电动导排间隙水脱除底泥内源氮的性能

以电动土工合成材料（EKG）作为电极，采用电动导排间隙水装置，在室内模拟了氮素污染底泥修复过程，研究了间歇通电（12h On/12h Off）和持续通电2种工作模式下脱除底泥内源氮的效果，分析了底泥不同形态氮在修复过程中的迁移转化特征.实验底泥体积为0.06m³，含水率为72.82%，总氮（TN），氨氮（NH₄⁺-N）和硝酸盐氮（NO₃^－-N）初始浓度分别为2350.16，1635.38和297.02mg/kg.在电压梯度为1V/cm条件下修复8d后，间歇通电和持续通电模式下间隙水导排量分别为8535和8370mL，重力流约占总排水量的80.43%~82.02%.电迁移是底泥中不同形态氮迁移的主要驱动力，间歇通电和持续通电模式下TN脱除量分别为544.48和552.26mg，其中80.71%和78.02%的TN从阴极排出.经过电动导排间隙水修复实验后，底泥含水率下降了4.95%~6.16%，间歇通电和持续通电模式下NH₄⁺-N的去除率分别为40.41%、39.27%，NO₃^－-N的去除率分别为25.82%、27.94%.综合考虑TN去除率和能耗2个因素，间歇通电是一种效益较高的模式，修复后底泥TN去除率为32.61%，电能消耗为15.57（kW·h）/m³.

Performance of separating sediment endogenous nitrogen via electrokinetic drainage of pore water

In this study, indoor nitrogen-contaminated sediment remediation experiments has been conducted via pore water electrokinetic drainage equipment, with novel electrokinetic geosynthetics (EKGs) as electrode. Performance of endogenous nitrogen separation from sediments matrix as well as the characteristics of fractional nitrogen migration and transformation under intermittently (12h On/12h Off) and continuously powered scenarios has been assessed. The volume and moisture content of sediment was 0.06m³ and 72.82%, the initial contents of total nitrogen (TN), ammonia nitrogen (NH₄⁺-N) and nitrate nitrogen (NO₃^--N) in sediment was 2350.16mg/kg, 1635.38mg/kg and 297.02mg/kg, respectively. After 8days of remediation with voltage gradient of 1V/cm, the total pore water drainage volume was 8535mL and 8370mL for intermittently and continuously powered group, respectively, and gravity drainage accounted for 80.43%~82.02% of the total volume. Electromigration was the main driving force for migrating fractional nitrogen in the sediment matrix, and TN separation amount was 544.48mg and 552.26mg for intermittently and continuously powered group, respectively. Moreover, 80.71% and 78.02% of separated TN was originated from the cathode effluent. After the remediation, the sediment moisture contents decreased by 4.95%~6.16%, and the average NH₄⁺-N removal rates for intermittently and continuously powered group was 40.41% and 39.27%, while 25.82% and 27.94% for NO₃^--N removal, respectively. When considering the two factors of TN removal rate and energy consumption, intermittently powered was a relatively cost-effective mode with 32.61% of the sediment TN removal rate and 15.57(kW·h)/m³ of the power consumption.