单元在生物膜中未被检测到，而其他分类单元，如副球菌属、假单胞菌属、不动杆菌属和肠杆菌属，在整个处理过程中在生物滤池中显著富集。
本研究中开发并表征的硅胶珠填充床生物膜反应器能够显著净化厌氧消化的OMW。因此，厌氧 - 好氧集成工艺的应用为OMW的回收利用和去污处理提供了一个改进的系统。
