Department of Environmental Engineering, Technical University of Crete, Chania, Greece.
Water Res. 2010 May;44(9):2773-80. doi: 10.1016/j.watres.2010.02.015. Epub 2010 Feb 16.
A hybrid process comprising biological degradation in a vertical-flow constructed wetland (CW) and electrochemical oxidation over boron-doped diamond electrodes to decolorize, mineralize and detoxify a leachate from olive pomace processing (OPL) was investigated. Two alternative treatment schemes were compared: According to the first treatment scheme, OPL was treated by electrochemical oxidation followed by treatment in a constructed wetland pilot unit (CW-A). The second scheme comprised of treatment in a constructed wetland followed by electrochemical treatment (CW-B). The constructed wetlands units were planted with Phragmites australis (reeds) and were fed intermittently at organic loadings between 5 and 15 g COD m(-2) d(-1) and a residence time of 3 d. Electrochemical oxidation (EO) was performed for 360 min at 20 A. Treatment of OPL in the wetland at 15 g COD m(-2) d(-1) led to mean COD and color reduction of 86% and 77%, respectively; the wetland effluent with a COD of about 800 mg L(-1) was polished electrochemically for 360 min after which the overall COD and color removal of the combined process (i.e. CW-B/EO) was around 95%, while the final effluent was not toxic against the marine bacteria Vibrio fischeri. Electrochemical oxidation of the original OPL at COD values between 6250 and 14 100 mg L(-1) led to moderate COD and color reduction (i.e. less than 40%) through zero order kinetics. When this was coupled to constructed wetland post-treatment (i.e. EO/CW-A), the overall COD and color removal was 81% and 58%, respectively. The decreased efficiency may be assigned to the increased toxicity of the electrochemically treated effluent which was only partially removed in the natural treatment system.
采用垂直流人工湿地（CW）中的生物降解和掺硼金刚石电极的电化学氧化相结合的工艺，对橄榄废渣渗滤液（OPL）进行脱色、矿化和解毒。对比了两种替代处理方案：根据第一种处理方案，OPL 先经过电化学氧化处理，然后再进入中试规模的人工湿地单元（CW-A）处理。第二种方案由人工湿地处理后，再进行电化学处理（CW-B）。人工湿地单元种植芦苇（Phragmites australis），间歇性进水，有机负荷为 5 至 15 g COD m(-2) d(-1)，停留时间为 3 d。电化学氧化（EO）在 20 A 下进行 360 min。在 15 g COD m(-2) d(-1)的负荷下，OPL 在湿地中的处理导致 COD 和色度分别平均降低了 86%和 77%；COD 约为 800 mg L(-1)的湿地出水在电化学氧化后进行 360 min 抛光处理，然后组合工艺（即 CW-B/EO）的总 COD 和色度去除率约为 95%，而最终出水对海洋细菌发光菌（Vibrio fischeri）无毒性。电化学氧化原始 OPL 时，COD 值在 6250 至 14100 mg L(-1)之间，通过零级动力学导致适度的 COD 和色度降低（即低于 40%）。当与人工湿地后处理（即 EO/CW-A）结合时，总 COD 和色度去除率分别为 81%和 58%。效率降低可能归因于电化学处理出水的毒性增加，而该毒性在自然处理系统中仅部分去除。
