Lopez Antonio, Pagano Michele, Volpe Angela, Di Pinto Appio Claudio
Consiglio Nazionale delle Ricerche, Istituto di Ricerca Sulle Acque, Reparto di Chimica e Tecnologia delle Acque, Via Francesco De Blasio, 5, 70123 Bari, Italy.
Chemosphere. 2004 Feb;54(7):1005-10. doi: 10.1016/j.chemosphere.2003.09.015.
The aim of this study was to check the effectiveness of the Fenton's reagent (Fe2+ + H2O2 + H+) for the pre-treatment of a municipal landfill leachate with the objective of improving its overall biodegradability, evaluated in terms of BOD5/COD ratio, up to a value compatible with biological treatment. The leachate came from a municipal sanitary landfill located in southern Italy and the average values of its main parameters were: pH=8.2; COD=10,540 mgl(-1); BOD5=2,300 mgl(-1); TOC=3,900 mgl(-1); NH4-N=5210 mgl(-1); conductivity=45,350 microScm(-1); alkalinity=21,470 mgl(-1) CaCO3. The effect of initial pH value on the pre-treatment effectiveness was evaluated by titrating the amount of acidic by-products formed. The extent of leachate oxidation was monitored and controlled by both pH and redox potential measurements. The best operational conditions for achieving the desired goal (i.e., BOD5/COD> or =0.5) resulted: Fe2+=275 mgl(-1); H2O2=3,300 mgl(-1); initial pH=3; reaction time=2 h. At the end of the Fenton's pre-treatment, in order to permit a subsequent biological treatment, residual ferric ions were removed increasing the pH up to 8.5 by adding 3 gl(-1) of Ca(OH)2 and 3 mgl(-1) of a cationic polyelectrolyte, the latter as an aid to coagulation. This final step also resulted in a further modest removal of residual COD due to co-precipitation phenomena.
本研究的目的是检验芬顿试剂（Fe2+ + H2O2 + H+）对城市垃圾渗滤液进行预处理的效果，目标是提高其整体生物降解性，以生化需氧量与化学需氧量的比值（BOD5/COD）来评估，使其达到与生物处理相兼容的值。渗滤液来自意大利南部的一个城市卫生填埋场，其主要参数的平均值如下：pH = 8.2；COD = 10540 mg/L；BOD5 = 2300 mg/L；总有机碳（TOC）= 3900 mg/L；铵态氮（NH4-N）= 5210 mg/L；电导率 = 45350 μS/cm；碱度 = 21470 mg/L碳酸钙（CaCO3）。通过滴定所形成的酸性副产物的量来评估初始pH值对预处理效果的影响。通过pH和氧化还原电位测量来监测和控制渗滤液的氧化程度。实现预期目标（即BOD5/COD≥0.5）的最佳操作条件如下：Fe2+ = 275 mg/L；H2O2 = 3300 mg/L；初始pH = 3；反应时间 = 2小时。在芬顿预处理结束时，为了能够进行后续的生物处理，通过添加3 g/L的Ca(OH)2和3 mg/L的阳离子聚电解质将pH值提高到8.5，以去除残留的铁离子，后者用于辅助混凝。由于共沉淀现象，这最后一步还导致了残留COD的进一步适度去除。
