The uncontrolled disposal of olive oil mill wastewater (OMW) is hazardous for the health of water and soil, since this wastewater shows low pH and high contents of organic matter and polyphenols (PP). Lagooning is one of the most common treatment systems for agro-industrial wastewater (such as OMW), due to its low cost and easy management. Aeration allows reducing the low depuration time, which is a constraint for this system. Despite this potential feasibility, literature about OMW lagooning is not abundant. Moreover, the effects of the aeration rates, concentration of polyphenols and nitrogen shortage on depuration performance of lagoons treating OMW have not been properly explored. This study analyzes the removal rates of COD and PP, and variations of pH in OMW treated in aerated tanks at the laboratory scale simulating lagooning systems. Compared to the non-aerated tanks, aeration of OMW increased the removal rates from 61% to 90% (for COD) and from 52% to 64% (for PP). Permanent aeration was more advisable compared to intermittent flow rates. Increasing concentrations of PP noticeably reduced the COD removal rates, which were halved at a 4-fold PP concentration. In contrast, the PP removal rate was constant at every concentration experimented. Compared to the COD:N value suggested by literature for aerobic processes (100:5), a shortage in nitrogen availability reduced both COD (by about 20–25%) and PP removal rates (by 25%), the latter only when COD:N was higher 400:5. The pH was less influenced by the variations in aeration rates, PP concentration and COD:N ratio compared to COD and PP removal. This investigation provides indications about the most suitable operation parameters (airflow rates, inhibiting PP concentration, and optimal COD:N) in aerated lagooning of OMW towards environmentally sound treatments of highly polluting wastewater.

中文翻译：

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模拟泻湖曝气池处理不同风量、多酚和氮浓度下橄榄油厂废水的净化性能

橄榄油厂废水 (OMW) 的不受控制的处置对水和土壤的健康有害，因为这种废水的 pH 值低，有机物和多酚 (PP) 含量高。由于成本低且易于管理，泻湖是农业工业废水（如 OMW）最常见的处理系统之一。曝气可以减少低净化时间，这是该系统的一个限制条件。尽管有这种潜在的可行性，但关于 OMW 泻湖的文献并不多。此外，曝气率、多酚浓度和氮短缺对处理 OMW 的泻湖净化性能的影响尚未得到适当探索。本研究分析了 COD 和 PP 的去除率，以及在实验室规模模拟泻湖系统的曝气池中处理的 OMW 中 pH 值的变化。与非曝气罐相比，OMW 曝气将去除率从 61% 提高到 90%（对于 COD）和从 52% 到 64%（对于 PP）。与间歇性流速相比，永久性曝气更为可取。PP 浓度的增加显着降低了 COD 去除率，在 PP 浓度增加 4 倍时 COD 去除率减半。相比之下，PP 去除率在每个实验浓度下都是恒定的。与文献建议的有氧过程 (100:5) 的 COD:N 值相比，氮可用性的短缺降低了 COD（约 20-25%）和 PP 去除率（25%），后者仅当 COD :N 高于 400:5。与 COD 和 PP 去除相比，pH 值受曝气速率、PP 浓度和 COD:N 比率变化的影响较小。