Abstract Alkaline leachate from bauxite residue disposal areas is likely to require treatment for post-closure. Traditional treatment methods are not attractive in the long-term due to management requirement, energy input and operational logistics and passive approaches offer an alternative approach. Constructed wetlands are widely cited as a potential treatment option but there is limited data on long term field-scale applications. Treatment of alkaline residue leachate was assessed over a 52 month period and showed effective pH reductions from ca. pH 11.2 (inflow) to 7.2 (outflow). Trace element content measured during the 4th year of operation demonstrated effective reduction in trace element (Al 17,256 μg/l to 330 μg/l; V 140 μg/l to 13 μg/l) with no evidence of toxicity in test species Vibrio fischeri, Skeletonema costatum, Tisbe battagliai and Oncorhynchus mykiss in the wetland outflow. Sediment analysis found some increases in trace element content but no evidence of accumulation in Phragmites was found in vegetation sampling. Longevity and management requirements for constructed wetland treating alkaline bauxite residue leachate are more likely to be impacted from increases in soil Na and pH. Increases are more evident in front sections of wetland but it is proposed that loading to wetlands can be decreased by incorporation of other passive technologies within the overall treatment approach and by feeding different sections of the wetlands on a cyclical basis.

中文翻译：

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用于处理铝土矿浸出液的人工湿地：长期现场证据和管理意义

摘要 来自铝土矿渣处理区的碱性渗滤液很可能需要在关闭后进行处理。由于管理要求、能源输入和运营物流和被动方法提供了一种替代方法，从长远来看，传统的处理方法没有吸引力。人工湿地被广泛认为是一种潜在的处理选择，但关于长期田间规模应用的数据有限。对碱性残留浸出液的处理进行了 52 个月的评估，结果表明 pH 值从大约 pH 11.2（流入）至 7.2（流出）。在运行的第 4 年期间测量的微量元素含量表明微量元素有效减少（Al 17,256 微克/升至 330 微克/升；V 140 微克/升至 13 微克/升），没有证据表明对试验物种费氏弧菌具有毒性，中肋骨线虫，Tisbe battagliai 和 Oncorhynchus mykiss 在湿地流出。沉积物分析发现微量元素含量有所增加，但在植被采样中没有发现芦苇中积累的证据。人工湿地处理碱性铝土矿残渣渗滤液的寿命和管理要求更有可能受到土壤 Na 和 pH 值增加的影响。湿地前部的增加更为明显，但建议通过在整体处理方法中结合其他被动技术并通过周期性地喂养湿地的不同部分来减少湿地的负荷。人工湿地处理碱性铝土矿残渣渗滤液的寿命和管理要求更有可能受到土壤 Na 和 pH 值增加的影响。湿地前部的增加更为明显，但建议通过在整体处理方法中结合其他被动技术并通过周期性地喂养湿地的不同部分来减少湿地的负荷。人工湿地处理碱性铝土矿残渣渗滤液的寿命和管理要求更有可能受到土壤 Na 和 pH 值增加的影响。湿地前部的增加更为明显，但建议通过在整体处理方法中结合其他被动技术并通过周期性地喂养湿地的不同部分来减少湿地的负荷。