化工污染场地修复EDTA渗滤液处理工艺研究

摘要/Abstract

摘要： 乙二胺四乙酸（EDTA）化学性质稳定，含EDTA废水难以达到直接排放标准。某化工污染场地修复采用含EDTA的修复药剂，产生含EDTA的渗滤液，需处理至化学需氧量（COD）不高于50mg/L。针对COD分别为100,502,1503 mg/L的低、中、高3种EDTA浓度的废水，研究了电化学氧化和Fenton氧化降低COD的效果。结果表明：电化学氧化对不同初始COD废水的COD降低率基本相同，全程控制废水pH为3时的COD降低率为43.6%，比不控制pH时提高了7.8百分点，电化学氧化的最佳工艺参数为电流密度15 mA/cm²、pH=3（全程控制）、反应时间120 min；Fenton氧化对中高COD废水的COD降低率大于60%，对低COD废水的COD降低率仅为6%，Fenton氧化的最佳工艺参数为pH=3，Fe²⁺、H₂O₂、COD物质的质量比1:6:2，反应时间90 min。综合两种高级氧化工艺去除EDTA的特点，确定了“Fenton氧化+电化学氧化+絮凝沉淀”工艺路线。组合工艺将电化学氧化效率进一步提升至49.8%，对实际EDTA渗滤液COD的降低率达到84.6%，出水满足国家直接排放标准。

关键词: 乙二胺四乙酸, 化学污染场地修复, 渗滤液, 电化学氧化, Fenton氧化, 组合工艺

Abstract: Ethylenediaminetetraacetic acid (EDTA) is chemically stable, and EDTA wastewater is difficult to meet direct discharge standards. During the remediation of a chemical-contaminated site inspected by the Central Environmental Protection Inspector, remediation agents containing EDTA were used, generating leachate containing EDTA that required treatment to achieve a chemical oxygen demand (COD) ≤ 50 mg/L. For low, medium, and high concentrations of EDTA wastewater with COD of 100,502,1503 mg/L respectively, the effectiveness of electrochemical oxidation and Fenton oxidation in COD removal was studied. The results showed that the COD removal rate by electrochemical oxidation was essentially the same for different initial concentrations. Controlling the wastewater at pH=3 throughout the process achieved a COD removal rate of 43.6%, which was 7.8 percentage points higher than thatofwithout pH control. The optimal parameters for electrochemical oxidation were a current density of 15 mA/cm², maintaining wastewater pH=3 throughout the process, and a reaction time of 120 minutes. Fenton oxidation achieved a COD removal rate of over 60% for medium and high concentrations but only 6% for low-concentration wastewater. The optimal parameters for Fenton oxidation were pH=3, the mass ratio of Fe²⁺，H₂O₂ and COD substances of 1:6:2 , and a reaction time of 90 minutes. By integrating the characteristics of the two advanced oxidation processes for EDTA removal, a combined process of "Fenton oxidation+ electrochemical oxidation+ flocculation sedimentation" was determined. The effluent COD of the combined process could meet the national direct-discharge standards with a COD removal rate of 84.6% for real EDTA leachate, and further improved the electrochemical oxidation efficiency to 49.8%.

Key words: ethylenediaminetetraacetic acid, chemical-contaminated site remediation, leachate, electrochemical oxidation, Fenton oxidation, combined process

张超周作绪. 化工污染场地修复EDTA渗滤液处理工艺研究[J]. 石油炼制与化工, 2026, 57(5): 130-135.

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