亚铁联合不同氧化剂对石油烃污染场地热脱附废水的处理

Ferrous Iron Combined with Different Oxidants for Thermal Desorption Wastewater Treatment from Petroleum Hydrocarbon Contaminated Sites

摘要:

采用亚铁（Fe²⁺）分别联合次氯酸钠（NaClO）、过硫酸钠（Na?S?O₈）和过氧化氢（H₂O₂） 3种氧化剂处理某原油浸染土壤的热脱附废水，考察了pH值、Fe²⁺投加量、氧化剂投加量和反应时间对处理效能的影响。Fe²⁺/H₂O₂和Fe²⁺/ Na?S?O₈均能有效去除热脱附废水中的典型污染物——石油烃物质，去除率分别达到100.0%和97.8%，但Fe²⁺/H₂O₂体系对化学耗氧量（COD）的去除效果明显优于Fe²⁺/Na?S?O₈。Fe²⁺/H₂O₂可将有机物彻底氧化分解，而Fe²⁺/NaClO和Fe²⁺/Na?S?O₈仅是将有机物氧化分解为中间物质。多元变量分析结果表明，pH值和氧化剂投加量是影响去除效果的主要因素，Fe²⁺/H₂O₂处理热脱附废水的吨水处理成本较高，但是综合效果最好；Fe²⁺/Na?S?O₈处理成本次之，但无法彻底降解COD；Fe²⁺/NaClO成本最低，但对有机物去除效果最差。综合去除效果和经济因素考量， Fe²⁺/H₂O₂体系更适用于处理热脱附废水。

Abstract:

Ferrous iron （Fe²⁺） combined with three oxidants， sodium hypochlorite （NaClO）， sodium persulfate （Na?S?O₈） and hydrogen peroxide （H₂O₂） were used to treat thermal desorption wastewater from the crude oil-contaminated soil. The influences of pH， Fe²⁺ dosage， oxidant dosage and reaction time on the treatment efficiency were investigated. The results show that PHCs （typical pollutants in thermal desorption wastewater） can be effectively removed by Fe²⁺/H₂O₂ and Fe²⁺/Na?S?O₈， with a removal efficiency of 100.0% and 97.8%， respectively. However， the chemical oxygen demand （COD） removal efficiency of Fe²⁺/H₂O₂ system is significantly higher than that of Fe²⁺/Na?S?O₈. Fe²⁺/H₂O₂ can oxidize and decompose organic matters completely， while Fe²⁺/NaClO and Fe²⁺/Na?S?O₈ can only convert organic matters into intermediate substances. The multivariate analysis results indicate that pH and oxidant dosage are the main factors affecting the removal efficiency. The cost of Fe²⁺/H₂O₂ in the treatment of thermal desorption wastewater is higher， but it has the best removal efficiency. The cost of Fe²⁺/Na?S?O₈ is lower than that of Fe²⁺/H₂O₂. However， COD cannot be degraded completely. Fe²⁺/NaClO has the lowest cost but the worst removal efficiency. Hence， considering the removal effect and economic factors， the Fe²⁺/H₂O₂ system is more suitable for the treatment of thermal desorption wastewater.